Semester One 2001/2002 Sheffield Hallam University1 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 University2 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 University3 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 University4 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 University5 Overview of PC Components System unit Monitor Keyboard and mouse Printer Software

Semester One 2001/2002 Sheffield Hallam University6 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 University7 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 University8 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 University9 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 University10 Software Minimum software requirement is OS Other kinds of software are applications –word processors –spreadsheets –games –programming languages

Semester One 2001/2002 Sheffield Hallam University11 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