Introduction to computer science dessalegn Mequanint Yehuala Foreword

STORAGE : 
Computer has the capacity to store mass volume of data with
appropriate format.
•
DILIGENCE: 
Computer never feels bored and it can work for hours and hours
without any break and creating error.
•
VERSATILITY: 
Computers are multipurpose. A Computer can perform
completely different types of work at the same time.
•
POWER OF REMEMBERING:
It stores data for future use.
•
NO IQ: 
Computer needs to be instructed to do its job.
•
NO FEELING: 
Computer does not have emotions, knowledge, experience and
feeling.

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Unit 1: Introduction to Computer Systems
23
Types of Computers
There are different types of Computers. Besides size and purpose of application, their
differences also stem from variations in terms of how they function or method of operation[2].
Classification by the Method of Operation (processing)
On the basis of their method of operations Computers are further classified into three:
Analog Computers
: Analog computers operate by measuring. They deal with continuous
variables; as opposed to discrete values or numbers, rather, they operate by measuring
physical magnitude such as pressure, temperature, voltage, current etc.
Examples:
a. Thermometer, Voltmeter, Speedometer
b. Gasoline pump – Contains an analog Computer that converts the flow of pumped
fuel into two measurements the price of the delivered gas and the quantity of
pumped fuel.
Note:
They are special purpose computers, and they are known for limited accuracy.
Digital Computers
Digital computers deal with discrete variables; they operate by counting rather than measuring.
They operate directly upon numbers (or digits) that represent numbers, letters, or other special
symbols.
Examples:
• Abacus
• Desk & pocket computers
• The general purpose computers