Version 3 Updated 01/01/2015

CompTIA A+ Certification 220-801 Exam Notes

Features a l l exam-relevant information from the Professor Messer v ideos, the Mike Meyers CompTIA A+ Cert i f icat ion Al l - in-One Exam Guide, 8th Ed. , Sk i l l soft , Wraysoft , Transcender Test Engine, S imulat ionExams, and E l i the Computer Guy v ideos.

Contents HARDWARE ............................................................................................................................................................................ 3

BIOS ................................................................................................................................................................................... 3

Motherboards .................................................................................................................................................................... 4

Form Factors .................................................................................................................................................................. 4

Power Supplies .............................................................................................................................................................. 5

Expansion Slots .............................................................................................................................................................. 7

Busses & Chipsets .......................................................................................................................................................... 8

CPU .................................................................................................................................................................................... 9

Types and Sockets ......................................................................................................................................................... 9

CPU Operation ............................................................................................................................................................. 12

RAM ................................................................................................................................................................................. 14

Storage Devices ............................................................................................................................................................... 16

Hard Disk Drive Operation ........................................................................................................................................... 16

PATA Drives ................................................................................................................................................................. 17

SATA Drives .................................................................................................................................................................. 18

SCSI Drives ................................................................................................................................................................... 19

Implementing RAID ...................................................................................................................................................... 20

Optical Formats ........................................................................................................................................................... 21

Flash Memory .............................................................................................................................................................. 22

External Connection Types .............................................................................................................................................. 23

Designing Custom Computer Systems ............................................................................................................................. 25

Display Devices and Connections .................................................................................................................................... 25

Display Devices ............................................................................................................................................................ 25

Display Connectors ...................................................................................................................................................... 29

Computer Peripherals ...................................................................................................................................................... 30

NETWORKING ...................................................................................................................................................................... 31

Network Connectors & Cabling ....................................................................................................................................... 31

TCP/IP .............................................................................................................................................................................. 34

IP .................................................................................................................................................................................. 35

2 | P a g e

TCP ................................................................................................................................................................................... 38

Wireless Networking ....................................................................................................................................................... 40

Wireless Standards ...................................................................................................................................................... 40

SOHO Configurations ................................................................................................................................................... 42

Internet Connection Types .............................................................................................................................................. 43

Network Types and Topologies ....................................................................................................................................... 45

Network Devices .............................................................................................................................................................. 46

Networking Tools ............................................................................................................................................................. 48

LAPTOPS .............................................................................................................................................................................. 49

Laptop Expansion Options ............................................................................................................................................... 49

Laptop Features ............................................................................................................................................................... 51

Laptop Displays ................................................................................................................................................................ 52

PRINTERS ............................................................................................................................................................................. 52

Laser Printers ................................................................................................................................................................... 52

Inkjet Printers .................................................................................................................................................................. 54

Thermal Printers .............................................................................................................................................................. 55

Impact Printers ................................................................................................................................................................ 56

Installing and Configuring Printers .................................................................................................................................. 56

OPERATIONAL PROCEDURES ............................................................................................................................................... 57

Computer Safety Procedures ........................................................................................................................................... 57

Environmental Controls ................................................................................................................................................... 58

Communication and Professionalism .............................................................................................................................. 58

3 | P a g e

HARDWARE BIOS

BIOS (Basic Input/Output Services) o Lets the CPU understand the codebook for an attached device in order to communicate with it o Usually 2MB in size

Option ROM = BIOS information stored on outside devices that are not part of the system BIOS. Usually it is a chip on a piece of hardware.

Device drivers have largely replaced the Option ROM, with the exception of video cards o Virtual machines are controlled by the BIOS o The RTC (Real Time Clock) is a chip that stores BIOS clock information

CMOS (Complementary Metal-Oxide Semiconductor) o Chip that stores system settings o Battery is known as the clock battery o Now built into the Southbridge o Resetting is useful for hardware compatibility issues

Additionally, using a jumper or choosing the default configuration option in the setup utility will reset the BIOS

o To overclock a CPU in CMOS setup utility, go to the CPUID value under Performance Alternatively, some BIOS software offers M.I.T (MB Intelligent Tweaker) that is used to

overclock on some systems o Disable writing to boot sector to prevent certain viruses from writing to it

POST (Power On Self-test) o In POST:

1. BIOS is initialized and checked 2. CPU registers are verified 3. Size of RAM, and its integrity are checked 4. System devices are checked and initialized 5. Boot device with highest priority is selected and MBR is executed

o POST card is needed if BIOS POST doesnt work TPM (Trusted Platform Module)

o Used for cryptographic acceleration (i.e. BitLocker Drive Encryption) DRM (Digital Rights Management) for network access and control

ACPI Power States o Full On = no power management o ACPI Enabled = only the unused devices are shut down o ACPI Standby = CPU is stopped o ACPI Suspend = Hibernation mode o GO (SO) = working state o G1 (Sleeping state mode)

S1: computer is on, monitor is blank S2: computer is on, processor is off S3: computer is off, RAM is on (sleep mode) S4: RAM contents are copied to hard drive, then computer is turned off

o G2 (Soft power mode) o G3 (Mechanical off mode)

4 | P a g e

Motherboards Form Factors

AT o 12 x 13 o Original motherboard, used throughout the 1980s and into the 1990s o Only had a keyboard connector o P8/P4 split power socket o Includes Baby AT (BAT)

LPX (Low Profile Extended) NLX

o Goes into a riser card o Low end systems o 8 x 10 to 9 x 13.6 o Largely replaced by microATX

ATX (Advanced Technology Extended) o Improved cooling by placing the CPU and memory in-line with the PSU fan o Standard ATX

12 x 9.6 20 or 24 pin power connector (24 pin for more graphics/high end processing) Maximum of seven expansion slots

o microATX 6.75 x 6.75 to 9.6 x 9.6 Limited expansion slots 4 DIMM slots Backwards compatible Can possibly be used for an HTPC, but Mini-ITX is better due to low power requirements

o Mini-ATX = 5.9 x 5.9 o FlexATX

For customized systems 9 x 7.5 Has its own power supply, even though ATX ones work

SFX12V Standard power supply ITX

o Mini-ITX: 6.7 x 6.7 (used in HTPCs) 2 DIMM slots

o Nano-ITX: 4.7 x 4.7 o Pico-ITX: 3.9 x 2.8 o Mobile-ITX: 2.4 x 2.4 o Low power, less fan noise o For small form factor o Less expandable o Fits with ATX cases

BTX o Made in 2004 o Cant fit in ATX case, but can use ATX power supply o Designed to optimize airflow by placing the CPU at the front of the motherboard to receive

more cool air coming in from the front of the computer case In nonintegrated motherboards, each component is in an expansion slot Old motherboards used jumpers to determine the bus speed

5 | P a g e

Case fans o Motherboard layout must be efficient o Fan sizes include 80mm, 120mm, and 200mm

Standouts are metal connectors that attack the motherboard to the case NIC is integrated on the motherboard

o Contains a link light that indicates network status Solid green = connectivity Flashing green = intermittent connectivity No green = no connectivity Flashing amber = collisions on network

Power Supplies A power supply converts AC (Alternating Current) from the wall to DC (Direct Current) that the PC can

use o Provides three rails: 3.3V, 5V, and 12V o Onboard electronics use 3.3V and 5V rails o Hard drives and optical drives (or anything with a motor) use 12V rails o AC = direction of current constantly reverses and distributes electricity efficiently over long

distances Represented by squiggly line A multimeter or circuit tester can be used to test AC output

Red = hot, black = ground o DC = current moves in one direction with a constant voltage

Represented by solid black line over a dotted black line Has polarity

o USA/Canada: 110 to 120 volts @ 60 Hz (~115V) o Europe: 220 to 240 volts @ 50 Hz (~230V) o Sag = when the voltage drops bellow 115/230 o Spike/Surge = when the voltage jumps above 115/230 o Some power supplies have cables built in, others just have the option to connect, but no cables o Power supplies may have a 115V and 230V switch (switching power supply)

Electricity = the flow of negatively charged particles through matter Ampere (A) = the rate of electron flow/current (1A = 6.242x1018 electrons per second) Voltage (V) = electrical pressure pushing electrons (like a garden hose) Watt (W) = measurement of real power usage

o Volts x Amps = Watts o Also known as Work

Resistance = friction that resists the flow of electrons Inverter = DC to AC Rectifier = AC to DC Transformer = ratio of voltage to current Circuit Breaker = detects heat and is rated at a certain amperage. It stops flow of electricity if it gets too

hot Power Conditioner = protects from RFI (Radio Frequency Interference) and EMI (Electromagnetic

Interference) Surge Suppressor = protects from spikes/surges

o Spikes are diverted to ground o Will also filter out line noise (high dB is better) o Energy measured in Joules (200, 400 are good, but look for 600 as that is best) o Higher amp ratings are better

6 | P a g e

o Complies with the UL 1449 standards o Ratings at 500, 400, and 330 volts (lower is better)

UPS (Uninterruptable Power Supply) = contains a battery and uses AVR (Automatic Voltage Regulation) to protect against brownouts and blackouts

o Come in three different types: Online: always powered by the battery Standby: battery is only used when power sags below 80-90V Line-interactive: contains special circuitry to handles sags without the use of the battery Features of a UPS include auto shutdown, battery capacity, outlets, and phone line

suppression Any outlet must be grounded in order to be suitable for PC use

The golden rule is to use 33% more power than required for a computer system o Power supplies never run at 100% efficiency, but rather 80%

Power Supply Dimensions = 150mm x 140mm x 86mm Power supplies usually come with the motherboard case Power supplies are a FRU (Field Replaceable Unit)

o FRUs are what every technician should have that is immediately accessible o Hard drives and RAM are also FRUs

