Software: Programs that run on the computer (you can't hold them in your hand)
Systems software: Set of programs needed to control the hardware
This is comprised of 4 parts:
1. Operating System (O/S): A suite of programs that control the operation of the computer.
2. Utility Programs - Computer programs designed to perform a Common task (e.g.Defrag, ScanDisk)
(Look at the Utilities available under the Windows Control Panel)
Utility programs that manage files are known as File Handlers
File Handlers perform functions such as;
searching for lost files,
sorting files of data into a particular order etc.
Transfering files between storage devices (FTP)
Other handy utility programs Back up and Archive data
Format disk Utility
Screen Saver Utility
Disk Maintenance Utility
3. Library Programs - A collection of programs each, with a specific job available to all users
These are written by experienced programers, debuged, tested and can be called upon by a developer without having to write the code again. (e.g. Direct X or DLL files in Windows)
4. Compilers / Interpreters - Programs that interpret / translate between programming Languages
Usually translating from High Level Language (with statements written in English for the User to understand)
to Low Level Language (written in Machine Code for the Computer to understand)
Applications software: Programs that allows the user to carry out a specific task or produce something.
Generic Applications Software - Versatile programs used by organisations to fullfill common tasks
e.g. A Word Proccessor can be used for writing a letter, a book, an invoice, an essay even a price list
A Spreadsheet can be used to do household accounts, predict future trends and many other uses.
these applications have a relatively large number of different use
They are tailored to user’s specific needs (rather than the task)
Software can be divided into two types:
Off-The-Shelf Software
Generic ready-made computer programs, available for buy, install and use straight away.
(straight Off The Shelf of your local computer software seller)
ready and available for immediate use
Relatively cheap
Thoughrally tested and debuged
May need customisation or adapting to fit the organisation
Bespoke or Custom-written software
Software developed specifically to solve a particular problemfor an organisation
Goes through the entire Systems Life Cycle before being ready to use (often a long time)
Is unique to the organisation and designed to exactly match their needs
Needs all staff to be trained on how to use it
An example application might be software to control a specific process on a production line, which therefore may well be the only one of its kind, and so would not appear in a local computer shop.
Off-the-shelf (OTS) Vs Bespoke software (s)
Ad
Implementation time: No development time for OTS (ready to buy)
Cost to buy: Smaller cost for OTS
Cost to maintain may be higher with OTS and not shared
Support: Wider Support from other users with OTS s/w
Training existing and new staff easier wth OTS
Books and training course available
Tested: So hopefully bug free
Uniqueness: Bespoke designed for specific business
No Waste: No unneeded functionality
is defined as: Activites that keep a computer system operational
Once a system has been implemented, that is not the end of the System Development Life Cycle.
vantages and Disadvantages
Corrective - to fix bugs in the system not picked up during testing
Adaptive - to adapt system to cope with changes (e.g. a new tax or tax rate, extra tasks, new products etc)
Preventative - to stop things going wrong