processing, storage and dissemination of vocal, pictorial,
textual and numeric information by a micro-electron based
combination of computing and telecommunication.
Technology is a merging of computing and telecommunication.
information is called data.
General term for
numbers , symbols, and quantities that serve as input for
computer processing are called data.
Data is a
collective noun and may be either singular or plural.
Different pieces of data combine to form complete information
is the process of changing data to acquire the desired result.
Data Processing is a process
of collecting the data together and converting the data into
information. The method used for collecting the data may be
manual, mechanical or electronic.
There are many
types of data processing systems. These systems vary in size,
complexity, speed, cost and application. A computer based data
processing cycle has four basic components i.e. machine,
program, data and people. Machines and programs are hardware
The major steps
involve in data processing consists of three basic steps:
that is delivered to data-processing device from the external
world, the process of delivering this data or equipment that
performs this process is referred to as input. Input may
contain any type of data - commercial, engineering,
scientific, statistical and so on.
compile, generate, interpret, compute and otherwise act in
information in a computer is referred to as Process.
processed by a data-processing operation or the information
that is objective or goal in data processing is referred to as
BITS & BYTES
The smallest piece of data
that can be recognized and used by a computer, is the
bit, a binary digit. A bit is a single binary value,
either a 1 or 0. A group of eight bits is called a byte.
The byte is the basic unit for measure of the size of the
memory, with todayís computer memory sizes. It is more common
to hear the term kilobyte (KB) or megabyte (MB).
Hardware is the
term used to describe the electrical and mechanical parts of
the computer as well as the peripheral devices. In other words
the physical, tangible and permanent components of a computer
are referred to as Hardware.
Hardware is made
up of various metal, silicon and plastic components. It can
basically be divided into four segments: a central processing
unit, input devices, output devices and memory. We select
specific components according to the function we want the
machine to perform.
PARTS OF HARDWARE
Some of the
major parts of hardware are listed below:
Power Supply and many more.
It is important to note that
computer cannot do anything on its own. It must be instructed
to do our desired job. It is the program that controls the
activity of processing by the computer and the computer
performs precisely what the program wants it to do. The term
software refers to the set of computer programs, procedures.
To be precise software means a collection of programs whose
objective is to enhance the capabilities of hardware machine.
Computer software is
normally classified into two broad categories.
2. System software
Application software is
also known as an application package is a set of one or more
programs designed to carry out operations for a specified
application e.g., a pay roll package produces pay slips as the
major output and an application package for processing
examination results produces mark sheet. Similarly a program
written by a scientist to solve his particular research
problem is also an application software.
System software also known
as a system package is a set of one or more programs designed
to control the operations of computer system. These programs
do not solve specific problems. They are general program
written to as human in the use of computer system by
performing task such as controlling all the operations
required to move data into and out of the computer and all
these steps in executing and application program. In general
system packages support the running of other software,
communicate with peripheral devices. System software makes the
operation of the computer system more effective and efficient.
used in many field in the world, and some of the names are
Controlling Electronic Devices
Animation & robotic Engineering
Signal Controlling, etc.
The computer has
following internal parts:
Central Processing Unit (CPU)
Control Unit (CU)
Arithmetic & Logic Unit (ALU)
Primary Storage Unit
processing system's activities include input, processing and
output. These activities make up the electronic data
processing cycle. CPU supports the actual processing of data.
Processing Unit is the brain of computer. We use CPU to
control all input and output connections inside and outside of
the computer and take a look on the programs that are
currently present in a computer. In all PCs, CPU is the chip
that runs programs. It carries out a variety of computations,
numeric comparisons and data transfers in response to programs
stored in memory.
The CPU response
the computer's basic operation by sending and receiving
control signals, memory addresses and data from one part of
the computer to another along a group of interconnecting
electronic pathways called a BUS. Located along the bus are
input and output (I/O) ports that connect the various memory
and support chip to the bus. Data passes through these I/O
ports while it travels to and from the CPU and the other parts
must contain three of the following fundamental units:
Control Unit (CU).
