Computer HardwareComputer Hardware

Preview the exam questions.

RAM

SECONDARY

STORAGE

CPU

COMPUTER FACTSCOMPUTER FACTS

A computer is an electronic device A computer is an electronic device which works within a binary digital which works within a binary digital system and has 4 functions:system and has 4 functions:– Accept input (Accept input (datadata – – isolated factsisolated facts))– Process input (Process input (datadata))– Produce output (Produce output (informationinformation – – processed dataprocessed data))– StorageStorage

Binary Digital SystemBinary Digital SystemA system that works with two A system that works with two

states. For the computer states. For the computer these two states are on/off or these two states are on/off or

the digits of 1 and 0.the digits of 1 and 0.

Tower CPU

RAM

BUS Hard Drive

Floppy CD

Drive Drive

Ports

printermouse

Monitor

keyboard

Peripheral

devices

Some Hardware DefinitionsSome Hardware Definitions

TowerTower – – box that holds CPU, RAM, etc.box that holds CPU, RAM, etc.

Peripheral DevicesPeripheral Devices – – input/output devices such input/output devices such as the printer, monitor, etc.as the printer, monitor, etc.

BusBus – – electronic device that connects all the electronic device that connects all the internal parts of the computerinternal parts of the computer

PortPort – – connectors for all peripheral devicesconnectors for all peripheral devices

MAIN

MENU

CPUCPUCentral Processing UnitCentral Processing Unit

Diagram of parts

FF

AA

CC

TT

SS

How does How does this work?this work?

MAIN

MENU

Control Unit

ALU

Registers

MAIN

MENU

CONTROL UNITCONTROL UNITFetches and Interprets Fetches and Interprets

InstructionsInstructionsFromFromRAMRAM

MAIN

MENU

ALUALU(arithmetic/logic unit)(arithmetic/logic unit)

Executes instructionsExecutes instructions

MAIN

MENU

RegisterRegister

Fast accessing storage Fast accessing storage

Inside the CPUInside the CPU

MAIN

MENU

CPU FACTSCPU FACTS

Megahertz – unit of Megahertz – unit of speed for the speed for the

CPUCPU CPU works with the CPU works with the

machine cyclemachine cycle

How are numbers, How are numbers, letters, graphics etc. letters, graphics etc. represented in binary represented in binary digits contained in digits contained in registers?registers?

MAIN

MENU

MACHINE CYCLEMACHINE CYCLE

INSTRUCTIONINSTRUCTION

1. Fetched

2. Interpreted

3. Executed

What part of the CPU fetches, What part of the CPU fetches, interprets, and executes?interprets, and executes?

Fetch

Interpret

Execute

CPU

Control

Unit

ALU

RAMRAMRandom Access MemoryRandom Access Memory

FF

AA

CC

TT

SS

How does this work?

Physically a Physically a series of series of chips.chips.

Storage Units

MAIN

MENU

RAM FACTSRAM FACTS

Holds data and instructions Holds data and instructions waiting for processing by the CPUwaiting for processing by the CPU

Temporary storageTemporary storage Contents are deleted when power Contents are deleted when power

source removed.source removed.

What is What is CACHE?CACHE?

MAIN

MENU

Click to view facts.

CACHECACHE

Cache is fast accessing intermediate Cache is fast accessing intermediate memory that holds the most needed memory that holds the most needed data and instructions.data and instructions.

It is smaller than RAM.It is smaller than RAM. Because it is smaller than RAM a Because it is smaller than RAM a

search of cache is faster memory search of cache is faster memory access.access.

Therefore it is always searched first Therefore it is always searched first when available.when available.

CPU

CACHE RAM

BIT= smallest unit of storage

binary digit; 1 or a 0

BYTE

= 8 bits

KILOBYTE

MEGABYTE

GIGABYTE

TERABYTE

BYTE

= 1,000 bytes

= 1,000,000 bytes

= 1,000,000,000

bytes

= 1,000,000,000,000 bytes

MAIN

MENU

SECONDARY SECONDARY STORAGESTORAGE

DISKS/DRIVES

FloppyDrives

Hard Drives

CD Drives

MAIN

MENU

All secondary storage All secondary storage has 2 parts:has 2 parts:

A disk – a platter which stores the A disk – a platter which stores the data/inforamtiondata/inforamtion

A drive – mechanism which reads the diskA drive – mechanism which reads the disk

NOTE: a read/write head is part of the drive NOTE: a read/write head is part of the drive which sits over the disk and read the datawhich sits over the disk and read the data

A CRASH is when the read/write head touches the disk and destroys data.

All Disks have two parts:

SECTORS TRACKS

All Disks have two parts:

This makes an

Addressable

Space.

Therefore,

Disks are

Randomly

Accessible.

Hard DrivesHard Drives

Composed of several Composed of several disks.disks.

Large, permanent Large, permanent storage.storage.

Not portable storage.Not portable storage.

Disks are magnetic.Disks are magnetic.

Floppy DrivesFloppy Drives

Composed of one Composed of one disk.disk.

Large, permanent Large, permanent storage.storage.

Portable storage.Portable storage.

Disks are Disks are magnetic.magnetic.

CD DrivesCD Drives

Composed of one disk.Composed of one disk.

Very large, permanent Very large, permanent storage.storage.

Portable storage.Portable storage.

Disks work with light Disks work with light waves.waves.

Graphic ResourcesGraphic Resources

www.bedford.lib.nh.us/ Basics.htm www.bedford.lib.nh.us/ Basics.htm members.iweb.net.au/~pstorr/ members.iweb.net.au/~pstorr/

pcbook/book2/memchips.htmpcbook/book2/memchips.htm www.aiyamicro.com/htm-1/www.aiyamicro.com/htm-1/

computer-parts/ computer-parts-n... computer-parts/ computer-parts-n... webhome.idirect.com/~jadams/ webhome.idirect.com/~jadams/

electronics/identify2.htm electronics/identify2.htm www.csd.uwo.ca/bitbybit/ www.csd.uwo.ca/bitbybit/