Page 10 - DCAP105_WORKSHOP_ON_COMPUTER_HARDWARE_AND_NETWORK

Workshop on Computer Hardware and Network

Notes The clock speed of CPU is measured in terms of Mega Hertz (MHz) or Millions of Cycles
per second. The clock speed of CPU varies from one model to another in the range
4.77 MHz (in 8088 processor) to 266 MHz (in Pentium II). CPU speed is also specified in
terms of Millions of Instructions Per Second (MIPS) or Million of Floating Point Operations Per
Second (MFLOPS).
The relation between various hardware components of a computer system is depicted in the
figure 1.1:

Figure 1.1: Internal Working of CPU

BUS

Primary
CPU
Memory

ALU CU

Secondary

Storage

I/O Unit

Task Compare and contrast Arithmetic Logic Unit (ALU) and Control Unit.

1.1.2 Input Devices

Input devices are used to input data, information and instructions into the RAM. These are
“stand-alone” data entry stations. These units usually have a small processor attached to a
keyboard and a visual display unit. The processor checks for the accuracy of data at the time of
entry.

The common input devices are mentioned below.

Keyboard
Figure 1.2: Keyboard

The keyboard is one of the most common input devices of computers. The layout of the keyboard
is like that of the traditional QWERTY typewriter. Most keyboards have three sections of keys:
the standard typing keys, cursor movement keys and the numeric keypad. To help users enter

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