Data - Organisation | Data processing

Tape - Traditional (logical) file structures

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A tape may be used to store many files. Generally files on tape are organised serially and/or sequentially and processed sequentially. This means one-after-another and does not imply any order though they can be sorted as required.

The files on a tape drive are organised in one long string; after one file is read, another is immediately available. Since processing is done sequentially files may be compressed when storing to a tape drive, and decompressed when retrieved.

Within each file records may be organised serially (for example: stored in the order they occurred), or sequentially (eg, Ordered by Name, or Client code).

So, if the records are needed in one particular order, the file access time can be very short.

Traditionally Payroll was an application that was well suited to tape drives. This suits this application because the order of the files can be arranged ahead of time. Nowadays payroll is being tied to Personnel management systems or Human resource systems, so the basic function of a payroll is changing. Hence, Hard disks have now replaced tape drives as a storage medium.
Backups, archiving and transaction logging are other common applications, but are being challenged by writable CD-ROMs.