Basic concepts of computer generations

2014
ZUNAIRA SAEED BALOUCH
ISLAMIC INTERNATIONAL UNIVERSITY
OF ISLAMABAD
3/21/2014
THE BASIC CONCEPTS OF
COMPUTER

THE BASIC CONCEPTS OF COMPUTER
CONTENTS
GENERATIONS OF COMPUTERS..................................................................................................................... 0
First Generation (1940 to 1956): Using Vacuum Tubes ............................................................................. 0
Hardware Technology................................................................................................................... 0
Software Technology .................................................................................................................... 0
Computing Characteristics............................................................................................................ 0
Physical Appearance ..................................................................................................................... 0
Application.................................................................................................................................... 1
Examples ....................................................................................................................................... 1
Second Generation (1956 to 1963): Using Transistors .............................................................................. 1
Application.................................................................................................................................... 1
Examples ....................................................................................................................................... 1
Third Generation (1964 to 1971): Using Integrated Circuits...................................................................... 2
Application.................................................................................................................................... 2
Examples ....................................................................................................................................... 2
Fourth Generation (1971 to present): Using Microprocessors.................................................................. 2
Application.................................................................................................................................... 3
Examples................................................................................................................................................ 3
Fifth Generation (Present and Next): Using Artificial Intelligence ............................................................. 3

Printer............................................................................................................................................................. 4
Modern printer technology: ...................................................................................................................... 4
Toner-based printers ............................................................................................................................. 4
Impact printer ............................................................................................................................................ 0
Typewriter-derived printers .................................................................................................................. 0
Computer memory ......................................................................................................................................... 0
Read only memory ..................................................................................................................................... 0
PROM..................................................................................................................................................... 1
Random access memory ............................................................................................................................ 1
DRAM:.................................................................................................................................................... 1
Buses .............................................................................................................................................................. 1
System buses:............................................................................................................................................. 1
Data bus:................................................................................................................................................ 1
Expansion bus: ........................................................................................................................................... 2
ISA bus: .................................................................................................................................................. 2
Software: ........................................................................................................................................................ 2
System software:........................................................................................................................................ 2
Operating system:.................................................................................................................................. 2
Application software:................................................................................................................................. 2
HARDWARE..................................................................................................................................................... 2
INPUT DEVICES........................................................................................................................................... 3
The Mouse ............................................................................................................................................. 3
The Keyboard......................................................................................................................................... 3
Pointing devices..................................................................................................................................... 3
OUTPUT DEVICES ....................................................................................................................................... 3
Tactile .................................................................................................................................................... 4
Audio...................................................................................................................................................... 4
Hardware ............................................................................................................................................... 4
Software................................................................................................................................................. 4
REFERENCES ................................................................................................................................................... 5

GENERATIONS OF COMPUTERS
COMPUTER
BASIC CONCEPTS OF COMPUTER
GENERATIONS OF COMPUTERS
The computer has evolved from a large-sized simple calculating machine to a smaller but much
more powerful machine. The evolution of computer to the current state is defined in terms of
the generations of computer. Each generation of computer is designed based on a new
technological development, resulting in better, cheaper and smaller computers that are more
powerful, faster and efficient than their predecessors. Currently, there are five generations of
computer. In the following subsections, we will discuss the generations of computer in terms
of—
the technology used by them (hardware and software),
computing characteristics (speed, i.e., number of instructions executed per second),
physical appearance, and
Their applications
FIRST GENERATION (1940 TO 1956): USING VACUUM TUBES
HARDWARE TECHNOLOGY
The first generation of computers used vacuum tubes for circuitry and magnetic drums for
memory. The input to the computer was through punched cards and paper tapes. The output
was displayed as printouts.
SOFTWARE TECHNOLOGY
The instructions were written in machine language. Machine language uses 0s and 1s for coding
of the instructions. The first generation computers could solve one problem at a time.
COMPUTING CHARACTERISTICS
The computation time was in milliseconds.
PHYSICAL APPEARANCE
These computers were enormous in size and required a large room for installation.

