Computer material

CreativeCOMPUTER EDUCATION &
TRAINING CENTRE
creative computer education
COMPUTER BASICS

 DEFINITION:
computer is an electronic
data processing machine which
receives and stores large volumes of
data in the form of symbols and
digits and processes them at a high
speed as per the instructions and
outputs the results with great speed
and accuracy.

Speed:
any work in milli and micro seconds of time .speed of computer will be
calculated in hertz.
Accuracy:
computers are very accurate. If the input data entered into computer are
correct and if the program of instructions is reliable, then we can expect
the computer generally to produce accurate output.
Reliability:
The high speed of a computer is accompanied by an equally high level
of reliability. Thus a computer practically never makes a mistake of its
own accord.
Memory capability:
Every piece of information that is stored with in the computer’s
memory . It can store the data as binary code that is the combination of
zeros and ones.
Versatility:
The ability to communicate with the other systems and adopt to several
modes like audio visual, users friendly etc.
Characteristics of computer:

APPLICATIONS OF COMPUTER
Scientific research
Business applications
Payroll and personal records
Office automation
Electronic office

Stock controls and sales
Banking
Insurance and stock broking
Education and research
Transport and communication
APPLICATIONS OF COMPUTER

BLOCK DIAGRAM OF COMPUTER

Mainly a computer consists of three parts like
1 Input unit.
2 central processing unit
3 output unit.
1 Input unit: It receives data or information from the user.

2 Central processing unit: It process the data according to
user instructions at high speed. It contains 3 units .
a. storage or memory unit: It is used to store the data.
b. control unit: It is used to control the all the parts of
computer.
c. Arithmetic and logic unit: All calculations are performed
inALU of the computer.

CREATIVE COMPUTER EDUCATION
3 Output unit: It gives output to the user whenever they
need.

GENERATIONS OF COMPUTER
The first electronic computer was designed and built at the
University of Pennsylvania based on vacuum tube technology.
Vacuum tubes were used to perform logic operations and to
store data. Generations of computers has been divided into five
according to the development of technologies used to fabricate
the processors, memories and I/O units.
I Generation : 1945 – 55 .
II Generation : 1955 – 65.
III Generation : 1965 – 75.
IV Generation : 1975 – 89 .
V Generation : 1989 to present.

first generation:
1.Vacuum tubes were used – basic arithmetic operations took
few milliseconds .
2 Punched cards and paper tape were invented to feed
programs and data and to get results.
3 Consume more power with limited performance
4 High cost

Second generation:
1 Transistors were used in place of vacuum tubes. (invented at
AT&T Bell lab in 1947)
2 Small in size
3 Lesser power consumption and better performance .

Third generation:
1 ICs were used
2 Small Scale Integration and Medium Scale Integration
technology were implemented in CPU, I/O processors etc.
3 Smaller & better performance
4 Comparatively lesser cost

Fourth generation:
1 Microprocessors were introduced as CPU– Complete processors
and large section of main memory could
be implemented in a single chip
2 Tens of thousands of transistors can be placed in a single chip
(VLSI design implemented) .
3 Less power consumption
4 High performance, lower cost and very compact
5 Much increase in the speed of operation .

Fifth generation:
1 Introduced ULSI (Ultra Large Scale Integration) technology –
Intel’s Pentium 4 microprocessor contains 55 million transistors
millions of components on a single IC chip,.
2 Computers based on artificial intelligence are available.
3 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)
4 Object oriented language like JAVA suitable for internet
programming has been developed

Classification of computers
Computers are classified into 4 types. They are
1. Super Computers . 2. Main Frame Computers .
3. Mini Computers . 4. Micro Computers .
1.Super computers:
 Large and fast memory (Primary and Secondary)
Uses multiprocessing and parallel processing
Supports multiprogramming
 High power consumption
CPU speed: 100 MIPS .

2. Main Frame Computers:
 computers with large storage capacities .
 very high speed of processing
 Supports multi-user facility
 Number of processors varies from one to six.

