Write once read many

WORM is an acronym for "write once read many " or " write once read multiple" (English " write once, read many "). She describes precautions in Information Technology, which exclude the delete, overwrite and modify data permanently on a storage medium. The data storage that are used can be described only read and continued until their capacity.

History and definition

The term WORM was primarily used in conjunction with optical storage media and tape storage. Through the further development, the term now on all storage media that does not leave the information be changed or deleted.

In a broader sense WORM also appears in connection with archiving programs that reach through the type of formatting a Einmalbeschreibbarkeit Connected media.

Not all fall under WORM solutions of the temporary write protection or encryption.

A distinction is made in the narrow sense: Hardware - WORM and WORM systemic. While in the former, the WORM property generated by irreversible physical changes in the storage medium, the deletion protection results in the second from the interaction of storage processor / controller and the memory medium. In the other version, software - WORM be added as a third category.

WORM Hardware

From hardware WORM (also: TrueWORM called ) is when the write-once property is given physically. In this case, either recesses or blisters are generated in the interior of the medium by a laser beam. These can not be changed at a later point in time.

Unlike a multi-session CD WORM memory can be like an early CD -R to no deletion of data. Originally, the term referred to specific WORM media and drives. This media is in a protective case and were first with 14 ", 12", 8 ", 5 1/ 4" and 3 1/2 " Diameter available. In 2006, only played by the media with 5 1/ 4" in diameter, a role. In electronic archive systems since 2006 are mostly modern TrueWORM in UDO or PDD technology used.

TrueWORM systems based on rotating media have the problem of low disk space, so holds a current UDO2 medium only 60 GB, while archiving systems with software WORM are also available in the TB area.

Systemic WORM

In the systemic WORM unique writability is achieved either via the addressing or management by the internal processor / controller.

In the form of a WORM USB sticks the unique writability is determined by the internal controller of the USB sticks for example, when SECUMEM memory.

The Magneto Optical Disk is available with drives with WORM properties.

Content Addressed Storage (CAS ) is a technique which produces the write-once property of the software. CAS is mostly sold as a dedicated hard disk system. Examples are the Centera EMC, Caringo, Silent Cubes or iTernity iCAS.

Software WORM

WORM but can also be the pure software functionality in a network storage system, as it is with SnapLock or gray Data AG offered for example by NetApp with FileLock. In this case we speak of software WORM (also: SoftWORM called ).

It is, for example, special magnetic tapes ( WORM tape ) is possible with the corresponding drives. Come hard disk drives to use as is often spoken of WORM raid.

A special form of WORM sealing systems used by FAST LTA. As media are used here as in SoftWORM commercial hard disk, WORM functionality is provided by a external hard drive controller. This controller distributes data evenly across the hard drives connected and writes the data purely linear. Commands to delete or overwrite does not know this controller. Since the special file system is also firmly anchored in the controller, the disks can not be manipulated by connecting it to another hard drive or RAID controller.

Use and safety

Memory as the CD - R are in the age of server-based storage and cloud solutions as a carrier of digital information out of fashion.

A major application of WORM media, however, is the digital archiving. These come with large amounts of unchanging documents and records used. They are increasingly gaining in importance again since the legislature that allows for financial management and compliance regulations digital documents stored in immutable way, or even prescribe. Here comes the particular GDPdU to bear. But regulations such as SOX, Basel II and others rely on the immutability of stored documents.

When using all WORM systems should however be noted that only a comprehensive solution, including a document management and safe operation, can meet the legal information. The use of WORM media, is not sufficient. Content and storage data can be usually easily manipulate before storing. Remedy the integration in holistic archiving systems and volumes with its own timer and use monitoring such as the SECUMEM memory.

Particularly in software WORM, but also in systemic WORM, immutability can not be fully demonstrated. Programming errors resulting vulnerabilities in software or hardware can be exploited to bypass the overwrite protection.

Swell

• Secumem Description
• Avisaro - Glossary storage medium
• Grau Data FileLock