1. Lesson Objectives To understand why computer systems must be reliable To investigate the consequences of an unreliable system

2. Reliability Computer systems are important and are involved in most human activities: – Safety – Travel – Business – Entertainment – Education – Science Given our dependence on them, it is vital we are able to trust in the reliability of these systems.

3. Internet Research Use the internet to research the consequences of unreliable computer systems. Collect your data and produce a powerpoint slide to explain – The business/system that was in place – What went wrong – What the consequence were – You will be sharing your story with the class

4. How do we make systems more reliable? There are several ways of doing this One of them is to make all systems stick to the same conventions and rules, known as Standards There are various categories of standards. In computing, standards exist for – programming languages, – operating systems, – data formats, – communications protocols – electrical interfaces.

5. Why are standards important? Enables equipment from different manufacturers to work together Makes learning new systems easier Minimises waste Helps ensure fair play and access to markets Brings costs down by opening markets to competition The user?The Industry?The Environment?

6. Types of Standards Proprietary Industry De Facto Open

7. Proprietary These are standards owned by an organisation. They ensure compatibility between the company’s products. They can also be used to exclude others from competing with rival products. For example, Apple computers lock users into using Apple software.

8. Industry Some standards are agreed across the computing industry, many of which relate to hardware. used to connect printers, cameras, mobile phones and other computer peripherals USB used to connect entertainment systems and monitors HDMI standard connector to connect to wired network points RJ45

9. De Facto “in practice but not necessarily ordained by law” Some standards develop through common usage until they become accepted as standard.

10. De Facto HTML started life as a De Facto standard and as it gained in popularity, it eventually become a rule in all web development. Microsoft Word is a proprietary standard, however it has started to become a De Facto standard for supplying Word Processed documents. Now all word processed documents need to be able to write and read doc file.

11. Open Standards Open standards are publicly available standards that are often agreed by a group of collaborators and are not for profit. In the case of Open Source Software, the Source Code is available in the public domain, so anyone with the time and expertise can make changes. Usually the software produced is updated by a community of developers therefore updates are often regularly available for free and problems are fixed quicker.

12. Open Standards Some of the most important computer standards include – The World Wide Web – C# programming language – Mozilla Firefox – Linux – Python programming language