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1LGA = Land Grid Array 775=755 pins 
2BIOS = Basic input/output system (created more than 25 years ago)
3UEFI = Unified Extensible Firmware Interface (designed to replace legacy BIOS) BOOT FROM 2.2TB and up hard drives, FAT, flash drives, pre-boto enviorment for troubleshooting
4CMOS = Complementary metal-oxide semiconductor (old battery backup for BIOS condiguration), has been replaced with flfasah memory - likely used only to maintain date/time settings, if this battery dies you would have to reconfigure the BIOS every boot so replace with a new battery, can also be used to reset BIOS configuration by removing the battery
5BIOS system setups are usually launched with pressing del, f1,f2,ctrl-s,ctrl-alt-s at boot
6Can be used to view system information of components such as RAM, hard drive, optical drive, CPU 
7ATX>micro-atx>mini-itx>nano>pico - ATX=advanced technology extended created in 1995 (20 or 24+4/8 pin power connector)
8PCI eXtended = based on PCI designed for servers, has higher bandwidth four times the clock speed, built to handle higher-speed communication
9PCIe=PCI Express, replaced PCI,PCI-X and AGP, communicates serially instead of parallel, duplex=back and fourth communication at same time
10mini PCI/PCIE is for laptops, shrunk down for mobile uses  (wifi adapters, mobile broadband etc, it's inside of the laptop connected to the motherboard
11RAM=random access memory, one of the most important componets of computers - has a lot to do with the speed of computer - DIMM (dual inline memory module has 64 bit data width, 184 pins while DDR3 SDRAM is 184 pins, DDR2 and DDR3 SDRAM are 240 pins)
12BUS= size of communication path measured in bits
13Laptop RAM referred to as SODIMM(Small outline dual in-line Memory Module, DDR/DDR2 SDRAM - 200 pins - DDR3 SDRAM 204 pins)
14Micro-DIMM=smaller form factor RAM for mobile devices (DDR - 172 pins - ddr2/ddr3 - 214 pins)
15ZIF= Zero Insertion Froce (CPU socket)
16PGA= Pin Grid Array (pins are on the CPU)
17LGA= Land Grid Array (pins are on the motherboard)
18Northbridge ( memory controller hub) connects the cpu to the memory and graphics card, high bandwidth communication
19Southbridge (I/O controller hub [USB Ethernet IDE SATA etc]) manages connections like PCI interface slots and pripherals (keyboard mouse etc), onboard graphics controllers, BIOS
20modern CPUs have integrated memory controllers and even graphics processing units
21jumper enables and disables certain feature of motherboard from your documentation
22ROM=Read only memory (bios) - cant be changed or erased while EPROM can be erased or replaced PROM=Programmable memory, can be written once - EEPROM=electrically erasble PROM (flash memory)
23SRAM=Static RAM - very fast memory, expensive, large chip size used often in processor caches (L1,L2,L3)
24DRAM=Dynamic Random Access Memory - RAM you will typically see in computers, dynamic means needing constant refreshing, without refreshing the data in memory disappears. random access means any storage location can be accessed directly unlike magnetic tape
25SDR SDRAM=Single data rate  synchronous DRAM - 168 pins,SDRAM is synchronousa queue up one process while waiting for another - classic DRAM didnt wait for a clock signal, Dont confuse SDRAM with Static RAM(SRAM)
26DDR=Double Data Rate SDRAM- twice the data rate as SDR SDRAM but at the same clock speed, 184 pins
27DDR-200=200 million transfers per second, multiply by 8 to get throughput in megabytes per second (200x8=1600=PC1600)
28DDR2 SDRAM was made for faster speeds, twice as fast as DDR with 240 pins
29DDR3 SDRAM was made as an upgrade for DDR2 being twice as fast with twice the data rate, larger chip capacities yet also 240 pins, same as DDR2, not backwards compatible, does not fit in DDR2 slot
30Parity memory=adds an additional parity bit but wont always detect an error and cant correct an error, used to inform of issue
31ECC=Error correcting code memory - detects errors and corrects on the fly, not all systems use ECC, generally for servers and enterprise system, looks the same as non-ECC memory
32Registered memory (buffered memory)= includes an additional register beteween the RAM module and memory controller used mostly on servers for a more stable operating eenviorment, rarely used on desktop systems
33multi channel memory is installed in pairs or trios for maximum throughput, use same colors for same ram modules
34CDROM 700MB, DVD-ROM 4.7GB, DVD+DL 8.5GB, bluray 25GB BD+DL 50GB
35RAID=Redundant Array of Indepedent Disks
36Software-based RAID is a feature of the operating system and doesn't require any special hardware, usually lower-performance than hardware-based 
37Hardware-based RAID is a feature of the hard drive controller configured outside of the OS that is high performance and designed for speed
38Trusted Platform Module (TPM)
39In PCIe architecture, a single full-duplex point-to-point serial communication path consisting of two pairs of wires (where one pair is used for transmitting data and the other pair for receiving data) is known as a lane
40In this case, primary storage typically refers to random access memory (RAM), while secondary storage refers to the computer's internal hard drive. RAM, commonly called "memory," is considered primary storage, since it stores data that is directly accessible by the computer's CPU.
41There are different RAID levels, 0 (striping) 1 (mirroring) 5 (striping with parity) nested RAID/Raid 1+0 aka RAID 10 (stripe of mirrors)
42file blocks are split between two or more physical drives, RAID0 needs at least 2 physical drives, high performance, no redunancy so drive failure breaks the array aka RAID means RAID0redunancy
43RAID1 file blocks are duplicated between two or more drives, high disk utilzation - every file is duplicated and required disk space is doubled, has high redundancy so drive failure does not affect data availibility
44RAID5 file blocks are striped along with a parity block, requirs at least three disks - efficient use of disk space, files arent duplicated but is still used for parity, has high redundancy because data is available after drive failure, parity calculation may affect performance
45RAID1+0 has the speed of striping and the redundancy of mirroring, the best of both worlds, needs at least 4 drives
46To prevent the loading of malware and unauthorized OSs during system start-up , which UEFI functionality is used
47Secure boot
48RAID type with the highest disk overhead? raid level 5
49Maximum length of a fiber-optic Thunderbolt cable is 60 meters
50A computer on a network where most functions are carried out on a central server, or a client-server model software wherein the server performs all the processing is commonly referred to as a Thin client
51For automated discovery of networked services on LANs SLP is used
52Allocated for wireless communication a portion of the available Radio Frequency (RF) band is known as a channel
53The traditional PSTN lines is used by Dial-up
54The relative vertical and horizontal size of a digital image which is displayed on the graphics monitor screen is known as aspect ratio
55The 16:10 aspect ratio is used by WUXGA
56The correct sequence of steps in the laser printing process is Processing, charging, exposing, developing, transferring, fusing, cleaning
57PCL=Printer Command Language-To describe the appearance of a printed page
58For a copper twisted-pair Ethernet cable A typical cable segment length is 100 meters
59Computers running Microsoft Windows Oss has the basic disk , most commonly used storage type.
60Each computer in the workgroup has own policy for security
61
62
63
64
65CPU socket types
66LGA775 775 pins, LGA(land grid array) package (all pins are on motherboard and cpu is flat (named for the cancelled Tejas core)), seen in later pentium 4, core 2 duo, xenon, celeron
67LGA1366 has 1,366 pins, LGA package, also called socket B which replaced the LGA 775, used by core i7 CPUs
68LGA 1156 has 1,156 pins, LGA package also called Socket H or H1, also replaces LGA 775, released in 2009 and integrates Northbridge onto the chip itself (used to be seperate chip on motherboard)
69LGA1155 has 1,155 pins, LGA package aso called Socket H2, replacement for LGA 1156, not compatible with LGA1156 but looks very similar, released in 2011 and supports intel sandy bridge and ivy bridge microprocessors 
70LGA115 has 1,150 pins, LGA package also called Socket H3 which replaces the LGA1155, released in 2013 used by Haswell and Broadwell microarchitecture 
71LGA2011 has 2,011 pins, LGA package also called Socket R, replaced LGA 1366 and LGA 1567, released in november 2011 for high-end desktop and servers, sandy bridge
72
73AMD CPU
74
75AM3 has 941 pins on socket, PGA-ZIF socket which replacs the AM2/AM2+ socket, released in 2009, AM3 processors could be used in AM2/AM2+ with a BIOS update
76AM3+ socket contains 942 pins on socket, PGA-ZIG package, one more pin than the AM3, released in 2011, use an AM3 processor in an AM3+ motherboard
77FM1 socket has 905 pins, PGA-ZIG package, 2011 release, AMD 10h CPU architecture, AMD A-series processors for faster speeds, DDR3 support and integrated PCIe 2.0 controller
78FM2 has 904 pins, PGA-ZIF package, released in 2012, piledrive architecture
79FM2+ 906 pins, micro PGA-zig package, also called FM2b, two more pins than FM2, incompatible with FM2, differen't pin configureation, released in january 2014, steamroller architecture
80
81processor speed, real speed = CPU clock, historical qualification of speed measured in magaherts (MHz) or gigahertz (GHz), actual speed is combination of different factors such as clock speed, architecture, bus speed, cach sizes, manufactures have moved away from marketing performance in clock cycles, no broadly accepted measure of performance, use a benchmark that works for you
82dual core/quad core/octa-core/,ulticore (number of cores in the physical processor)
83CPU cache is super faster memory, not large in size, holds data, insutrctions/results
84level 1 cache = first check, fastest
85level 2 cache = secondary data
86Hyper-threading Technology (HTT)=one CPU acts like two, doesn't work as fast as two, generally 15-30% improvement over having non-HTT CPU. Windos XP and beyond support HTT
87Virtualization=run other operating systems within a single hardware platform, sharing physical hardware componets, virtualization in software was limited and had perfomance and hardware management challaenges
88Intel virtualization technology (VT)
89AMD version AMD-V
90DATA WIDTH= Data path, integer size, memory addresses , registers address bus, data bus, much greater in 64 bit than 32 bit
91larger bus sizes move more data, 64 bit can move twice as much as a 32 bit CPU e
92bus size may not necessarily match the CPU architecture
93software must be optimized to take advantage of 64 bit archs, operating systems, drivers, etc
94Integrated GPU(graphcis processing unit)=part of a video adapter, motherboard or CPU
95graphics rendering requires a lot of work, dedicated hardware speeds the process. on-die GPUs are increasingly common but not as powerful as GPU standalone hardware
96NX bit=No-eXecute bit=intel refers as XD bit, amd eNHANCED vIRUS pROTECTION - DESIGNATES SECTIONS OF MEMORY AS EXECUTING CODE OR DATA, code cant run from protected memory locations, prevents malware and viruses from executing - the OS must support this feature (windows calls it Data Execution Prevention [DEP]), usually enabled automatically as a default
97heatsink=dissipate heat through thermal conduction, made of copper or aluminum alloy, fins/grid increase surface area of componet, heat is then transferred to the cooler air, thermal paste creates a good contact between the chip and the heat sink. componets can become very hot with or without heat sinks, without can cause failures
98proper thermal paste application is a small pea-sized drop and the heat sink will spread a proper layer over the CPU
99onboard fans can be used to provide extra airflow to cool components such as graphics card
100case fans pulls cool air from the front and exhaust hot air from the rear, motherboard layout and wiring becomes important to not block airflow
101standard sizes of case fans are 80mm,120mm,200mm, variable speed fans also exist
102liquid cooling is where coolant is circulated through a computer, used in automobiles, mainframe computers and other high-end systems, overclocking, gaming
103fanless/passive cooling creates no noise, silent operating, used in DVR, set top box, media servers, low powered devices taking advantage of heat sinks
104USB=universal serial bus
105USB 1.1 low speed: 1.5 megabits per second, 3 meter length is max, full speeed: 12 megabits per second, 5 meters
106USB2.0 480 megabits per second, 5 meters
107USB3.0 aka SuperSpeed, 5 gigabits per second, 3 meters - backwards compatible with all USB
108USB is used for hot-pluggable devices, bootable devices, serial communication interface
109Standard-A plug (common, laptop desktop etc), B-plug (printers), mini/micro-B plug (phones etc)
110Firewire/IEEE 1394= apple trademarked connector, 4.5 meters distance limitation) non-apple devices refer to it as IEEE1394/lynx/ilnk, daisy chain devices together up to 63 - Firewire 400 (alpha mode, IEEE1394a SUPPORTS 100,200 OR 400mBIT/S HALF-DUPLEX) Firewire 800 (beta mode/IEEE 1394b) supports 800Mbit/s full-duplex, optical connections support 100 meter distance (6-pin alpha powered, 4pin alpha unpowered, 9 pin firewire beta)
111Addition of primary storage modules to the motherboard is allowed by RAM
112SATA=Serial AT Attachment - 1.0 max speed 1.5Gbit/s, 1 meter max length, 2.0 3.0Gbit/s, 1 meter, 3.0 6.0/Gbit/s, 1 meter, eSata External SATA, matches the sata version, 2 meters max length - 15 pins power connector, 7 pins data connector, sometimes supports molex
113VGA=Video graphics array - DB-15 connector or DE-15 technical term, typically blue color stadnardized by PC System Design Guide - analog signal only, no digital - image quality degrades after 5-10 meters
114HDMI=high-definition multimedia interface - video and audio stream - all digital no analog signal - 20 meter distance before losing too much signal - 19 pins and proprietary connector - miniHDMI type C connector was designed for smaller devices
115DVI=digital visual interface - signle link and dual link single=3.7gbps (HDTV at 60FPS) dual=7.4gbps (HDTV at 85fps), DVI-A (analog) DVI-D (digital) DVI-I (integrated, digital and analog in same connector)
116analog audio ports, common 6.3mm(1/4"[music etc]) 3.5mm(1/8"[phones,computers])-TRS=tip/ring/sleeve 
117Digital audio TOSLINK(toshiba lINK), optical fiber created in 1993 used on consumer electronics, max length <10 meters
118RJ11=registered jack 11 - analog modem, DSL line -telephone connection - RP2C 6 position 2 conductur - some RJ standards use the same physical interface but different wiring
119RJ45=ETHERNET (patch, crossover cable, connector) RJ45 (registered Jack 45_ 8pc8c ( 8 positions, 8 conductors)
120Thunderbolt=high-speed serial connector, data and power on same cable based on mini displayport (MDP) standard - v1= 10Gbit/s per channel, 20Gbit/s total throughput, V2 20  gBIT/S AGGREGATED CHANNELS, v3 40Gbit/s - max legnth of 3 meters for copper, 60 meters for optical, daisychain up to 6 devices
121
122Wireless interface
123
124Infared-stadnards from the IrDA (infrared data association) - 4Mbit/s speed, line of sight - 1 meter distance limitation - laptops, phones cameras
125NFC=Near Field Communication - 106kbit/s,212kbit/s,424kbit/s - range of 10cm or less - mobile devices, payments (credit cards)
126bluetooth categorized into classes - class1 industrial use 100 meters distance, class 2 used in many mobile devices 10 meter distance , class 3 short-range use 1 meter distance - version 1.2 created in 1995 for faster connection and recover - verion 2.0+EDR (enhanced data rate) version 3.0+HS (high speed) used bluetooth for negotiation and establishment but 802.11 used for actual data transfer, version 4.0 includes a low-power spec
127802.11 networking=modern wifi 
128802.11a=5GHZ 54mbit/s - 120 meter 
129802.11b=2.4GHz 11mbit/s 140 meter
130802.11g=2.4ghz 54mbit/s 140 meter
131802.11n=5ghz/2ghz 150mbit/s 250 meters
132802.11ac=5zx 866.7mbit/s 250 meters
133
134analog modulation=sends an analog signal over an analog channel (AM/FM audio over radio frequencies)
135digital modulation=sends a digital bitstream over an analog channel (send digital audio signal over satellite radio frequencies Sirius/XM etc)
136all signals degrade, electrical or optical - there's often a set of standards and all devices must adhere to the standard but it's possible you can go farther ie pushing the envelope - almost alway need advanced testing gear to measure the signal to see what kind of distance you can get
137Data transfer speeds=data between A and B (how quickly can it get there?) - rarely a straightforward calculation, bytes used by storage devices, bits transmitted across the medium are two completely different things
138quality=signal strength - how "loud" is the signal? how much signal is getting tot he other side?
