PC Hardware Overview

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PC Hardware Overview

• David Turton
• Conestoga College
• Institute of Technology and Advanced Learning
• http//www.conestogac.on.ca/dturotn
• Doon 1D17, x3610

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ESD Electrostatic Discharge

• Wear a ground bracelet or static strap
• Place components on a ground mat
• Place loose components in static shielding bags
• No static strap
• touch the computer chassis before touching
  components

• If you feel a static shock
• you've discharged 3,000 volts.
• If you see a spark
• you've discharged 8,000 volts
• Less than 3,000 volts can damage electronic
  components

• Never go into a monitor casing or into the
  power supply.
• There are no user-maintained components
• Capacitor discharge can kill you.

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Handling Electronic Cards

• Hold cards by the edges
• Avoid touching edge connectors, solder joints and
  chips
• Dont use magnetised screwdrivers or graphite
  pencils
• Use a ballpoint pen to set switches on a board

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Functions of Hardware
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Hardware

• Central processing unit (CPU)
• Most important hardware device
• Receives input and sends output
• Stores data and instructions performs
  calculations
• Requirements of hardware devices
• Method to communicate with the CPU
• Software to instruct and control the device
• Electricity to power the device

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Binary Communication

• A pair of wires isn't required for each key
• keyboard sends a different bit pattern for each
  key
• 8 bits byte - value from 0 to 255
• quite enough for a 102-key keyboard

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Byte 8 bits
128 32 8 2 64
16 4 1
1 20 2 21 4 22 8 23 128 27
128 32 8 2 64
16 4 1

• Number or character?
• "A" is same bit pattern as 65 (64 1)
• depends on "context"
• consider the source what are you expecting?
• consider the target what can it handle?
• keyboards HTML pages - expect characters
• Word documents mixed "escape" patterns switch
  expectations

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Ports for peripheral I/O devices
Power in
Monitor power
PS2-style mouse keyboard
USB ports (2 of 6)
Serial (COM) port
Parallel (LPT1) printer port
Network (RJ45), USB 34
Microphone, speaker, headphones
Video out
FireWire
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Different devices, different connectorsnotice
keyboard 6 pins for 102 or more keys
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Hardware Inside the Computer Case
Power supply
CD-RW drive
Power cables
Data cables
CPU
Floppy drive
Hard drive
Video card in AGP port
PCI expansion slots (blue PCI-X)
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Microchips are manufactured two ways

• TTL
• transistor-to-transistor logic
• CMOS
• Complementary metal-oxide semiconductor
• Require less electricity
• Produce less heat
• Hold data longer after electricity is turned off
• Are a lot slower

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The System Board
CPU mount
RAM
Power connection
Hard drive Floppy drive controllers
chipset
AGP accelerated graphics
Battery
PCI expansion slots
BIOS
PCI-X expansion slot
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On-Board peripheral connections
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Components Used Primarily for Processing

• CPU or microprocessor
• Executes most computer processes
• Chip set
• Relieves CPU of some processing
• prioritizes CPU interruption requests
• Provides careful timing of activities
• increases overall speed
• Interfaces between slow fast busses

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The CPU
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Chip Set
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Temporary Storage Devices (aka primary storage
or memory)

• Used by the CPU to process data and instructions
• Provided by DRAM (dynamic random access memory)
• SIMMs (single inline memory modules)
• DIMMs (dual inline memory modules)
• RIMMs (Rambus inline memory module)
• Also by SRAM or Cache memory
• Static random access memory

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SIMMS and DIMMS Dynamic RAM
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(No Transcript)
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Permanent or Secondary Storage Devices

• Remote to the CPU
• Permanently hold data, even when PC is turned off
• Most popular devices
• Hard disks
• Floppy disks
• CD-ROM, CD-RW, DVD, DVDR
• USB disk drives, flash memory, memory sticks

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Hard Drives
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EIDE Disk Connections to Motherboard
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EIDE Connections - close-up
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disk floppy connections
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Disk Connectionsin Use disk drives need to
communicate with CPU2 controller ports usually
providedprimary secondary
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Floppy Drive connectionDrive after twist in
cable is A
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Motherboard communication paththe bus

• Metal lines etched onto the motherboard
• carry signals, power
• a voltage represents 1
• no voltage represents 0
• system bus
• fastest bus on motherboard
• to memory
• memory bus, local bus, front side bus
• other buses
• to ISA, PCI AGP expansion slots
• data path
• bits sent simultaneously
• 8, 16 (ISA, RIMM), 32 (PCI, SIMM), 64 (DIMM,
  PCI-X), 128 (?)

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sample 8-bit busknown as a parallel bus 8 bits
travel side-by-sideall 8 bits arrive
simultaneously
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System Bus Speed

• system clock
• crystal that oscillates, creating pulses
• establishes frequency/speed of system bus (aka
  memory bus)
• pulses carried on one line in each bus
• everything works in sync with system clock
• some devices take two or more pulses
• clock speed in hertz (cycles per second)
• MHz (1 million cps) or GHz (1 billion cps)
• common 1066MHz, 800MHz, 533MHz, 400MHz
• CPU works at a multiple of system clock
• on its internal bus
• can't put instructions on system bus faster than
  the clock speed

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Expansion Slots- common cards video, sound,
network, modem- can also add parallel, serial,
USB firewire ports- determine use by ports
they expose to outside
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AGP, PCI ISA slots
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The Electrical SystemProvides 3.3, 5, and 12
volts DC to system board and other installed
devices
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Instructions and Data Stored on the System Board

• ROM chips
• Contain permanent programming code
• Sometimes called BIOS chips
• CMOS configuration chips
• Hold configuration or setup information
• can be reprogrammed
• system battery keeps contents alive
• Jumpers or DIP switches
• Hold configuration information

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CMOS settings changed by CMOS setup program on
BIOS
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Three Types of Software and What They Do

• Firmware (BIOS)
• Controls POST and the computers input/output
  functions
• Operating systems (OS)
• Provide instructions to hardware (directly or via
  BIOS) to perform tasks
• Applications software
• Provide user interface

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Software Layers Applications depend on OS to
interface with hardware and it may depend on
drivers or BIOS
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Functions of BIOS

• Perform POST (power-on self-test)
• set up CMOS, if requested at boot
• Assign system resources to devices (IRQ, I/O
  address, memory address, DMA channel)
• perform PnP initialization (plug-and-play)
• Load the OS boot program into memory execute it
• even the OS cant be executed from disk
• Act as an interface between OS and memory, hard
  drives, floppy drives

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Chapter Summary

• Individual components that make up a computer
  system hardware and software
• Hardware
• Devices used for input, output, processing, and
  storage of data
• Components that make up the electrical system
• Components used for communicating data and
  instructions from one device to another
• buses chipsets on the system board

continued
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Chapter Summary

• CPU
• Central processing point for all data and
  instructions
• Both data and instructions must be stored in
  memory with assigned memory addresses before
  processing can begin

continued
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Chapter Summary

• Software
• Works in layers
• Lowest layer (BIOS and device drivers) interfaces
  with hardware
• Highest layer (applications software) interfaces
  with user
• OS is the middleman layer coordinating everything