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Introduction to Computer Software
Actually a Computer is designed in such a way that it cannot
work by itself. Even if we provide it power, it will not perform its duties.
The main reason is that Computer has no information about its function, task,
purposes etc. So to inform the Computer about its tasks, functions, purposed,
and to operate it in a useful manner we need Software.
Software is divided into three main categories:
1)
Language
2)
System / Managerial Software
3)
Application Software
1) Language
Language is a source through which we can talk or
communicate with each other. There are many languages, which are understood in
the world. Some languages are International while the others are local.
Similarly to communicate with Computer, we need a language
which Computer should understand. There are several languages which can be used
for this purpose e.g. BASIC, COBOL, ASSEMBLY, MACHINE, C, C++, Visual Basic,
Visual C etc.
These languages are of two types:
a)
High Level Language
b)
Low Level Language
a)
High Level Languages
English like languages are called
high level languages OR the languages consisted of command or statements just
like English are known as high level languages. These are also called compiler
languages since they require a special program called compiler, which translate
program written in that language into machine language e.g.
·
FORTRAN
·
COBOL
·
BASIC
·
PASCAL etc.
b)
Low Level Languages
The language, which is consisted on
machine codes, is called low level language.
Machine language is the only
language, which is understood by the Computer (because Computer can not
understand any type of high level language. That’s why each high level language
has its own compiler which translates programs in machine language.
Familiar low level languages are:
·
Machine Language
·
Assembly Language
·
Machine Language
Machine language is consisted on
only two digits i.e. 0 and 1.
Whenever a word/instruction is
entered into Computer, the system translates it into machine language e.g. if
we have entered ‘A’ then Computer will translate it in binary or machine
language and it will become 11000001.
·
Assembly Language
In this language special codes are
used which are called mnemonics (memory-aiding, alphabetic codes), e.g. ADD for
addition, SUB for subtraction, LDA for load etc.
2) System/Managerial
Software
As discussed above, whenever we start a Computer it doesn’t
know how to work? So we need such a type of Software which instruct the
Computer how to start, how to work, how to accept data, how to process data,
how to provide outputs and how to control the devices attached with it?
Software, which performs the above tasks, is called system
or managerial Software. Major types of system/managerial Software are:
a)
Operating System
b)
Language Translators
c)
Service Utilities
a)
Operating System
Operating System is a collection of
certain Software programs. It provides link between Computer and user. Mainly
an operating system performs following operations:
·
I/O operations: Manages
information of data to a suitable place.
·
Fault Monitoring:
Detects errors in command.
·
File & Directory
maintenance: Deletion, copy etc.
·
Multi access system
Commonly there are two types of
operating systems are in practice.
1)
Single user operating
system
2)
Multi-user operating
1)
Single user operating system (e.g. DOS)
Such a type of operating system
allows only one user to use the Computer. Single user operating systems are
designed for Personal Computers.
2)
Multi-user operating system (e.g. UNIX, XENIX, Windows NT etc.)
Such a type of operating system
allows more than one user to share the Computer resources.
b)
Language Translators
As we know, Computers cannot
understand high level or English like languages, so to translate programs
written in these languages into machine language we use Language Translators.
c)
Service Software
Software, which provides general
services, likes copying, deletions, undeletions etc. to the user.
The Software designed for the benefit and use of Computer
users is called application Software. Application Software can be categorized
as:
1)
User programs
2)
Application or user
packages
1)
User/Source Programs
A program is set of instructions
written in a certain language. The programs written by a Computer user are
called user programs. E.g. a program for maintaining the library or a program
for monthly budget etc.
OR
A program is a package of several
data processing instructions by which we process our database information in
different ways according to our requirements. A program gives us the following
benefits.
·
We can store our data
in a particular named file.
·
We can call the stored
data file any time.
·
We can make changes in
the stored data file again and again.
·
We can modify the
stored shape of stored data.
·
We can save the
modified data file again.
2)
Application / User Packages
These are ready-made programs
available in market. A package may be a single program or the combination of
two or more programs. Packages are generally provides by the Software
Development Companies.
Packages can be categorized as:
·
Data Bases
·
Word Processor
·
Spread Sheets
·
Graphics etc.
·
Data Bases
Data base packages are important due
to record keeping and programming facilities e.g. Fox-Pro, ORACLE etc.
·
Word Processor
Word processor packages like Word
Perfect, MS Word etc. are used for letter writing, reports and other
documentation purposes.
They also provide spelling checker
and thesaurus. It can also import spreadsheet, pictures, graphs etc.
Moreover it provide newspaper
columns, tables, equations, user boxes and lines facilities.
·
Spread Sheets
Spread sheet packages like Lotus
123, MS Excel etc. are useful in Banking, Accounting etc. They also provide
facilities of calculating, record keeping etc.
·
Graphics
These kinds of packages are used for
drawing purposes.