Arithmetic & Logic Unit (ALU).
Primary Storage Unit.
CONTROL UNIT (CU)
The control unit
essentially governs all computer activities and monitors the
execution of programs.
and controls the computer system much as the brain directs the
Once it has
executed an instruction, the control unit must determine where
to store the results for series of operations for each
LOGIC UNIT (ALU)
The Arithmetic &
Logic Unit (ALU) performs the addition, subtraction, addition
with carry, subtraction with borrow, incrementing,
decrementing, ANDing, ORing, shifting, moving, comparing,
storing, temporarily holding the results in a storage unit
known as the ACCUMULATOR.
The ALU is
responsible for performing all arithmetic and logic operations
and transferring data between storage locations. The ALU also
handles logic operations. Logic operations involve
comparisons. Logic operation can use numeric, alphabetic or
alphanumeric quantities. The sign (negative or positive) and
the value of the difference tell the processor that the first
number is equal to, less than, or greater than the second
number. Alphabetic data may also be compared according to an
assigned order sequence.
capacity of the CPU is called the Primary Storage Unit. Over
the years the storage unit has been called Main Storage,
Primary Storage, Core or Memory. Primary storage provides the
capability to store input data, statements from programs
currently undergoing processing, data resulting from
processing and data in preparation for output.
Data input to
the computer stays in primary storage until it is used in
processing. During processing, primary storage is used to
store the intermediate and final results of all arithmetic and
primary storage unit is easily accessible to the CPU. The main
memory is also called primary storage memory is used for four
purposes. Three of these relate to the data being processed:
Data are fed
into an input storage area where they are held until ready to
storage space that's like a sheet of scratch paper is used to
hold the area being processed and the intermediate results of
is holds the finished results of the processing operations
until they can be released.
In addition to
these data-related purposes, the primary storage section also
contains a program storage area that holds the processing
has a storage area to store any kind of information for
temporary use. We call this area as Internal Storage or Memory
of a computer. Internal memory is used to store software and
data currently being processed. The software comprises the
operating system and the application program. The internal
memory provides the means by which the control unit gains fast
access to the next to be processed and the data, which is
currently being operated on.
A device or
medium that can accept data, hold them, and deliver them on
demand at a later time is referred to as Memory.
These are two of
the following types of memory in a computer:
1. VOLATILE MEMORY
It is a kind of
memory used for temporary purpose, when we turn off the power
of computer the contents of memory is lost. Upon reapplying
power to the computer, the data must rewritten into the memory
area. As a general rule, higher speeds of operation can be
used for the read/write cycles. Volatile memory is also
called Random Access Memory (RAM) or Read Write Memory (RWM).
ACCESS MEMORY (RAM)
The kind of
memory used to read/write any program is called Random Access
Memory (RAM). It is a memory, a computer always busies to read
and write any kind of information to get the required result.
In this memory we can store data, values programs and results
for temporary use.
RAM in any
computer system plays very important role because it is an
area where the computer can be able to handle and process our
provided values by the help of a well-defined sequence of
instructions called a Program.
New types of RAM
are available nowadays. Some names of memory based on the
Random Access Metallic Oxide Semi-conductor (MOS) are listed
Static MOS Memories.
Dynamic MOS Memories.
Silicon-On-Sapphire (SOS) Memories.
Integrated Injection Logic (IIL) Memories.
It is a kind of
memory, which is used for permanent purposes; it is not lost
when the power is turned off because they are permanently
built in the system. Some kinds of non-volatile memory are
Read Only Memory (ROM).
Programmable Read Only Memory (PROM).
Electrically Alterable Read Only Memory (EAROM).
Electrically Programmable Read Only Memory (EPROM).
