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Introduction to Computers and
Programming
Chapter 1
Basics of Computers: Definition,
Computer Generations.
Computer Definition:
• A computer is an electronic machine that can
input, process, store and output a vast
amount of information at an extremely high
speed.
Or
• A computer is an electronic device that
manipulates information, or data. It has the
ability to store, retrieve, and process data.
Computer Diagram
Central Processing Unit(c p u)
Arithmetic
Arithmetic
andUnit
Logic
and Logic
Unit
Input Unit
Keyboard, mouse
Output Unit
Printer, Monitor
Control Unit
Memory Unit
Main memory: ROM, RAM
Secondary memory: hard disk
Input Unit and Output unit
• Input unit:-Used to enter the data or program
(instructions)
• Output unit:-Output the results or data
Central Processing Unit
CPU:-The data is processed in this unit.
1. Arithmetic and Logic Unit (ALU)
2. Control Unit (CU)
3.Memory Unit (MU)
Arithmetic and Logic Unit (ALU)
• An ALU can do arithmetic operations like
addition (+), subtraction (-), multiplication (*),
division (/).
• It also can do logic operations like true or
false, yes or no.
Control Unit (CU)
• The unit controls and co-ordinates all parts of
computer system.
Memory Unit (MU)
• Memory unit:-This is the storage device
(used to store programs and data)
• Types of memory:
1. Main memory
2. Secondary memory
3. Cache memory
Main memory
• Temporary memory because the data is
erased. When the power goes off. (in RAM)
• It consists of RAM and ROM
• RAM – Random access Memory
• ROM – Read only Memory
Secondary memory
• permanent memory or back up memory.
• It stores a large amount of information for a
long time,
• speed is less than main memory.
Cache memory
• high speed memory and placed between the
CPU and the main memory.
Generations of Computers
•
•
•
•
•
•
1st
2nd
3rd
4th
5th
6th
Generation : 1945 – 55
Generation : 1955 – 65
Generation : 1965 – 75
Generation : 1975 – 89
Generation : 1989 to present
Generation : Future
1st Generation : 1945 – 55
1st Generation : 1945 – 55
• During the period of 1940 to 1956 first
generation of computers were developed.
• The first generation computers used vacuum
tubes for circuitry and magnetic drums for
memory, and were often enormous, taking up
entire rooms.
•
The vacuum tube was developed by Lee De
Forest. A vacuum tube is a device generally
used to amplify a signal by controlling the
movement of electrons in an evacuated space.
CHARACTERISTICS
•
•
First generation computers were based on vacuum tubes.
The operating systems of the first generation computers
were very slow.
• They were very large in size.
• Production of the heat was in large amount in first
generation computers.
•
Machine language was used for programming.
• First generation computers were unreliable.
• They were difficult to program and use.
UNIVAC -1951
(Universal Automatic Computer)
UNIVAC -1951
•First fully electronic digital computer
built in the U.S.
•Created at the University of
Pennsylvania
•ENIAC weighed 30 tons contained
18,000 vacuum tubes
•Cost a paltry $487,000
It is the Bendix G-15 General Purpose
Digital Computer, a First
Generation computer introduced in 1956.
SECOND GENERATION OF
COMPUTERS
SECOND GENERATION OF
COMPUTERS
• The computers built in the 1950s and 1960s are
considered the 2nd generation computers. These
computers make use of the transistors invented
by Bell Telephone laboratories and they had many
of the same components as the modern-day
computer. For instance, 2nd generation
computers typically had a printer, some sort of
tape or disk storage, operating systems, stored
programs, as well as some sort of memory. These
computers were also generally more reliable and
were solid in design.
SECOND GENERATION OF
COMPUTERS(TRANSISTORS)
• A transistor computer is a computer which uses
discrete transistors instead of vacuum tubes. The
"first generation" of electronic computers used
vacuum tubes, which generated large amounts of
heat, were bulky, and were unreliable. A "second
generation" of computers, through the late 1950s
and 1960s featured boards filled with individual
transistors and . magnetic memory cores they
were first developed in 1947 They. Transistors are
most often used to regulate the flow of an
electrical current and to switch electricity on and
off.
Characteristics
(second generation computer)
 Second generation computer machines were based on transistor
technology.
 Second generation computers were smaller as compared to
the first generation computers
 The computational time of Second generation computers was
reduced to microseconds from milliseconds.
 Second generation computers were more reliable and less prone
to hardware failure. Hence, such computers required less frequent
maintenance.
 Second generation computers were more portable and generated
less amount of heat.
 Assembly language was used to program Second generation
computers. Hence, programming became more time-efficient and
less cumbersome.
 Manual assembly of individual components into a functional unit
was still required.
3rd generation of computers
3rd generation of computers
• The 3rd Generation computers replaced
transistors with “integrated circuits” or I.C.
was inverted by Jack Kilby as Texas
instruments in 1958.
• The 3rd generation computers using integrated
circuits proved to be highly reliable, relatively
inexpensive, and faster. Less human labour is
required at assembly stage.
Fourth Generation (1971-Present)
Fourth Generation (1971-Present)
• In 1981 IBM introduced its first computer for
the home user, and in 1984 Apple introduced
the Macintosh. Microprocessors also moved
out of the realm of desktop computers and
become more advanced.
• As these small computers became more
powerful, they could be linked together to
form networks, which also led to the
development of the Internet. Fourth
generation computers also saw the
development of the mouse and handheld
devices.
Fourth Generation (1971-Present)
• The microprocessor brought the fourth
generation of computers, as thousands of
integrated circuits were built onto a single
silicon chip. What in the first generation
filled an entire room could now fit in the
palm of the hand. The Intel 4004 chip,
developed in 1971, located all the
components of the computer—from the
central processing unit and memory to
input/output controls—on a single chip.
Fourth Generation (1971-Present)
Time Period: 1975 to Today
Technology: VLSI (Very Large Scale
Integration)
Incorporated many millions of transistors &
electronic circuits on a single chip.
Size: Small as compared to first generation
computer.
Processing: Faster then first generation
computer
FIFTH GENERATION COMPUTERS
FIFTH GENERATION COMPUTERS
Fifth generation computing devices, based
on artificial intelligence, are still in development,
though there are some applications, such as voice
recognition, that are being used today. The use
of parallel processing and superconductors is
helping to make artificial intelligence a
reality. Quantum computation and molecular
and nanotechnology will radically change the face
of computers in years to come. The goal of fifthgeneration computing is to develop devices that
respond to natural language input and are
capable of learning and self-organization.
FIFTH GENERATION COMPUTERS
• Less power consumption .
• High performance, lower cost and very compact.
• Computers based on artificial intelligence are
available.
• Portable note book computers introduced .
• Memory chips up to 1 GB, hard disk drives up to
180 GB and optical disks up to 27 GB are
available (still the capacity is increasing) .
End of Chapter 1