AS Computing

AS Computing

1. Hardware

2. Processor

   • Program Counter
     • Keeps a check on where the next instruction is in the RAM
   • Registers
     • Memory Address Register (MAR)
       • This is where the location of the data that was sent from the program counter is stored.
     • Memory Data Register (MDR)
       • This is a copy of the instruction found by the memory address register
     • Current Instruction Register
       • The Memory data register give it's instruction here. It is then split and decoded. So e.g. ADD 20. It would send ADD back into the processor to ask what is ADD and it would check the RAM for space 20 and find it's data then send it to the ALU
   • ALU (Arithmetic Logic Unit)
     • This does all the computers maths.
   • Buses
     • Data Bus
       • Carry's Data from one bus to another.
     • Control Bus
       • Sends the signals from the Control Unit to the other parts of the processor
     • Address Bus
       • Carries the location of the data

3. Memory

4. Application Design

   • System Life Cycle
     • 1) Problem Definition
       • This step is too find what the problem is and what the ideal solution would be
     • 2) Fesability Study
       • This is a study to see if the solution that has been conceeved is possible. (Financial, Legal, Using Current Systems, Social Effect, Customer Effect)
     • 3) Information Collection
       • Information Needs to be collected so that the analyst knows the problem better and can design the correct solution
         • Types of information collection:
           • Questionairs
             • Meetings
               • Observation
                 • Interview
     • 4) Analyis
       • The data that was collected is analyised and flow charts and DFD's are produced. A spec. is produced for the design and coding stages.
     • 5) Design
       • This is a design of the UI and also how the system will function using DFD's and what modules need to be created and coded.
     • 7) Testing
       • The software that has been created is tested using testing techiniques
     • 6) Coding
       • The designs from the prev. stage are taken and fully coded into working software.
     • 8) Evaluation
       • This is an evalutation of how all the process whent and anything which needs chaging for next time from what whet wrong
     • 9) Installation / implementation
       • The analyst needs to decide how the system should be installed / implemented
         • Types of implementation:
           • Direct: One on, One off
           • Parrel: Both System ruuning at the same time then the old system is discontinued
           • Phased: This where parts that the old system would do is replaced slowly until the new system has fully taken over.
           • Pilot: This is where a test system would run in a seperate area to teach and train whilst the new system takes over.
     • 10) Maintence
       • Maintaining the software in accordance with the contract with the software contractee. This can be cructial updates of adding of features to the software.

5. OS's

6. Networks

7. Security and Backups

8. Number Systems

9. SDLC

10. Digital Sound

11. Implacations Bullshit

    • Economic Implications
    • Social implications
    • Legal implications
    • Ethical implecations