Computing chapter 2

Computing chapter 2

1. Purpose of the CPU

   • The CPU is responsible for executing a sequence of stored instructions called a program
   • It is where all the searching, sorting, calculating and decision making takes place in the computer
   • Fetch - Decode - Execute

2. Memory

   • RAM
     • Purpose of RAM
       • random access memory
       • It is where the operating system, application programs and data in use is stored
       • It can be reached quickly by the processor
     • How does RAM effect performance
       • RAM is like a work surface for the system
       • The more space it has to temporarily store thing that it's using, the faster it will be
   • Cache memory
     • Cache is relatively small but is accessed very quickly
     • It stores things that are likely to be used again
   • Flash memory
     • A type of non-volatile storage
     • Solid state

3. Input and output devices

   • Input
     • To give the computer instructions
     • To give information
     • Keyboard
     • Mouse
     • Scanner
     • Camera
     • Microphone
   • Output
     • To communicate with the user in many forms
     • speaker
     • Monitor/display
     • Printer

4. Secondary storage

   • Devices that are not directly accessible from the CPU
   • USB drive
   • Hard drive
   • Used to back up important/irreplaceable files
   • Non-volitile

5. Optical, magnetic and solid state

   • Magnetic
     • Large storage space
     • Fast to access