Software

1
Software

• What is software?
• General term used to describe all the programs
  which run on a computer. There are three
  categories of software
• System
• Application
• General-purpose

2
System Software

• Operating system
• An Operating system is the set of programs that
  controls all the hardware and application
  programs that constitute the computer. It acts
  as an interface between the user and the
  hardware, which allows the user to perform tasks
  without having to know how they are done.
• Egs. Windows Xp Pro, XP Home, 2000, 98, etc.
• DOS Disk Operating System
• UNIX
• Linux

3
Functions of an OS

• Executes programs prematurely terminates those
  not working properly.
• It allocates and schedules the resources of a
  computer. These resources include CPU time and
  input/output/storage devices.
• It manages memory.
• It manages files
• It provides utilities to keep the computer in
  good working order.
• It provides an interface with which the user can
  interact.

4
System Software cont

• Utility programs
• perform common useful tasks such as search for
  lost files, sort files of data into a particular
  sequence, copy disk files to magnetic tape for
  backup purposes and so on.
• Programming language compilers/interpreters
• - are different types of program used to
  translate the statements in a programming
  language such as Pascal, Visual Basic or C into a
  form that the computer can understand.

5

• Performance monitoring software
• is used to monitor, analyse and report on the
  performance of a computer and its components. It
  can provide information such as the overall
  utilisation of the processor and number of disk
  accesses over a given period of time.
• Communications software
• In a mainframe environment, this is executed on a
  separate, dedicated processor (front-end
  processor) and controls the flow of data to and
  from remote locations.

6
Application Software

• Applications software is written to perform
  specific tasks such as order entry, payroll,
  stock control hospital appointments. The
  software may be designed for one particular
  company (bespoke software) and written especially
  for them using a programming language or software
  such as a database management system.
  Alternatively, the software may be purchased off
  the shelf.

7
General Purpose Software

• All common application packages such as word
  processing, desktop publishing, spreadsheet,
  database, computer aided design (CAD) and
  presentation packages fall in this category.
  Most general purpose software is sold as a
  package, including a CD containing the software
  and manuals to help you get started and to be
  used as a reference.