Active PFC = Built into some PSUs, it is a method of including extra circuits to eliminate harmonics and smooth overall electricity flow

o Harmonics = back pressure from electrical current that creates a humming noise o Active PFC provides environmentally friendly power

Motherboard Power Supply o Has a 20-pin or 24-pin P1 power connector o Power supplies supply the motherboard 5V at all times o AMD CPUs used Aux power connections while Intel used P4 o Uses Molex connectors

Molex makes the standard 4-pin power connector used to power peripherals Red wires are 5V and yellow wires are 12V

Does not provide 3.3V o ATX12V Standard

Included the P4 power connector to provide dedicated power to a high-end CPU Included a 6-pin Aux connector to supply additional 3.3V to 5V to the motherboard

o ATX12V 2.0 Standard Included a 24-pin power connector, but extra 4-pins detached for backwards

compatibility in v2.1 (v2.2 did not have the detachable feature) Extra 4-pins gives an extra 12V Included SATA power connectors

o EPS12V Standard Used for servers Provided a 24-pin power connection Included an Aux, P4, and an 8-pin connector for the CPU

o TFX12V Standard was used for low profile ATX systems o SFX12V Standard was used for Flex-ATX systems o The 6/8-pin Aux PCIe power connector increases the power consumption limit for devices

6-pin increases to 75W 8-pin increases to 150W

o The 4/8-pin Aux power connecter is used to supply dedicated power for a high-end CPU

7 | P a g e

Expansion Slots PCI

o Capable of running in sync with system clock o Uses parallel communication o Had a burst mode feature that allowed more efficient data transfers o 2 IDE controllers on a standard motherboard o PCI Speeds:

133 MB/s (32-bit at 33 MHz): 5v 266 MB/s (32-bit at 66 MHz or 64-bit at 33 MHz) 533 MB/s (64-bit at 66 MHz): 3.3v

o 64-bit expansion slots are bigger but more rare than 32-bit ones o If a PCI card has a 32-bit data transfer, there will equivalently be 32 wires to make the

connection Mini-PCI = for laptops, not multipurpose like regular PCI PCI-X (PCI eXtended)

o Designed for servers o 4x clock speed of regular PCI (1064 MB/s) o Mainly 64-bit slots, but 32-bit also exists o PCI-X 2.0:

PCI-X 66 (66 MHz) PCI-X 133 (133 MHz) PCI-X 266 (266 MHz) PCI-X 533 (533 MHz)

AGP (Accelerated Graphics Port) o Graphics slot before PCIe o Can be thought of as a PCI slot with a direct connection to the Northbridge o Parallel communication o Uses strobing

Increases signals 2, 4 and 8 times per clock cycle o Uses Pipelining commands (just like the CPU) o Uses sidebanding

A 2nd data bus that sends commands directly to the Northbridge while receiving other commands at the same time

o Uses system memory access If onboard VRAM is full, it is allowed to steal chunks from the system RAM

o Dark brown and shorter than PCI o AGP Types:

AGP 1x (266 MB/s) AGP 2x (522 MB/s)

AGP 1.0, 3.3v AGP 4x (1.07 GB/s)

AGP 2.0, 1.5v AGP 8x (2.1 GB/s)

AGP 3.0, 0.8v PCI Express (PCIe)

o Has individual/unidirectional serial lanes so it doesn't slow down the system o Point-to-point serial communication (instead of PCIs shared parallel)

Direct connection to the Northbridge o Uses a 6-pin (75 watts) or 8-pin (150 watts) power connector o Comes in different forms: x1, x2, x4, x8, x16, x32

8 | P a g e

x1 is for general purpose x16 is the most common and used for video cards

o Duplex lanes (two per "x[]") One wire to send, one wire to receive

o Supports AGPs and system memory access o Up to 16 GB/s o Per lane throughput:

v1.x = 250 MB/s (2.5 Gbps) v2.x = 500 MB/s (5 Gbps) v3.0 = 1 GB/s (8 Gbps) v4.0 = 2 GB/s 16 (Gbps)

o Yellow colored, vary in size depending on number of lanes o PCIe Mini exists for mobile devices

Has a 52-pin card edge ISA = legacy, black, 2 sections, up to 8 MB/s AMR/CNR

o No longer in use (legacy) o AMR was for AMD motherboards exclusively o CNR was for Intel motherboards exclusively o For modems, soundcards, and network cards o Small yellow expansion slot

Riser cards are also known as daughterboards o Usually dark brown o 1/3 the size of a PCI slot

The expansion bus is not in sync with the system clock, but instead has a different speed that is set by the expansion bus crystal

o Runs slower than the front side bus, so the chipset compensates for this with wait states and buffering areas

Missing expansion slot covers can cause a PC to overhead because it disrupts the airflow inside the case Steps for installing an expansion card:

1. Knowledge Does it work with the PC and the operating system?

2. Physical Installation Grab card at edges and do not touch the contacts Wear an anti-static wrist strap Cleaning is a bad idea

3. Device Drivers Install the card first Better idea to install the drives that came with the disk, rather than going through the

Add Hardware Wizard 64-bit drives must be approved by Microsoft in Vista and Windows 7

4. Verify To ensure that the card is working, send it through a test run

Busses & Chipsets Front Side Bus (FSB) connects CPU and Northbridge

o Composed of the address bus and the external data bus o Controlled by system clock, 66-333 MHz o Connection between CPU and memory controller o 1333 MHz or 1.33 GHz max speed

9 | P a g e

Double pumping = sending instruction on rise and fall of clock signal, multiplying data transfer rate by 2

Quad pumping = sending instruction on the rise, fall, and midway points, multiplying data transfer rate by 2 CPU and MCC send 64-bits of data 2-4 times per clock cycle @ 400 MHz

Back Side Bus (BSB) connects CPU to CPU cache (usually L2) o Same clock rate as the CPU

Bus Architecture o Bus Width = 8 64 bits o Address Bus sends commands to all motherboard-connected components (analogy: envelope) o External Data Bus sends data to all the motherboard-connected components (analogy: contents) o High-Speed Graphics Bus connects Northbridge to Graphics Adaptor Slot o Memory Bus connects Northbridge to Memory Banks o Internal Bus connects Northbridge to Southbridge o PCI Bus connects Southbridge to Onboard Graphics Controller & also the PCI Expansion Slots o Low Pin Count (LPC) Bus connects Southbridge to Flash BIOS ROM and Super I/O

Intel and NVIDA are the two biggest chipset manufactures Northbridge = Memory Controller Chip (MMC)

o Needs heat sink, possibly fan o Modern CPUs do the function of the Northbridge, so they are no longer found

Southbridge = I/O Controller Hub (ICH) for Intel or Fusion Controller Hub (FCH) for AMD o Connects lower speed devices such as USB, FireWire, SATA, NIC, etc o Onboard graphics controller has a Southbridge connection

Super I/O (Serial & Parallel Port Control, Floppy Drive Control, Keyboard & Mouse o Separate chip from Southbridge

Jumpers o Both pins covered = shorted o Un-jumpered is both not covered o Alt-jumped = more than two-pins and moving the cap to a different set of pins o Cable Select (CS) = determines master and slave positions of drives

Common with ATA 66/100/133 cables Needs a special cable with a pinhole through one wire

Clock Speed = how much data is passing per second o Computer clock speed refers to the CPUs operating speed o Clock/bus speed doesn't equal data transfer rates o Local bus: in sync with system clock

The system crystal sets the data speed for the entire motherboard Thus every chip that connects to the motherboard will have a CLK wire

CPU

Types and Sockets CPU Types (not specifically listed in 220-801 exam objectives, but useful to know for socket questions)

History of Intel CPUs History of AMD CPUs

Pentium 60 233 MHz

64-bit data bus, 32-bit address bus

Pentium Pro

K5 Competitive with Pentium 75-133MHz 246-pin PGA

10 | P a g e

36-bit 150-200 MHz

Pentium II

Used SECC instead of PGA Slot 1

Celeron 266 MHz

Pentium III

PGA 370-pin

Up to 1.4 GHz

Pentium IV Fast FSB

PGA 423-pin or 478-pin

Up to 3.8 GHz

Pentium M For laptops Socket 479

Pentium D

Featured two cores 2.8 3.2 GHz per core

Pentium EE

Only worked with Intel 955x or NVidaForce4

Intel Core

De-emphasized clock speed and focused on speed of FSB, L2 Cache, and IPC

Featured Core and Core 2 (Duo, Quad, and Extended)

Nehalem 256-bit L2 cache, 12 MB L3 cache

2, 4, or 6 cores (i3, i5, i7) Sandy Bridge

i3 3MB L3 cache, turbo boost disabled i5 6MB L3 cache

i7 15MB L3 cache, 3.3-3.9 GHz Operated on LGA 1153

K6 Competitive with Pentium II 166-550MHz 296-PGA Introduced 3D NOW K7 (Athlon) 560 MHz to 1.4 GHz Athlon XP (competitive with Pentium 4) 1.3-2.16 GHz Duron (Celeron) 600 MHz to 1.8 GHz K8 (Athlon 64) Sempron (1.8 to 2.6 GHz w/ L2 cache of 250 KB) Turion (1.8 to 2.4 GHz) K10 (Athlon X2) 1.9-2.9 GHz 2MB L3 cache Athlon II X2 (3 GHz) Phenom (1.8-3.3 GHz 3-core)

CPU Sockets

Intel AMD

LGA 775 Also called Socket T

Used in Pentium 4, Intel Core 2 Duo, Xeon, and Celeron processor

Supports DDR2/DDR3 memory

LGA 1366 Also called Socket B

Replacement to LGA 775 Used in Intel Core i7 (Nehalem)