APPLICATION
They were used for scientific applications as they were the fastest computing device of their
time.
EXAMPLES
Universal Automatic Computer (UNIVAC), Electronic Numerical Integrator and Calculator
(ENIAC), and Electronic Discrete Variable Automatic Computer (EDVAC).
SECOND GENERATION (1956 TO 1963): USING TRANSISTORS
HARDWARE TECHNOLOGY
Transistors replaced the vacuum tubes of the first generation of computers. Transistors
allowed computers to become smaller, faster, cheaper, energy efficient and reliable.
The second generation computers used magnetic core technology for primary memory.
They used magnetic tapes and magnetic disks for secondary storage. The input was still
through punched cards and the output using printouts. They used the concept of a
stored program, where instructions were stored in the memory of computer.
SOFTWARE TECHNOLOGY
The instructions were written using the assembly language. Assembly language uses
mnemonics like ADD for addition and SUB for subtraction for coding of the instructions.
It is easier to write instructions in assembly language, as compared to writing
instructions in machine language. High-level programming languages, such as early
versions of COBOL and FORTRAN were also developed during this period.
The computation time was in microseconds.
PHYSICAL APPEARANCE
Transistors are smaller in size compared to vacuum tubes, thus, the size of the computer
was also reduced.
APPLICATION
The cost of commercial production of these computers was very high, though less than
the first generation computers. The transistors had to be assembled manually in second
generation computers.
EXAMPLES
PDP-8, IBM 1401 and CDC 1604.

Second generation computers generated a lot of heat but much less than the first generation
computers. They required less maintenance than the first generation computers.
THIRD GENERATION (1964 TO 1971): USING INTEGRATED CIRCUITS
HARDWARE TECHNOLOGY
The third generation computers used the Integrated Circuit (IC) chips. In an IC chip, multiple
transistors are placed on a silicon chip. Silicon is a type of semiconductor. The use of IC chip
increased the speed and the efficiency of computer, manifold. The keyboard and monitor
were used to interact with the third generation computer, instead of the punched card and
printouts.
SOFTWARE TECHNOLOGY
The keyboard and the monitor were interfaced through the operating system. Operating system
allowed different applications to run at the same time. High-level languages were used
extensively for programming, instead of machine language and assembly language.
The computation time was in nanoseconds.
PHYSICAL APPEARANCE
The size of these computers was quite small compared to the second generation computers.
APPLICATION
Computers became accessible to mass audience. Computers were produced commercially, and
were smaller and cheaper than their predecessors.
EXAMPLES
IBM 370, PDP 11.
The third generation computers used less power and generated less heat than the second
generation computers. The cost of the computer reduced significantly, as individual components
of the computer were not required to be assembled manually. The maintenance cost of the
computers was also less compared to their predecessors.
FOURTH GENERATION (1971 TO PRESENT): USING MICROPROCESSORS
HARDWARE TECHNOLOGY
They use the Large Scale Integration (LSI) and the Very Large Scale Integration (VLSI)
technology. Thousands of transistors are integrated on a small silicon chip using LSI
technology. VLSI allows hundreds of thousands of components to be integrated in a
small chip. This era is marked by the development of microprocessor. Microprocessor is