Some of the
systems programs that the computer needs to manage its
operations are permanently built into it and they are called
Read Only Memory (ROM). this memory contains programs that are
used to check all connections inside the computer and controls
present in the ROM can never be changed, deleted or lost if we
switch off the power of computer. The ROM chip contains a
program named BIOS. BIOS stands for Basic Input Output
System, which is a program, used to control the working of
Language is a system for
representation and communication of information or data. Like
human beings, a language or signal is required to communicate
between two persons. Similarly, we cannot obtain any result by
computer without langtage. Computer does not understand
directly what we are communicating with computer as English or
Arabic, it understands only machine language (binary codes
0-1). Computer translates English language into machine codes
through interpreter then process instructions and give us the
The computer languages
can be divided into two main levels.
Symbolic language (A-Z)
Symbolic languages are further divide into two main levels
Although computers can be
programmed to understand many different computer language.
There is only one language understood by the computer without
using a translation program. This language is called the
machine language or the machine codes. Machine codes are the
fundamental language of the computer and is normally written
as strings of binary 0-1.
LIMITATIONS OF MACHINE LANGUAGE
Programs written in
machine language can be executed very fast by the computer.
This is mainly because machine instructions are directly
understood by the CPU and no translation of program is
However, writing a
program in machine language has several disadvantage.
Because the internal
design of every type of computer is different from every other
type of computer and needs different electrical signals to
operate. The machine language also is different from computer
DIFFICULT TO PROGRAM
Although easily used by
the computer, machine language is difficult to program. It is
necessary for the programmer either to memorize the dozens of
code number for the commands in the machineís instruction set
or to constantly refer to a reference card.
DIFFICULT TO MODIFY
It is difficult to
correct or modify machine language programs. Checking machine
instructions to locate errors is difficult as writing them
In short, writing a
program in machine language is so difficult and time
In symbolic languages,
alphabets are used (a-z). symbolic languages are further
divide into two main levels.
A language is one step
higher than low-level languages in human readability is called
high-level language. High - level languages are easy to
understand. They are also called English oriented languages in
which instruction are given using words. Such as add,
subtract, input, print, etc. high level language are very easy
for programming, programmer prefer them for software designing
thatís why these languages are also called userís
friendly languages. Every high level language must be
converted into machine language before execution, therefore
every high level language has its own separate translating
program called compiler or interpreter.
Thatís why some time these languages are called compiler
langauges. COBOL, BASIC, PASCAL, RPG, FORTRAN are some
high level languages.
An interpreter is a set
of programs which translates the high-level language into
machine acceptable form. The interpreters are slow in speed as
compared to compilers. The interpreter takes a single line of
the source code, translates that line into object code and
carries it out immediately. The process is repeated line by
line until the whole program has been translated and run. If
the program loops back to earlier statements, they will be
translated afresh each time round. This means that both the
source program and the interpreter must remain in the main
memory together which may limit the space available for data.
Perhaps the biggest drawback of an interpreter is the time it
takes to translate and run a program including all the
repetition which can be involved.
A language which is one step
higher than machine language in human readability is called
Assembly Language or a low-level language. In an assembly
language binary numbers are replaced by human readable symbols
called mnemonics. Thus a low-level language is better in
understanding than a machine language for humans and almost
has the same efficiency as machine language for computer
operation. An assembly language is a combination of mnemonic,
operation codes and symbolic codes for addresses. Each
computer uses and has a mnemonic code for each instruction,
which may vary from computer to computer. Some of the commonly
used codes are given in the following table.
An assembly language is very
efficient but it is difficult to work with and it requires
good skills for programming. A program written in an assembly
language is translated into a machine language before
execution. A computer program which translates any assembly
language into its equivalent machine code is known as an
entered into the computer for processing purposes is termed as
that assist us in getting data into the computer, such as a
keyboard, mouse, trackball, voice recognition system,
graphical tablet or modem is termed as Input Device.
There are a
number of input devices available to input data into the
computer system. Without these devices computer never perform
any kind of work. These are the essential part used with
computers and are listed below:
A device used to
feed information into the computer in the shape of alphabets,
numbers, puntuation marks, graphic symbols and foreign
currency marks in know as Keyboard.