Supports DDR3 (triple-channel) memory

LGA 1156 Also called Socket H1 or simply

Socket H

Socket 940 PGA, ZIF package Used in Opteron and Athlon 64 FX Designed for 64-bit servers Support for DDR memory Socket AM2 940 pins PGA, ZIF package No backward compatibility with Socket 940 Used in Athlon 64 (FX, X2) and Phenom Xx Supports DDR2 memory Athlon 64 X2 will have limited capabilities if used with Socket 940 Socket F

11 | P a g e

Also replaces LGA 775 Used in Core i3/i5/i7 (Nehalem)

First CPU types to integrate Northbridge on the CPU

Supports DDR3 (dual-channel) memory

LGA 1155 Also called Socket H2

Used in Intel Sandy Bridge and Ivy Bridge microprocessors (Core i3/i5/i7) Not compatible with LGA 1156

Supports DDR3 (dual channel) memory

1,207 pins LGA package Designed for servers Used in Athlon 64 FX Supports DDR2 memory Faster throughput to FSB Socket AM2+ 940 pins PGA, ZIF package Backwards compatible with Socket AM2 (may need BIOS upgrade) Faster communication than Socket AM2 and better power management Socket AM3 940 pins PGA, ZIF package Backwards compatible (with BIOS upgrade) Used with Athlon II/Phenom II Support for DDR2/DDR3 (dual channel) memory Socket AM3+ 942 pins PGA, ZIF package AM3 processor can fit in socket, but not the other way around Used with Athlon II/Phenom II Support for DDR2/DDR3 (dual channel) memory Socket FM1 905 pins PGA, ZIF package Used with A-Series processors/ Athlon II Supports DDR3 (dual-channel) memory

Socket form factors o DIP = Dual In-line Package

Intel 8088 Old, difficult to install

o SECC (Single Edge Contact Cartridge) Intel Pentium II Slot 1 Looks like an expansion card, easier to install Took up a lot of room due to heat sinks

o PGA (Pin Grid Array) - pins on CPU Intel Pentium III Socket 370

o ZIF (Zero Insertion Force) socket o LGA (Land Grid Array)

Reverse PGA (pins on motherboard, so easier to damage the motherboard) Intel Pentium 4, AMD Opteron, Intel Sandy Bridge (i3, i5, i7), Ivy Bridge

12 | P a g e

CPU Operation

Reference signal, otherwise known as the bus speed or system speed, is the signal entering the CPU o CPU speed is thus how many times faster it is than the reference signal

MMX and SSE are new CPU registers for streaming Pipelining (CPU processing stages)

1. Fetch = CPU pulls data from the EDB 2. Decode = CPU finds a command to execute 3. Execute = CPU performs the calculation 4. Write = CPU sends the result of the calculation back to the EDM o Sub processors to do different types of calculations

ALU (integer unit) handles basic math calculations and comparisons FPU (floating point unit) handles complex numbers

Parallel Execution = executing multiple commands in parallel o Useful when running many programs at once o Dual core processors use third-level parallelism (TLP) o The CPU will run multiple pipelines simultaneously

Cache memory o Small amount of SRAM built into the CPU

System RAM is too slow, CPU needs RAM that is more accessible Having CPU cache memory greatly reduces pipeline stalls

o Very fast o Holds data, instructions, or results o Cache Levels:

Level 1 = smallest and fastest Data is stored as it waits to be processed, on the CPU

Level 2 = larger and slower Located off the CPU

Level 3 = largest, slowest Located off the CPU, between the L2 cache and system memory

Hyperthreadding (HTT) o Takes one CPU and makes it look like two CPUs o Doesn't work as fast as two, but performance increase is 15% to 30% o Rule is two virtual cores for every physical core

How a CPU works:

There is an External Data Bus (EDB) that sends data all around the computer. The EDB meets the CPU at its pins and goes into the CPU. Voltage is applied to certain pins to indicate if that pin is on (1) or off (0). This data of on/off wires from the EDB is stored in the internal CPU Registers (Ax, Bx, Cx, Dx) where charges from EDB are stored. Once data is in CPU registers, it is processed thanks to a thing called the Instruction Set, where these 8-bit (or more) lines of code consisting of 1s and 0s are made into language that the CPU can understand. A Clock Wire (CLK Wire) has voltage applied to which tells the CPU to process the next set of instructions. Voltage applied per second is determined by the Clock Chip, which gives the CLK Wire voltage. The system crystal (quartz oscillator) is responsible for sending out pluses of electricity in the first place. Thus the Clock Speed is the number of processes the CPU makes per second, all determined by the amount of pulses sent by the Clock Chip. Then it can be understood that Overclocking is simply manually setting the Clock Chip to send pulses faster than the designated CPU speed. Old processors like the Intel 8088 required careful calculations to make sure the motherboard provides the correct Clock Speed it needs, but todays CPU tells the motherboard the Clock Speed it needs, and the Clock Chip automatically adjusts.

13 | P a g e

o OS must be written for HTT (Windows XP or later) o Form of simultaneous multithreading (SMT)

Throttling = running CPU at a lower voltage to reduce heat and energy o Demonstrated by Intels SpeedStep

CPU runs at low power until higher power is needed Used in mobile processors often

Overclocking = running at a higher voltage and speed to improve performance Virtualization = running more than one OS on a machine

o Introduced in Pentium 4s, used VT-X (Intels virtualization) o AMDs Virtualization is AMD-V o Page table virtualization with RVI o Hypervisor is a software program designed to manage multiple operating systems on a single

computer Math co-processor = used to perform additional complicated processes Graphics processing Unit (GPU)

o Latest CPUs have the GPUs integrated on the chip o Also called APU o GPGPU = helps process algorithms in parallel with CPU

Only for non-graphics applications Multicore processors requires less space and generate less heat than multi-processor systems

o Cache memory and RAM are shared IRQ Codes = Lets a device interrupt the CPU from what it is currently processing to instead process what

that particular device is requesting PIO (Programmable Input/Output)

o Programmed instructions guide data across the correct data path o CPU talks to peripherals via BIOS to send/receive o CPU must interpret these instructions, so it slows the system down considerably

DMA (Direct Memory Access) = Moves data directly to and from the RAM without any CPU intervention by use of a controller.

o Third-party DMA = requires a controller (the third party) that is shared by multiple peripherals and integrated into the chipset to move data between a device (first party) and the RAM (third party).

Slowest mode of DMA o First-party DMA (Bus Mastering) = improves speed by using only half the bus cycles of PIO or

third-party DMA. The DMA controller will take over the system bus and notify the CPU when the data transfer is complete.

CPUs can now house processor cores, memory controller, and graphics processing unit (GPU) CPU Cooling:

o Heat sink Thermal grease is designed to keep a good connection between CPU and heat sink

o Liquid cooling For high end systems, gaming PCS, and overclocked PCS

o Phase-change cooling o Liquid immersion o Heat Pipe

Hollow pipe where liquid coolant is in the pipe No moving parts, but ineffective above certain temperatures

14 | P a g e

RAM When a file is opened, it gets taken from the hard drive and copied to RAM, and then once it is finished,

the same data, now updated, gets copied back to the hard drive. o RAM acts as a buffer for data between hard drives and CPU

RAM stores bytes in rows (8 bits per row) in which the MCC grabs and puts it on the EDB for the CPU to process.

32-bit systems = 4GB max 64-bit systems = 17 billion GB max (128GB limit that Windows puts on machines) Volatile = not permanent, requires electrical current Better to use a larger stick than multiple smaller ones Bandwidth = "width" of memory bus

o Bytes transferred per clock cycle o Memory bandwidth = 8, 16, 32, 64 bits

Width of memory module Virtual Memory = allows the use of hard drive space as memory

o A page file is stored on a block of cylinders on the hard drive to make this work Page file size is always 1.5 times the amount of installed RAM File is called PAGEFILE.SYS located in root directory C: and hidden

2 slots = 1 bank RAM Types

o Read Only Memory (ROM) PROM (Programmable ROM)

Write once EPROM (Erasable PROM)

Write/Erase/Write Again EEPROM (Electrically Erasable PROM)

Flash memory o SIMM (Single In-line Memory Module)

30 & 72 Pin Not all follow the standard/not swappable

o DIMM (Dual Inline Memory Module) 64 bit data width = more info per clock cycle Include SDRAM, DDR, DDR2, and DDR3

o RIMM (Rambus Inline Memory Module) 16 bit (184 pins) and 32-bit (232 pins) Holds RDRAM Generates a lot of heat and is expensive Every slot must be filled, even if you need to put blank modules such as:

32-bit: Continuity and Termination RIMMs (CT-RIMM) 16 bit: Continuity RIMMs (C-RIMM)

o SRAM (Static RAM) Very fast, very expensive Used in processor caches (L1, L2, L3) Don't refresh, but still volatile

o DRAM (Dynamic RAM) Dynamic = needs constant refreshing Uses additional electricity which slows speed

o SDRAM (Synchronous DRAM) 168-pins

15 | P a g e

Clock Speeds: 66, 100, or 133 MHz Data Transfer Rates: 528 MB/s 1.1 GB/s Synchronous with system clock Labeled with same speed of memory clock bus: ( ie: 133 MHz = PC133) 3.3V

o RDRAM (Rambus DRAM) 189-pins Clock Speeds: 300 800 MHz Data Transfer Rates: 1.2 GB/s 6.4 GB/s Introduced with the 400 MHz FSB Pentium 4 Expensive, third party, uncommon

o DDR SDRAM (Double Data Rate SDRAM) 184-pins Clock Speeds: 100 250 MHz (double pumps) Data Transfer Rates: 1.6 4 GB/s NOT synchronous with system clock 2.5V

o DDR2 SDRAM 240-pins Clock Speeds: 200 500 MHz Data Transfer Rates: 3.2 8.3 GB/s Buffers (4-bits) were added to increase I/O circuits on chips, effectively clock doubling

them Latency was thus increased

1.8V o DDR3 SDRAM

240-pins but wont fit into DDR2 slot (different notch locations) Clock Speeds: 400 800 MHz Data Transfer Rates: 6.4 12.8 GB/s Twice the buffer size of DDR2 (8-bit) Introduced a feature called XMP (Extreme Memory Profile) which allowed for

overclocking of RAM Also is capable of triple-channel memory

Only supported by Intel LGA 1366 1.5V

CAS (Column Address Strobe/Select) o CL (CAS Latency) = time it takes for electricity to charge wires/pins