a chip containing millions of transistors and components, and, designed using LSI and
VLSI technology. A microprocessor chip is shown in Figure 1.7. This generation of
computers gave rise to Personal Computer (PC). Semiconductor memory replaced the
earlier magnetic core memory, resulting in fast random access to memory. Secondary
storage device like magnetic disks became smaller in physical size and larger in capacity.
The linking of computers is another key development of this era. The computers were
linked to form networks that led to the emergence of the Internet. This generation also
saw the development of pointing devices like mouse, and handheld devices.
SOFTWARE TECHNOLOGY
Several new operating systems like the MS-DOS and MS-Windows developed during this
time. This generation of computers supported Graphical User Interface (GUI). GUI is a
user-friendly interface that allows user to interact with the computer via menus and
icons. High-level programming languages `1are used for the writing of programs.
The computation time is in picoseconds.
PHYSICAL APPEARANCE
They are smaller than the computers of the previous generation. Some can even fit into
the palm of the hand.
APPLICATION
They became widely available for commercial purposes. Personal computers became
available to the home user.
EXAMPLES
The Intel 4004 chip was the first microprocessor. The components of the computer like Central
Processing Unit (CPU) and memory were located on a single chip. In 1981, IBM introduced the
first computer for home use. In 1984, Apple introduced the Macintosh.
The microprocessor has resulted in the fourth generation computers being smaller and cheaper
than their predecessors. The fourth generation computers are also portable and more reliable.
They generate much lesser heat and require less maintenance compared to their predecessors.
GUI and pointing devices facilitate easy use and learning on the computer. Networking has
resulted in resource sharing and communication among different computers.
FIFTH GENERATION (PRESENT AND NEXT): USING ARTIFICIAL INTELLIGENCE
The goal of fifth generation computing is to develop computers that are capable of learning and
self-organization. The fifth generation computers use Super Large Scale Integrated (SLSI) chips
that are able to store millions of components on a single chip. These computers have large
memory requirements.

This generation of computers uses parallel processing that allows several instructions to be
executed in parallel, instead of serial execution. Parallel processing results in faster processing
speed. The Intel dual-core microprocessor uses parallel processing.
The fifth generation computers are based on Artificial Intelligence (AI). They try to simulate the
human way of thinking and reasoning. Artificial Intelligence includes areas like Expert System
(ES), Natural Language Processing (NLP), speech recognition, voice recognition, robotics, etc.
THE FIVE GENERATIONS OF COMPUTER (TABLE)
GENERATIONS
YEARS SOFTWARE HARDWARE
COMPUTATION
TIME
EXAMPLES
1ST 1940 to
1956
machine
language
Vacuum Tubes Milliseconds.
UNIVAC,
ENIAC and
EDVAC
2ND 1956 to
1963
programming
languages
Transistors microseconds
PDP-8, IBM
1401 and CDC
1604
3RD 1964 to
1971
Operating
system
Integrated
Circuits
nanoseconds
IBM 370, PDP
11
4TH 1971 to
present
MS-DOS and
MS-Windows
Microprocessors
picoseconds
Intel 4004
chip
5TH Present and
Next
parallel
processing
(SLSI) chips
PRINTER
In computing, a printer is a peripheral which makes a representation of an electronic document
on physical media. Individual printers are designed to support local and network users at the
same time. Some printers can print documents stored on memory cards or from digital cameras
and scanners. Consumer and some commercial printers are designed for low-volume, short-
turnaround print jobs; requiring virtually no setup time to achieve a hard copy of a given
document. However, this is offset by the on-demand convenience and project management
costs being more controllable compared to an out-sourced solution.
MODERN PRINTER TECHNOLOGY:
The following printing technologies are routinely found in modern printers:
TONER-BASED PRINTERS

