Reference Work Entry

Encyclopedia of Database Systems

pp 3570-3570

Write Once Read Many

  • Kenichi WadaAffiliated withHitachi Limited

Synonyms

Write once read mostly; Write one read multiple; WORM

Definition

A data storage technology that allows information to be written to storage media a single time only, and prevents the user from accidentally or intentionally altering or erasing the data. Optical disc technologies such as CD-R and DVD-R are typical WORM storage.

Key Points

There are two types of WORM technology: physical and logical WORM.
  1. 1.

    Physical WORM uses storage media which physically can be written only once, and prevents the user from accidentally or intentionally altering or erasing the data. Optical storage media such as CD-R and DVD-R are good examples. Offering fast access and long-term storage capability, physical WORM has historically been used for archiving data that requires a long retention period.

     
  2. 2.

    Logical WORM uses storage systems which provide a WORM capability by using electric keys or other measures to prevent rewriting even if with non-WORM storage media, such as disk d ...

     
This is an excerpt from the content