1. Software
Chapter 11

2. OCR GCSE Computer Science
Chapter 11: Software – an overview
Software refers to the programs that run on a computer. Programs are:
implementations of algorithms
stored sets of instructions
written by programmers who use programming languages to produce runnable programs from algorithms.

3. OCR GCSE Computer Science
Software can be applications (apps):
Programs that perform useful tasks for us
Software can be systems software:
Programs that control the hardware and make the computer usable by humans and applications

4. OCR GCSE Computer Science
Platforms
A platform is a combination of hardware and systems software that supports the running of applications.

5. OCR GCSE Computer Science
Procurement of software
Choosing and getting hold of software can be a serious business, especially for an organisation.

6. OCR GCSE Computer Science
Off-the-shelf software
This is software that is already available for purchase or free download. It has been developed and tested, usually for a variety of potential users.
Bugs get spotted and fixed over time because many users will notice and report them.

7. OCR GCSE Computer Science
Custom-made software
Sometimes called bespoke software, this is software that has been commissioned and specially written for a client.
It usually costs more than off-the-shelf software because its development costs have to be met by one or just a few customers.

8. OCR GCSE Computer Science
Custom-made software (cont.)
It may contain bugs because it has not been used by many users over time.
It is usually supported by the developers under a maintenance contract that has to be paid for.

9. OCR GCSE Computer Science
Repositories
Software repositories are useful for individuals.
They are online collections of software, usually for a specific platform such as Debian Linux or Android.
They are safe because only malware-free programs should be put in the repository.

10. OCR GCSE Computer Science
Repositories (cont.)
They are usually reliable because they have been tried and tested by many users.
They are easily downloaded and installed using software such as a package manager.