3. Mini Computers:
Perform better than micros
 Large in size and costlier than micros
 Designed to support more than one user at a time
 Posses large storage capacities and operates at higher
speed
 Support faster peripheral devices like high speed printers
 Can also communicate with main frames .

4. Micro Computers:
A microcomputer uses a microprocessor as its central
Processing Unit. Microcomputers are tiny computers that can
vary in size from a single chip to the size of a desktop model
 They are designed to be used by only one person at a time
 Small to medium data storage capacities 500MB – 2GB
 The common examples of microcomputers are chips used
in washing machines, TVs, Cars and Note book/Personal
computers

Input devices
The device which takes data from the user and gives it to the
CPU. some of the input devices are given below………….
 Keyboard
Mouse
Trackball
Touchpad
Touchscreen
Joystick
Bar code reader
Scanner
Light Pen
OMR(Optical mark recognition)
OCR(Optical character reader) etc.

Keyboard: The computer keyboard is probably the most often
used input device. A keyboard contains keys that allow a user to
enter data and instructions into the computer. This is also known
as standard input device.
Keyboard has three categories of keys.
1. Alpha numeric keys: The alpha numeric keys comprise
alphabets,numbers & special characters.
ex: !, #, @, %,………….etc
2. Function keys: The function keys perform a set of
operations by a single key stroke. These are used for various
functions .
ex: F1, F2, F3, ……F12.
3. Special keys: These keys performs special tasks. Some of
special keys are del, ctrl, shift, ……etc
mouse : A mouse is the most widely used pointing device with a
GUI
environment on personal computers. Using a mouse to select
items or move to a particular position on the screen is faster than
using a keyboard. It is not easy and convenient to input text with
a mouse.

Trackball:
A trackball is a stationary pointing device with a ball mechanism
on its top. A trackball is a stationary pointing device with a ball
mechanism
on its top.
Touchpad:
Is a small pressure- and motion-sensitive area on a portable computer
that you can use
to move the mouse pointer. Easy and Fast one finger control. Ideal for
portable devices.
Touchscreen:
A touch screen is an input/output touch-sensitive display. Touch screens
are also used for ATM machines to allow easy access of bank accounts. A
touch screen allows easy access to commands, which are usually
identified by words or symbols on the screen.
Joystick:
A joystick is a pointing device with a vertical lever mounted on a base. A
joystick allows fast interactions required in most games.
OMR:
Optical mark recognition (OMR) readers can sense hand-drawn marks
such as small circles or rectangles made on pre-printed forms in certain
places.

Output devices
A device which is used to display accurate results as output is
known as output device. most frequently used output devices
are…………….
•Monitor,Printer,Speakers,Projector,plotters etc.
Monitor :
• The device which displays computer output.
• The monitor displays the video and graphics information
generated by the computer through the video card.
• Monitors are very similar to televisions but usually display
information at a much higher resolution.
Printer:
•Printer is an external hardware device responsible for taking
computer data and generating a hard copy of that data.
Printers can be categorized into:
•Impact Printer.
•Non-Impact Printer.

Plotter:
• The plotteris a computer printer for printing vector graphics
• Plotters are used in applications such as computer-aided design such
as diagrams, layouts, specification sheets and banners.
• Plotters are considerably more expensive than printers
Speakers:
• A hardware device connected to a computer's sound card that
outputs sounds generated by the computer.
• Speakers can be used for various sounds meant to alert the user, as
well as music and spoken text
Projector:
• An output device that can take the display of a computer screen and
project a large version of it onto a flat surface.
• Projectors are often used in meetings and presentations so that
everyone in the room can view the presentation.

Storage devices
Data and programs that are keyed into the computer are to
be temporarily held for processing . The results that are
obtained are also to be retained temporarily or even
permanently for later usage . To hold this data, programs,
results, etc., Storage devices have been introduced.
There are two classes of memory devices called
1. primary memory storage device
2. secondary storage device
1. Primary memory storage device: In these devices we
can’t store the data permanently . When the data going
to be processed then only that data is stored in the
primary memory.
The primary memory is divided into two types:
a. RAM(Random Access Memory)
b. ROM(Read Only Memory)

Storage devices
a. Random Access Memory: RAM is a primary memory where
data and instructions are held temporarily while the
program being executed. It has a capability of readwrite
memory and volatile. The data is lost when the power is
switch off & it is used to store and retrieve data and
instructions directly.
b. Read Only Memory: It is a non-volatile memory. It has
only read capability. The data can’t be lost when power is
switch off.

