(Topic two) computing hardware

(Topic two) computing hardware

1. The CPU

   • CU
     • The control unit. Controls the data flow of the CPU
   • ALU
     • (Arithmetic logic unit) performs all mathematical/ logical oprations
   • Registers
     • (cache) small, superfast amounts of memory incredibly close to the CPU

2. Input and output devices

   • Input devices are used to input instructions into the computer
   • Output devices display the results of whatever is happening inside the computer

3. Binary logic

   • There are 3 types of logic gate
     • AND
       • 2 inputs, both must =1 our the output is 0
     • OR
       • 2 inputs, as long as one input =1 the output is 1
     • NOT
       • 1 input, output is the opposite

4. Memory

   • ROM and RAM
     • ROM
       • Read only memory. usually quite small, cannot be saved into
     • RAM
       • Random access memory. Unlike ROM it is volatile. Usually quite large
   • Secondary storage
     • Anything other than ROM, RAM or CACHE
       • Needed because you can't save into ROM; RAM and cache are volatile