tape-end-of-data · shipping · also EOD (tape), end of recorded data

Tape end of data (EOD)

Tape end of data is the logical boundary denoting the end of the recorded user-data sequence on a tape or partition.

Related Observatory article: Tape end of data (EOD) on hesela.com

In the cited tape-format glossary, EOD is a recorded dataset denoting the end of user data. It differs from a filemark separating logical files and from the medium boundary. The Ultrium sense table distinguishes filemark detection (ASC/ASCQ 00h/01h), EOM (00h/02h) and EOD (00h/05h). Interpret these with the command and sense data, not as interchangeable reports that a tape is full. [3] [4]

The Linux SCSI tape driver documents MTEOM as spacing to the end of recorded data despite the ioctl name. Its read interface signals EOD with two consecutive zero-byte reads; end-of-medium early-warning write behavior is documented separately. Those are Linux driver semantics, not a universal API for every tape format. [1]

Practical implication: reaching EOD identifies where the recorded sequence ends. It does not verify that an application produced all intended records, that every preceding record remains readable or that a restore is usable. Compare recovered contents with the expected backup inventory and perform recovery tests. [2]

Relations

related

Magnetic tape storage, Tape filemark, Tape buffer synchronization, LTFS, Restore test

Limitations

• A recorded-data boundary is not a backup-completeness or recoverability guarantee. [3, 2]

Citations

1. Linux kernel: SCSI tape driver, block modes, filemarks and EOM behavior (accessed 2026-10-18)
2. CISA, MS-ISAC, NSA and FBI: StopRansomware Guide, offline backups and recovery testing (accessed 2026-10-18)
3. IBM Storage Archive LE 2.4.8: glossary, End of data (accessed 2026-10-18)
4. IBM TS2900 Ultrium tape-drive sense data: filemark, EOM and EOD conditions (accessed 2026-10-18)

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