139signal quality of the noisereceived - how much of it is any good, there will always be a signal to noise ratio - important for network communication
140DRM=Digital Rights Management=controls over digital media - associated with every media types like games, videos, movies, documents - may be controlled in software or hardware like motherboard details, USB key, passphrase-every application is different and some DRM implementations are better than others, be aware when moving computers or parts around
141Frequencies=the number of cycles in a second(hertz)
142
143Power connections
144
145SATA=15 pins, +3.3v, +5v and +12v, 3.3v is rarely used by most drives
146Molex=4 pin peripheral power connector created by the Molex connector company - AMP MATE-N-LOK - provides +12V and +5V - used to power many devices inside the computer case like storage devices, optical drives, fans and other peripherals
147ATX+12V=4 pin atx+12v - ATX12V Advanced technology extended motherboards - additional 12 volt power for older motherbords used primarily for cpu - MAY BE LABELED LABELED atxv12,p4,cpu and keyed for the appropriate connector
148EPS+12v=8 pins, referred to as EPS12V cable, entry level power supply spec - 4+4 connector, includes an atx+12v 4PIN - seen mostly on servers - not 8pin PCIe power connector, keyed differently
149PCIe 6/8pin connector - additional power for PCIe adapters, 6pin (75 watt) 8pin  (150 watts) provides +12v - seen on high-power componets like GPUs , same cables have two pieces in one
150motherboard power connector (20/24 pin) - main motherboard power, provides 3.3v +/+5v and +/- 12v - 20 pin connector was the original atx standard, 24 pin was added for PCIe power - you can connect a 24 pin connector to a 20 pin motherbaord, some cables are 20pin+4 pin- orientation matters, double check
151amp=ampere (amp,A) - the rate of electron flow past a point in one second
152voltage= (volt,V) - electrical "pressure" pushing electrons
153watt=wattage (W) - measurement of real power use - volts * amps=watts 120V*0.5A=60W
154Alternting current=(AC) - direction of current cosntantly reverses - distributes electricity over long distances - frequency of this cycle is important - US/CANADA=110-120volts of AC(VAC), 60 hertz(Hz) - Europe-220-240 VAC, 50hz
155DC=Direct Current - current moves in one direction with a constant voltage
156single rail= a single 12v rail power supply - one output circuit generating 12 volts
157multiple rails=multiple 12v rail power supply - each 12v rail has seperate circuitry inside of the power supply - each 12v connector on the outside of the power supply is connected to one of the rails - multiple rails provide additional protection - a high-powered overload of a single rail usually means there's a lot of smoke - overloading smaller capacity rails shuts down the PSU instead
158When sizing a power supply, bigger isnt necessarily better - more expensive, doesnt make your computer faster - physical size is relatively standard but older cases and systems may have proprietary sizes - calculate the watts required for all  components (CPU storage devices, GPU) - many online calculators - GPUs are usually the largest power draw and many GPU specs list a recommended power supply wattage, 50% capactity is a good rule of thumb, power supply runs efficiently and there's room to grow
159
160Power supply connectors can be fixed (connected to the power supply) or modular (cables connect to the PSU) - fixed connector PSU may have too many unneeded connectors or not enough - modular PSU you can add cables as needed, fewer leftover wires for better airflow but cost a bit more than fixed connect PSU
161power supply dimensions are standardized so most power supplies fit in ATX and microATX cases but some older power supplied are physically quite large so microatx cases may not be an option, some microatx cases require particular deminsions like in proprietary case
162Some PSU offer dual-voltage options due to voltages varrying by country, has a manual switch on back of PSU to switch between voltage but DO NOT plug a 115v PSU into a 230V power source.
163CAD=computer aided design/manufacturing requies higher end equipment, multicore processor for 3D modeling and calculations and gpu for complex graphics as well as max RAM due to significant memory use 
164A/V editing workstations require a lot of high end components as well, duel monitors (edit in one monitor and view output in the other) is helpful for this setup
165Virtualization workstaions require a large amount of RAM as every OS needs it's own memory and it adds up quickly
166Gaming computers require high end components as well and a lot of RAM and proper cooling
167LCD= liquit cystal display - light shines through liquid crystals - liquid crystal molecules sit between two polarizing filters - turn the molecules and light passed- requies some type of backlight which shines through the LEDs
168TN=twisted nematic type of LCD -- the most common technology, fast response times for gaming, low power draw but poor viewing angles, color shifts
169IPS=in plane switching LCD technology, excellent color representation, no tailing when touched (moble devices), more expensive than TN
170CCFL=cold cathode fluorescent lamp- high voltage and power needed - used a power inverter for DC to AC power -a dded thickness to the display - no longer a common backlight
171LED-backlit LCD diplay=backlight is LEDs instead of florescent - LEDs around the edge of the screen and diffused to evenly light the display - an array of lEDs are behind the screen - maybe dimmed individually
172plasma display=a display of tiny cells using noble gas and mercury - voltage forms a plasma, mercury sheds energy as UV light - UV lights strikes colored phosphor and you see a picture - deep blacks and fast response times - very good color representation but no longer in active production, LED display prices and features have won the market
173digital projectors are not always LCD but common to be LCD - metal-halide lamp, very bridge and very hot light, expensive up to $350 - always let bulbs cool before turning off device as fans will turn off
174OLED=Organic light emitting diode - organic compound emits light when deceiving an electric current - thinner and lighter so flexible and mobile, no glass needed - no backlight bcause the organic compound provides the light, true black color - lifespan can be shorter than LED as organic materials degrade
175
176Display specifications
177
178Refresh rate=number of times per second the screen is redrawn (measured in hertz)-
179lcd displays no electron beams, refreshes the entire screen at 60/120/144hz and up which is really a frame rate
180display resolution=number of pixels on a display, width x height, actually pixel dimensions
181aspect ratio=the ratio of width to height 
182standard monitor aspect ratio 4:3 1600x1200,2048x1536
183wide screen monitor 16:10 1920x1200,2560x1600
184HD-16:9 1920x1080,2560x1440
185native resolution=an LCD display is fixed, the number of pixels doesn't change and a 
186display looks best when the video settings match a display's native resolution, a mismatch can cause distortion - if changing the display resolution, try using a multiple of the native resolution (2560x1600 is the same ratio as 1920x1200)
187
188Display brightness 
189Luminance=candela per square meter (cd/m^2), more is better
190Lumens=an ANSI test, 3,000 lumens works in a dim room, 6,000 lumens works in a sunlit room
191privacy display filter=fade the screen to black or gold when viewed at an angle, placed on the front of display so only the one facing screen can see it
192anti-glare=glossy screens are common can this reduces glare, improve viewing and useful in bright light
193multiple displays=connect more than one display for a flexible work enviorment - extend a desktop (each display is independent, location is determined in the OS), mirror a desktop makes each display shows identical information
194
195Displayport=VESA (video electronics standards association, royalty free standard) standard display connector-data is sent in packetized form like ethernet and PCIe, compatible with HDMI and DVI with a passive adapter
196RCA connect=designed in the 1940s by RCA, phono connector for audio, composite video signal -single RCA connector, one channel of analog video, yellow marking, red(right) and white(left) for audio connector
197component video=three RCA connectors (YPbPr=Luminance and sync, Blue, Red)
198BNC connectors= Bayonet Neill-Concelman - used on higher-end video, maintain connectivity - used likely in componet video
199Mini-DIN=mini-din-4 connector (S[seperate]-video) - 2 channel analog signals intensity and color
200PS/2 connector=6 pin mini-DIN mouse(green) keyboard (purple), PC systems design guide standard colors - named after the IBM PS/2 1987 - replaced by USB,typically found on older motherboards
201KVM=Keyboard, video mouse
202Sometimes laptops don't have ethernet ports so you can use a USB to Ethernet converter
203DVI-A to VGA converters ar backward compatible with VGA but only support 640x480 officially
204Thunderbolt carries both DisplayPort and PCIe
205mouse=USBor PS/2 connection pointing device - modern mice are optical and have few moving parts, may need the proper surface
206keyboard is connected via USB or PS/2 with adapter
207scanner is connected via USB or 802.11 wireless
208barcode reader is connected via serial or USB or 802.11wireless, built into phones
209biometric devices like fingerprint scanners/face recognition are built-in or connected via USB
210Digitizer=design and art related, USB connectors, pressure sensitive and more accurate than a mouse
211SOHO= Small office/home office (printer, scanner, fax)
212
213Printing
214
215duplex=printing on both sides of the page without manually flipping over the paper, not all printers can do this
216Collate= print multiple copies in their proper order - non-collated 1,1,2,23,3,4,4, - collated= 1,2,3,4,1,2,3,4
217orientation=protrait vs landscape, the paper doesnt rotate the printer compensates
218printers typically use USB type B - parallel is old connecteor also called DB-25 - ethernet RJ45 connector
219laser print=combines a laser, high voltage, charged ions, powdered ink, heat and paper-very fast printing speeds and high quality - complex, many moving parts, requires on-printer memory, messy
220imaging drum=image is drawn onto a photosensitive drum, painted with a laser-picks up toner, transfer toner to the paper, can be seperate from the toner cartridge or combined
221fuser assembly uses heat and pressure to melt plastic toner powdr and permanently bbond toner to paper
222transfer belt and roll, color laser printers use cyan,yellow,magenta and black - four seperate toner cartridges,image is transferred from all cartridge to the single belt and then to a single transfer roller
223pickup rollers pick up paper, should be a single page at a time, problems if no paper is picked up or multiple sheets are picked
224seperation pad pull just the top sheet from thepaper tray, not multiple sheets, small and inexpensive, easy to clean or replace
225duplexing assembly, printers usually print on a single side not both sides simultaneously - printing on both sides is a two step process, print side one, print side two, you need mechanics to flip the page automatically, can be built in to the printer or added later
226
227Inkjet printers are inexpensive compared to laser printers, more quit, has high-resolution -ink is expensive and proprietary and eventually fades over time and clogs easily 
228ink cartridges place drops of ink onto a page pulled from a set of cartridges
229PRINT HEAD=some consumer printers integrate the print head into the ink cartridge, change the cartridge, get a new print head while others seperate the ink cartridge from the print head
230feed rollers pick up and feed paper through the printer, must be clean and not worn
231carriage and belt-ink cartridges are moved over the paper, carriage may include it's own print head, belt moves the carriage back and forth
232
233A toner vacuum is a specialized piece of equipment used for removing toner dust from inside your printer. It is also anti-static so that it won’t damage any other of the sensitive components inside the printer.
234The Printer Spooler service is the part of the operating system that manages the majority of print-related tasks. This is usually the main communications mechanism for sending print jobs from a computer to a printer.
