WORM storage is the technical foundation of audit-proof archiving. The acronym stands for ​‘Write Once, Read Many’: data is written once and is then neither overwritable, deletable nor modifiable in any way for a configured retention period. The decisive distinction lies in the level at which this property is enforced.

Hardware WORM enforces immutability at the only level no software can access: the hardware controller itself. Once the write process is complete, an integrated hardware controller sets write protection directly at the device level — independent of operating system, firmware, drivers or user privileges. No software error, no firmware update, no administrator account however highly privileged can alter or delete a committed dataset.

Software WORM, by contrast, enforces immutability through software policies — , retention policies, immutability flags. These policies only exist as long as the software is correctly configured and no user with sufficient rights deactivates them. attacks specifically escalate administrator rights to circumvent exactly these locks. For auditors and reviewers, the difference is fundamental: hardware WORM is a physical property — software WORM is a policy that someone can comply with or not.

Application areas include: long-term archiving of tax-relevant documents (10 years, §257 HGB / §147 AO in Germany), archiving of medical imaging data (30 years), research data archiving, SAP archiving and document management in regulated industries.

Frequently asked questions

Software WORM stores data and then applies a software-based lock. This lock can be deactivated by a user with sufficient rights — such as a domain administrator, a cloud root account or a compromised service account. Hardware WORM sets write protection directly in the storage controller at device level. This protection exists independent of operating system, firmware, drivers or user privileges. It cannot be overridden by software, an administrator or a ransomware attack.
Configurable retention periods enable retention periods from a few years to several decades. Silent Cubes from FAST LTA support retention periods of 30+ years — sufficient for the longest statutory retention obligations (e.g., blood product documentation: 30 years). The storage media themselves are designed for a service life of at least 30 years.
Yes. Modern WORM systems support deadline-based retention management: after the configured retention period expires, the dataset is released for controlled deletion. Deletion does not happen automatically but must be actively triggered — and is fully logged. This allows retention obligations and GDPR deletion requirements (Art. 17: right to erasure) to be met within a single system.