1. GCSE OCR 3 A451 Computing Professional standards
2-1-1 Fundamentals of computer systems 3

2. Objectives
Understand the need for standards in the development and maintenance of computer systems
Give examples of standards in computer systems
Understand how standards help to ensure that computer systems are free of errors, easy to maintain and easy to use

3. Who needs standards? In the UK, we drive on the left
Some standards come about through constant usage
In the UK, we drive on the left
In many other countries, people drive on the right
Does this ever cause a problem?

4. De facto standards
De facto standards are ones which come about through common usage
Americans write dates in the format MM-DD-YYYY
How do we write them?
Could this ever cause problems in software usage?
Think of some other de facto standards in everyday life and in the context of computing. Are they the same all over the world?

5. Software development
Many computer systems involve tens of thousands or even millions of lines of code
Teams of programmers work on the project, each developing a small part of the system
People leave, teams change, and new programmers must take over in the middle of a project
Good organisation, “rules” and standards are essential!

6. Stages in creating a computer system
Analysis
Design
Programming
Testing
Maintenance

7. Software development standards
How to document what the system needs to do
How to break the system up into small parts that can be developed by teams of programmers
How to allocate staff to teams
How to keep track of changes
How to code programs
How to test
How to document the whole system

8. Standards in Analysis and Design
Companies involved in the creation of complex computer systems don’t start from scratch in documenting their design
There will be professional standards defining the structure of the document, ensuring that all essential areas are covered
You probably know yourself that it is much easier to write a lengthy document explaining your ideas, when you are given a structure to work to

9. Worksheet 4 Coding standards Then look at Worksheet 5
Suggest how this program could be made easier to understand and amend
Then look at Worksheet 5

10. Programming standards
Even a small team of programmers working on a class project would find it difficult to come up with a maintainable system if they had no agreed standards

11. Developing standards
What aspects of the programming and testing need to be agreed on?
Suggest some standards that a team of prgrammers might agree before they start

12. Standards for coding programs
Comments in the code
Variable names and naming conventions
Passing information from one module to another
Formatting the code
Version names and numbers
Suggest some “rules” for certain comments that MUST be included in every module
Suggest some “rules” for variable names

13. Example of standards for program comments
Every source code file should begin with a comment block describing the content and its purpose
The author and any revision authors should be identified
The date of original code and all revisions should be given
Comment blocks should be delineated as follows:
/********************************/
/Comment Lines….

14. Benefits of software standards?
Efficiency: any member of a software team can work on any part of the software code without having to adapt to a different programming style
Fewer errors and easier debugging: standards result in more accurate coding
Easy to maintain: any programmer will find it relatively easy to look through the code, understand its structure and find what they are looking for when a change needs to be made

15. What about the user?
Users have certain expectations when they use hardware and software
If standards are not followed throughout a piece of software, how does this affect the user?
When a user buys a new computer system or a new piece of software, what documentation would they expect to find?

16. Recap
Professional standards cover every phase of software development – analysis, design, development, implementation and maintenance
Adherence to standards helps make the development process faster, more efficient, and less error-prone
Standards make the end product easier to use
Can you give examples to explain each of these points?