Memory and Storage

Memory and Storage

1. Primary Storage

   • Holds data and instructions currently in use
   • Read Only Memory(ROM)
     • Non-Volatile
       • Data can't be changed
     • Stores the BIOS
       • Basic input output system
     • Stores the boot up instructions
   • Random Access Memory(RAM)
     • Volatile
       • When computer is turned off memory is lost
     • Holds operating system
     • Holds currently running programs
     • Virtual Memory
       • Slower then RAM
       • Used when RAM is full
       • Stores unused programs
       • Inside secondary storage
   • Fast because it's built into the computer
   • Smaller than secondary storage
   • https://www.bbc.co.uk/bitesize/guides/zd4r97h/revision/1
   • Cache
     • Stores frequently used instructions
     • Inside the CPU
     • L1 Cache
       • Really fast
       • Store the most common instructions
     • L2 Cache
       • Bigger
       • Stores less common instructions
     • Faster then RAM
       • More expensive then RAM
   • Flash Memory
     • Non-volatile
     • Requires little power
     • Used in phones
     • Fast, but slower then RAM
     • Can be read from and written to
     • Also secondary storage

2. Secondary Storage

   • Characteristics

3. Units

4. Data Storage

5. Compression