235
236terhmal printers use white paper and turns black when heated so it doesnt use ink, it's very quiet, almost silent - sensitive to light and heat and clear tape (used for receipts etc)
237feed assembly pulls paper through the printer, relatively small paperpath
238heating element, full length heating element, no moving print head
239thermal paper covered with a chemical that changes color when heated, asch registers, credit card terminals and quiet area, looks like normal paper but feels different due to chemical coating
240
241Impact printer=dot matrix printer-print head with small matrix of pins, presses against a ribbon to make a mark on paper - good for carbon.multiple copies, low cost per page, noisy, poor graphics compared to other printers, designed mainly for text
242moves back and forth, pins hit ribbon and paper, one matrix must move along the page
243printer ribbon is fabric, one long ribbon, never ending circle, easy to replace, proprietary size
244tractor feed, papper pulled through with holes on side of paper instead of using friction, continuous paper feed, perforations between pages - holes have to line up perfectly manully
245
246virtual printers output to a digital document, no additional hardware required, no printer or paper, useful for sending electronically and easy to manage (PDF[portable document format])
247XMPS= XML paper specification, used to view virtually printed documents in windows
248
249Networking
250
251ST connector=straight tip, bayonet (BNC) connector
252SC connector=subscriber connector/standard connector or square connector
253LC=Lucent connector/local connector or little connector
254RJ11 connector=6 position,2 conductor (6P2C) telephone connection
255RJ45 connector=8 position, 8 conductor (8P8C) module connector similiar in shape to an RJ48C- used for ethernet
256T568A/T568B terminination= pin assignments from EIA/TIA-568-B standard (eight conductor 100-ohm balanced twisted-pair cabling) = T568A and T568B are different pin assignments for 8P8C connectors, assigns the T568A pin-out to horizontal cabling - many organizations traditionally use 568B (difficult to change in mid-stream) - you can't terminate one side of the cable with 568A and the other with 568B it won't work
257F-connector=coaxial used for cable television/modem RG-6 cable with threadeded connector
258
259Fiber communications=transmission by light, the visible spectrum - no RF signal so very difficult to monitor or tap, signal slow to degrade so transmission over long distances - immune to radio or electrical interference since there's no RF
260multimmode fiber=short-range communication up to 2km (bounces light signal within cable)
261single-mode fiber allows long-range communication up to 100km without processing, expensive light source like a laser, signal doesn't bounce, one straight path
262twisted pair copper cabling=balanced pair operation, two wires with equal and opposite signals (transmit+,transmit-/receive+,receive-) the twist is the secret, keeps a signal wire constantly moving away from the interference, the opposite signals are compared on the other end - pairs in the same cable have different twist rates
263UTP=unshielded twisted pair - no additional shielding from interference, the most  common twisted pair cabling
264STP=shielded twisted pair - additional shielding protects against interference, requires the use of an electrical ground
265Plenum-rated cable - cable jacket flourinted ethylene polymer (FEP) with low-smoke polyvinyl - plenum-rated cable may not be as flexible, may not have the same bend radius -worst-case planning important concerns for any structure
266coaxial cable-two or more forms share a common axis - RG-6 used in television/digital cable and high-speed internet - RG59 used as patch cables not designed for long distances
267
268
269Incorrect BIOS date and time settings usually point to an issue with the CMOS battery. This is used to keep the settings intact within the BIOS, even when the PC loses power after you shut it down.
270The two form factors used for SSD memory for laptops include a 1.8 inch and 2.5 inch.
271An inverter is used with older technology to convert the DC power inside your computer into AC power that can be used for the display. This is found with older displays that use CCFL cold cathode fluorescent lamps.
272the Lightning connector is solely used on Apple devices, such as iPhones and iPads. It is able to output a larger amount of power than traditional chargers for faster charging, and it does not have to be turned a specific way to connect it to the charge port on your phone.
273Changes in decibel is logarithmic in nature. This means that a 20 decibel change could potentially result in a signal loss or signal strength by a factor of 1000 times that amount.
274
275The public IPv4 address space has been exhausted for quite some time now, meaning that all of these addresses have been purchased or allocated, usually by an Internet Service Provider (ISP). Many technical savvy companies have already began the transition to using IPv6, which contains a possible 340 undecillion addresses, or 2 to the 128th power (yes, a lot of addresses). Many, if not all ISPs have IPv6 enabled equipment already in operation.
276
277Static addresses are those that are manually assigned and entered on a device. This will effectively disable DHCP. He should also reserve the IP address in the DHCP pool as good practice, to prevent it from being leased to another device.
278
279LDAP (Lightweight Directory Access Protocol) often works in conjunction with Active Directory to provide user authentication and management in a network. It is the successor to the DAP (Directory Access Protocol).
280This is an enterprise grade solution built off of WPA2 encryption. This disables shared wireless access using one password and requires each user to use unique credentials for access.
281By creating a DMZ (demilitarized zone), you are setting up a subnet of your network that is accessible to outside users typically Internet traffic. A DMZ makes certain services available to external users while denying access to the rest of your network. Services typically segmented by a DMZ could include: email servers, Web servers, and FTP servers.
282Digital Subscriber Line (DSL) is limited to 10,000 feet from the central office for communication and can make use of existing phone lines already in place at your home or business.
283
284ISDN (Integrated Services Digital Network) uses bearer (B) channels to send data and uses D channels for signaling and control.
285Wide Area Networks, also known as WAN, are networks that are connected across long distances, such as city to city or state to state.
286PAN (Personal Area Networks ) are networks designed just for you, typically in a very short range. Connecting your cell phone to your car via Bluetooth, or connecting a set of Bluetooth speakers to your cell phone, would both qualify as a PAN.
287A repeater can re-send the wireless signal into an area that is not covered by the original access point. This would be a good alternative option to buying another access 
288point and can easily repeat the signal onto another floor of a home.
289This is commonly referred to as a Layer 3 switch, as routing decisions work at Layer 3 of the OSI model (network layer) and switches are normally considered Layer 2 devices.
290By plugging in a tone generator at the jack of one end of the cable, you can find the other end by waving a toner probe around the area you think it could be. A loud tone noise will generate when you have found the end of the cable.
291Grounding provides a way to safely transport any excess electrical charges away from the device receiving the voltage. This prevents the electrical spike from causing damage directly to the connected device.
292Using ESD straps and mats will effectively reduce or eliminate the risk of ESD and damaging computer components. The straps and mat work in tandem to balance the amount of static electricity between you and the components.
293For electrical fires, you should always use special dry fire prevention or extinguishing chemicals. Carbon dioxide is one of those chemicals.
294The Occupational Safety and Health Administration (OSHA) oversees and administers the MSDS programs within the United States. Any concerns or comments about the MSDS should ultimately be directed to OSHA.
295For storing active electronic equipment, it is wise to balance humidity levels as best as possible, which will avoid too much condensation or too much static discharge. If in doubt, always consult the material safety data sheet (MSDS).
296When working inside computers or other electrical devices, only specialized vacuums should be used. These devices are specially made so that they do not damage your electrical components.
297The amount of surge a suppressor can handle will be measured in joules. A higher rating in this category will equate to being able to protect more effectively against higher voltages on the line.
298Enclosures are specially made housings for computers in warehouse or factory settings. They protect the computing devices from dust and particles moving around in such an environment.
299With Windows Ultimate and Enterprise editions, as well as Windows 8 and 8.1, BitLocker, allows users to encrypt the entire drive protecting the data from loss or theft.
300When a PC is configured to use Wake-on-LAN, it will power on when a print job is being sent. There is a similar feature available for modems that allows the PC to be powered up when the modem determines a call is being received. This is Wake-On-Ring, often used when PCs are configured to receive Faxes.
301A DHCP (Dynamic Host Configuration Protocol) server is used to automatically configure the parameters needed by a network interface card when a PC is first booted up. It provides central management of IP address allocation.
302The Msconfig utility has a Startup tab that displays the processes launched at startup and allows you to disable any process.
303The Disk Cleanup utility is used to delete temporary files from a hard drive. To perform Disk Cleanup, from Start, enter Disk Cleanup.
304Enter the Recovery Console by pressing F8 during bootup, select the option to Repair your computer, enter your username and password, then choose the option Command Prompt.
305
306When she powered on her computer, it should connect to the DHCP server to acquire an IP address. If the DHCP server is down, her system will assign itself an APIPA address in the range of 169.254.0.1 through 169.254.255.254, then sends a broadcast to ensure no other PC is currently using that address. Unfortunately, the address 169.254.17.200 that her system randomly chose is not on her network so she will not be able to communicate.
307
308The system tool used to verify disk integrity is chkdsk which is run from the system command prompt. When run with no parameters set, it will simply display the disk status, if the /r option is added to the command, chkdsk will locate bad sectors and attempt to recover lost data.
309Windows 7 supports RAID level 0 and 1. Raid level 0 (Striped) writes across both drives simultaneously, which improves drive access. However, the customer needs to know that if one drive fails, he would lose all his data.
310RAID level 1 sets up mirroring, so as data is written to the drive, it is written to both drives. This arrangement allows for fault tolerance at the cost of using twice as much disk space.
311
312If the link integrity indicator does not light up when the cable is plugged in, it indicates there is no connection to the remainder of the LAN.
313If the default gateway goes down, it would not affect the local area network so he would be able to print. However, if the default gateway went down, users would not be able to access the Internet.
314
315The copy command will concatenate (add together) numerous files into a single file. The copy file1.txt + file8.txt + file17.txt filenew.txt will take the contents of file1.txt and file8.txt and file17.txt to create a new file called filenew.txt
316To erase a directory, the command is RD; RMDIR will do the same.
317The command CD (Change Directory) .. (two dots) means the directory above, so ../.. would move you up two directories.
318
319Enabling Time Machine requires using an external storage media, such as an external hard drive or Time Capsule. When enabled, it will perform incremental or historical backups in this manner: hourly backups for the past 24 hours, daily backups for the past month, and weekly backups for all previous months. It’s also important to note that the oldest backups are deleted when your storage becomes full.
320
321The Mac address (Media Access Control) is a 48-bit number (written as a 6-bit hexadecimal number) that uniquely identifies a device on a local area network. The IP address is used to locate the proper network; the MAC address is used to locate the device on the local area network.
322
323A socket number uniquely identifies one end of a communication session between two applications running on a network. A socket number shows the IP address and the port number of one end of a session. For example, 192.168.7.10:23 is a socket number that shows the network address (192.168.7.0) the host address where the application is running, which in the above example is .10 on the 192.168.7.10 network, and the port number of the application, which is delimited with a colon :23. So a socket number locates the network, as well as the host on the network, and the specific application running on the host.
324The subnet mask that defines a full class C network is 255.255.255.0, while a full class B subnet mask would be 255.255.0.0.
325Any software program in which advertising banners are displayed while the program is running is referred to as adware.
326The best practice for the removal of malware is to perform these steps in order: identify malware symptoms, quarantine infected system, disable system restore, remediate infected systems, schedule scans and run updates, enable system restore and educate the end user.
327The master boot record (MBR) is located on the first sector of the hard disk, and contains very important roles for a computer. One of these responsibilities is to begin the process of loading the operating system (OS). If a virus were to find its way into the MBR, it can cause serious issues, such as preventing the OS from loading.
328Restart the system, launch the Console application, and check All Messages for log errors that may indicate the original issue. When a system running Mac OS has a kernel panic, restart the machine and check for any errors that would be indicated in error logs shown in the Console Application
329System File Check (SFC) will verify all system files are working properly.
330The Event Viewer not only displays the events running but also errors, log files, and system warnings, which are all very useful in troubleshooting.
331
332LVM Snapshots, the Linux Logical Volume Manager, performs functions similar to System Restore in Windows.
333BitLocker-to-go works like BitLocker. BitLocker-to-go will encrypt flash drives as well as external drives thereby providing data security on portable devices.
334PPTP (Point to Point Transfer Protocol) is used to implement a secure VPN (Virtual Private Network) across an otherwise unsecure link.
335
336
337
338It is vital to preserve information to maintain the integrity of the collected evidence. If everything is not accurately and timely documented when switching hands, this could come under attack and be thrown out in a serious investigation.