Delay between when Northbridge requests data to when it is actually available on the pins

Lower the CL number, faster the data transfer Error checking:

o Parity memory Additional parity bit, won't always detect, can't correct itself Parity Checking = adds an extra bit to every bite

Odd parity = 1 if sum of bits in byte is even, 0 if odd Even parity = 0 if sum of bits in byte is even, 1 if odd

o ECC (Error Correcting Code) Detects errors and corrects them immediately, but operates slower because of this 72-bit RAM is 64-bit RAM with 8-bits for ECC Only found in specialized systems, making it very rare

16 | P a g e

o RAM has a SPD (Serial Presence Detect) chip that tells the OS information about it If the chip is bad the OS will not boot

Single-sided vs. Double-sided memory o Ranks = groups of memory on a module that can be independently accessed o RAM has 8, 16 or 32 chips per module o Single-sided memory = all memory can be accessed at once o Double-sided memory = only one bank at a time

Dual-channel o Started with RDRAM and DDR RAM o Filling up both RAM sockets of the same color with 64-bit RAM will achieve this if the

motherboard/OS supports dual-channel memory o May improve performance, but doesnt make a huge difference over single-channel memory

Mixing RAM speeds is doable, but will certainly lead to system instability o Not even possible if double pumping

Storage Devices

Hard Disk Drive Operation Microscopic magnetized regions on the platter act as 1s and 0s in a sense. Because these regions are

polar, they sometimes switch magnetic fields in what is called a flux reversal. The read/write head is able to identify locations of these flux reversals by identifying the electrical current they give off and thus read data. This process, throughout history, has been done in two ways:

o RLL (Run Length Limited) Any combination of 0s and 1s can be preset into 15 different runs in which the

read/write heads read as a group. Max run length = 7

o PRML (Partial Response Maximum Likelihood) Uses circuitry to make a best guess in determining locations of flux reversals Max run length = 16-20

Perpendicular recording = a method of storing flux reversals vertically in order to increase storage capacity.

Hard drive capacity is determined by the following equation: o (# of cylinders) x (# of heads) x (sectors/track) x (bytes/sector)

Inside a hard disk drive: o Platters several of them, each with their own ID and can be recorded on both sides

Middle of platter is called the spindle Two read/write head per platter (plus a one or two for the drives own use)

o Tracks groups of circles on a platter o Sector 512 bytes, slice-size groups on a platter o Cluster multiple sectors

Smallest file sizes exist here (512 bytes of one sector is too small for a file) o Cylinder tracks of the same diameter on both sides of all platters

One empty cylinder used to be dedicated to a landing zone in which the read/write head would rest on when the drive is not in operation.

o Thus, cylinder on a track, cluster on a track, sector on a cluster o Actuator controls the arm, the arm has the read/write head which reads the data off of the

platter Read/write head doesnt actually rest on the platter, just a hairs thickness above it

17 | P a g e

A stepper motor originally moved the actuator, but proved to misalign over time, causing data transfer errors.

The voice coil currently moves the actuator in hard drives Voice coils uses magnetic fields to move actuator

Seek time the time it takes for read/write head to move from one track to the other HDDs have a cache size of 2-64MB Spindle speed = 5400 RPM 15,000 RPM

o Bay fans fix overheating problems with high RPM drives. Sector translation identifies locations of each block on HDD

o Provided a work around to the BIOS hard drive size limit of 1024/16/63 by having the hard drive tell CMOS its physical geometry when it is really telling CMOS its the logical geometry

o LBA (Logical Block Addressing) for WesternDigital o ECHS (Extended CHS) for Seagate

Master Boot Record (MBR) o On the first sector of the hard drive (512 bytes) o Contains table of primary partitions, disk signature, and directions for starting OS

DriveLock (ATA Security Mode Feature Set) o Located in BIOS, it protects the hard drive from unwanted access

Microdrive (MD) o A miniature 1-inch HDD designed to fit into a CF (Compact Flash) Type II slot

Also called a CF Card Now obsolete

PATA Drives PATA (Parallel AT Attachment)

o Dates back to PC/AT o Built-in controller o Initially intended for hard drives o Blue connectors on the drive are used to set master/slave o 18-inch length limit o 4-pin Molex power connecter o IDE controllers have the IRQ code of 9 o Originally called IDE (Integrated Drive Electronics)

2nd generation EIDE (Enhanced IDE) o IDE, EIDE, and PATA are all interchangeable (they mean the same thing) o Speeds range from 16 MB/s to 133 MB/s

Cable types: o 40-wire

Device 0 = Master (closest to motherboard) Device 1 = Slave

o 80-wire Device 1 = Slave (closest to motherboard) Device 0 = Master Additional 40 wires on 80-wire cable are grounding wires, eliminating cross-talk

ATA Standards o ATA-1: Introduced BIOS compatibility, offered no more that two devices per computer, and used

PIO and Single-word DMA speed methods PIO:

Mode 0 = 3.3 MB/s Mode 1 = 5.2 MB/s

18 | P a g e

Mode 2 = 8.3 MB/s Single-word DMA:

Mode 0 = 2.1 MB/s Mode 1 = 4.8 MB/s Mode 2 = 8.3 MB/s

o ATA-2: Called EIDE, allowed non-hard drive devices using a primary and secondary controller (thus introducing ATAPI), introduced sector translation (LBA) to obtain higher storage capacities (up to 4 GB), allowed 4 devices per controller, and introduced new PIO modes and Multi-word DMA.

ATAPI (ATA Packet Interface) A standard which allows non-hard drive devices to be connected via PATA Required OS to load drivers rather than communicate with the BIOS

PIO: Mode 3 = 11.1 MB/s Mode 4 = 16.6 MB/s

Multi-word DMA: Mode 0 = 7.2 MB/s Mode 1 = 13.3 MB/s Mode 2 = 16.6 MB/s

o ATA-3: Introduced S.M.A.R.T which prevents drive failure (was not widely implemented) o ATA-4: Uses Ultra DMA modes by using DMA bus mastering

Ultra DMA modes: Mode 0 = 16.7 MB/s Mode 1 = 25.0 MB/s Mode 2 = 33.3 MB/s

o ATAPI-4: Ultra ATA/33 Features include 80 conductor cables and Cyclic Redundancy

Checking o ATA-5: Introduced two more UDMA modes and offered INT13 to replace LBA, bringing hard

drive storage capacity up to 137 GB. Ultra DMA modes:

Mode 3 = 44.4 MB/s Mode 4 = 66.6 MB/s (ATAPI-5)

o ATAPI-5: Ultra ATA/66 o ATA-6: Introduced Big Drive to replace INT13 and allowed for maximum storage capacity.

Ultra DMA mode 5 = 100 MB/s ATAPI-6: Ultra ATA/100

o Features include 48-bit LBA expansion and disk noise reduction o ATA-7: Introduced SATA and UDMA mode 6

Ultra DMA mode 6 = 133 MB/s ATAPI-7: UDMA 6 (Ultra ATA/133)

o Features include multimedia streaming SATA Drives

SATA (Serial AT Attachment) o Point-to-point communication between devices and the HBA (Host Bus Adapter), or SATA

controller o ATA-7 defines the SATA standard o SATA gives you 20% encoding, and 80% pure bandwidth

SATA Revisions (all revisions have distance limitation of 1 meter):

19 | P a g e

o SATA I (Revision 1.x) 1.5 Gbps / 150 MB/s

o SATA II (Revision 2.x) 3 Gbps / 300 MB/s

o SATA III (Revision 3.x) 6 Gbps / 600 MB/s

Hard drive may or may not have 4-pin Molex power connector to backwards power compatibility SATA data cable is 7-pin while power is 15-pin AHCI (Advanced Host Controller Interface) is needed for Windows to automatically detect SATA drivers NCQ (Native Command Queuing) is an extension of the SATA protocol that allows faster read/write

speeds for hard drives SCSI Drives

SCSI (Small Computer Systems Interface) o Designed to string many peripherals together o Hot swappable o Has an IRQ of 9 o Up to 15 devices in a SCSI chain using a wide bus (subtracting controller)

If it is a narrow bus, you are limited to 7 devices (subtracting controller) o Last device must have terminator at the end of the chain

SCSI ID o Every SCSI device on a single bus is assigned a separate ID number o Jumpers on a SCSI device can be used to determine ID number o LUN (Logical Unit Number) identifies each SCSI ID o SCSI ID priority:

7 0 on an 8-bit 15 8 on a 16-bit 7 is the highest SCSI ID, 8 is the lowest

SAS (Serial Attached SCSI) have no jumpers, terminators, or settings o Currently the newest SCSI standard

HVD (High Voltage Differential) reduces noise on SCSI bus circuits, but doesnt work with SE (single-link) based SCSI

