Secondary Storage

Secondary Storage

1. Capacity- The quantity of data that the storage medium can hole

2. Speed- The access time to transfer data onto the secondary storage medium

3. Portability- The ease with which a secondary storage medium can be connected from one device to another

4. Durability- How susceptible the secondary storage medium is to damage

5. Reliability- How likely it is to fail through continuous use

6. Magnetic Hard Drive

   • Main secondary data storage device (hard disk)
   • Consists of metal platters coated in special magnetic material and a series of read/write heads
   • Read/Write heads move across a disks surface to access and store data
   • Spins at 7000 RPM

7. Magnetic Tape

   • Used by organisations to back up data
   • Use serial access to find the data file
   • Stars at beginning of the tape and fast forwards until targeted files are located
   • Similar the Magnetic Hard drive however read/write heads driven by a magnetic motor
   • It's slow to retrieve data but because it's used for backup this doesnt matter
     • Company's store these off-site in case of fire or disaster at main sites

8. Optical Storage Devices

   • Compact disks were data is burned onto surface using laser beam
   • Burned on CD (compact disk) or DVD (Digital Versatile Disk)
   • CD-ROM disks are disks used by game company's as they are one way and data is permanently burned on
   • CD-RW allows data to be saved one and erased (used more than once)

9. Solid State Devices

   • Solid-state Flash memory composed of a series of logic gafes stores data in binary format
   • Lightweight,removable,can be re-written,easy to carry round (used by students for exanple)
   • Consiists of printed circuit board encased in plastic or metal casinng
     • usually fitted with a removable cap which covers/protects the end which goes in the USB port
   • Flash memory cards are used in digital cameras and mobile phone devices
   • Widley used in tablets
   • Cannot hold large amounts of data