339IPV4=internet protocol version 4 - OSI layer 3 address 
3408 bits=1byte=1 octet, since one byte is 8 bits, the maximum decimal value for each byte is 255, IPV4 is 32 bits in legnth or 4 bytes total
341IPV6=internet protocol 6, 128-bit address, 128bits=16 bytes total-first 64 bits is generally the network prefix(/64)-last 64 bits is then the host network address - groups of zeros can be abbreviated with a double colon ::
342APIPA=Automatic private IP addressing - link-local address, no forwarding by routers - IETF has reserved 169.254.0.1 through 169.254.255.254-first and last 256 addresses are reserved - functional block of 169.254.1.0 through 169.254.254.255 - automatically assigned, uses arp to confirm the address isn't currently in use
343IPV6 link-locacl address=a non-routable local network address, will only work on the local subnet - required on every IPV6 enabled interface, you may see many ipv6 addresses per interface-fe80::/10 with only one subnet allocated ( all zeros) effectievly becomes fe80::/64 - the last 64 bits are usually created with a modified EUI-64
344
345the ingredients for addressing=IP address eg 192.168.1.165(every device needs a unique IP address), subnet mask eg 255.255.255.0 (used by the local workstation to determine what subnet ir's on, the subnet mask isn't usually transmitted across the network, youll have to ask for the subnet mask all the etime, "what's the subnet mask of this network
346default gateway eg 192.168.1.1 is the router that allows you to communicate outside of your local subnet, the default gateway must be an IP address on the local subnet
347domain name system translates human-readable names into computer-readable ip addresses, only need to remember www.google.com - distributed database, many dns servers, 13 root server clusters, hundreds of generic gTLDs (.com .org .net etc), over 275 country code top level domains (.us .uk etc) IP addresses of DNS seervers is provided by the network admin, two addresses for redunancy
348Configuring DHCP where IP address configured used to be static, IP addy, subnet mask,gateway,dns servers,ntp servers etc
349DHCP=Dynamic host configuration protocol - released in 1997 and updated through the years-automatic IP,subnet mask, default gateway 
350CIDR=Classless inter-domain routing - created around 1993, removed the restructions created by classful subnet masks, "Cider" block notation - subnet masks can be expressed as decimal or in CIDR notation (IP address, slash, number of subnet bits; 192.168.1.44/24)
351classless subnetting=youll usually be provided an IP address, subnetmask, default gateway and DNS servers, some operating systems are expecting decimal masks while some areexpecting CIDR notation masks
352TCP=transmission control protocol - connection-oriented, reliable delivery (acknowledgement) - can manage out-of-order messages or retransmissions-loads andunloads the moving truck - checks for out-of-order or missing argo is good example
353UDP=user datagram protocol-connectionless (no acknowledgement) coined unreliable due to this, no reordering of data or retransmissions - loads and unloads the moving truck but doesnt care about out-of-order or missing cargo is good example
354IPv4 with TCP/UDP, server IP address, server app portnumber, client IP, client portnumber 
355non-ephemeral ports=permanent portnumbers, usually on a server or service
356ephemeral port=temporary port number determined inreal time by client workstation
357TCP/UDP port numbers can be any number between 0 and 65,535 - most services use non-ephemeral portnumbers but isnt always the case, just a number
358port numbers are for communication, not security, server port numbers need to be well-known such as port 80 for hTTP traffic
359TCP portnumbers arent the same as UDP port numbers
360FTP=file transfer protocol, uses tcp port 20 (acivemode data ) and tcp port 21 (control) - transfers files between systems
361SSH=secure shell -encryptedcommunication link uses TCP port 22, looks and acts the same as telnet
362Telnet=telecommunication network uses tcp port23 to loginto devices remotely, console access, unencrytped communication, not a safe choice
363email client protocols- receiving mail=pop3 and IMAP4
364SMTP=simple mail transfer protocol - sending emailand server to server email transfer
365DNS converts names to IP addresses - UDP/53
366web browsing protocols communicationin thebrowser and other apps, in the clear or encrypted, 80=HTTP 443=HTTPS(secure)
367RDP=Remote desktop protocol - share a desktop froma remote location over tcp/3389 - remote desktop services on many windows version
368SMB=SERVER message block - protocol used by microsoft windows for filesharing, printer sharing, also called cifs COMMON INTERNET FILE SYSTEM
369AFP=apple filing protocol,fileserverices in mac OS,TCP/548, workswith SLP(servicelocation protocol)
370LDAP=Lightweight directory access protocol - protocol for reading and writing directories over an IP network - an organized set of records like a phone directory-X.500 SPEC WAS WRITTEN by the internet telecommunications union (ITU)
371DAP ran on the OSI protocol stack 
372SNMP=simple network management protocol-gather statistics from network devices
373WEP=Wired equivalent privacy -64 bit or 128 bit key size-WEP cryptographic vulns identified in 2001-deprecated DO NOT USE
374WPA=Wifi protected access - RC4 with tkip(temporal key integrity protocol)-short term workaround for WEP
375WPA2 AES(advanced encryption standard) - replaces TKIP
376WPA2 Enterprise adds 802.1X - auth sever auth - user/password 
377port forwarding=24/7 access to a service hosted internally - web server,gaming server etc - external IP/port number maps to an internal IP also called static NAT or destination NAT - destination address is translated from a public IP to private IP
378port triggering=similar to a port forward, but a trigger is not static say if internal client communicates externally-file transfer/gaming - when service is stopped port is remove- reverse port forward is dynamically created, only one person can trigger at a time, multiple users must use port forwarding
379QoS=quality of service - change priority of your traffice (voice is high, WOw IS LOW ETC)- prioritize apps, ports of MAC addresses - a feature of high-end SOHO routers, could cause apps to slow down if not configured properly
380UPnP=universal plug and play - allows network devices to automatically configure and find other devices - zero configuration - apps on the internal network can open inbound ports using upnp - no approval needed, used for many P2P apps - best practice would be to disable UPnP- only enable if app requires it and maybe not even then
381DOCSIS=Data on the "cable" network - cable modem - high-speed networking 4mbit/s - 250mbit/s or higher on newer docsis networks
382ADSL=asymmetric digital subscriber line - uses telephone lines - download speed is faster than upload speed (assymetric) - 10,000 ft limitation from central office - 24mbit/s downstream 3.3mbit/s upstream
383dialup=network with voice telephone lines - analog lines with limited feequency response - 56kbit/s modems, compression up to 320kbit/s - slow throughput compared to DSL or cable connections - difficult to scale - legacy systems, network utlity - difficult to find a modem nowadays
384Fiber=fiber optics to the home-high speed networking - converged services voice video data - enhanced features, HD cahnnels, 1gbit/s speeds, 1tb cloud storage, 2TB DVR
385satellite networking=communication to a satellite - non-terrestial communication - high cost relative to terrestrial networking - 15mbit/s down, 2mbit/s up - remote locations, difficult to network locations- high latency, 250ms up 250ms down - line of sight so rain can disrupt connection
386ISDN=integrated services digital network - BRI (basic rate interface)  two 64kbit/s bearer (B) channels, one 16kbit/s signaling (D) channel
387Cellular networks are used on mobile devices such as cell phones, seperate land into cells (antenna coverages a cell with certain frequencies communicate) - tethering - turn your phone into wireless router 
388line-of-sight services - visual path between antennas, high frequencies- common in metropolotian areas
389LAN=local area network, local is relative - building or group of buildings, high speed connectivity - likely using ethernet or 802.11 wireless, any slower and it isn't "local"
390WAN=wide area network - spanning the globe or even the neighborhood - generally connects LANs across a distance - generally much slower than the LAN - 
391MAN=metropolitan area network (a network in your city) larger than a LAN but often smaller than a WAN - historically MAN-specific topologies
392PAN=personal area network (bluetooth,NFC,IR) - you own a private network - used in cars or headsets also health monitors etc
393HUB - multiport repeater - traffic going in one port is repeated to every other port - everything is half-duplex (only one device can communicate at one time) - becomes less eddicient as network speeds increase - 10mbit
394Switch=bridging done in hardware - application specific integrated circuit (ASIC)- FORWARDs traffic based on data link addresses (intelligent) many ports and features- the core of an enterprise network, may provide power over ethernet (POE) - multilayer switch which includes routing functionality exists
395router=routes traffic between IP subnets, makes forwarding decisions based on IP address - routers inside of switches sometimes called layer 3 switches - often connects diverse network types - LAN WAN COPPER FIBER
396WAP=Wireless access point - not a wireless router, WAP is a bridge - extends the wires network onto the wireless network - makes forwarding decisions based on MAC address
397modem=modulator/demodulator - converts analog sounds to digital signals - need a modem on both sides of connection - uses standard phone lines (limited frequencies, limited bandwidths) POTS (plan old telephone system), ASDL used nowadays
398Firewalls=filters traffic by TCP or UDP port numbers - some firewalls can filter applications-can encrypt traffic into/out of the network  to protect your traffic between sites - can proxy traffic (a common security technique)-most firewalls can be routers, usually sits on the ingress/egress of the network
399patch panels=combination of punch-down blocks and RJ-45 connectors, runs from desks are made once (permanently punched down to patch panel) patch panel to switch can be easily changed - no special tools and use existing cables
400copper line drivers and extenders - extend the range of copper wire well beyond normal ranges - serial links or copper ethernet used inside and outside of data centers - powered device required power supply, regenerates the signal - troubleshooting
401PLC=Power-line communication - may be marked as ethernet over power EOP - 500 megabits per second 
402POE=Power over ethernet - power provided on an ethernet cable-one wire for both network and electricity-phones cameras WAP - power provided at the switch, built-inpower=endspans - in-line power injector=midspans - mode a = power on the data pairs - mode b=power on the spare pairs
403cable crimpers are used to pinch the connector onto a wire (coaxial, twisted pair, fiber) - connect the modular connector to the ethernet cable - metal prongs are pushed through the insulation permanently pressed into connector
404multimeter is used to measure AC/DC voltages ie wall outlets - also used for continuity
405toner probe= follow the tone given off by wire follow the tone, tone generator puts an analog sound on the wire - inductive probe doesnt need to touch the copper, hear through a small speaker
406loopback plugs are useful for testing physical ports 
407punch-down tools punch a wire into a wiring block (66 or 110 block), trims the wires during the punch
408wireless analysis - wireless networks are incredibly easy to monitor-purpous-built hardware or mobile devices add-on 802.11 - identify errors and interference
409
410Laptop expansion options
411ExpressCard - laptop expansion device - easy to add and remove - 34mm and 54mm wide, 54mm slot also accepts 34mm cards - ExpressCard /34-/54 - 480mbit/s (usb 2 mode), 5.0gbit/s (usb 3 mode) 2.5gbit/s (PCIe mode)
412SSD hard drives come in 2.5 inch and 1.8 inch form factors-silent, no moving parts, less latency
413smart card reader can be integrated into laptop or using an external USB readr
414POST=Power on self test - test major system componets before booting the operating systems, CPU CMOS RAM GPU etc, failurs usually noted with a beeps or codes
415power supply tester - check the power without the motherboard load, quick red/green light diagnostics, LCD panel can show voltages
416POST card- detailed diagnostics during POST, LED numbers and letters
417S.M.A.R.T. = self monitoring, anonlysis and reporting technology use third-party utilities to detect hard drive health and errors
418CHKDSK /f runs a program to fix errors on hard drive
419CHKDSK /r locates bad sectors and recovers readable information
420defragmentation moves file fragments so they are contiguous - omproves read and write time 
421MBR=master boot record - the first sector of first hard drive - usually 512 bytes, contains table of primary partitions, disk signature, directions for starting the OS
422BOOTREC command can repair the MBR - bootrec /scanos - scan disks for windows installations - bootrec /fixboot writes a new boot sector - - bootrec /rebuildbcd creates a new boot config data store 
423DISKPART can make changes to HD partitions
424PING=test reachability - determine round-trip time, uses ICMP (INTERNET CONTROL MESSAGE PROTOCOL) 
425TRACERT = determine the route a packet takes to a destination - map the entire path - traceroute on POSIX style OS
426NETSTAT=Network statistics
427NBTSTAT=Netbios over TCP/IP 
428NETDOM=manage active directory 
429NSLOOKUP=lookup information from DNS servers - canonical names, IP address, cache timers etc
430DIR=list files and directories 
431DEL=DELETE FILE OR DIRECTORY
432MD=MAKE DIRECTORY
433CD=CHANGE DIRECTORY
434RD=REMOVE DIRECTORY
435COPY=copy file /a /v (verifies that the new files are written correctly) /y (skip override prompt)
436XCOPY=copries files and directory trees
437ROBOCOPY= robust copy - a better version of XCOPY included with win7 and win 8/8.1 
438TASKLIST/TASKKILL= manage tasks from the command line to view and end tasks 
439SFC=Scan integrity of all protected system files
440SHUTDOWN=shut down the computer
441EXPAND= windows stores files ina file "cabinet" .CAB files, the EXPAND command is used to remove files from the cabinet or extract files
442Apple's Thunderbolt 3 protocol uses the USB-C connector type. Thunderbolt 3 is also compatible with USB-C, so a Thunderbolt 3 port will work with both a Thunderbolt 3 and USB-C connector. Similarly the Thunderbolt versions 1 and 2 use a standard Display Port connector.
443Hubs are not intelligent enough to route packets to their destination. Instead they broadcast any data they receive out of every port (except the port they receive it on). Hubs cause large amounts of unnecessary packets that will clog a network.
444The CMOS battery (complementary metal-oxide semiconductor) is a small battery that provides power to a motherboard while it is powered off. This power source is used to store the BIOS configuration data (but not the BIOS firmware itself) and powers the Real Time Clock (RTC).
445SFTP (SSH File Transfer Protocol) is a protocol for securely uploading files to a remote server. SSH alone is not enough to upload a file and is incorrect. SSH provides the encryption & authentication but does not meet the requirement to upload a file. As SFTP builds upon SSH with functionality for file upload it is the correct answer.
446After a printer applies toner to paper the fuser assembly rolls over the paper and applies heat to fuse the toner to the paper. Occasionally, the toner can stick to the fuser assembly and will be applied to the next sheet of paper passed through the printer.
447POP3 (Post Office Protocol) uses TCP 110 to communicate.
448Lightweight Directory Access Protocol (LDAP) is an open-standard protocol used to query directory based databases such as Active Directory. LDAP uses TCP 389 by default.
449Power-line communication will allow a SOHO network to be built using ethernet power adapters which is much cheaper than running cable. Power-line communication allows the use of the ethernet protocol over electrical power wiring. If the company doesn't want employees working from home to use wireless networks or to pay the expense of running ethernet from the modem to the office then power-line is a cheap alternative.
450
451Dots per Inch (DPI) is the standard measurement used for printers. It refers to the amount of dots that are placed by the printer in a one inch space. This is similar to Pixels Per Inch (PPI), which is used to measure how many pixels are placed in an inch by a monitor or screen. Aspect/Contrast Ratios are used to compare height and width of paper, monitors, etc. For example 4x1 would be 4 height for every 1 width - this could be 400x100 or 800x200.
452TPM (Trusted Platform Module) is a standard cryptoprocessor used to store cryptographic keys
453If using a daisy chain IEEE 1394 (FireWire) can support up to 63 devices at one time.