LVD (Low Voltage Differential) works with SE based SCSI for 12 meters of cable o Any SCSI cable capable of SE and having LVD can have 12 meters of cable

SCSI Types: o SCSI - 1

25-pins (used mainly for Apple computers) 6 meters max (thus longest cable length of all SCSI standards) 5 MB/s Narrow bus (8-bit/7 devices)

o Fast SCSI (SCSI 2) 50-pins 3 meters max 10 MB/s Narrow bus (8-bit/7 devices)

o Ultra SCSI (SCSI 3) 50-pins 1.5 meters max 20 MB/s Narrow bus (8-bit/7 devices)

20 | P a g e

o Ultra 2 SCSI (SCSI 4) 50-pins 12 meters with LVD 40 MB/s Narrow bus (8-bit/7 devices)

o Ultra 320 SCSI 68-pin 12 meters with LVD 320 MB/s (fastest of all SCSI standards) Wide bus (16-bit/15 devices)

Formats of SCSI are all backwards compatible SCSI drives use various types of connectors (25-pin, 50-pin, 68-pin) Pin 1 on cable must go into pin 1 on the HBA

Implementing RAID

RAID (Redundant Array of Independent Disks) o But not all RAID levels are redundant

Disk Duplexing = Each hard drive has its own controller RAID Types

o RAID 0 (Striping) File blocks are split between physical drives High data performance No redundancy, no way to recover data 2 drives minimum

o RAID 1 (Mirroring) File blocks are duplicated between physical drives High disk utilization (twice as much disk space required) High redundancy, drive failure does not affect data availability 2 drives minimum

o RAID 2 (Striping with multiple parity drives) Never implemented

o RAID 3 (bit level striping with dedicated parity) o RAID 4 (block level striping with dedicated parity) o RAID 5 (Striping with Parity)

File blocks are striped, along with a parity block One block dedicated to parity will be applied to every drive Efficient use of disk space High redundancy, but parity calculation may affect performance Minimum of 3 drives

o RAID 6 (striping with extra parity) Requires 5 drives

o RAID 10 (RAID 1+0) (Stripe of Mirrors) The speed of striping, the redundancy of mirroring Needs at least 4 drives

Software vs. Hardware RAID o Software RAID has lower performance than hardware based RAID o Hardware based RAID allows for hot swapping o Windows 2000 and above support software configuration for RAID 1 and RAID 5 o Windows XP and Vista only support software configuration for RAID 0

21 | P a g e

o Windows 7 software can configure RAID 0 and RAID 1 Striping

o Bit-Level = splitting data into bits then distributing them to drives o Block-Level = splitting data into blocks, then distributing across drives

RAID can be implemented using eSATA drives as well SATA can now be used to connect RAID arrays

o SCSI used to be used, but it was very expensive Optical Formats

CD (Compact Disk) o Uses the file format ISO-9660 (CDFS) o Data is stored just beneath the top layer in the form of lands and pits, which a laser reads and

translates to binary o One laser is designed just to read the disk, but a second laser that writes the disk is 10x as

powerful o Goes at speeds that are multiples of 150 KB/s (x2 = 300 KB/s, x4 = 600 KB/s) o CD-ROM = cant write, only read o CD-R = write once o CD-RW = write multiple times (10,000 maximum)

Three speeds = Write, Rewrite, and Read DVD (Digital Versatile Disk)

o Uses UDF (Universal Disk Format) that replaces ISO-9660 o Uses a 650nm red laser to read o Common DVD Formats:

Single-side/Single layer (DVD-5) = 4.7 GB Single-side/Dual layer (DVD-9) = 7.95 GB Double-side/Single layer (DVD-10) = 8.74 GB Double-side/Dual layer (DVD-18) = 15.9 GB

o DVD-RAM = special rewritable disk contained within a proprietary cartridge Need a special disk drive to read

o DVDRW = Universally compatible rewritable DVD DVD+RW is Sony/Phillips proprietary DVD-RW is used by other manufactures

o DVD region codes: Region 0 = Anywhere Region 1 = United States and Canada Region 2 = Europe, Middle East, South Africa, Japan and Greenland Region 3 = Southeast Asia, South Korea, Taiwan and Hong Kong Region 4 = South America, Central America, Mexico, New Zealand and Australia Region 5 = India, Nepal, Afghanistan, Russia, Ukraine, Kazakhstan, Pakistan and Africa Region 6 = China Region 7 = Reserved for future use Region 8 = For cruise ships and aircraft

o Video codecs: MPEG-1 = 352 x 240 @ 30fps MPEG-2 = 720 x 480 or 1280 x 720 @ 60fps MPEG-4 = Good for multimedia and Blu Ray

Contained IPMP (Intellectual Property Management and Protection) MPEG-7 = Multimedia content searching tool

22 | P a g e

MPEG-21 = Protects from illegal file sharing Contained REL (Rights Expression Language) and Rights Data Dictionary

Blu-ray o Uses a 405nm blue laser to read o 25 GB single-layer / 50 GB dual-layer o Mini Blu-ray = 7.8 GB single-layer / 15.6 GB dual-layer

Only optical format that is 8cm instead of 12cm o BD-RE = Rewritable Blu-ray o Highest quality optical format o Beat HD DVD as the optimal optical format o Specifications for burning Blu-ray disk

1 GB of RAM (Windows XP) or 2 GB of RAM (Windows Vista and Windows 7) Processor must be Pentium 4 or newer OS must be HDCP compliant

o All disks are 12cm besides where noted o When we burn them, photosensitive dye creates the usual bumps you would find o If you insert a disk and AutoRun does not start, launch it in the disks root folder as autorun.inf o If a CD or DVD burn fails, it is likely that buffer underrun is the problem

Flash Memory SSD drives

o Flash memory o No moving parts, but cost more than HDDs o Use NAND to retain data o Never defragment an SSD o Can be either 1.8, 2.5, or 3.5 o Can be either:

MLC (Multi-Level Cell) Cheaper, low write rates, poor performance

SLC (Single-Level Cell) More expensive, but extremely reliable

Flash Drives o ReadyBoost in Windows allows flash drives to act as virtual memory

Compact Flash (CF) o PCMCIA bus o CF1 = 3.3mm o CF2 = 5mm (not backwards compatible with

CF1) Smart Media

o For cameras SD (Secure Digital)

o Have a physical write protection switch o Evolved from MMC (Multimedia Card) o Mini SD o Micro SD o Standard SD (4 MB to 4 GB) o SDHC (32 GB) o SDXC (32 GB to 2 TB)

Other types of storage devices:

Floppy Drives o Use 34-pin cable to connect

to motherboard o A twist in the wires is used to

identify drives on the cable o Connect with drive letters A

or B o Uses the 4-pin Mini power

connector o Drives use a stepper motor o 3.5 inch (1.44 MB storage) o 5.25 inch (360 KB to 1.2 MB) o 8-inch

Tape Drives o 20 GB to 1.3 TB o Cost effective o Formats are DDS-1, DDS-4,

DAT72, DDS-5, LTO, Ultrium2, LTO Ultrium4, DLT, IV, DLT-4

Lomega Zip o 100 250MB

23 | P a g e

Memory Stick o A proprietary format for Sony o Standard o Pro o Duo o Pro Duo o Micro

xD (Extreme Digital) o Proprietary picture cards that were mainly used in Olympus and Fujifilm cameras o Standard (Type M) o Hi Speed (Type H)

External Connection Types

USB (Universal Serial Bus)

o 127 devices per controller o USB A and B ports have 4-pins, the rest have 5-pins o Always install drives before you plug the USB device in o USB ports lead to the root hub (bus) to the host controller o USB 1.1

Low speed: 1.5 Mbit/s 3 meters max

Full speed: 12 Mbit/s 5 meters max Most common USB 1.1 mode (1.5 MB/s)

Uses the Standard Open HCD Host Controller o USB 2.0 (full speed)

480 Mbit/s 5 meters max Usually 60 MB/s Uses the Standard Enhanced Host Controller

o USB 3.0 (SuperSpeed) 4.8 Gbit/s 3 meters max Usually 625 MB/s Sometimes connection is colored blue An 11-pin version that supplies extra power exists Backwards compatability with USB 2.0 Uses the Extendable Host Controller (xHCI)

o USB Form Factors Type A (regular type) Type B (square type at the device end) Micro-B (mobile devices) Mini-B (larger than micro)

Cameras use Alternate Mini-B

FireWire (IEEE 1394) o Also called i.LINK or Lynx

24 | P a g e

o Uses more power than USB o Supports bus mastering o Can daisy-chain, tree, or peer-to-peer up to 63 different devices o 4.5 meter distance limitation period for all FireWire standards o FireWire 400 (Alpha mode) / IEEE1394a

100, 200, or 400 Mbit/s (half-duplex) 6-pin or 4-pin 4.5 meter distance limitation, 72 meters max (for the entire configuration)

o FireWire 800 (Beta mode) / IEEE1394b 800 Mbit/s (full-duplex) 4, 6, or 9-pins Grey input Optical connections can support 100 meters max

o FireWire pin characteristics 4-pin is non-powered and is used for cameras 6-pin is powered and used on desktop PCs 9-pin is powered, high speed, but uncommon

eSATA o Provides throughput of 3 Gbit/s o 2 meters distance limitation o Hot-swappable o eSATAp = a port allows connection with an internal-style drive without an enclosure

Fits both eSATA and USB connections Ethernet (RJ-45) IrDA

o 4 Mbit/s per second speed o Half-duplex

Can be configured for full-duplex emulation, but will never actually be full-duplex o Line-of-sight only o Operates in ad hoc mode o 1 meter distance limitation

