1.3 Storage Devices V2

1.3 Storage Devices V2

1. Storage

   • Secondary Storage
     • Where devices are not constantly connected to the computer or Devices not directly accessible by the computer’s CPU.
       • External secondary storage device
         • CDs
         • Memory card
         • Flash drive
       • Internal secondary storage device
         • Hard disk drive (HDD)
         • Solid state drive (SSD)
     • Another name for Secondary Storage is Auxiliary
   • Optical
     • A laser light creates marks in a pattern on the disk. A laser light detects where the marks are and translates this into a readable format
       • Advantages
         • Inexpensive
         • Reliable
         • Relatively large capacity
   • Magnetic
     • Read/write move across the medium and change how magnetised that part of the medium is
       • Advantages
         • Store large capacity
         • Cost-effective
         • Reliable
   • Solid State
     • This is made of microchips .The state of the switches determine if a 1, or 0 is stored
       • Advantages
         • No setup requirements
         • Can be used for portable devices
         • Inexpensive

2. Characteristics of of Storage Devices

   • Capacity
     • How much data can it store
   • Speed
     • How fast can it access the data
   • Portability
     • How easy is it to move it from one place to another
   • Durability
     • How well does it last e.g. if it is dropped
   • Reliability
     • How consistently does it perform
   • Cost
     • How much does it cost per KB, MB or GB

3. Storage Size

   • Bit (Binary Digit)
     • A binary digit is logical 0 and 1 representing a passive or an active state of a component in an electric circuit.
   • Nibble
     • A group of 4 bits is called nibble.
   • A group of 8 bits is called byte. A byte is the smallest unit, which can represent a data item or a character.
     • Kilobyte (KB)
       • 1 KB = 1024 Bytes
       • Megabyte (MB)
         • 1MB = 1024 KB
         • GigaByte (GB)
           • 1 GB = 1024 MB
           • TeraByte (TB)
             • 1 TB = 1024 GB
   • Byte

4. Internal and External secondary storage

   • Internal
     • Solid State Drive (SSD)
     • Hard Disk Drive(HDD)
   • External
     • Flash drive