454
455902  NOTES
456
457Windows vista released jan 30, 2007 - uses Aero GUI, integrated search-UAC(User account control, prompt for auth)-
458
459LGA = Land Grid Array 775=755 pins 
460BIOS = Basic input/output system (created more than 25 years ago)
461UEFI = Unified Extensible Firmware Interface (designed to replace legacy BIOS) BOOT FROM 2.2TB and up hard drives, FAT, flash drives, pre-boto enviorment for troubleshooting
462CMOS = Complementary metal-oxide semiconductor (old battery backup for BIOS condiguration), has been replaced with flfasah memory - likely used only to maintain date/time settings, if this battery dies you would have to reconfigure the BIOS every boot so replace with a new battery, can also be used to reset BIOS configuration by removing the battery
463BIOS system setups are usually launched with pressing del, f1,f2,ctrl-s,ctrl-alt-s at boot
464Can be used to view system information of components such as RAM, hard drive, optical drive, CPU 
465ATX>micro-atx>mini-itx>nano>pico - ATX=advanced technology extended created in 1995 (20 or 24+4/8 pin power connector)
466PCI eXtended = based on PCI designed for servers, has higher bandwidth four times the clock speed, built to handle higher-speed communication
467PCIe=PCI Express, replaced PCI,PCI-X and AGP, communicates serially instead of parallel, duplex=back and fourth communication at same time
468mini PCI/PCIE is for laptops, shrunk down for mobile uses  (wifi adapters, mobile broadband etc, it's inside of the laptop connected to the motherboard
469RAM=random access memory, one of the most important componets of computers - has a lot to do with the speed of computer - DIMM (dual inline memory module has 64 bit data width, 184 pins while DDR3 SDRAM is 184 pins, DDR2 and DDR3 SDRAM are 240 pins)
470BUS= size of communication path measured in bits
471Laptop RAM referred to as SODIMM(Small outline dual in-line Memory Module, DDR/DDR2 SDRAM - 200 pins - DDR3 SDRAM 204 pins)
472Micro-DIMM=smaller form factor RAM for mobile devices (DDR - 172 pins - ddr2/ddr3 - 214 pins)
473ZIF= Zero Insertion Froce (CPU socket)
474PGA= Pin Grid Array (pins are on the CPU)
475LGA= Land Grid Array (pins are on the motherboard)
476Northbridge ( memory controller hub) connects the cpu to the memory and graphics card, high bandwidth communication
477Southbridge (I/O controller hub [USB Ethernet IDE SATA etc]) manages connections like PCI interface slots and pripherals (keyboard mouse etc), onboard graphics controllers, BIOS
478modern CPUs have integrated memory controllers and even graphics processing units
479jumper enables and disables certain feature of motherboard from your documentation
480ROM=Read only memory (bios) - cant be changed or erased while EPROM can be erased or replaced PROM=Programmable memory, can be written once - EEPROM=electrically erasble PROM (flash memory)
481SRAM=Static RAM - very fast memory, expensive, large chip size used often in processor caches (L1,L2,L3)
482DRAM=Dynamic Random Access Memory - RAM you will typically see in computers, dynamic means needing constant refreshing, without refreshing the data in memory disappears. random access means any storage location can be accessed directly unlike magnetic tape
483SDR SDRAM=Single data rate  synchronous DRAM - 168 pins,SDRAM is synchronousa queue up one process while waiting for another - classic DRAM didnt wait for a clock signal, Dont confuse SDRAM with Static RAM(SRAM)
484DDR=Double Data Rate SDRAM- twice the data rate as SDR SDRAM but at the same clock speed, 184 pins
485DDR-200=200 million transfers per second, multiply by 8 to get throughput in megabytes per second (200x8=1600=PC1600)
486DDR2 SDRAM was made for faster speeds, twice as fast as DDR with 240 pins
487DDR3 SDRAM was made as an upgrade for DDR2 being twice as fast with twice the data rate, larger chip capacities yet also 240 pins, same as DDR2, not backwards compatible, does not fit in DDR2 slot
488Parity memory=adds an additional parity bit but wont always detect an error and cant correct an error, used to inform of issue
489ECC=Error correcting code memory - detects errors and corrects on the fly, not all systems use ECC, generally for servers and enterprise system, looks the same as non-ECC memory
490Registered memory (buffered memory)= includes an additional register beteween the RAM module and memory controller used mostly on servers for a more stable operating eenviorment, rarely used on desktop systems
491multi channel memory is installed in pairs or trios for maximum throughput, use same colors for same ram modules
492CDROM 700MB, DVD-ROM 4.7GB, DVD+DL 8.5GB, bluray 25GB BD+DL 50GB
493RAID=Redundant Array of Indepedent Disks
494Software-based RAID is a feature of the operating system and doesn't require any special hardware, usually lower-performance than hardware-based 
495Hardware-based RAID is a feature of the hard drive controller configured outside of the OS that is high performance and designed for speed
496Trusted Platform Module (TPM)
497In PCIe architecture, a single full-duplex point-to-point serial communication path consisting of two pairs of wires (where one pair is used for transmitting data and the other pair for receiving data) is known as a lane
498In this case, primary storage typically refers to random access memory (RAM), while secondary storage refers to the computer's internal hard drive. RAM, commonly called "memory," is considered primary storage, since it stores data that is directly accessible by the computer's CPU.
499There are different RAID levels, 0 (striping) 1 (mirroring) 5 (striping with parity) nested RAID/Raid 1+0 aka RAID 10 (stripe of mirrors)
500file blocks are split between two or more physical drives, RAID0 needs at least 2 physical drives, high performance, no redunancy so drive failure breaks the array aka RAID means RAID0redunancy
501RAID1 file blocks are duplicated between two or more drives, high disk utilzation - every file is duplicated and required disk space is doubled, has high redundancy so drive failure does not affect data availibility
502RAID5 file blocks are striped along with a parity block, requirs at least three disks - efficient use of disk space, files arent duplicated but is still used for parity, has high redundancy because data is available after drive failure, parity calculation may affect performance
503RAID1+0 has the speed of striping and the redundancy of mirroring, the best of both worlds, needs at least 4 drives
504To prevent the loading of malware and unauthorized OSs during system start-up , which UEFI functionality is used
505Secure boot
506RAID type with the highest disk overhead? raid level 5
507Maximum length of a fiber-optic Thunderbolt cable is 60 meters
508A computer on a network where most functions are carried out on a central server, or a client-server model software wherein the server performs all the processing is commonly referred to as a Thin client
509For automated discovery of networked services on LANs SLP is used
510Allocated for wireless communication a portion of the available Radio Frequency (RF) band is known as a channel
511The traditional PSTN lines is used by Dial-up
512The relative vertical and horizontal size of a digital image which is displayed on the graphics monitor screen is known as aspect ratio
513The 16:10 aspect ratio is used by WUXGA
514The correct sequence of steps in the laser printing process is Processing, charging, exposing, developing, transferring, fusing, cleaning
515PCL=Printer Command Language-To describe the appearance of a printed page
516For a copper twisted-pair Ethernet cable A typical cable segment length is 100 meters
517Computers running Microsoft Windows Oss has the basic disk , most commonly used storage type.
518Each computer in the workgroup has own policy for security
519
520
521
522
523CPU socket types
524LGA775 775 pins, LGA(land grid array) package (all pins are on motherboard and cpu is flat (named for the cancelled Tejas core)), seen in later pentium 4, core 2 duo, xenon, celeron
525LGA1366 has 1,366 pins, LGA package, also called socket B which replaced the LGA 775, used by core i7 CPUs
526LGA 1156 has 1,156 pins, LGA package also called Socket H or H1, also replaces LGA 775, released in 2009 and integrates Northbridge onto the chip itself (used to be seperate chip on motherboard)
527LGA1155 has 1,155 pins, LGA package aso called Socket H2, replacement for LGA 1156, not compatible with LGA1156 but looks very similar, released in 2011 and supports intel sandy bridge and ivy bridge microprocessors 
528LGA115 has 1,150 pins, LGA package also called Socket H3 which replaces the LGA1155, released in 2013 used by Haswell and Broadwell microarchitecture 
529LGA2011 has 2,011 pins, LGA package also called Socket R, replaced LGA 1366 and LGA 1567, released in november 2011 for high-end desktop and servers, sandy bridge
530
531AMD CPU
532
533AM3 has 941 pins on socket, PGA-ZIF socket which replacs the AM2/AM2+ socket, released in 2009, AM3 processors could be used in AM2/AM2+ with a BIOS update
534AM3+ socket contains 942 pins on socket, PGA-ZIG package, one more pin than the AM3, released in 2011, use an AM3 processor in an AM3+ motherboard
535FM1 socket has 905 pins, PGA-ZIG package, 2011 release, AMD 10h CPU architecture, AMD A-series processors for faster speeds, DDR3 support and integrated PCIe 2.0 controller
536FM2 has 904 pins, PGA-ZIF package, released in 2012, piledrive architecture
537FM2+ 906 pins, micro PGA-zig package, also called FM2b, two more pins than FM2, incompatible with FM2, differen't pin configureation, released in january 2014, steamroller architecture
538
539processor speed, real speed = CPU clock, historical qualification of speed measured in magaherts (MHz) or gigahertz (GHz), actual speed is combination of different factors such as clock speed, architecture, bus speed, cach sizes, manufactures have moved away from marketing performance in clock cycles, no broadly accepted measure of performance, use a benchmark that works for you
540dual core/quad core/octa-core/,ulticore (number of cores in the physical processor)
541CPU cache is super faster memory, not large in size, holds data, insutrctions/results
542level 1 cache = first check, fastest
543level 2 cache = secondary data
544Hyper-threading Technology (HTT)=one CPU acts like two, doesn't work as fast as two, generally 15-30% improvement over having non-HTT CPU. Windos XP and beyond support HTT
545Virtualization=run other operating systems within a single hardware platform, sharing physical hardware componets, virtualization in software was limited and had perfomance and hardware management challaenges
546Intel virtualization technology (VT)
547AMD version AMD-V
548DATA WIDTH= Data path, integer size, memory addresses , registers address bus, data bus, much greater in 64 bit than 32 bit
549larger bus sizes move more data, 64 bit can move twice as much as a 32 bit CPU e
550bus size may not necessarily match the CPU architecture
551software must be optimized to take advantage of 64 bit archs, operating systems, drivers, etc
552Integrated GPU(graphcis processing unit)=part of a video adapter, motherboard or CPU
553graphics rendering requires a lot of work, dedicated hardware speeds the process. on-die GPUs are increasingly common but not as powerful as GPU standalone hardware
554NX bit=No-eXecute bit=intel refers as XD bit, amd eNHANCED vIRUS pROTECTION - DESIGNATES SECTIONS OF MEMORY AS EXECUTING CODE OR DATA, code cant run from protected memory locations, prevents malware and viruses from executing - the OS must support this feature (windows calls it Data Execution Prevention [DEP]), usually enabled automatically as a default
555heatsink=dissipate heat through thermal conduction, made of copper or aluminum alloy, fins/grid increase surface area of componet, heat is then transferred to the cooler air, thermal paste creates a good contact between the chip and the heat sink. componets can become very hot with or without heat sinks, without can cause failures
556proper thermal paste application is a small pea-sized drop and the heat sink will spread a proper layer over the CPU
557onboard fans can be used to provide extra airflow to cool components such as graphics card
558case fans pulls cool air from the front and exhaust hot air from the rear, motherboard layout and wiring becomes important to not block airflow
559standard sizes of case fans are 80mm,120mm,200mm, variable speed fans also exist
560liquid cooling is where coolant is circulated through a computer, used in automobiles, mainframe computers and other high-end systems, overclocking, gaming
561fanless/passive cooling creates no noise, silent operating, used in DVR, set top box, media servers, low powered devices taking advantage of heat sinks
562USB=universal serial bus
563USB 1.1 low speed: 1.5 megabits per second, 3 meter length is max, full speeed: 12 megabits per second, 5 meters
564USB2.0 480 megabits per second, 5 meters
565USB3.0 aka SuperSpeed, 5 gigabits per second, 3 meters - backwards compatible with all USB
566USB is used for hot-pluggable devices, bootable devices, serial communication interface
567Standard-A plug (common, laptop desktop etc), B-plug (printers), mini/micro-B plug (phones etc)
568Firewire/IEEE 1394= apple trademarked connector, 4.5 meters distance limitation) non-apple devices refer to it as IEEE1394/lynx/ilnk, daisy chain devices together up to 63 - Firewire 400 (alpha mode, IEEE1394a SUPPORTS 100,200 OR 400mBIT/S HALF-DUPLEX) Firewire 800 (beta mode/IEEE 1394b) supports 800Mbit/s full-duplex, optical connections support 100 meter distance (6-pin alpha powered, 4pin alpha unpowered, 9 pin firewire beta)
569Addition of primary storage modules to the motherboard is allowed by RAM
570SATA=Serial AT Attachment - 1.0 max speed 1.5Gbit/s, 1 meter max length, 2.0 3.0Gbit/s, 1 meter, 3.0 6.0/Gbit/s, 1 meter, eSata External SATA, matches the sata version, 2 meters max length - 15 pins power connector, 7 pins data connector, sometimes supports molex
571VGA=Video graphics array - DB-15 connector or DE-15 technical term, typically blue color stadnardized by PC System Design Guide - analog signal only, no digital - image quality degrades after 5-10 meters
572HDMI=high-definition multimedia interface - video and audio stream - all digital no analog signal - 20 meter distance before losing too much signal - 19 pins and proprietary connector - miniHDMI type C connector was designed for smaller devices
573DVI=digital visual interface - signle link and dual link single=3.7gbps (HDTV at 60FPS) dual=7.4gbps (HDTV at 85fps), DVI-A (analog) DVI-D (digital) DVI-I (integrated, digital and analog in same connector)
574analog audio ports, common 6.3mm(1/4"[music etc]) 3.5mm(1/8"[phones,computers])-TRS=tip/ring/sleeve 
575Digital audio TOSLINK(toshiba lINK), optical fiber created in 1993 used on consumer electronics, max length <10 meters
576RJ11=registered jack 11 - analog modem, DSL line -telephone connection - RP2C 6 position 2 conductur - some RJ standards use the same physical interface but different wiring
577RJ45=ETHERNET (patch, crossover cable, connector) RJ45 (registered Jack 45_ 8pc8c ( 8 positions, 8 conductors)
578Thunderbolt=high-speed serial connector, data and power on same cable based on mini displayport (MDP) standard - v1= 10Gbit/s per channel, 20Gbit/s total throughput, V2 20  gBIT/S AGGREGATED CHANNELS, v3 40Gbit/s - max legnth of 3 meters for copper, 60 meters for optical, daisychain up to 6 devices
579
580Wireless interface
581
582Infared-stadnards from the IrDA (infrared data association) - 4Mbit/s speed, line of sight - 1 meter distance limitation - laptops, phones cameras
583NFC=Near Field Communication - 106kbit/s,212kbit/s,424kbit/s - range of 10cm or less - mobile devices, payments (credit cards)
584bluetooth categorized into classes - class1 industrial use 100 meters distance, class 2 used in many mobile devices 10 meter distance , class 3 short-range use 1 meter distance - version 1.2 created in 1995 for faster connection and recover - verion 2.0+EDR (enhanced data rate) version 3.0+HS (high speed) used bluetooth for negotiation and establishment but 802.11 used for actual data transfer, version 4.0 includes a low-power spec
585802.11 networking=modern wifi 
586802.11a=5GHZ 54mbit/s - 120 meter 
587802.11b=2.4GHz 11mbit/s 140 meter
588802.11g=2.4ghz 54mbit/s 140 meter
589802.11n=5ghz/2ghz 150mbit/s 250 meters
590802.11ac=5zx 866.7mbit/s 250 meters
591
592analog modulation=sends an analog signal over an analog channel (AM/FM audio over radio frequencies)
593digital modulation=sends a digital bitstream over an analog channel (send digital audio signal over satellite radio frequencies Sirius/XM etc)
594all signals degrade, electrical or optical - there's often a set of standards and all devices must adhere to the standard but it's possible you can go farther ie pushing the envelope - almost alway need advanced testing gear to measure the signal to see what kind of distance you can get
595Data transfer speeds=data between A and B (how quickly can it get there?) - rarely a straightforward calculation, bytes used by storage devices, bits transmitted across the medium are two completely different things
596quality=signal strength - how "loud" is the signal? how much signal is getting tot he other side?