Computer memory
A laser printer rapidly produces high quality text and graphics. As with digital photocopiers and
multifunction printers (MFPs), laser printers employ a xerographic printing process but differ
from analog photocopiers in that the image is produced by the direct scanning of a laser beam
across the printer's photoreceptor.
IMPACT PRINTER
Relay on a forcible impact to transfer ink to the media. The impact printer uses a print head that
either hits the surface of the ink ribbon, pressing the ink ribbon against the paper (similar to the
action of a typewriter), or hits the back of the paper, pressing the paper against the ink ribbon
(the IBM 1403 for example). All but the dot matrix printer rely on the use of fully formed
characters, letterforms that represent each of the characters that the printer was capable of
printing. In addition, most of these printers were limited to monochrome, or sometimes two-
color, printing in a single typeface at one time, although bolding and underlining of text could be
done by "overstriking", that is, printing two or more impressions in the same character position.
TYPEWRITER-DERIVED PRINTERS
Main articles: Friedan Flex writer and IBM Electric type writertype ball print element
from IBM Electric-type printer several different computer printers were simply computer-
controllable versions of existing electric typewriters. The Friedan Flex writer and IBM Electric-
based printers were the most-common examples. The Flex writer printed with a conventional type
bar mechanism while the Electric used IBM's well-known "golf ball" printing mechanism. In
either case, the letter form then struck a ribbon which was pressed against the paper, printing one
character at a time. The maximum speed of the Electric printer (the faster of the two) was 15.5
characters per second.
COMPUTER MEMORY
The computer memory is a temporarystoragearea. It holds the data and instructions that the
Central Processing Unit (CPU) needs. Before a program can be run, the program is loaded from
some storage medium into the memory. This allows the CPU direct access to the program.
Memory is a need for any computer.
A computer is usually an electrical device, which understands only electricity on and electricity
off. This is expressed by using two symbols – 0 and 1 – which are called binarydigits or bits.
Numbers and text characters are represented as codes, which are made up of combinations of 0s
and 1s. Simple character codes are called ASCII (the American Standard Code for Information
Interchange). In ASCII, eight bits – any combination of 0s and 1s – form one character or symbol.
For example, the letter A is denoted by the code 01000001.
As a result, the computer's memory usually consists of two parts:
READ ONLY MEMORY
Read only memory (ROM) is the permanent memory which is used to store important control
programs and systems software to perform a variety of functions, such as booting up or starting
up programs. ROM is non-volatile. That means the contents are not lost when the power is

switched off. Its contents are written at the time of manufacture, but in modern (2012) computers
may be changed using special software.
PROM
Prom stand for programmable read only memory .this form of ROM is initially blank .the user
can write data on it using special devices.
RANDOM ACCESS MEMORY
Random access memory (RAM) is used as the working memory of a computer system. It stores
input data, intermediate results, programs, and other information temporarily. It can be read
and written. It is usually volatile, that is all data will be lost when the power is turned off. In
most cases it is loaded again from hard disk
DRAM:
DRAM stand for dynamic random access memory.it require an electric current to maintain its
state. The electric charge of dram decreases with the time that may result in loss of data.
Operation of AND (.)
x y z
Nil
0 0 0
0 1 0
1 0 0
1 1 1
BUSES
A computer system consist of different devices. The devices are connected together by a
communication channel called bus.it is used to move a large amount of bits in the form of
electric pulses from one unit to another.
SYSTEM BUSES:
Different types of system buses as follows:
Data bus
Address bus
Control bus
DATA BUS:

It is used to carry data .it is an electrical path that connects CPU, memory, input/output devices
and secondary storage devices. The bus contain parallel set of lines. A data bus with more lines
carry more data.
EXPANSION BUS:
The buses that connect CPU to the peripheral devices are called expansion buses. Expansion
buses are typically 16 to 64 bits wide and are mounted on motherboard.
Different types of expansion buses as follows:
ISA BUS:
Isa stand for industry standard architecture.it has been around since 1984.it has developed
for IBM personal computer .it is most common and slowest expansion bus. Isa bus
transmit 8 to 16 bits at one time.
SOFTWARE:
A set of instructions given to the computer to solve a problem is called software. Software also
known as program. Different software are used to solve different problems. A computer
software specifies a sequence of operations to be performed by computer.
SYSTEM SOFTWARE:
System software is a set of programs to control and manage the actual operations of a computer
hardware.it control the usage and allocation of different hardware components.it enables
application program to execute properly.
OPERATING SYSTEM:
An operating system is a set of programs that manages all computer components and
operations. A computer cannot do anything without an operating system. Operating system
must be installed on every computer.
APPLICATION SOFTWARE:
Application software is used to perform various application on the computer.it helps a computer
user to perform various tasks. People use application software according to their needs.it is also
known as application package. The application software uses the operating system in order to
function.it run on the top of the operating system.
HARDWARE
Hardware is a physical device something that you’re able to touch and see. For example, the
computer monitor you’re viewing this text on or the mouse you’re using to navigate is

