Hardware - BH
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Transcript of Hardware - BH
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GCSE Information Technology
Computer Systems
Computer System involves 3 stages
Input, Process, Output
Also a need to store data
Backing StorageDevices
InputDevices
Central ProcessingUnit (CPU)
OutputDevices
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GCSE Information Technology
Hardware and SoftwareComputer programs that tell (instruct)
the hardware how to work.
Files:Anything that can be stored is
also called software. Saving a word-
processed letter, or a spreadsheet, as a
computer file.
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GCSE Information Technology
Hardware- any part of acomputer that you can touch.
Hardware
The basic hardware of any computer consists of: central processing unit (CPU)
memory,
input, outputand backing storagedevices.
An individual piece ofhardware is called a device.
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GCSE Information Technology
Components (1)
Motherboard.CPU/Processor.
Memory/RAM.
Video Card/Graphics Adapter.Sound Card.
Modem.
Hard DrivePorts.
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GCSE Information Technology
The central processing unit (CPU)
where the searching and sortingof data, calculating and decision-
making goes on.
The CPU contains the
Cache Memory Control Unit Arithmetic and Logic Unit (ALU).
The Control Unitfetches instructionsfrom the main
memory, decodes themand causes them to beexecuted by the ALU.
TheALUperforms calculationsand makes decisionsusing these instructions.
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GCSE Information Technology
CPU
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GCSE Information Technology
Random Access Memory (RAM)
RAM is the computers
working memory.
RAM temporarilystoresprograms and datathat are
being used
The contents of RAM can be changed and are lostwhen the computer is turned off.
Memory which is wiped clean when the computeris turned off is called volatile memory.
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GCSE Information Technology
RAM Memory
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Read Only Memory (ROM)
ROM memory chips stores the program that runswhen the computer is turned on which loads theoperating system (e.g. Windows) from disk.
The contents of ROM cant be changedand arenot lostwhen the computer is switched off.
Memory which isn't wiped clean when thecomputer is turned off is called non-volatilememory.
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GCSE Information Technology
BITS and BYTES
Computers store and process data. These areelectronic charges represented by binarynumbers.
A single unit in binary is a bit which stands for
binarydigit.Computer memory is measured in bytes.One byte is made up of eight bits.One byte can store one character.
0 1 0 0 0 0 0 1
The eight bit binary code in thisbyte represents the letterA
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GCSE Information Technology
The size of a computersmemory is normally
measured in kilobytes (Kb), megabytes(Mb) or gigabytes (Gb). The table belowshows some of the main units of size that weuse to measure computer memory.
Measurement Size (bytes) Symbol
kilobyte 1,024 Kb
megabyte 1,048,576 Mb
gigabyte 1,073,741,824 Gb
BITS and BYTES (cont.)
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GCSE Information Technology
Switches and binaryComputers only understand switches being turned on
and off
these become signalsProgrammers interpret each combination of signals todo different things (e.g. to put things on the screen)
How powerful a computer is depends on how many
different signals it can receive.8 bit computers could receive 255 signals
Each time a switch is added, the number of signalsdoubles
Signals are added in multiples of 8
1 0 0 0 0 0 1 0
255 8 bit
1 0 0 0 0 0 1 0
16,000,00024 bit
1 0 0 0 0 0 1 0
65,00016 bit
1 0 0 0 0 0 1 0
4,000,000,000,000
32 bit
?
1 0 0 0 0 0 1 01 0 0 0 0 0 1 0 1 0 0 0 0 0 1 0 1 0 0 0 0 0 1 0
64 bit
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Mobile Computing
Laptops/Notebooks
Palmtops
PDAs
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Microcomputers
Microcomputers are sometimes called PCs, or
personal computers or desktops.
A typical PC system consists of:
A base, or tower unit that contains a CPUand
backing storage devices, normally a CD/DVD drive,and a hard disk drive.
Input devices, normally a mouse and keyboard.
Output devices, typically a screen, printer andspeakers.
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