Computing Hardware

Computing Hardware

1. CPU

   • Is responsible for all processing in the the computer.
   • Consists of up to a million electrical switches called transistors.
   • Main parts are: Control unit and the ALU.
     • Control unit controls the operations carried out by the CPU.
     • The ALU carries out mathematical and logical computations.
   • There is a clock with vibrating quartz. The quicker the clock the faster the computer.
     • Overclocking causes overheating.
   • CPU cores can be dual-core and quad-core and this can speed up processing but not all tasks can be shared equally between the cores.

2. Fetch Decode System

   • Fetch
     • Instructions are transferred from the memory to the CPU.
   • Decode
     • the CPU works out what the instructions mean.
   • Execute
     • the control unit carries out the instructions using the ALU for instructions involving logical or mathematical operations.

3. Cache Memory

   • Temporary memory while computer stores it in permanent area.
   • Level 1- smallest and closest to to CPU.
   • Level 2- usually separate chip next to CPU.

4. Binary data, logic gates and truth tables.

   • Electronic devices can be analogue or digital.
   • Binary data
     • Digital technologies use binary values to represent data.
     • Binary is used to encode date using values 1 and 0. Each 1 and 0 is called a bit and a string of 8 bits is called a a byte.
     • In a computer there are small circuits. If the output of a circuit is high or ON, it is represented as 1. If the output is low or OFF, it is represented by 0.
     • 1 = TRUE and 0 = FALSE.
     • Transistors can be wired together in circuits to perform logical calculations.
       • These are called logic gates. Logic gates have inputs and outputs.
         • AND= both must be 1 (true)
         • OR = at least one must be a 1.
         • NOT = whatever goes in, the opposite comes out.

5. RAM

   • Stands for Random Access Memory
     • RAM is volatile, so it loses its data when the electricity is turned off.
     • Program instructions and data currently being accessed by the CPU are stored in RAM.
     • The greater amount of RAM, the more instructions it can store.