597signal quality of the noisereceived - how much of it is any good, there will always be a signal to noise ratio - important for network communication
598DRM=Digital Rights Management=controls over digital media - associated with every media types like games, videos, movies, documents - may be controlled in software or hardware like motherboard details, USB key, passphrase-every application is different and some DRM implementations are better than others, be aware when moving computers or parts around
599Frequencies=the number of cycles in a second(hertz)
600
601Power connections
602
603SATA=15 pins, +3.3v, +5v and +12v, 3.3v is rarely used by most drives
604Molex=4 pin peripheral power connector created by the Molex connector company - AMP MATE-N-LOK - provides +12V and +5V - used to power many devices inside the computer case like storage devices, optical drives, fans and other peripherals
605ATX+12V=4 pin atx+12v - ATX12V Advanced technology extended motherboards - additional 12 volt power for older motherbords used primarily for cpu - MAY BE LABELED LABELED atxv12,p4,cpu and keyed for the appropriate connector
606EPS+12v=8 pins, referred to as EPS12V cable, entry level power supply spec - 4+4 connector, includes an atx+12v 4PIN - seen mostly on servers - not 8pin PCIe power connector, keyed differently
607PCIe 6/8pin connector - additional power for PCIe adapters, 6pin (75 watt) 8pin  (150 watts) provides +12v - seen on high-power componets like GPUs , same cables have two pieces in one
608motherboard power connector (20/24 pin) - main motherboard power, provides 3.3v +/+5v and +/- 12v - 20 pin connector was the original atx standard, 24 pin was added for PCIe power - you can connect a 24 pin connector to a 20 pin motherbaord, some cables are 20pin+4 pin- orientation matters, double check
609amp=ampere (amp,A) - the rate of electron flow past a point in one second
610voltage= (volt,V) - electrical "pressure" pushing electrons
611watt=wattage (W) - measurement of real power use - volts * amps=watts 120V*0.5A=60W
612Alternting current=(AC) - direction of current cosntantly reverses - distributes electricity over long distances - frequency of this cycle is important - US/CANADA=110-120volts of AC(VAC), 60 hertz(Hz) - Europe-220-240 VAC, 50hz
613DC=Direct Current - current moves in one direction with a constant voltage
614single rail= a single 12v rail power supply - one output circuit generating 12 volts
615multiple rails=multiple 12v rail power supply - each 12v rail has seperate circuitry inside of the power supply - each 12v connector on the outside of the power supply is connected to one of the rails - multiple rails provide additional protection - a high-powered overload of a single rail usually means there's a lot of smoke - overloading smaller capacity rails shuts down the PSU instead
616When sizing a power supply, bigger isnt necessarily better - more expensive, doesnt make your computer faster - physical size is relatively standard but older cases and systems may have proprietary sizes - calculate the watts required for all  components (CPU storage devices, GPU) - many online calculators - GPUs are usually the largest power draw and many GPU specs list a recommended power supply wattage, 50% capactity is a good rule of thumb, power supply runs efficiently and there's room to grow
617
618Power supply connectors can be fixed (connected to the power supply) or modular (cables connect to the PSU) - fixed connector PSU may have too many unneeded connectors or not enough - modular PSU you can add cables as needed, fewer leftover wires for better airflow but cost a bit more than fixed connect PSU
619power supply dimensions are standardized so most power supplies fit in ATX and microATX cases but some older power supplied are physically quite large so microatx cases may not be an option, some microatx cases require particular deminsions like in proprietary case
620Some PSU offer dual-voltage options due to voltages varrying by country, has a manual switch on back of PSU to switch between voltage but DO NOT plug a 115v PSU into a 230V power source.
621CAD=computer aided design/manufacturing requies higher end equipment, multicore processor for 3D modeling and calculations and gpu for complex graphics as well as max RAM due to significant memory use 
622A/V editing workstations require a lot of high end components as well, duel monitors (edit in one monitor and view output in the other) is helpful for this setup
623Virtualization workstaions require a large amount of RAM as every OS needs it's own memory and it adds up quickly
624Gaming computers require high end components as well and a lot of RAM and proper cooling
625LCD= liquit cystal display - light shines through liquid crystals - liquid crystal molecules sit between two polarizing filters - turn the molecules and light passed- requies some type of backlight which shines through the LEDs
626TN=twisted nematic type of LCD -- the most common technology, fast response times for gaming, low power draw but poor viewing angles, color shifts
627IPS=in plane switching LCD technology, excellent color representation, no tailing when touched (moble devices), more expensive than TN
628CCFL=cold cathode fluorescent lamp- high voltage and power needed - used a power inverter for DC to AC power -a dded thickness to the display - no longer a common backlight
629LED-backlit LCD diplay=backlight is LEDs instead of florescent - LEDs around the edge of the screen and diffused to evenly light the display - an array of lEDs are behind the screen - maybe dimmed individually
630plasma display=a display of tiny cells using noble gas and mercury - voltage forms a plasma, mercury sheds energy as UV light - UV lights strikes colored phosphor and you see a picture - deep blacks and fast response times - very good color representation but no longer in active production, LED display prices and features have won the market
631digital projectors are not always LCD but common to be LCD - metal-halide lamp, very bridge and very hot light, expensive up to $350 - always let bulbs cool before turning off device as fans will turn off
632OLED=Organic light emitting diode - organic compound emits light when deceiving an electric current - thinner and lighter so flexible and mobile, no glass needed - no backlight bcause the organic compound provides the light, true black color - lifespan can be shorter than LED as organic materials degrade
633
634Display specifications
635
636Refresh rate=number of times per second the screen is redrawn (measured in hertz)-
637lcd displays no electron beams, refreshes the entire screen at 60/120/144hz and up which is really a frame rate
638display resolution=number of pixels on a display, width x height, actually pixel dimensions
639aspect ratio=the ratio of width to height 
640standard monitor aspect ratio 4:3 1600x1200,2048x1536
641wide screen monitor 16:10 1920x1200,2560x1600
642HD-16:9 1920x1080,2560x1440
643native resolution=an LCD display is fixed, the number of pixels doesn't change and a 
644display looks best when the video settings match a display's native resolution, a mismatch can cause distortion - if changing the display resolution, try using a multiple of the native resolution (2560x1600 is the same ratio as 1920x1200)
645
646Display brightness 
647Luminance=candela per square meter (cd/m^2), more is better
648Lumens=an ANSI test, 3,000 lumens works in a dim room, 6,000 lumens works in a sunlit room
649privacy display filter=fade the screen to black or gold when viewed at an angle, placed on the front of display so only the one facing screen can see it
650anti-glare=glossy screens are common can this reduces glare, improve viewing and useful in bright light
651multiple displays=connect more than one display for a flexible work enviorment - extend a desktop (each display is independent, location is determined in the OS), mirror a desktop makes each display shows identical information
652
653Displayport=VESA (video electronics standards association, royalty free standard) standard display connector-data is sent in packetized form like ethernet and PCIe, compatible with HDMI and DVI with a passive adapter
654RCA connect=designed in the 1940s by RCA, phono connector for audio, composite video signal -single RCA connector, one channel of analog video, yellow marking, red(right) and white(left) for audio connector
655component video=three RCA connectors (YPbPr=Luminance and sync, Blue, Red)
656BNC connectors= Bayonet Neill-Concelman - used on higher-end video, maintain connectivity - used likely in componet video
657Mini-DIN=mini-din-4 connector (S[seperate]-video) - 2 channel analog signals intensity and color
658PS/2 connector=6 pin mini-DIN mouse(green) keyboard (purple), PC systems design guide standard colors - named after the IBM PS/2 1987 - replaced by USB,typically found on older motherboards
659KVM=Keyboard, video mouse
660Sometimes laptops don't have ethernet ports so you can use a USB to Ethernet converter
661DVI-A to VGA converters ar backward compatible with VGA but only support 640x480 officially
662Thunderbolt carries both DisplayPort and PCIe
663mouse=USBor PS/2 connection pointing device - modern mice are optical and have few moving parts, may need the proper surface
664keyboard is connected via USB or PS/2 with adapter
665scanner is connected via USB or 802.11 wireless
666barcode reader is connected via serial or USB or 802.11wireless, built into phones
667biometric devices like fingerprint scanners/face recognition are built-in or connected via USB
668Digitizer=design and art related, USB connectors, pressure sensitive and more accurate than a mouse
669SOHO= Small office/home office (printer, scanner, fax)
670
671Printing
672
673duplex=printing on both sides of the page without manually flipping over the paper, not all printers can do this
674Collate= print multiple copies in their proper order - non-collated 1,1,2,23,3,4,4, - collated= 1,2,3,4,1,2,3,4
675orientation=protrait vs landscape, the paper doesnt rotate the printer compensates
676printers typically use USB type B - parallel is old connecteor also called DB-25 - ethernet RJ45 connector
677laser print=combines a laser, high voltage, charged ions, powdered ink, heat and paper-very fast printing speeds and high quality - complex, many moving parts, requires on-printer memory, messy
678imaging drum=image is drawn onto a photosensitive drum, painted with a laser-picks up toner, transfer toner to the paper, can be seperate from the toner cartridge or combined
679fuser assembly uses heat and pressure to melt plastic toner powdr and permanently bbond toner to paper
680transfer belt and roll, color laser printers use cyan,yellow,magenta and black - four seperate toner cartridges,image is transferred from all cartridge to the single belt and then to a single transfer roller
681pickup rollers pick up paper, should be a single page at a time, problems if no paper is picked up or multiple sheets are picked
682seperation pad pull just the top sheet from thepaper tray, not multiple sheets, small and inexpensive, easy to clean or replace
683duplexing assembly, printers usually print on a single side not both sides simultaneously - printing on both sides is a two step process, print side one, print side two, you need mechanics to flip the page automatically, can be built in to the printer or added later
684
685Inkjet printers are inexpensive compared to laser printers, more quit, has high-resolution -ink is expensive and proprietary and eventually fades over time and clogs easily 
686ink cartridges place drops of ink onto a page pulled from a set of cartridges
687PRINT HEAD=some consumer printers integrate the print head into the ink cartridge, change the cartridge, get a new print head while others seperate the ink cartridge from the print head
688feed rollers pick up and feed paper through the printer, must be clean and not worn
689carriage and belt-ink cartridges are moved over the paper, carriage may include it's own print head, belt moves the carriage back and forth
690
691A toner vacuum is a specialized piece of equipment used for removing toner dust from inside your printer. It is also anti-static so that it won’t damage any other of the sensitive components inside the printer.
692The Printer Spooler service is the part of the operating system that manages the majority of print-related tasks. This is usually the main communications mechanism for sending print jobs from a computer to a printer.
