Types of Computers
                     MODULE 1
 Types of Computer
1
Types of Computers…
• Based on the operational principle, computers 
 can be classified into three categories:
1. Analog computer
2. Digital computer
3. Hybrid computer
2
Analog Computers
• Analog computers are used to process analog 
 data.
• Analog data is of continuous nature and which is 
 not discrete or separate such as temperature,  
pressure, speed weight, voltage, depth etc.
• Utilize mechanical or electrical energy to 
 operate.
• Analog computers are the first computers being 
 developed and provided the basis for the  
development of the modern digital computers.
3
Analog Computers…
• Analog computers are widely used for certain  
specialized engineering and scientific  
applications, for calculation and measurement of 
 analog quantities.
• These computers are ideal in situations where 
 data can be accepted directly from measuring 
 instrument without having to convert it into  
numbers or codes.
Examples: The Speedometer of a car measures  
speed, the change of temperature is measured by 
 a Thermometer, etc.
4
Digital Computers
• They use digital circuits and are designed to  
operate on two states, namely bits 0 and 1. They 
 are analogous to states ON and OFF.
• Data on these computers is represented as a 
 series of 0s and 1s.
• Digital computers are suitable for complex  
computation and have higher processing speeds.
• They are programmable.
5
Digital Computers…
• Digital computers are either special purpose 
 computers or general purpose ones.
• Special purpose computers, as their name suggests, 
 are designed for specific types of data processing  
while general purpose computers are meant for  
general use.
• Most of the computers available today are digital 
 computers.
• The most common examples of digital 
computers  are accounting machines and 
calculators.
• Analog computers lack digital memory where as 
 digital computers store information.
6
Digital Computers…
Examples:
• IBM PC
• Apple Macintosh
• Digital calculators
• Digital watches etc
7
Hybrid Computers
• These computers are a combination of both 
 digital and analog computers.
• In this type of computers, the digital segments  
perform process control by conversion of analog 
 signals to digital ones.
• Hybrid computers for example are used for 
 scientific calculations, in defense and 
radar  systems.
8
Hybrid Computers…
• For example a petrol pump contains a processor 
 that converts fuel flow measurements into  
quantity and price values.
• In hospital Intensive Care Unit (ICU), an 
analog  device is used which measures 
patient's blood  pressure and temperature etc, 
which are then  converted and displayed in the 
form of digits.
• Radar systems are another example.
9
Cont’d
• Based on their proc…essing power (speed), cost  
and size computers can be classified into 4 types:
a) Micro computers
b) Minicomputers
c) Mainframe computers
d) Super computers
10
1. Micro/Personal computers
Desktop
Laptop/notebook 
 PALMTOP
PDA (PERSONAL 
DIGITAL ASSISTANT)
(The smallest 11
classification of 
computers)
2. Minicomputer
• Minicomputers are also called 
 mid-range systems or  
workstations.
• They contain one or more
microprocessors.
• Mini computers can be used to 
 handle the processing for  
many users simultaneously  
who are connected via  
terminals.
• Used in different software 
 application development.
• Examples:
 IBM AS/400
 IBM SYSTEM 360
 HP 3000
 PRIME 9755
12
3. Mainframe computers
• Mainframes are data processing  
system employed mainly in large  
organizations for various  
applications, including bulk data  
processing, process control, industry  
and consumer statistics, and financial 
 transaction processing.
 Mainframes typically cost several 
 hundred thousand dollars.
 They are used in situations where a 
 company wants the processing  
power and information storage in a 
 centralized location.
13
Mainframe computers…
• A mainframe computer may contain several 
 microprocessors.
• A single mainframe computer can be used by 
 hundreds of people at once.
• A mainframe computer system is usually composed 
 of several computers in addition to the mainframe, 
 or host processor.
Examples:
• IBM S/390
• Amdahl 580
• Control Data Cyber 176
14
4. Super computers
 are the largest, fastest, 
most  powerful, and most 
expensive  computers made.
 are used for extremely calculation- 
 intensive tasks such simulating  
nuclear bomb detonations,  
aerodynamic flows, and global  
weather patterns.
 Use multiple processors
 cost several million dollars
15
Super computers…
Features:
• The aerospace, automotive, chemical, electronics 
 and petroleum industries use supercomputers  
extensively.
• Supercomputers are used in weather forecasting.
• The ultra supercomputer will simulate nuclear  
explosions (eliminating the need to explode any 
 bombs).
• Supercomputers can perform at up to 128 gigaflops, 
 and use bus widths of 32 or 64 bits. This capability  
makes supercomputers suitable for processor-  
intensive applications, such as graphics.
16
Super computers…
EXAMPLE:
Cray-1
Cray-2
Control Data Cyber 205
 ETA
17