programs. Figure 1-1 shows the CPU and the types of
peripheral (input and output [I/O]) devices you will find
in a computer system. The devices are interconnected
by electrical cables thru a bus to allow communications
The CPU communicates with the
peripheral devices through input/output (I/O) channels.
The brain of a computer system is the central
processing unit, which we refer to as the CPU. THE
CPU IS THE COMPUTER. It receives the data
transferred to it from one of the various I/O devices. It
processes the data and transfers the intermediate or final
results to an I/O device for storage or distribution.
The CPU executes stored programs and does all the
processing and manipulating of data. It contains the
circuits that control and perform the execution of
instructions using various types of memories. The I/O
devices simply aid the computer by providing and
receiving data and programs.
In this section, youll learn about the control unit,
the arithmetic-logic unit, primary storage, secondary
storage, peripheral devices, I/O channels, and modems.
Figure 1-1.Units/devices of a computer system.