1.3 Storage

1.3 Storage

1. Solid State

   • made of microchips (switches)
   • the state of the switches determine if a 1 or 0 is stored
   • e.g. Solid State drive, SD Card, USB Memory Stick

2. Magnetic

   • read/write move across the medium
   • change how magnetised that part of the medium is
   • e.g. one level of magnetism will be a 1 and the second will be 0
   • e.g. Hard disk drive, Tape drives

3. Optical

   • laser light
     • creates marks in a pattern on disk
     • detects where marks are and translates them into a readable format
   • e.g. Blu ray, DVD ROM, CD ROM

4. characteristics

   • a feature, attribute or distinguishing trait
   • characteristics of a storage device
     • capacity (how much data can it store?)
     • speed (how fast can it access data?)
     • portability (how easy is it to move it from one place to another?)
     • durability (how well does it last?)
     • reliability (how well does it perform?)
     • cost (how much does it cost per KB/MB etc?)

5. UNITS OF STORAGE (Highest to lowest)

   • GB (1 000 000 000 bytes)
     • MB (1 000 000 bytes)
       • KB (1 000 bytes)
         • Nibble (4 bytes)
           • byte (8 bits)
             • bite

6. Data

7. Secondary Storage

   • used for long term storage of data
   • e.g. hard disk drive, DVD-R
   • non volatile
   • no access via input/output

8. Cache

   • very fast
   • holds commonly used instructions
   • small amount of memory on processor chip
   • acts as intermediary between processor and main memory
   • closer to CPU than RAM

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