Bluetooth o 3Mb/s max o Uses ad hoc mode for device-to-device communication o Uses infrastructure mode when connection to a WAP (Wireless Access Point) o Uses 79 different frequencies via the FHSS broadcast method o Defined by 802.15 (WPAN standard) o Version 1.1 and 1.2

1 Mb/s o Version 2.0

Added EDR (Enhanced Data Range) 3 Mbit/s per second 10 meters max for Class 2 devices 1 meter max for Class 3 devices

o Class A = 100m / 100mW o Class B = 10m / 2.5mW o Class C = 1m / 1mW

PC 99 Standard o Defined colors for audio inputs o These were 1/8 jacks usually found on soundcards

25 | P a g e

o Pink = microphone o Green = front left/right speaker or headphone o Blue = line level audio input o Orange = subwoofer o Black = surround sound o Grey = mid left/right + surround o Gold = S-Video

Hot Swappable = add and remove while system is running Serial ports data only goes in one direction

o One wire to send, one wire to receive o Windows calls the COM ports o Contained a UART (Universal Asynchronous Receiver/Transmitter) chip that coverts between

parallel and serial devices o 9-pins o Defined by the RS-232 standard

Two serial devices must talk to each other in 8-bit chunks of data Flexible in speed and error checking RS-232 itself is manually configured

Parallel ports data goes in both directions at the same time Designing Custom Computer Systems

Graphics Technologies = OpenGL, Pixel Shader, DirectX, and Direct3D CAD/CAM Systems need a powerful processor, maximum amount of RAM, and a high-end video card Audio/Video Editing Workstations need high-end audio/video cards, large, fast SSD hard drives, and

possibly dual-monitors Virtualization Workstations need maximum RAM, and maximum CPU cores Gaming PCs need a powerful processor, high-end video card, better sound card, and high-end cooling

methods o 500-700W PSU needed o SLI (Scalable Link Interface) = Improves graphics performance on a computer

Links two or move video cards together into a single output Home Theater PCs need surround sound audio, HDMI output, HTPC compact form factor and a TV tuner Thick Clients need to support desktop applications and recommended requirements for running

Windows Thin Clients need to only support basic application usage Applications are actually run on a remote server (VDI) Home Server PCs have media streaming, file sharing, print sharing, and needs gigabit NIC for high speed

transfers and RAID arrays for redundant storage Display Devices and Connections

Display Devices CRT (Cathode Ray Tube)

o 4:3 aspect ratio o Uses analog signals o Electron guns shoot through a yoke which touches electrons on a screen with phosphor coating

These phosphors are RBG dots

26 | P a g e

o Shadow mask = sits behind the phosphors and only allows the designated Red, Green, or Blue electron guns to light up the corresponding phosphor

o Horizontal Refresh Rate = the rate at which the electron guns move across the screen o Vertical Refresh Rate = the time it takes for the electron guns to fill the entire screen and return

to the upper left corner If this is set too low, flickering will occur If this is set too high distortion can occur (will potentially destroy the screen)

o Raster lines = the horizontal sweeps across the screen (left to right) made my the electron guns o One pixel must contain one red, one blue, and one green phosphor

CRT pixel size changes with resolution o Sizes include 15", 19", and 21"

All displays are measured diagonally o Resolution modes include:

VGA (640 x 480) SVGA (800 x 600) XGA (1024 x 768) SXGA (1280 x 1024) UXGA (1600 x 1200)

o Has a refresh rate rated in Hz o Convergence = horizontal and vertical alignment of colors on a screen o Dot pitch = predefined measurement in mm between pixels

Typical is 0.27mm LCD (Liquid Crystal Display)

o Uses electronic signals to light up rectangular pixels o Pixels are fixed and wont change with resolution o Use a CCFL (Cold Cathode Fluorescent Lamp) backlight

Backlight is always on, and background transistor polarizes the light, that is why the backlight is never pitch black

Most LCD monitors have two backlights Needs AC power, so an inverter is needed to convert the DC power used by all the other

electronics built into the screen A transformer is used to convert this AC power back to DC

o Viewing angle is less o No electron beam o Refreshes screen at a 60 Hz frame rate o Fixed native resolution o Opaque crystals produce black o Passive matrix

Vertical and horizontal circuits pass through every row and column of subpixels to create matrices

These circuits intersect one another and single LCD element enables light to pass through

Poor image quality: blurry due to pixel overlap Dual-scan passive matrix fixed this, but was not a permanent solution

o Active matrix Uses TFT (Thin Film Display)

The most common TFTs use twisted nematic (TN) panels The best TFTs use IPS (In-Plane Switching) which provide wider viewing angles

and better color than TN panels Transistors behind each pixel stimulate electrodes that rearrange liquid crystals

27 | P a g e

Sharper image quality and higher refresh rates o 17 screens are 1280 x 1024 (SXGA) or higher o 20 screens are 1920 x 1080 (HD 1080) or higher o LCDs that run lower than the native resolution must use an anti-aliasing filer to blur the edges of

pixels o The refresh rate for an LCD monitor is the time it takes for subpixels to go from pure black to

pure white and back again Measured in milliseconds, lower is better

o Have a contrast ratio of 250:1 to 1000:1 o Brightness ranges from 100 to 1000 nits

LED (Light Emitting Diode) o LEDs are simply LCD monitors with LED backlights instead of CCFL

LEDs may be around the edge of the screen or behind the screen This makes for thinner screens and lower power consumption Also no AC power is used, so an inverter is not necessary

o Backlight provides better image at any viewing angle OLED (Organic Light Emitting Diode)

o Organic compound emits light when receiving electrical current o High cost, power efficient, wider viewing angles, and fast response time

Plasma o A display of tiny cells filled with noble gas and mercury o Mercury sheds energy as UV light o UV light strikes colored phosphor o Deep blacks, fast response time o High power, shimmering, doesnt work in high altitudes, lots of radio interference o Wider viewing angles than any other display o Not optimal for computer usage due to burn-in problems where the image gets burnt onto the

screen o Overscan is another problem with plasma displays

Image is cropped at the edge of the screen LCD screens have this problem as well

Projectors o Can be DLP (which uses DMD/thousands of mirrors) or LCoS (combination of LCD and DLP) o Not always an LCD projector, CRT projectors provide the best image quality, but are really bulky

and expensive o Throw = the distance needed from the screen to create the best image o Lamps = the most important part of a projector

Very bright and hot light, so fans are built in to cool it down Very expensive to replace when broken

Refresh Rates = measured in Hz o Large displays need to be set at 72 Hz or higher to prevent flickering o 60 Hz is the standard refresh rate for all screens o A 120 Hz refresh rate requires a video card capable of supporting dual-link DVI

Resolution = number of pixels on a display o Width x Height (Row x Column) or Horizontal Pixels x Vertical Pixels o Video settings must match a display's native resolution

Brightness o Usually measured in nits (cd/m2) or luminance o Lumens (ANSI test, 3000 for dim room, 6000 for sunlit)

Used for projectors

28 | P a g e

Contrast Ratio = ratio between black and white o A wider range is better o Dynamic contrast ratios are much larger than regular ones, but not that important

Analog Video = transmitted as continuous signal Digital Video = transmitted as discrete values Display Filters

o Privacy filter o Fade the screen to black or gold when viewed at an angle o Placed on the front of a display o Anti-glare filter

Video Cards o Have a RAMDAC chip that takes digital signals from video and convert it to analog when needed o Any monitor, such as an LCD, with a VGA input will use the RAMDAC chip in the video card to

convert the LCDs natively digital signal to analog for VGA use o Types of video card RAM include:

VRAM, WRAM, SGRAM, DDR SDRAM, DDR2 SDRAM, GDDR3 SDRAM, GDDR4 SDRAM, and GDDR5 SDRAM

o Video card color depth: 2 colors = 1 bit 4 colors = 2 bits 16 colors = 4 bits 256 colors = 8 bits 64,000 colors = 16 bits 16.7 million colors = 24 bits

Monitors that meet the VESA standard for DPMS (Digital Power Management Signaling) can reduce power consumption to up to 75%

Table of Common Resolution Modes: Mode Resolution Aspect Ratio Common Uses VGA 640 x 480 4:3 SVGA 800 x 600 4:3 Small monitors HDTV 720p 1280 x 720 16:9

XGA 1024 x 768 4:3 SXGA 1280 x 1024 5:4 Native

resolution for LCD monitors

WXGA 1366 x 768 4:3 Widescreen laptops

WSXGA 1440 x 900 16:10 Widescreen laptops

SXGA+ 1400 x 1050 4:3 Large CRT projectors

UXGA 1600 x 1200 4:3 Large CRT projectors

HDTV 1080p 1920 x 1080 16:9

WUXGA 1920 x 1200 16:10 24 Widescreen QWXGA 2048 x 1152 16:9 WQXGA 2560 x 1600 16:10 27: Widescreen WQUXGA 3840 x 2400 16:10 Newer monitors

29 | P a g e

Display Connectors

DVI (Digital Visual Interface) o Single-link (3.7 Gbit/s, HDTV at 60 fps)

Resolutions of 1920 x 1080 and 1280 x 1028 o Dual-link (7.4 Gbit/s, HDTV at 85 fps)

Resolutions of 2048 x 1536 o DVI-A: analog o DVI-D: digital o DVI-I: integrated (digital and analog in same connector) o DVI-D and DVI-I come in both single-link and dual-link varieties

DisplayPort o Video and audio in one cable o Follows the VESA standard o Royalty-free o 20 pins o 17.28 Gb/s o Data is sent in packets (like Ethernet and PCIe) o Compatible with HDMI and DVI with a passive adaptor

HDMI (High-Definition Multimedia Interface) o Video and audio in one cable o 19 pin (Type A) connector o miniHDMI (Type C) for smaller form factors o microHDMI (Type D)

