2.11 Fundamentals of computer systems

2.11 Computer Systems

(a) Define a computer system
A system is a collection of parts that work together for a common purpose.
An embedded system is a computer system that forms part of an electronic device (e.g. A SatNav)

(b) describe the importance of computer systems in the modern world

• Safety- computer systems are used for guiding aircrafts, controlling traffic lights and monitoring patients in hospitals.
• Business- computer systems are used to take orders, control stocks, manage payrolls and monitor taxes.
• Politics- computer systems are used in political campaigns, as well as for voting and taxes.

(c) explain the need for reliability in computer systems
Unreliable systems can cause very serious problems (e.g. Aircraft accidents if systems fail). To prevent such problems from occuring, testing can be carried out purposefully to reveal errors. Beta testing is carried out under real-life conditions whereas alpha testing is carried out by developers.

(d) explain the need for adherence to suitable professional standards in the development, use and maintenance of computer systems
If a new system is developed adhering to certain standards, it is more likely to be succesful. The ISO (International Organisation for Standardisation) are responsible for monitoring standards.

• Proprietary standards- these standards are owned and maintained by one company, making them familiar and predictable, e.g. Windows
• Industry standards- these are standards that are agreed accross the computing industry which allows for easy interconnection, e.g. USB (Universal Serial Bus)
• Open standards- these are publicly available and are non profit, available at no or minimal cost and there is no single developer, e.g. HTML
• De facto standards- these are standards that have developed through common usage, the accepted way of doing things, e.g. Microsoft Word
• De Jure standards- de jure means 'by law', standards which everyone must adopt and adhere to e.g. HTML

(e) explain the importance of ethical, environmental and legal considerations when creating computer systems
Ethical considerations- The BCS (British Computer Society) has set ethical standards (what is morally right) for computing professionals to adhere to. These include: Do not undertake work beyond your capability, do not bring your profession into disrepute, do not take bribes etc.

Environmental considerations- E-waste (old computer equipment) contains many toxic components such as Mercury. Much e-waste is shipped to developing countries and sent to landfill sites where chemicals may leech into the soil and cause pollution.

Legal considerations- The Data Protection Act (1998) was created to protect people's privacy. It requests that those who keep personal data on a computer must take care of it and that people should be able to inspect any personal data held about the, to ensure accuracy. In 1990, the Computer Misuse Act made it illegal to gain unauthorised access to computer systems or to modify their data.

Security and the cloud- SaaS (Software as a Service) stores data remotely in a 'cloud' which removes the need to employ IT staff, reducing infrastructure requirements.