considered computer hardware. Software is a program that enables a computer to perform a
specific task, as opposed to the physical components of the system (hardware).
INPUT DEVICES
In computing, an input device is any peripheral (piece of computer hardware equipment) used
to provide data and control signals to an information processing system such as a computer or
other information appliance. Examples of input devices include keyboards, mouse, scanners,
digital cameras and joysticks.
THE MOUSE
Used to ‘drive’ Microsoft Windows
THE KEYBOARD
A 'keyboard' is a human interface device which is represented as a layout of buttons. Each
button, or key, can be used to either input a linguistic character to a computer, or to call upon a
particular function of the computer. Traditional keyboards use spring-based buttons, though
newer variations employ virtual keys, or even projected keyboards.
Examples of types of keyboards include:
Computer keyboard
Keyes
Chorded keyboard
LPFK
POINTING DEVICES
Keyboard devices are the most commonly used input devices
today. A pointing device is any human interface device that
allows a user to input spatial data to a computer. In the case
of mice and touchpads, this is usually achieved by detecting
movement across a physical surface. Analog devices, such as
3D mice, joysticks, or pointing sticks, function by reporting
their angle of deflection. Movements of the pointing device
are echoed on the screen by movements of the pointer,
creating a simple, intuitive way to navigate a computer's GUI.
OUTPUT DEVICES
An output device is any piece of computer hardware equipment used to communicate the
results of data processing carried out by an information processing system (such as a computer)
which converts the electronically generated information into human-readable form.Some types

of output are text, graphics, tactile,[4]
audio, and video. Text consists of characters (letters,
numbers, punctuation marks, or any other symbol requiring one byte of computer storage
space) that are used to create words, sentences, and paragraphs. Graphics are digital
representations of non-text information such as drawings, charts, photographs, and animation
(a series of still images in rapid sequence that gives the illusion of motion). Tactile output such
as raised line drawings may be useful for some individuals who are blind. Audio is music, speech,
or any other sound. Video consists of images played back at speeds to provide the appearance
of full motion.
TACTILE
Haptic technology, or haptic, is a tactile feedback technology which takes advantage of the
sense of touch by applying forces, vibrations, or motions to the user. Several printers and wax
jet printers have the capability of producing raised line drawings. There are also handheld
devices that use an array of vibrating pins to present a tactile outline of the characters or text
under the viewing window of the device.
AUDIO
Speech output systems can be used to read screen text to computer users. Special software
programs called screen readers attempt to identify and interpret what is being displayed on the
screen and speech synthesizers convert data to vocalized sounds or text.
HARDWARE SOFTWARE
Definition
Devices that are required to store and
execute (or run) the software.
Collection of instructions that
enables a user to interact with the
computer. Software is a program that
enables a computer to perform a
specific task, as opposed to the
physical components of the system
(hardware).
Types
Input, storage, processing, control, and
output devices.
System software, Programming
software, and Application software.
Examples
CD-ROM, monitor, printer, video card,
scanners, label makers, routers, and
modems.
QuickBooks, Adobe Acrobat,
Windom’s-Cs, Internet Explorer ,
Microsoft Word , Microsoft Excel

Function
Hardware serve as the delivery system
for software solutions. The hardware of
a computer is infrequently changed, in
comparison with software and data,
which are “soft” in the sense that they
are readily created, modified, or erased
on the computer
To perform the specific task you need
to complete. Software is generally not
needed to for the hardware to
perform its basic level tasks such as
turning on and responding to input.
Inter
dependency
Hardware starts functioning once
software is loaded.
To deliver its set of instructions,
Software is installed on hardware.
Failure
Hardware failure is random. Hardware
does have increasing failure at the last
stage.
Software failure is systematic.
Software does not have an increasing
failure rate.
Durability Hardware wears out over time.
Software does not wear out over
time. However, bugs are discovered
in software as time passes.
Nature Hardware is physical in nature. Software is logical in nature.
REFERENCES
WWW.GOOGLE.COM
WWW.WIKIBOOK.COM
WWW.ASK.COM

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