VGA (Video Graphics Array) o Goes by the names DE-15, DB-15 or HD-15 o 15-pins o PC System Design Guide makes it so it's always blue o Analog signal

RCA connectors (Composite Cables) o Known as a phono connector, Cinch connector, and A/V jack o Combines luminance and chrominance into one signal o Red/White = left/right audio o Yellow = analog (SD) video

PbPrPy (Component Cables) o 3 RCA connectors o Create separate signal for luminance

BNC connectors (Bayonet Neill-Concelman) o Used with higher-end video o Connector has a twisting lock o Has both:

RGBGV (red, green, blue, horizontal, sync, vertical sync) Component video (VPbPr)

miniDIN o S-Video (Separate Video)

S-Video can have either 4, 7, or 9 pins o Analog signals o 2 channels (intensity and color)

Thunderbolt

30 | P a g e

o up to 20 GB/s and 7 daisy chained RS-232

o 50ft (15.25m) o Old 9-pin serial cable

Computer Peripherals

Input Devices o Mouse o Connects from USB, PS/2, or serial ports

Green colored PS/2 port Most mice are using optics now

Glass may cause a problem o Keyboard

Connects from USB or PS/2 Purple colored PS/2 port

May require drivers for extra features Configuration may include repeat rate, repeat delay, or cursor blink rate

o PS/2 devices are not hot swappable o Touch Screen

Needs connection to video adapter and USB ports to function properly o Scanner

The 5 important scanner values: 1. Resolution 2. Color Depth 3. Grayscale Depth 4. Connection 5. Speed

Scanners have color depth of 24-bits, 36-bits, or 48-bits (most common) The grayscale depth can be 8-bits, 12-bits, or 16-bits (most common)

TWAIN is the default scanner driver Some come with OCR (Optical Character Recognition) to turn image into text Types:

All-in-one (prints, scans, copies) Flatbed (only scans)

o Barcode Reader Connects from USB, PS/2, or serial ports If it doesn't work, just replace it

o KVM (Keyboard, Video, and Mouse) Allows you to use many computers with a single keyboard, video display, and mouse Uses peripheral emulation to communicate with all system connections

o Microphone Integrated into most new laptops and multimedia devices External microphones connect from analog (TRS) or digital (USB)

o Biometric Devices Use biological features such as your retina, fingerprint, or keystroke dynamics

o Gaming Input Like the joystick

o Digitizer

31 | P a g e

Output Devices o Printers o Speakers o Monitors

Multimedia Devices o Digital Cameras

May need drivers o Microphone o Webcam

Connects with USB but may be 802.11 wireless o Camcorder

Stores data in built in hard drive or flash memory (CF, SD) Connects with FireWire, HDMI, or USB

o MIDI Can connect with RJ-45, USB or DIN connectors

NETWORKING Network Connectors & Cabling

Structured Cabling

o A cabling standard with the flexibility to allow a network to grow according to its needs and then to upgrade when needed.

o Built on the basis that a work area will need to connect to a main server room, or telecommunications room via horizontal cabling to achieve a network connection.

o Telecommunications Room Acts as the server room where all cables in a network connect Has large equipment racks

19 inches wide Height is measured in Us (1U = 1.75in)

o Horizontal Cabling Defines the runs of cabling that go to the computers Requires CAT 5e or better Must be solid core cables

o Work Area Where all the PCs reside PCs connect via sockets in the wall Use stranded cabling

o Crosstalk (XT) = concept of structured cabling which refers to the interference between signals over adjacent wires

POTS (Plain Old Telephone System) o Uses an RJ-11 connection o 6P2C connection o Standard telephone connection

Twisted Pair o Uses an RJ-45 connection

8P8C connection

32 | P a g e

Modular cable o Contains two wires with equal and opposite signals o Twisting eliminates interference across wires o Each cable is twisted differently o UTP (Unshielded Twisted Pair)

Most common No additional shielding Come in solid core and stranded core varieties

Solid Core o Wires are in one pair o Better conductor, but stiff and fragile

Stranded Core o Wires are made up of smaller wires o Easier to work with than solid core

o STP (Shielded Twisted Pair) Additional shielding against EMI (Electromagnetic Interference) Requires an electrical ground

o Plenum = Cables that will not emit toxic chemicals when burned Required for cables that run between floors in a building Low Smoke PVC or FEP may exist in plenum cables

Note that PVC alone without the Low Smoke prefix emits toxic fumes when burned

May not be as flexible o Ethernet types that use twisted pair:

10BASET = 10 Mb/s, 100m 100BASETX = 100 Mb/s, 100m 1000BASET = 1 Gb/s, 100m

o EIA/TIA-568 Cabling Standards: CAT 3 = 10 Mb/s

Configurable up to 100 Mb/s if four pairs of wires are used CAT 5 = 100 Mb/s CAT 5e = 1 Gb/s (Gigabit Ethernet) CAT 6 = 10 Gb/s (fire resistant) CAT 6e = many Gb/s, greater lengths supported CAT 7 = LAN Cabling

Uses a GG45 connector o T568A and T568B Termination

Part of the EIA/TIA-568-B standards For 8 conductor, 100-ohm balanced twisted-pair cabling T568A and T568B have different pin assignments T568B is the most common Pin 1 = white/green (T568A) or white/orange (T568B) Pin 2 = green (T568A) or orange (T568B) Pin 3 = Reverse of Pin 1 Pin 4 = blue (T568A/B) Pin 5 = white/blue (T568A/B)

33 | P a g e

Pin 6 = Reverse of Pin 2 Pin 7 = white/brown Pin 8 = brown Crossover Cable = Linking two computers (NICs) with one end being T568A and the other

being T568B Fiber Optic

o ST Connector (Straight Tip Connector) Bayonet connector Push and turn to lock Less susceptible to damage Half-duplex, two cables are needed

o SC Connector (Square/Standard/Subscriber Connector) Square shape Have locking mechanism Push/Pull connector Commonly used in networks Half-duplex, two cables are needed

o LC Connector (Lucent/Local/Little Connector) Smallest form factor Used for high end applications Have caps on the end Have locking mechanism Used for high density networks Will fit into the smallest form factor Looks like SC, but larger and not as wide

o MJ-45 is another fiber connector High end

o No RFI (Radio Frequency Interference) because data is transmitted by light o Light degrades slower than electrical signal on a copper connection o Fiber transmits the longest distances o Two types of communications in fiber:

Single-mode fiber = high bandwidths and used for long distances (not for small networks)

Up to 100 Gb/s and 20 miles Use laser light

Multi-mode fiber = most common implementation (used for smaller networks) Up to 10 Gb/s and 600m Use LED light

o WDM (Wavelength-Division Multiplexing) = fiber cable that carries more than two signals at a time

o DWDM (Dense WDM) = 200 or more signals at a time

34 | P a g e

o SONET (Synchronous Optical Networking) = fiber standard for North American o SDH (Synchronous Digital Hierarchy) = fiber standard for the rest of the world o Types of overhead in fiber networks:

Section = for links between repeaters Line = for connecting devices Path = for disassembling frames (like routers and switches)

o Attenuation = signal loss in fiber over long distances o Microbending = signal loss if cable is bent slightly o Macrobending = signal loss if cable is bent too much o Fiber based Ethernet networks include:

1000BASESX 10GBASESR

Coaxial o Used for high bandwidth and broadband Internet o Usually these cables do not exceed 50 Mb/s o Two or more forms sharing a common axis o Used in older Ethernet networks in a bus topology

10BASE2 (Thinnet) uses RG-58 (185m, 10Mb/s) 10BASE5 (Thicknet) uses RG-8 (500m, 10Mb/s)

o RG-59 75-ohm impedance Thinner than RG-6 Not used for long distances Often packed with VCRs and other electronic equipment due to its short distance

limitation o RG-6

75 ohm impedance Used for satellite dish into home Connects with an F-Connector or a BNC (Bayonet Neil-Concelman) connector

F-Connectors o Used for cable television (CATV) and security camera applications o Screws in o Has a pin in the middle

BNC o Used for 10Base2 Ethernet connections along with various radio and

video applications o 50-75 ohms o Rigid and bulky o Pin in the middle, but not as emphasized as the F-Connector

AutoMDIX = automatically detects and configures cable connection types

TCP/IP o

The entire basis surrounding the TCP/IP protocol is that it is really two different protocols: the TCP (Transmission Control Protocol) and the IP (Internet Protocol) that are used in order to allow two given computers in a network to identify each other and then send data to each other. IP is used so two

35 | P a g e

computers can establish a connection with each other across a large and vast network and TCP is used to ensure that the data they send over this network will not be lost.

The OSI Model (Not explicitly listed in the exam objectives, but very useful to know) o Describes network operations using different layers in order to explain the fundamentals of how

a network works. o Layer 7: Application = User driven applications such as HTTP, FTP, SMTP, etc. o Layer 6: Presentation = Files that are the basis of the transfer like JPG, MPEG, OGG, DOCX, etc. o Layer 5: Session = Coordinates a connection and logical ports between different groups of data

and manages the direction of data flow o Layer 4: Transport = Ensures reliability of data transfer (TCP) o Layer 3: Network = Routes data across a network of different nodes (Router and IP) o Layer 2: Data Link = Transfers data between network nodes (Switch and Bridge) o Layer 1: Physical = Sends data across the physical medium and translates it (Hub and Repeater)

The DOD Model (Also not in exam objectives, but is worth mentioning due to the similarity with OSI) o Process: OSI Model Layer 7, Layer 6, and Layer 5 o Host-to-Host: OSI Model Layer 4 o Internet: OSI Model Layer 3 o Network: OSI Model Layer 2 and Layer 1

IP NetBIOS/NetBEUI

o Came before TCP/IP when there were less computers o Assigned each computer a unique name that could be any combination of letters or numbers o Each computer broadcasted frames to every other computer in the entire network o This worked for LANs, but when the world network expanded into WANs, each computer

broadcasting frames to every computer would not be practice. IP (Internet Protocol) = consists of a 32-bit address which allows different computers to communicate

with each other, then uses a router (having its own IP address) to communicate outside the network when needed.

