Computer System Components; Hardware; Central Processing Unit (Cpu) - NCR PC4i Owner's Manual

HISTORICAL DATA
3. Exchange information with other users.
Another arrangement that is becoming more popular is for a person,
whose professional duties can be performed from a computer
terminal, e.g., a computer programmer, or a technical writer, to
actually work from a home computer which is dialed-up as a terminal
from the employer's central computer.
Bank-from-home and shop-from-home services can also be used by a
home computer user who installs the necessary communications
adapter and modem and makes arrangements where these services
are available.

COMPUTER SYSTEM COMPONENTS

A computer system has two component categories, hardware and
software.

HARDWARE

Hardware encompasses all of the physical parts of a computer
system. Each component performs a particular function and plays a
specific role in processing data:
1. Central Processing Unit — Arithmetic Logic Unit.
2. Memory (internal).
3. Memory (external) — disk drives and disks, tape drives and tapes.
4. Input devices — keyboards, etc.
5. Output devices — cathode ray tube (CRT), display screens,
printers.
6. Communications adapters, modems.
7. Cables, circuit boards.

Central Processing Unit (CPU)

The CPU is the "heart" of a computer. Data are processed in the CPU.
It contains all the arithmetic and logical circuitry in the computer,
and often has a component called the Arithmetic and Logic Unit
(ALU). All other circuitry in the computer is essentially for data
transfer — to/from the CPU, internal memory, external memory —
under the control of the CPU.
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