Overview over the
H a r d w a r e
There are four main components of the hardware of a computer:
CPU and Memory
CPU: Contains electronic circuits, should transfer "data" into "information".
Microprocessor chip for PCs.
Computer memory or primary storage, RAM: holds data temporarily
before, during or after processing by the CPU.
Holds also the programs needed by the CPU.
- input devices
- output devices
- secondary storage
- scanner/bar code reader
- digital camera
like floppy disk, hard disk, CD, ...
Difference between primary and secondary storage
- primary storage (memory):
- most of it is RAM: volatile, limited, very quick access.
- only part of it is ROM (non-volatile)
Secondary storage: non-volatile, unlimited, "slow" (several milliseconds) access.
Secondary storage may be
- "random access" like magnetic disk (hard disk, diskette, CD), or
- "sequential access" (magnetic tape).
Classification of Computers
- Minicomputers, Workstations
- Notebooks, Laptops