Every device needs a unique IP address and subnet mask IP Address Classes

o Class A: 0.0.0.0 126.255.255.255 16,777,216 addresses allowed Allocated to huge companies and enterprises Default subnet mask: 255.0.0.0 127.x.x.x is classless and reserved for network testing and loopback operation

Called the local host address o Class B: 128.0.0.0 191.255.255.255

65,536 addresses allowed Allocated to medium size businesses Default subnet mask: 255.255.0.0

o Class C: 192.0.0.0 223.255.255.255 254 addresses allowed Allocated to LANs Default subnet mask: 255.255.255.0

o Class D (multicast): 224.0.0.0 239.255.255.255 o Class E (reserved): 240.0.0.0 255.255.255.255

Reserved for research purposes Private Addresses:

36 | P a g e

o RFC 1918 makes the standard allowing private addresses o When designing private addresses:

Class A: 10.0.0.0 - 10.255.255.255 Default subnet mask: 255.0.0.0 Single Class A Largest CIDR block = 10.0.0/8 Host ID is 24 bits

Class B: 172.16.0.0 - 172.31.255.255 Default subnet mask: 255.240.0.0 16 contiguous Class Bs Largest CIDR block = 172.16.0.0/12, Host ID is 20 bits

Class C: 192.168.0.0 - 196.168.255.255 Default subnet mask: 255.255.0.0 256 contiguous Class Cs Largest CIDR block = 192.168.0.0/16 Host ID is 16 bits

Number of addresses allowed in a network is defined by the formula: 2n-2; where n = hosts per network You can never have an IP address that ends in a 0 or a 255 because the one that ends with the 0 is the

network address and the one that ends in 255 is the broadcast address Subnet Mask = a secondary 32-bit address that goes along with the IP address to identify the network ID

and the host ID in the IP address o The amount of octets occupied by a 255 corresponds to the amount of octets in the IP address

that consist of the network ID. The amounts of 0s in the subnet mask, thus, correspond with the host ID within the IP address.

o For example, an IP address of 192.168.1.4 with a subnet mask of 255.255.255.0 has a network ID of 192.168.1 and a host ID of 4.

CIDR (Classless Inter-Domain Routing) o Useful for further dividing subnets beyond their preconfigured Class A, B, or C standards to

make more efficient use of allocated subnets and to perhaps have more control over the exact amount of hosts you need in a network without wasting a ton of IP addresses in the process.

o For example: 192.168.1.1/24 is the CIDR notation for really saying that your IP address is 192.168.1.1

and your subnet mask is 255.255.255.0 because the three octets of 255 equal 24-bits (8x3=24), so thus you can just say 192.168.1.1 to mean the same thing.

So to further divide beyond the preconfigured subnets of Class A, you will use the IP address of 10.1.0.1/26. This really means you have an IP address of 10.1.0.1 with a corresponding subnet mask of 255.255.255.192. The 26 means that, starting from the left, there are 26 bits that make up the network ID and the remaining 6 bits make up the host ID. This means that the first three octets of 255 were used along (8x3=24) along with two additional bits from the last octet are part of the network ID. The octet of 192 in the subnet mask comes from the fact that the two additional bits taken from the last octet of the IP address have the binary definitions of 128 and 64 respectively. 128 + 64 = 192, thus forming the last octet.

The number of octets that are common for all computers on a broadcast domain is the network ID Static IP = an IP address that remains the same

o Typing in an address manually on a device is giving that device a static IP address o For servers and network devices such as printers

Dynamic IP = an IP address that changes

37 | P a g e

o Used for clients in a network o Usually leased by DHCP for a finite amount of time

IANA (Internet Assigned Numbers Authority) distributes public IP addresses BOOTP (Bootstrap Protocol)

o Made all IP configuration automatic in 1993 before DHCP o Didn't have a built in mechanism to see what IP addresses have lost their lease o Some manual configuration required

DHCP (Dynamic Host Configuration Protocol) o Configures IP Addresses, subnet masts, default gateways, DNS servers, NTP servers, etc. o Network administrator will preconfigure the DHCP server to only give out IP addresses within

the networks range. o Four stages:

1. Discover = NIC uses UDP to located DHCP server 2. Offer = DHCP offers IP, gateway, and lease 3. Request = accepts first one it receives 4. Acknowledgement = resends with info that client requested

o Use IPCONFIG /RELEASE to view info about what DHCP gave to the PC APIPA (Automatic Private IP Addressing) = used to automatically assign an IP address to a machine

when DHCP is not available. o Link-local addresses

Can't communicate to other routers, but you can locally o IETF reserved 169.254.1.0 through 169.254.254.255

Last 256 addresses are reserved IPv6 reserves fe80::/10 (assigned as fe80::/64)

o These addresses are automatically assigned by the OS Uses ARP to confirm the addresses aren't taken

IPv4 (Internet Protocol version 4) o OSI Layer 3 address o Consists of four 8 bit octets for a total of 32 bits o 256 is the highest each byte or octet can get (192.168.1.131, each cluster being a byte or octet

with 8 individual bits) o Needs a server IP address, server application port number, client IP address, and client port

number IPv6 (Internet Protocol version 6)

o Improvements over IPv4: Address size increase from 32 to 128 bits Some header fields have been dropped Less rigid length limits and ability to introduce more options Packets will indicate traffic type Data integrity and confidentiality Header is 40 fixed bytes and has 8 fields of information

o NOT in a decimal format: it uses a hexadecimal format o One letter equals four bits o Windows makes the last 64-bits of each address random o DNS becomes very important with IPv6 o Example IPv6 address:

fe80:0000:0000:0000:5d18:0652:cffd:8f52 Notice it has 2 bytes per group, making a 128-bit address

o Shortcuts include removing leading zeros and abbreviate two or more groups of zeros with double colons (::) once per address:

38 | P a g e

1. fe80:0000:0000:0000:cabc:c800:00a7:08d5 2. fe80:0:0:0:cabc:c800:a7:8d5 3. fe80::cabc:c800:a7:8d5 Notice that in step two, the leading zeros were removed in each group, including groups

of only zeros leaving just one zero. The three groups of zeros after fe80 were replaced with a double colon

o Does not broadcast, only multicasts o IPv6s link-local IP address is the same as APIPA for IPv4, but IPv6 will always have a link-local

address o The NIC will have three IPv6 addresses: one link-local and two global addresses (one temporary

and one static) o Computers using IPv6 need a global address given to them by their router/default gateway to

access the internet o Steps in getting a global address:

1. The computer boots up and sends a router solicitation message (FF02::2) 2. The router sends an RA (Router Advertisement) with prefix and DNS 3. The computer adds the random 64-bits (EUI-64) to the end of the prefix forming a global

address 4. A global address will always start with a 2

o IPv6 loopback address = ::1 Unicast = communication from one node to the other Multicast = communication from one node to a select group of nodes Anycast = communication from one node to the nearest node Default Gateway used by the router to allow you to communicate outside your local subnet

o The router is usually referred to as the default gateway o Must be an IP Address on a local subnet o Email, Internet, LAN, Voice and Data, and Firewall are all types of gateways

Half-duplex analogy = Two people having a conversation via walkie-talkies. When one person is speaking, the other must wait till that person is finished speaking before talking back.

Full-duplex analogy = Two people having a conversation via a telephone. Both people can speak at the same time and their voice will get to the other end

o Modern NICs use full-duplex, but have an auto-sensing feature to accommodate old, half-duplex NICs

Wake-On-LAN = turns on a sleeping PC that is not physically close by sending magic packets which repeat the destination MAC address many times

o Found in Power Management TCP

TCP (Transmission Control Protocol) o Connection oriented

Both parties need to synchronize with each other o Reliable delivery (will always know if something went wrong) o Keeps track of out of order or duplicate messages sent o Analogy: loads and unloads moving truck and checks for missing cargo o Good in unicast communications

UDP (User Datagram Protocol) o Opposite of TCP, but performs much better o Acts as an interface between IP and upper layer protocols o Connectionless

39 | P a g e

o Good for multicast and broadcast communication o Analogy: loads and unloads moving truck, but doesn't check for missing cargo o Very unreliable

No confirmation that information was received No way to manage retransmissions UDP has no idea how many packets went through the network

Non-ephemeral ports = permanent port numbers o Found on servers

Ephemeral ports = temporary port numbers o Determined in real-time by client workstation

TCP and UDP ports can be any number between 0 and 65,535 Port numbers are only used for communications, not security Service port numbers need to be well known

o For example: port 80 for connecting to the Internet TCP Ports and Protocols:

o Port 20/21 = FTP (File Transfer Protocol) o Port 22 = SSH (Secure Shell)

Encrypted communication link Uses tunneling Looks and acts the same as Telnet, but is used for the entire Internet, not just LANs Used to encrypt data when working at the command line of a computer Also used to connect securely to another computer SFTP (SSH File Transfer Protocol)

FTP using SSH so its more secure Data is encrypted Provides file system functionality (remote file removal, resuming interrupted

transfers, directory listings, etc.) o Port 23 = Telnet

Used to connect remotely to servers Should only be used in LANs

o Port 25 = SMTP (Simple Mail Transfer Protocol) Used to send mail only

o Port 53 = D