693
694terhmal printers use white paper and turns black when heated so it doesnt use ink, it's very quiet, almost silent - sensitive to light and heat and clear tape (used for receipts etc)
695feed assembly pulls paper through the printer, relatively small paperpath
696heating element, full length heating element, no moving print head
697thermal paper covered with a chemical that changes color when heated, asch registers, credit card terminals and quiet area, looks like normal paper but feels different due to chemical coating
698
699Impact printer=dot matrix printer-print head with small matrix of pins, presses against a ribbon to make a mark on paper - good for carbon.multiple copies, low cost per page, noisy, poor graphics compared to other printers, designed mainly for text
700moves back and forth, pins hit ribbon and paper, one matrix must move along the page
701printer ribbon is fabric, one long ribbon, never ending circle, easy to replace, proprietary size
702tractor feed, papper pulled through with holes on side of paper instead of using friction, continuous paper feed, perforations between pages - holes have to line up perfectly manully
703
704virtual printers output to a digital document, no additional hardware required, no printer or paper, useful for sending electronically and easy to manage (PDF[portable document format])
705XMPS= XML paper specification, used to view virtually printed documents in windows
706
707Networking
708
709ST connector=straight tip, bayonet (BNC) connector
710SC connector=subscriber connector/standard connector or square connector
711LC=Lucent connector/local connector or little connector
712RJ11 connector=6 position,2 conductor (6P2C) telephone connection
713RJ45 connector=8 position, 8 conductor (8P8C) module connector similiar in shape to an RJ48C- used for ethernet
714T568A/T568B terminination= pin assignments from EIA/TIA-568-B standard (eight conductor 100-ohm balanced twisted-pair cabling) = T568A and T568B are different pin assignments for 8P8C connectors, assigns the T568A pin-out to horizontal cabling - many organizations traditionally use 568B (difficult to change in mid-stream) - you can't terminate one side of the cable with 568A and the other with 568B it won't work
715F-connector=coaxial used for cable television/modem RG-6 cable with threadeded connector
716
717Fiber communications=transmission by light, the visible spectrum - no RF signal so very difficult to monitor or tap, signal slow to degrade so transmission over long distances - immune to radio or electrical interference since there's no RF
718multimmode fiber=short-range communication up to 2km (bounces light signal within cable)
719single-mode fiber allows long-range communication up to 100km without processing, expensive light source like a laser, signal doesn't bounce, one straight path
720twisted pair copper cabling=balanced pair operation, two wires with equal and opposite signals (transmit+,transmit-/receive+,receive-) the twist is the secret, keeps a signal wire constantly moving away from the interference, the opposite signals are compared on the other end - pairs in the same cable have different twist rates
721UTP=unshielded twisted pair - no additional shielding from interference, the most  common twisted pair cabling
722STP=shielded twisted pair - additional shielding protects against interference, requires the use of an electrical ground
723Plenum-rated cable - cable jacket flourinted ethylene polymer (FEP) with low-smoke polyvinyl - plenum-rated cable may not be as flexible, may not have the same bend radius -worst-case planning important concerns for any structure
724coaxial cable-two or more forms share a common axis - RG-6 used in television/digital cable and high-speed internet - RG59 used as patch cables not designed for long distances
725
726
727Incorrect BIOS date and time settings usually point to an issue with the CMOS battery. This is used to keep the settings intact within the BIOS, even when the PC loses power after you shut it down.
728The two form factors used for SSD memory for laptops include a 1.8 inch and 2.5 inch.
729An inverter is used with older technology to convert the DC power inside your computer into AC power that can be used for the display. This is found with older displays that use CCFL cold cathode fluorescent lamps.
730the Lightning connector is solely used on Apple devices, such as iPhones and iPads. It is able to output a larger amount of power than traditional chargers for faster charging, and it does not have to be turned a specific way to connect it to the charge port on your phone.
731Changes in decibel is logarithmic in nature. This means that a 20 decibel change could potentially result in a signal loss or signal strength by a factor of 1000 times that amount.
732
733The public IPv4 address space has been exhausted for quite some time now, meaning that all of these addresses have been purchased or allocated, usually by an Internet Service Provider (ISP). Many technical savvy companies have already began the transition to using IPv6, which contains a possible 340 undecillion addresses, or 2 to the 128th power (yes, a lot of addresses). Many, if not all ISPs have IPv6 enabled equipment already in operation.
734
735Static addresses are those that are manually assigned and entered on a device. This will effectively disable DHCP. He should also reserve the IP address in the DHCP pool as good practice, to prevent it from being leased to another device.
736
737LDAP (Lightweight Directory Access Protocol) often works in conjunction with Active Directory to provide user authentication and management in a network. It is the successor to the DAP (Directory Access Protocol).
738This is an enterprise grade solution built off of WPA2 encryption. This disables shared wireless access using one password and requires each user to use unique credentials for access.
739By creating a DMZ (demilitarized zone), you are setting up a subnet of your network that is accessible to outside users typically Internet traffic. A DMZ makes certain services available to external users while denying access to the rest of your network. Services typically segmented by a DMZ could include: email servers, Web servers, and FTP servers.
740Digital Subscriber Line (DSL) is limited to 10,000 feet from the central office for communication and can make use of existing phone lines already in place at your home or business.
741
742ISDN (Integrated Services Digital Network) uses bearer (B) channels to send data and uses D channels for signaling and control.
743Wide Area Networks, also known as WAN, are networks that are connected across long distances, such as city to city or state to state.
744PAN (Personal Area Networks ) are networks designed just for you, typically in a very short range. Connecting your cell phone to your car via Bluetooth, or connecting a set of Bluetooth speakers to your cell phone, would both qualify as a PAN.
745A repeater can re-send the wireless signal into an area that is not covered by the original access point. This would be a good alternative option to buying another access 
746point and can easily repeat the signal onto another floor of a home.
747This is commonly referred to as a Layer 3 switch, as routing decisions work at Layer 3 of the OSI model (network layer) and switches are normally considered Layer 2 devices.
748By plugging in a tone generator at the jack of one end of the cable, you can find the other end by waving a toner probe around the area you think it could be. A loud tone noise will generate when you have found the end of the cable.
749Grounding provides a way to safely transport any excess electrical charges away from the device receiving the voltage. This prevents the electrical spike from causing damage directly to the connected device.
750Using ESD straps and mats will effectively reduce or eliminate the risk of ESD and damaging computer components. The straps and mat work in tandem to balance the amount of static electricity between you and the components.
751For electrical fires, you should always use special dry fire prevention or extinguishing chemicals. Carbon dioxide is one of those chemicals.
752The Occupational Safety and Health Administration (OSHA) oversees and administers the MSDS programs within the United States. Any concerns or comments about the MSDS should ultimately be directed to OSHA.
753For storing active electronic equipment, it is wise to balance humidity levels as best as possible, which will avoid too much condensation or too much static discharge. If in doubt, always consult the material safety data sheet (MSDS).
754When working inside computers or other electrical devices, only specialized vacuums should be used. These devices are specially made so that they do not damage your electrical components.
755The amount of surge a suppressor can handle will be measured in joules. A higher rating in this category will equate to being able to protect more effectively against higher voltages on the line.
756Enclosures are specially made housings for computers in warehouse or factory settings. They protect the computing devices from dust and particles moving around in such an environment.
757
758Your address, first and last name, social security number, date of birth, and employment details can all be considered PII. Your former teacher’s name from high school would not be likely to lead to any personally revealing information.
759With Windows Ultimate and Enterprise editions, as well as Windows 8 and 8.1, BitLocker, allows users to encrypt the entire drive protecting the data from loss or theft.
760When a PC is configured to use Wake-on-LAN, it will power on when a print job is being sent. There is a similar feature available for modems that allows the PC to be powered up when the modem determines a call is being received. This is Wake-On-Ring, often used when PCs are configured to receive Faxes.
761A DHCP (Dynamic Host Configuration Protocol) server is used to automatically configure the parameters needed by a network interface card when a PC is first booted up. It provides central management of IP address allocation.
762The Msconfig utility has a Startup tab that displays the processes launched at startup and allows you to disable any process.
763The Disk Cleanup utility is used to delete temporary files from a hard drive. To perform Disk Cleanup, from Start, enter Disk Cleanup.
764Enter the Recovery Console by pressing F8 during bootup, select the option to Repair your computer, enter your username and password, then choose the option Command Prompt.
765
766When she powered on her computer, it should connect to the DHCP server to acquire an IP address. If the DHCP server is down, her system will assign itself an APIPA address in the range of 169.254.0.1 through 169.254.255.254, then sends a broadcast to ensure no other PC is currently using that address. Unfortunately, the address 169.254.17.200 that her system randomly chose is not on her network so she will not be able to communicate.
767
768The system tool used to verify disk integrity is chkdsk which is run from the system command prompt. When run with no parameters set, it will simply display the disk status, if the /r option is added to the command, chkdsk will locate bad sectors and attempt to recover lost data.
769Windows 7 supports RAID level 0 and 1. Raid level 0 (Striped) writes across both drives simultaneously, which improves drive access. However, the customer needs to know that if one drive fails, he would lose all his data.
770RAID level 1 sets up mirroring, so as data is written to the drive, it is written to both drives. This arrangement allows for fault tolerance at the cost of using twice as much disk space.
771
772If the link integrity indicator does not light up when the cable is plugged in, it indicates there is no connection to the remainder of the LAN.
773If the default gateway goes down, it would not affect the local area network so he would be able to print. However, if the default gateway went down, users would not be able to access the Internet.
774
775The copy command will concatenate (add together) numerous files into a single file. The copy file1.txt + file8.txt + file17.txt filenew.txt will take the contents of file1.txt and file8.txt and file17.txt to create a new file called filenew.txt
776To erase a directory, the command is RD; RMDIR will do the same.
777The command CD (Change Directory) .. (two dots) means the directory above, so ../.. would move you up two directories.
778
779Enabling Time Machine requires using an external storage media, such as an external hard drive or Time Capsule. When enabled, it will perform incremental or historical backups in this manner: hourly backups for the past 24 hours, daily backups for the past month, and weekly backups for all previous months. It’s also important to note that the oldest backups are deleted when your storage becomes full.
780
781The Mac address (Media Access Control) is a 48-bit number (written as a 6-bit hexadecimal number) that uniquely identifies a device on a local area network. The IP address is used to locate the proper network; the MAC address is used to locate the device on the local area network.
782
783A socket number uniquely identifies one end of a communication session between two applications running on a network. A socket number shows the IP address and the port number of one end of a session. For example, 192.168.7.10:23 is a socket number that shows the network address (192.168.7.0) the host address where the application is running, which in the above example is .10 on the 192.168.7.10 network, and the port number of the application, which is delimited with a colon :23. So a socket number locates the network, as well as the host on the network, and the specific application running on the host.
784The subnet mask that defines a full class C network is 255.255.255.0, while a full class B subnet mask would be 255.255.0.0.
785Any software program in which advertising banners are displayed while the program is running is referred to as adware.
786The best practice for the removal of malware is to perform these steps in order: identify malware symptoms, quarantine infected system, disable system restore, remediate infected systems, schedule scans and run updates, enable system restore and educate the end user.
787The master boot record (MBR) is located on the first sector of the hard disk, and contains very important roles for a computer. One of these responsibilities is to begin the process of loading the operating system (OS). If a virus were to find its way into the MBR, it can cause serious issues, such as preventing the OS from loading.
788Restart the system, launch the Console application, and check All Messages for log errors that may indicate the original issue. When a system running Mac OS has a kernel panic, restart the machine and check for any errors that would be indicated in error logs shown in the Console Application
789System File Check (SFC) will verify all system files are working properly.
790The Event Viewer not only displays the events running but also errors, log files, and system warnings, which are all very useful in troubleshooting.
791
792LVM Snapshots, the Linux Logical Volume Manager, performs functions similar to System Restore in Windows.
793BitLocker-to-go works like BitLocker. BitLocker-to-go will encrypt flash drives as well as external drives thereby providing data security on portable devices.
794PPTP (Point to Point Transfer Protocol) is used to implement a secure VPN (Virtual Private Network) across an otherwise unsecure link.
795
796
797
798It is vital to preserve information to maintain the integrity of the collected evidence. If everything is not accurately and timely documented when switching hands, this could come under attack and be thrown out in a serious investigation.
