WORM - Write Once Read Many

WORM describes data storage media that allow data to be written only once and then read many times.  Once the data is written it is write protected and cannot be changed - this ensures that data cannot be tampered with or erased after is written/stored.

Most WORM media storage secures data by either using a physical process or manufacturers’ firmware.

  • A traditional solution is to use optical media in which there is a chemical change on the disk as data is written.  This data is locked onto a physical piece of media and therefore cannot be changed, tampered with or erased.
  • Newer technologies use software to achieve the same thing with different hardware.  For example there may be firmware on a disk that makes it appear that a chemical change has taken place.


  • The advantages to using a firmware/software solution are that it is quicker to write the data.
  • The disadvantages to using firmware to achieve the solution is that it is still only a magnetic disc with a software solution and so is hackable with a virus or software.
  • When looking at long-term/archive storage solutions speed is not as important a consideration as the necessity for security against malware or virus attacks, particularly when dealing with evidential data and records that may need to be retained for 30+ years.

Other advantages of WORM media:

  • As well as these considerations it is important that data written for long-term and archive storage remain accessible 20 to 30+ years down the road.  It is important to choose a solution that plans for possible redundancy of proprietary hardware and/or software solutions used to write and store data.
  • Archive data storage should also not be an unnecessary drain on resources and costs.  WORM data storage solutions can, for example, avoid the time and cost requirements associated with managing magnetic tape storage, or the hardware problems associated with long term storage on hard disk drives.

At Mercia Solutions we have the technologies that can use a standard hard disc and ensure the integrity of data in an evidential way.  By using a software mechanism to prove the integrity of data the benefit can be realised with other technologies - if there is no process in place to verify and audit data there is no evidence that the data is still the same as when it was originally collected.  Without this proof data loses its evidential value, for example, in court.

Products for WORM Storage

Sony Optical Disc Archive

Sony Optical Disc Archive

3.3TB Worm Cartridge solution from a single drive to petabytes of data in library

Netzon HMS jukebox

Netzon Blu ray Jukeboxes

Blu ray 100Gb discs and smaller in a robotic jukebox

Point Storage Manager

Point Storage Mangeer

Software defined worm storage that can combine tape, cloud, optical and disk solutions