They are used
for inputting data at a comparatively very slow rate of human
typing. Their major function is to enable the computer to
communicate with the computer operator.
Mouse is another
input device usually referred to as Pointing device. With the
help of mouse we can move around the screen with no time.
Nowadays mouse is always installed on AT-type computers.
All type of
mouse manufactured from different vendors available with two
or more than two keys or buttons and a small ball, which is
the guiding part where you wants to move the pointer on the
screen to select any kind of option. These selections are
available under WINDOWS. Mouse has a cable and a plug, which
is installed into the computer from rear side with the mouse
Any type of
joystick is always used to play games on the computer. This is
an input device always used to control all possible movement
around the screen during playing games. Any joystick has
switches for firing and a vertical stick placed at the 90į,
which is used to move and control any kind of object.
The process of
displaying or printing the results of processing operations is
A number of
different Output Devices are available for use on computer
items and various combinations of them will be found in common
use. The main form of computer output for human use is the
printed report with the help of Printers. The general use of
output devices are
representation of information, in words, numbers or drawings,
as on the cathode-ray tube or screen of a radar set,
navigation system or computer console is referred to as
It is a device
on which the information is projected.
output mechanism that prints characters one at a time or one
line at a time.
A printer is one
of the most common computer output devices used in business
applications. It takes data that has been processed by the
computer and print it on continuous forms.
system is a program or an organized collections of programs
and data prepared by software Designers to perform such
operations as managing computer resources, scheduling and
supervising work, operating and controlling mechanical
In other words
an operating system tells the computer what to do and how to
systems are program products that enhance the performance of
specific tasks. The operating loads and readies program for
systems normally include a number of utility programs in
addition to the control software. Operating systems is some
time referred to as Systems software.
of operating systems are listed below:
Control Program For Micro-Computer (CP/M) etc.
Here are some
description of operating systems:
It is a
collection of programs reside on the disk. DOS is a single
user operating system used with microcomputers, which provides
the communication link between user and hardware. DOS plays a
vital role in operation of a computer system. It facilitates
the user to copy, print, delete, rename etc a file. The DOS
contains three main files COMMAND>COM, IO.SYS, MSDOS.SYS and
two types of commands.
commands are those which are transferred into the memory at
the time of booting the computer. These commands are the part
of a program called COMMAND.COM. These commands are always
available to the user although they cannot be displayed,
delete, rename. Examples are CLS, TIME, DATE, COPY, VER.
commands are the conventional programs which are reside on the
disk they do not transferred into the memory at the time of
booting the computer. These commands can be displayed on the
screen by taking the directory of a disk. External commands
can be deleted, copy and even rename. Examples are diskcopy,
format, xcopy, chkdsk, diskcomp, backup.
UNIX is a
top-level operating system support multitasking, multi-user,
time-sharing and network upto a number of terminals.
Take advantage of advanced features, such as communication
facilities, a hierarchical file system, a programmer's "work
bench" and a flexible document-formatting system.
Perform complex tasks by connecting a number of program
modules to the system.
Allow several individuals to store and share files on an IBM
PC at different times.
Perform more than one task at the same time, print one file
while editing another.
Work in an efficient, flexible environment using the same
tools available on large multi-user UNIX systems.
Keep files confidential by preventing access by authorized
Track and control changing in program and documents with the
PC/IX SCCS System.
Exchange DOS files by undoing built-in utilities to transfer
files to and from IBM PC DOS.
Perform more effectively with the full screen editor; take
advantage of advanced features, such as windowing, full key
editing and automatic file backup.
Use high-level programming language for structural
XENIX is an
improved and enhanced version of the AT&T UNIX System III,
adopted or use by IBM PCs and its clones. Originally conceived
at Bell Laboratories in 1969 by Dennis Ritchie, UNIX has
grown to be a very popular operating system in the computer
A series of
operating system developed by Novell Inc. that runs in the
servers and control system resources and information
processing on an entire network or inter-network is called
Netware Operating System.