Professional standards

2-1-1 Fundamentals of computer systems

3

GCSEOCRComputingA451

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

Professional standards

2-1-1 Fundamentals of computer systems

Who needs standards?• 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?

Professional standards

2-1-1 Fundamentals of computer systems

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?

Professional standards

2-1-1 Fundamentals of computer systems

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!

Professional standards

2-1-1 Fundamentals of computer systems

Stages in creating a computer system

Analysis

Design

ProgrammingTesting

Maintenance

Professional standards

2-1-1 Fundamentals of computer systems

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

Professional standards

2-1-1 Fundamentals of computer systems

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

Professional standards

2-1-1 Fundamentals of computer systems

Worksheet 4• Coding standards

• Suggest how this program could be made easier to understand and amend

• Then look at Worksheet 5

Professional standards

2-1-1 Fundamentals of computer systems

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

Professional standards

2-1-1 Fundamentals of computer systems

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

Professional standards

2-1-1 Fundamentals of computer systems

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

Professional standards

2-1-1 Fundamentals of computer systems

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…. /********************************/

Professional standards

2-1-1 Fundamentals of computer systems

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

Professional standards

2-1-1 Fundamentals of computer systems

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?

Professional standards

2-1-1 Fundamentals of computer systems

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?