Computer systems

Computer systems

1. RAM

   • Random access memory
   • volatile
   • Fast
   • Loads faster if stored in RAM
   • If RAM is full it will be stored in digital memory

2. ROM

   • Read only memory
   • non=volatile
   • Can only be read to
   • cannot be written to
   • Tells the cpu to
     • Test the memory system is working ok
     • Set-up the computer
     • See what hardware is present
     • copy the operating system into the RAM
   • Main memory
   • Not part of the cpu

3. Storage

   • Primary
     • Places where the cpu can access quickly
   • secondary
     • here data is stored when not in use
   • Tertiary
     • long term purposes
   • Choices
     • Capacity
     • Speed
     • Portability
     • Durability
     • Reliability
   • Types
     • Magnetic hard disk
       • 5400 and 15000 rpm (revolutions per minute)
       • Traditional internal storage of PC's and laptops
       • Not very portable
       • Larger
       • Higher capacity
     • Solid state drives
       • No moving parts
       • Flash memory
       • A lot faster than a hard disk drive but a lot more expensive
       • Smaller
       • Used in phones
       • Portable
       • silent
     • Optical disk
       • CDs
         • 700MB
       • DVDs
         • 4.7GB
       • Blu-Rays
         • 25GB