Basic components of a computer

Main parts of a PC or workstation:

external devices:

user input keyboard, mouse
screen output graphic card
permanent storage hard disks
other sound card, printer, cdrom, network devices, ...


CPU: ``Central Processing Unit'', consists of:
arithmetic and logic unit = ALU (addition, multiplication, comparison etc.)
registers (extremely fast special memory for commands and operands)
control unit (gets commands, moves data to/from ALU and memory)

Type of commands, a CPU understands:
data movement
``get data from memory cell 4228 into register r3''
``add content of registers r1 and r2 and store the sum in r3''
program flow
``get the next command from memory cell 2001, if register r1 contains 0''

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Peter Junglas 8.3.2000