1. Fundamentals of Computer Systems

1. The Eight Principles of Data Protection • For the personal data that controllers store and process: • It must be collected and used fairly and inside the law. • It must only be held and used for the reasons given to the Information Commissioner. • It can only be used for those registered purposes and only be disclosed to those people mentioned in the register entry. You cannot give it away or sell it unless you said you would to begin with. • The information held must be adequate, relevant and not excessive when compared with the purpose stated in the register. So you must have enough detail but not too much for the job that you are doing with the data. • It must be accurate and be kept up to date. There is a duty to keep it up to date, for example to change an address when people move. • It must not be kept longer than is necessary for the registered purpose. It is alright to keep information for certain lengths of time but not indefinitely. This rule means that it would be wrong to keep information about past customers longer than a few years at most. • The information must be kept safe and secure. This includes keeping the information backed up and away from any unauthorised access. It would be wrong to leave personal data open to be viewed by just anyone. • The files may not be transferred outside of the European Economic Area (that's the EU plus some small European countries) unless the country that the data is being sent to has a suitable data protection law. This part of theDPA has led to some countries passing similar laws to allow computer data centres to be located in their area. The Kernel is the lowest level of an operating system and can be used across multiple platforms System Boundary Computer systems are based on processing data and producing information Computer systems are found in most electronic gadgets, these are often known as ‘embedded systems’ Computer systems are ‘dedicated’, this means they have a fixed purpose OUTPUT INPUT PROCESS Define a computer system MAIN MEMORY Computer Systems in the modern world Ethical, environmental, legal considerations 1. Fundamentals of Computer Systems • Are the computer systems reliable? • Why do computer systems fail? • Who should check this? • Why should they check this? • What should be checked? The Computer Misuse Act (1990) This was passed by Parliament and made three new offences: Accessing computer material without permission, eg looking at someone else's files. Accessing computer material without permission with intent to commit further criminal offences, eghacking into the bank's computer and wanting to increase the amount in your account. Altering computer data without permission, eg writing a virus to destroy someone else's data, or actually changing the money in an account. Computer systems should be tested, backed up and documented BACKING STORAGE Professional standards for computer systems • Types of computer misuse • Hacking • Illegal downloading • Email/ chat room abuse (trolling) • Financial abuse • Computer Virus • Proprietary standards are owned by a company, for example Flash animations must conform to Adobe standards if they are to work. • Industry standards are an agreement across different organisations. • De facto standards are developed through common use until they become the accepted way of doing something • Open standards are open to the public and can be changed HTML PDF txt doc

2. The processing of a computer program is carried out by the central processing unit (CPU) The CPU has two main components 1. The control unit 2. Arithmetic and logic unit (ALU) CPU Purpose, function & characteristics of CPUs Fetch Cache Decode 2. Computer Hardware (part 1) Main memory Memory Representing Data with Logic Diagrams and Truth Tables ROM RAM Virtual Memory Cache Memory Flash Memory Execute

3. Input/ Output Devices Specialist Input/ Output Devices Common storage technologies 2. Computer Hardware (part 2) Justifying the choice of secondary storage Definition of Secondary Storage

4. Functions of an operating system Purpose and use of common utility programs 3. Software Comparison of the sources of Software

5. The number 45 in binary Key terms Converting into binary (and why we do it) 4. Data in Computer Systems (part 1) Adding binary & overflow Hexadecimal

6. When a computer is instructed to run a program it is directed to the start address for these data instructions. A program instruction has two parts, the operator and the operand It is the operators job to tell the CPU what to do and the operands job to tell the CPU what to apply the instruction to. How binary is used to represent data Character sets (ASCII & Unicode) Instructions and data 4. Data in Computer Systems (part 2) Meta data and its use with images Sampling sound in digital format

7. Entity – Something that we store data about in a database Record – All the data about one item in a database Attribute – A characteristic of an entity. It becomes a field in a data table Field – A characteristic of something stored in a database A database is a persistent organised store of related data on a system. Persistent means the database is stored in secondary storage for access later on. Computer databases are handled with database software. Students lessons Teachers What is a database? The use and purpose of Database management software DBMS functions 5. Databases SQL Database structures with examples Relationship diagrams Sequential files – Data is stored in sequence, an index can be used to search for data quickly that has been sequenced. Flat file database – A database containing one file Hierarchical database- A database composed of individual parts that make up the whole. Relational database – Attributes are used to relate table (and data) that have a relationship, usually through the use of a primary key.

8. Network Hardware LANs & WANs Client/server & Peer to peer networks 6. Communication & Networking (part 1) Protocols, IP addressing, MAC addressing and packets Protocols are the rules for communication, in computing these means between computer devices. Network topologies

9. What is the internet? LANs & WANs Hardware required to connect to the internet 6. Communication & Networking (part 2) Compressing files Lossy and lossless compression IP addressing and DNS HTML and common file standards

10. Start Program If temp <19 turn heating on Else If temp >21 turn heating off FOR Continues a loop for a set number of times WHILE Continues a loop while a condition holds true REPEAT Continues a loop until the condition is met Start Is temp <19 Variables and constants Algorithms and pseudo code Yes Turn heating on What an IDE is and the tools available from IDEs No Data types integer, real, Boolean, character and string Is temp >21 7. Programming Yes Turn heating off Assemblers, compilers and interpreters No Manipulating Arrays High level and machine code Common operators Syntax errors and testing Valid –Test data that represents typical input into the system. Valid Extreme – Test data that is valid but at the extreme end of the range. Invalid – Test data that is out of range and should be rejected. Invalid Extreme – test data is invalid but only just at the limit of being unacceptable. Erroneous – Test data that should be rejected because it is the wrong type of input.