‘A’ Level Computing
Notes
MODULE 1
CHAPTER 2-CLASSIFICATION OF SOFTWARE
CATEGORISING SOFTWARE
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Software-all the programs that rub on a computer
There are several categories of software:
Systems software, general-purpose applications (generic) software,
Special purpose application software, bespoke software.
SYSTEMS SOFTWARE
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(SEE DEFINITIONS BOOKLET)
Systems software includes the following types:
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1- Operating system-acts as an interface between the user and the
computer hardware.
It provides us with a virtual machine.
An OS is a set of programs that allows the user to perform tasks
without the user actually knowing how they are done
Application programs are usually written for a specific operating
system, so using a program that was written for Windows will not work
on Apple Mac OS X.
2- Library programs-carries out common tasks that are usually used by
every user. These are usually called utility programs. (Example-a
search that searches for corrupt or lost files.)
3- Utility programs- designed to make life easier for users. A program
written that is used by all users, such as a compressing/decompressing
program is a very common utility used to make file sizes smaller so that
they can be easy to send via email.
4- Programming language compilers, interpreters and assemblers.
Compilers and interpreters are different types of program used to
translate programming language (Pascal, VB, C++) into a form that the
computer can execute. An assembler translates statements of a lowlevel programming language into machine code.
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APPLICATIONS SOFTWARE
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(See definitions booklet)
GENERAL PURPOSE APPLICATIONS SOFTWARE
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All common applications such as word processing, desktop publishing,
spreadsheet…etc…. are GPAS.
This is sold as a package with the CD and instruction manuals.
Complete software suites such as Microsoft office, offer four or more
software products packaged together.
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©Mikey Holder, 2006
‘A’ Level Computing

Notes
MODULE 1
Advantage of buying a suite of programs-all the programs are
compatible with each other so a user can export and import data from
one package to another.
GENERIC AND SPECIAL PURPOSE SOFTWARE.
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Word processing, database software, and spreadsheet software are
sometimes referred to as generic.
This is because they are not designed specifically for one type of
application.
SPECIAL PURPOSE SOFTWARE
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Software designed to do one specific task, such as work out a payroll
accounts or stock control
BESPOKE SOFTWARE
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Software designed for one particular organisation.
BESPOKE OR OFF-THE-SHELF?
Advantages of Bespoke
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It is designed to do exactly what the user wants
No unwanted features
Can be run on specified hardware.
Can be integrated with existing software
They may be no alternative solution. I.e a suitable off the shelf piece of
software
Advantages of off-the-shelf software
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Less expensive
Can be bought straight away and installed straight away
Software is tried and tested
Software is well documented.
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©Mikey Holder, 2006