Storage Devices and Media

Accessing Stored Data
1. Serial / Sequential Access
  1. A Serial Access storage device is one that stores files one-by-one in a sequence.
2. Direct / Random Access
  1. A Direct Access storage device is one that stores file so that they can be instantly accessed.
Magnetic Storage Devices / Media
1. Hard Drives
  1. They can be used to store vast amounts of data. Hard-drives are random access devices.
2. Fixed Hard Drive
  1. A hard-drive built into the case of a computer is known as 'fixed'. They are random access.
3. Portable Hard Drive
  1. It is one that is placed into small case along with some electronics that allow the hard-drive to be accessed using a USB or similar connection.
4. Magnetic Tape
  1. Tapes are used where large amounts of data need to be stored. Magnetic Tapes are a serial access medium.
Removable Media Magnetic Discs
1. Floppy Disc
  1. Floppy discs are random access devices used for transfer small amounts of data. A removable, portable, cheap, low-capacity storage medium. These are obsolete now.
2. Zip Disc
  1. A Removable and portable storage medium. Zip discs are random access devices which were used for data back-up or moving large files.
3. Jaz Disc
  1. A removable and portable storage medium. Jaz discs are random access devices which were used for data back-up or moving large files.
Optical Storage Devices / Media
1. Read-Only Optical Discs
  1. CD-ROM
    1. Compact Disc - Read-Only Memory discs. The data cannot be altered. CD-ROMS are random access devices. Used to distribute all sorts of data.
  2. DVD-ROM
    1. Digital Versatile Disc - Read-Only Memory disc. DVD-ROMS are random access devices.
2. High Capacity Optical Discs
  1. Blu-Ray
    1. Blu-Ray discs random access devices. Blu-Ray discs are used in the same way as DVD.ROMs.
  2. HD DVD
    1. High-density DVD. HD DVDs are random access devices. HD-DVD discs are used in the same way as DVD-ROMs.
  3. CD-R and DVD-R
    1. CD-Recordable and DVD-Recordable discs can have data burnt onto them, but not erased.
  4. CD-RW and DVD-RW
    1. CD-ReWritable and DVD-Rewritable discs can have data burnt onto them and also erased so that the discs can be re-used.
  5. DVD-RAM
    1. DVD-Random Access Memory discs are a type of re-writable DVD. DVD-RAM discs are random access devices. Used in many camcorders.
Solid-State Storage Devices
1. Flash Memory
  1. A type of Electronically-Erasable Erogrammable Read-Only Memory (EEPROM). Flash memory is a non-volatile. Flash memory can be found in many data storage devices.
2. USB Memory Sticks
  1. Memory sticks are non-volatile, random access devices. You can use it to move any type of file.
3. Memory Cards
  1. Many of our devices need compact, non-volatile data storage. Flash memory cards provide this. Many phones also have extra memory cards to store music, video, photos, etc.
4. Smart Cards
  1. Many credit cards, door entry cards, satellite TV cards etc. have replaces the very limited storage of the magnetic strip with flash memory.

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Storage Devices and Media

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	Created by maria.kjeldsen over 10 years ago