Information and communication technology
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Information and Communication Technology. File Access Modes Tsang Wing Luen S4C (28). File Access Modes. Sequential Access Mode Direct Access Mode Also called Random Access Mode. Sequential Access Mode. Not common Has to wind the tape until the desired record is underneath the read head

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Information and Communication Technology

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Information and communication technology

Information and Communication Technology

File Access Modes

Tsang Wing Luen

S4C (28)


File access modes

File Access Modes

  • Sequential Access Mode

  • Direct Access Mode

    • Also called Random Access Mode


Sequential access mode

Sequential Access Mode

  • Not common

  • Has to wind the tape until the desired record is underneath the read head

  • Need longer time and unpredictable

  • Mainly used for back up and recover of database and files of servers

  • E.g. magnetic tapes


Direct access mode

Direct Access Mode

  • When the target location is moved underneath the read/write head, the reading or writing process operation can proceed.


Hard disk

Hard disk

  • The most common storage

  • Most essential secondary storage device

  • Has high reliability, speed and capacity

  • Need shorter time and predictable to access data (access time: around 10ms)

  • Besides hard disk, floppy disk, optical disk and USB flash drive also support direct access mode.


Optical disks

Optical disks

  • Operate in direct access mode

  • Limited in capacity and speed of data access

  • Used for storage of multimedia files

  • E.g. DVD-R, DVD-RW, CD-R, CD-RW


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