ROM’S are mainly three types:
1.PROM(programmable Read Only Memory)
2. EPROM(Erasable programmable Read Only Memory)
3. EEPROM(Electrically Erasable programmable Read Only
Memory)
2.Secondary storage device: In secondary memory unit we can store
the data permanently. Initially , the data which taken from the input
devices are stored in the secondary memory during the execution of
data, that data is retrieved from the secondary memory unit and it is
placed on the primary memory unit. After the calculations are over ,
the data is again stored in the secondary storage devices with results.

Operating System
Definition of Operating System:
An Operating system is a program that controls the execution of
application programs and acts as an interface between the user of a
computer and the computer hardware
A more common definition is that the operating system is the one
program running at all times on the computer (usually called the
kernel), with all else being applications programs
Operating System Components :
1. Process Management
2. Main Memory Management
3. File Management
4. Secondary Storage Management
5. I/O System Management
6. Networking
7. Protection System
8. Command Interpreter System

TYPES OF OPERATING SYSTEM
1. Batch : Jobs with similar needs are batched together and run through
the computer as a group by an operator or automatic job sequencer. A
Batch system is good for executing large jobs that need little
interaction, it can be submitted and picked up latter.
2. Time sharing : Uses CPU s scheduling and multiprogramming to
provide economical interactive use of a system. The CPU switches rapidly
from one user to another i.e. the CPU is shared between a number of
interactive users.
3. Interactive : User is on line with computer system and interacts with it
via an interface. It is typically composed of many short transactions where
the result of the next transaction may be unpredictable.
4. Real time system : Real time systems are usually dedicated, embedded
systems. They typically read from and react to sensor data. The system
must guarantee response to events within fixed periods of time to ensure
correct performance.

TYPES OF OPERATING SYSTEM
5. Distributed : Distributes computation among several physical
processors. The processors do not share memory or a clock. Instead, each
processor has its own local memory. They communicate with each other
through various communication lines.
6. Multitasking: Multitasking, is a logical extension of multiprogramming.
Multiple jobs are executed by the CPU switching between them, but the
switches occur so frequently that the users may interact with each
program while it is running.
7.Embedded:“computer system” that performs a dedicated function or is
designed for use with a specific embedded software application.

FUNCTIONS OF OPERATING SYSTEM
Operating system performs three functions:
1. Convenience: An OS makes a computer more convenient to use.
2. Efficiency: An OS allows the computer system resources to be used in
an efficient manner.
3. Ability to Evolve: An OS should be constructed in such a way as to
permit the effective development, testing and introduction of new system
functions without at the same time interfering with service .
4.Memory Management :Memory is central to the operation of a modern
computer system . Depending on the memory management in use the
process may be moved between disk and memory during its execution .

COMPUTER LANGUAGES
Like the common languages as telugu, hindi computer also provides
languages to make the communication between system and user easy.
computer languages are classified into three types.
They are
 machine level language.
 assembly language.
 high level languages.

COMPUTER LANGUAGES
machine level language: this language is easily understand by the
computer. This is also known as fundamental or basic language. It is
coded as 0’s or 1’s. so it is not understandable by user.
assembly language:I t is one level over computer language. It can uses
certain predefined symbols commonly known as pnemonics instead of
byte code. These pnemonics are easy to understand than byte code.
By using assembler program we convert assembly level language into
machine level language.
assembly level language assembler machine level language

High level language: this language is known as third generation
language. It resembles to our English language. This language is easily
understandable by human. High level language is developed overcoming
the difficulties facing with machine level and assembly level languages.
By using compiler and interpreter programs we can easily convert the
high level language into machine level language.
high level language compiler /interpreter
Creative computer education
machine level
language

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