Transcript Lecture 1 - Sheffield Hallam University

What is a Computer?
• System for storage, processing,
communication of information
– Hardware refers to physical components
which, if dropped, would break!
– Software is the term for sets of programs:
specially coded instructions that tell the
hardware how to behave
Semester One
2001/2002
Sheffield Hallam University
1
What is a Personal Computer?
• Generally any computer small and
cheap enough to be owned by one
person - Archimedes, Macintosh, Atari
etc.
• Ususally refers to particular type - IBM
compatible
• Commonly known as PC
Semester One
2001/2002
Sheffield Hallam University
2
IBM and Clones
• In 1981 IBM produced first PC
– cost £3000
– 1% of power of today’s machines
• Other companies made ‘clones’
– higher specifications
– lower cost
• Now very few PCs are actually IBM
Semester One
2001/2002
Sheffield Hallam University
3
IBM and Clones
• Operating System is a set of programs
to:
– enable user communication
– control behind-the-scenes activity
• Microsoft supplied OS for IBM PCs
– PC-DOS (Disk Operating System)
• Also sold as MS-DOS to clone makers
Semester One
2001/2002
Sheffield Hallam University
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Overview of PC Components
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System unit
Monitor
Keyboard and mouse
Printer
Software
Semester One
2001/2002
Sheffield Hallam University
5
System Unit
• Otherwise known as computer or
machine
• Case with buttons, lights, slot for floppy
disks, plug sockets at the rear
• Inside
– hard and floppy disk drives
– motherboard
– processor, memory and expansion slots
Semester One
2001/2002
Sheffield Hallam University
6
Monitor
• Looks like a TV
– most frequently used output device
• means of viewing the results of the computer’s
processing
– connects to the system unit by two cables
• one draws power
• other receives information from display adaptor
housed on motherboard
Semester One
2001/2002
Sheffield Hallam University
7
Keyboard and Mouse
• Both input devices
• Keyboard communicates characters
typed via multi-core cable (signal and
power)
• Mouse is most common pointing device
– communicates different things according to
position when clicked
Semester One
2001/2002
Sheffield Hallam University
8
Printer
• After monitors, printer most common
output device
• Unlike components so far, printer can
be bought separately from PC package
• Two basic types:
– impact (Dot Matrix)
– non-impact (Laser and Inkjet
Semester One
2001/2002
Sheffield Hallam University
9
Software
• Minimum software requirement is OS
• Other kinds of software are applications
– word processors
– spreadsheets
– games
– programming languages
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2001/2002
Sheffield Hallam University
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Desktops and Notebooks
• Desktops
– sit on your desk and don’t move often
– plenty of room inside for expansion and
upgrading
• Laptops
– first of the portable PCs around 1980s
• Notebooks
– size of a telephone directory
– much dearer than desktops
Semester One
2001/2002
Sheffield Hallam University
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