Computer Sciene

Computer Sciene

1. Security

   • Anti-virus software: Designed to detect and block attacks from malware (Zombies, spybots ect).
   • Fire wall: Blocks any unexpected connections coming into the network.
   • Access level: An network mannager will nomaly set a level of access to certian people. e.g Headteacher a higher level access, student a lower access level.

2. The CPU

   • The use of the cpu is to do the fetch, decode, execute cycle. It maintains the hardware and can is measured in hertz (hz)
   • ALU is part of the cpu. its called the arithmetic logic unit. It works out any simple maths or logic gates. eg. 2+2=4-1 QUICK MATHS!
   • Cache is fast memory that stores common instructions that can be retrieved easily. Its seperate from the cpu but helps it.

3. Vonn Neumann Architecture

   • Address bus carries addresses from the processor to the Main Memory
   • 1.The Address is generated by the Program Counter. The address is copied into the Memory Address Register.
   • 2. The data/instruction from main memory is placed onto the Data Bus to travel to the processor · The data/instruction arrives at the Memory Data Register (MDR).
   • 3.The instruction is decoded and executed .Results of calculations are stored in the Accumulator.The Program Counter is incremented.
   • 4. ALU performs all arithmetic and logical operations .CU carries control signals · Cache speeds up execution by holding common instructions to save processor/disk transfers.

4. Memory

   • R.A.M
   • R.O.M
   • Optical
   • Flash
     • Virtual memory is a section of volatile memory created temporarily on the storage drive
   • Magnetic
   • Solid