Mapa mental
Computer science
Conteúdo do mapa
Computer science
Computer system
- A system is a collection of parts that work together for a common purpose.
- For a system to be useful, it must produce something – an output.
- It needs to receive and process inputs in order to produce outputs.
- Computer systems are based on processing data and producing information.
- They are fast, and the important thing about them is that they are programmable.
Embedded system
- Software that is programmed to carry out a number of dedicated functions.
- For example, the software to run a washing machine is stored on a computer chip and embedded into the system.
- Software that is programmed to carry out a number of dedicated functions.
System reliability
- Given our dependence on them, it is vital we are able to trust in the reliability of these systems.
- Badly designed IT systems failing to achieve the desired result can cost millions or even billions of pounds that cannot be recovered.
Standards
- Standards agreed by the IT industry are an essential element of system design and development.
- Software standards include agreement on various file types, enabling software to use data from other systems effectively
- Software standards include agreement on various file types, enabling software to use data from other systems effectively
- Platform independence: access is not restricted to a specific hardware platform.
- Long-term access: resources are openly developed and updated.
Data protection act
- Data is valuable and must be protected, and the Data Protection Act attempts to regulate organisations that store data.
- Data protection laws
- be processed fairly and lawfully
- be obtained for a specified and lawful purpose and used accordingly
- be limited to the specified data, be accurate, and up to date
- be kept only for as long as necessary for the specified purpose
- be kept securely
- not be transferred outside the EU
- be kept securely
- be kept only for as long as necessary for the specified purpose
- be limited to the specified data, be accurate, and up to date
- be obtained for a specified and lawful purpose and used accordingly
- be processed fairly and lawfully
- Computer misuse act
- Unauthorized access to computer material
- Unauthorized access with intent to commit or facilitate a crime
- Unauthorized modification of computer material
- Making, supplying or obtaining anything which can be used in computer misuse offences.
- Unauthorized modification of computer material
- Unauthorized access with intent to commit or facilitate a crime
- Unauthorized access to computer material
Environment
RAM
- RAM stores the programs and data that the computer is currently working on
- RAM is memory that can be accessed and changed by the computer at any time.
- The operating system will also be loaded into RAM in order to run.
- RAM needs power to store data and is volatile (i.e. if you turn off the power everything in RAM is lost)
- Computers need a lot of RAM to deal with the large amounts of data they need to make available at any one time for the CPU.
- Adding more RAM to a computer will improve the performance of that computer by making more memory available for direct access from the CPU.
ROM
- ROM is often used to store the boot program, a sequence of instructions to start the computer and load the operating system.
- Many devices, including music players, mobile phones and cameras, need ROM to boot them up.
- ROM cannot be overwritten by the computer, hence Read Only Memory.
- ROM does not need to contain very much data and is typically just 1 or 2MB in size
Virtual memory
- Virtual memory is part of the hard drive used as an extension to the RAM.
- A specific area of the hard drive will be allocated to temporarily store data from RAM that is currently not needed, while data that is needed will be loaded into RAM.
- It is used when the computer does not have enough RAM to hold all the data and programs that a user wants.