799IPV4=internet protocol version 4 - OSI layer 3 address 
8008 bits=1byte=1 octet, since one byte is 8 bits, the maximum decimal value for each byte is 255, IPV4 is 32 bits in legnth or 4 bytes total
801IPV6=internet protocol 6, 128-bit address, 128bits=16 bytes total-first 64 bits is generally the network prefix(/64)-last 64 bits is then the host network address - groups of zeros can be abbreviated with a double colon ::
802APIPA=Automatic private IP addressing - link-local address, no forwarding by routers - IETF has reserved 169.254.0.1 through 169.254.255.254-first and last 256 addresses are reserved - functional block of 169.254.1.0 through 169.254.254.255 - automatically assigned, uses arp to confirm the address isn't currently in use
803IPV6 link-locacl address=a non-routable local network address, will only work on the local subnet - required on every IPV6 enabled interface, you may see many ipv6 addresses per interface-fe80::/10 with only one subnet allocated ( all zeros) effectievly becomes fe80::/64 - the last 64 bits are usually created with a modified EUI-64
804
805the ingredients for addressing=IP address eg 192.168.1.165(every device needs a unique IP address), subnet mask eg 255.255.255.0 (used by the local workstation to determine what subnet ir's on, the subnet mask isn't usually transmitted across the network, youll have to ask for the subnet mask all the etime, "what's the subnet mask of this network
806default gateway eg 192.168.1.1 is the router that allows you to communicate outside of your local subnet, the default gateway must be an IP address on the local subnet
807domain name system translates human-readable names into computer-readable ip addresses, only need to remember www.google.com - distributed database, many dns servers, 13 root server clusters, hundreds of generic gTLDs (.com .org .net etc), over 275 country code top level domains (.us .uk etc) IP addresses of DNS seervers is provided by the network admin, two addresses for redunancy
808Configuring DHCP where IP address configured used to be static, IP addy, subnet mask,gateway,dns servers,ntp servers etc
809DHCP=Dynamic host configuration protocol - released in 1997 and updated through the years-automatic IP,subnet mask, default gateway 
810CIDR=Classless inter-domain routing - created around 1993, removed the restructions created by classful subnet masks, "Cider" block notation - subnet masks can be expressed as decimal or in CIDR notation (IP address, slash, number of subnet bits; 192.168.1.44/24)
811classless subnetting=youll usually be provided an IP address, subnetmask, default gateway and DNS servers, some operating systems are expecting decimal masks while some areexpecting CIDR notation masks
812TCP=transmission control protocol - connection-oriented, reliable delivery (acknowledgement) - can manage out-of-order messages or retransmissions-loads andunloads the moving truck - checks for out-of-order or missing argo is good example
813UDP=user datagram protocol-connectionless (no acknowledgement) coined unreliable due to this, no reordering of data or retransmissions - loads and unloads the moving truck but doesnt care about out-of-order or missing cargo is good example
814IPv4 with TCP/UDP, server IP address, server app portnumber, client IP, client portnumber 
815non-ephemeral ports=permanent portnumbers, usually on a server or service
816ephemeral port=temporary port number determined inreal time by client workstation
817TCP/UDP port numbers can be any number between 0 and 65,535 - most services use non-ephemeral portnumbers but isnt always the case, just a number
818port numbers are for communication, not security, server port numbers need to be well-known such as port 80 for hTTP traffic
819TCP portnumbers arent the same as UDP port numbers
820FTP=file transfer protocol, uses tcp port 20 (acivemode data ) and tcp port 21 (control) - transfers files between systems
821SSH=secure shell -encryptedcommunication link uses TCP port 22, looks and acts the same as telnet
822Telnet=telecommunication network uses tcp port23 to loginto devices remotely, console access, unencrytped communication, not a safe choice
823email client protocols- receiving mail=pop3 and IMAP4
824SMTP=simple mail transfer protocol - sending emailand server to server email transfer
825DNS converts names to IP addresses - UDP/53
826web browsing protocols communicationin thebrowser and other apps, in the clear or encrypted, 80=HTTP 443=HTTPS(secure)
827RDP=Remote desktop protocol - share a desktop froma remote location over tcp/3389 - remote desktop services on many windows version
828SMB=SERVER message block - protocol used by microsoft windows for filesharing, printer sharing, also called cifs COMMON INTERNET FILE SYSTEM
829AFP=apple filing protocol,fileserverices in mac OS,TCP/548, workswith SLP(servicelocation protocol)
830LDAP=Lightweight directory access protocol - protocol for reading and writing directories over an IP network - an organized set of records like a phone directory-X.500 SPEC WAS WRITTEN by the internet telecommunications union (ITU)
831DAP ran on the OSI protocol stack 
832SNMP=simple network management protocol-gather statistics from network devices
833WEP=Wired equivalent privacy -64 bit or 128 bit key size-WEP cryptographic vulns identified in 2001-deprecated DO NOT USE
834WPA=Wifi protected access - RC4 with tkip(temporal key integrity protocol)-short term workaround for WEP
835WPA2 AES(advanced encryption standard) - replaces TKIP
836WPA2 Enterprise adds 802.1X - auth sever auth - user/password 
837port forwarding=24/7 access to a service hosted internally - web server,gaming server etc - external IP/port number maps to an internal IP also called static NAT or destination NAT - destination address is translated from a public IP to private IP
838port triggering=similar to a port forward, but a trigger is not static say if internal client communicates externally-file transfer/gaming - when service is stopped port is remove- reverse port forward is dynamically created, only one person can trigger at a time, multiple users must use port forwarding
839QoS=quality of service - change priority of your traffice (voice is high, WOw IS LOW ETC)- prioritize apps, ports of MAC addresses - a feature of high-end SOHO routers, could cause apps to slow down if not configured properly
840UPnP=universal plug and play - allows network devices to automatically configure and find other devices - zero configuration - apps on the internal network can open inbound ports using upnp - no approval needed, used for many P2P apps - best practice would be to disable UPnP- only enable if app requires it and maybe not even then
841DOCSIS=Data on the "cable" network - cable modem - high-speed networking 4mbit/s - 250mbit/s or higher on newer docsis networks
842ADSL=asymmetric digital subscriber line - uses telephone lines - download speed is faster than upload speed (assymetric) - 10,000 ft limitation from central office - 24mbit/s downstream 3.3mbit/s upstream
843dialup=network with voice telephone lines - analog lines with limited feequency response - 56kbit/s modems, compression up to 320kbit/s - slow throughput compared to DSL or cable connections - difficult to scale - legacy systems, network utlity - difficult to find a modem nowadays
844Fiber=fiber optics to the home-high speed networking - converged services voice video data - enhanced features, HD cahnnels, 1gbit/s speeds, 1tb cloud storage, 2TB DVR
845satellite networking=communication to a satellite - non-terrestial communication - high cost relative to terrestrial networking - 15mbit/s down, 2mbit/s up - remote locations, difficult to network locations- high latency, 250ms up 250ms down - line of sight so rain can disrupt connection
846ISDN=integrated services digital network - BRI (basic rate interface)  two 64kbit/s bearer (B) channels, one 16kbit/s signaling (D) channel
847Cellular networks are used on mobile devices such as cell phones, seperate land into cells (antenna coverages a cell with certain frequencies communicate) - tethering - turn your phone into wireless router 
848line-of-sight services - visual path between antennas, high frequencies- common in metropolotian areas
849LAN=local area network, local is relative - building or group of buildings, high speed connectivity - likely using ethernet or 802.11 wireless, any slower and it isn't "local"
850WAN=wide area network - spanning the globe or even the neighborhood - generally connects LANs across a distance - generally much slower than the LAN - 
851MAN=metropolitan area network (a network in your city) larger than a LAN but often smaller than a WAN - historically MAN-specific topologies
852PAN=personal area network (bluetooth,NFC,IR) - you own a private network - used in cars or headsets also health monitors etc
853HUB - multiport repeater - traffic going in one port is repeated to every other port - everything is half-duplex (only one device can communicate at one time) - becomes less eddicient as network speeds increase - 10mbit
854Switch=bridging done in hardware - application specific integrated circuit (ASIC)- FORWARDs traffic based on data link addresses (intelligent) many ports and features- the core of an enterprise network, may provide power over ethernet (POE) - multilayer switch which includes routing functionality exists
855router=routes traffic between IP subnets, makes forwarding decisions based on IP address - routers inside of switches sometimes called layer 3 switches - often connects diverse network types - LAN WAN COPPER FIBER
856WAP=Wireless access point - not a wireless router, WAP is a bridge - extends the wires network onto the wireless network - makes forwarding decisions based on MAC address
857modem=modulator/demodulator - converts analog sounds to digital signals - need a modem on both sides of connection - uses standard phone lines (limited frequencies, limited bandwidths) POTS (plan old telephone system), ASDL used nowadays
858Firewalls=filters traffic by TCP or UDP port numbers - some firewalls can filter applications-can encrypt traffic into/out of the network  to protect your traffic between sites - can proxy traffic (a common security technique)-most firewalls can be routers, usually sits on the ingress/egress of the network
859patch panels=combination of punch-down blocks and RJ-45 connectors, runs from desks are made once (permanently punched down to patch panel) patch panel to switch can be easily changed - no special tools and use existing cables
860copper line drivers and extenders - extend the range of copper wire well beyond normal ranges - serial links or copper ethernet used inside and outside of data centers - powered device required power supply, regenerates the signal - troubleshooting
861PLC=Power-line communication - may be marked as ethernet over power EOP - 500 megabits per second 
862POE=Power over ethernet - power provided on an ethernet cable-one wire for both network and electricity-phones cameras WAP - power provided at the switch, built-inpower=endspans - in-line power injector=midspans - mode a = power on the data pairs - mode b=power on the spare pairs
863cable crimpers are used to pinch the connector onto a wire (coaxial, twisted pair, fiber) - connect the modular connector to the ethernet cable - metal prongs are pushed through the insulation permanently pressed into connector
864multimeter is used to measure AC/DC voltages ie wall outlets - also used for continuity
865toner probe= follow the tone given off by wire follow the tone, tone generator puts an analog sound on the wire - inductive probe doesnt need to touch the copper, hear through a small speaker
866loopback plugs are useful for testing physical ports 
867punch-down tools punch a wire into a wiring block (66 or 110 block), trims the wires during the punch
868wireless analysis - wireless networks are incredibly easy to monitor-purpous-built hardware or mobile devices add-on 802.11 - identify errors and interference
869
870Laptop expansion options
871ExpressCard - laptop expansion device - easy to add and remove - 34mm and 54mm wide, 54mm slot also accepts 34mm cards - ExpressCard /34-/54 - 480mbit/s (usb 2 mode), 5.0gbit/s (usb 3 mode) 2.5gbit/s (PCIe mode)
872SSD hard drives come in 2.5 inch and 1.8 inch form factors-silent, no moving parts, less latency
873smart card reader can be integrated into laptop or using an external USB readr
874POST=Power on self test - test major system componets before booting the operating systems, CPU CMOS RAM GPU etc, failurs usually noted with a beeps or codes
875power supply tester - check the power without the motherboard load, quick red/green light diagnostics, LCD panel can show voltages
876POST card- detailed diagnostics during POST, LED numbers and letters
877S.M.A.R.T. = self monitoring, anonlysis and reporting technology use third-party utilities to detect hard drive health and errors
878CHKDSK /f runs a program to fix errors on hard drive
879CHKDSK /r locates bad sectors and recovers readable information
880defragmentation moves file fragments so they are contiguous - omproves read and write time 
881MBR=master boot record - the first sector of first hard drive - usually 512 bytes, contains table of primary partitions, disk signature, directions for starting the OS
882BOOTREC command can repair the MBR - bootrec /scanos - scan disks for windows installations - bootrec /fixboot writes a new boot sector - - bootrec /rebuildbcd creates a new boot config data store 
883DISKPART can make changes to HD partitions
884PING=test reachability - determine round-trip time, uses ICMP (INTERNET CONTROL MESSAGE PROTOCOL) 
885TRACERT = determine the route a packet takes to a destination - map the entire path - traceroute on POSIX style OS
886NETSTAT=Network statistics
887NBTSTAT=Netbios over TCP/IP 
888NETDOM=manage active directory 
889NSLOOKUP=lookup information from DNS servers - canonical names, IP address, cache timers etc
890DIR=list files and directories 
891DEL=DELETE FILE OR DIRECTORY
892MD=MAKE DIRECTORY
893CD=CHANGE DIRECTORY
894RD=REMOVE DIRECTORY
895COPY=copy file /a /v (verifies that the new files are written correctly) /y (skip override prompt)
896XCOPY=copries files and directory trees
897ROBOCOPY= robust copy - a better version of XCOPY included with win7 and win 8/8.1 
898TASKLIST/TASKKILL= manage tasks from the command line to view and end tasks 
899SFC=Scan integrity of all protected system files
900SHUTDOWN=shut down the computer
901EXPAND= windows stores files ina file "cabinet" .CAB files, the EXPAND command is used to remove files from the cabinet or extract files
902Apple's Thunderbolt 3 protocol uses the USB-C connector type. Thunderbolt 3 is also compatible with USB-C, so a Thunderbolt 3 port will work with both a Thunderbolt 3 and USB-C connector. Similarly the Thunderbolt versions 1 and 2 use a standard Display Port connector.
903Hubs are not intelligent enough to route packets to their destination. Instead they broadcast any data they receive out of every port (except the port they receive it on). Hubs cause large amounts of unnecessary packets that will clog a network.
904The CMOS battery (complementary metal-oxide semiconductor) is a small battery that provides power to a motherboard while it is powered off. This power source is used to store the BIOS configuration data (but not the BIOS firmware itself) and powers the Real Time Clock (RTC).
905SFTP (SSH File Transfer Protocol) is a protocol for securely uploading files to a remote server. SSH alone is not enough to upload a file and is incorrect. SSH provides the encryption & authentication but does not meet the requirement to upload a file. As SFTP builds upon SSH with functionality for file upload it is the correct answer.
906After a printer applies toner to paper the fuser assembly rolls over the paper and applies heat to fuse the toner to the paper. Occasionally, the toner can stick to the fuser assembly and will be applied to the next sheet of paper passed through the printer.
907POP3 (Post Office Protocol) uses TCP 110 to communicate.
908Lightweight Directory Access Protocol (LDAP) is an open-standard protocol used to query directory based databases such as Active Directory. LDAP uses TCP 389 by default.
909Power-line communication will allow a SOHO network to be built using ethernet power adapters which is much cheaper than running cable. Power-line communication allows the use of the ethernet protocol over electrical power wiring. If the company doesn't want employees working from home to use wireless networks or to pay the expense of running ethernet from the modem to the office then power-line is a cheap alternative.
910
911Dots per Inch (DPI) is the standard measurement used for printers. It refers to the amount of dots that are placed by the printer in a one inch space. This is similar to Pixels Per Inch (PPI), which is used to measure how many pixels are placed in an inch by a monitor or screen. Aspect/Contrast Ratios are used to compare height and width of paper, monitors, etc. For example 4x1 would be 4 height for every 1 width - this could be 400x100 or 800x200.
912TPM (Trusted Platform Module) is a standard cryptoprocessor used to store cryptographic keys
913If using a daisy chain IEEE 1394 (FireWire) can support up to 63 devices at one time.
914
915902  NOTES
916
917Windows vista released jan 30, 2007 - uses Aero GUI, integrated search-UAC(User account control, prompt for auth)-