tape-buffer-synchronization · shipping · also tape buffer flush

Tape buffer synchronization

Tape buffer synchronization is completion of a supported operation that confirms previously buffered tape data and marks have been written to the medium.

Related Observatory article: Tape buffer synchronization on hesela.com

IBM 3592 documents WRITE FILEMARKS with IMMED=0 and transfer length zero for this purpose. Successful status matters, not just issuing a command. [3] In Linux v6.12, MT_ST_NOWAIT_EOF changes MTWEOF and close-time filemarks to immediate operation, including the MTWEOF zero-count path; check configuration before treating completion as a synchronization boundary. [2]

Relations

related

tape, lto, tape-filemark, restore-test

Limitations

• Confirmation of covered writes is not proof of long-term readability or an application-level restore. [3]

Citations

1. Linux v6.12: SCSI tape driver, buffering and MT_ST_NOWAIT_EOF (accessed 2026-10-16)
2. Linux v6.12 st.c: st_flush, st_set_options and st_int_ioctl (accessed 2026-10-16)
3. IBM 3592 SCSI Reference GA32-0968-07, section 5.2.52, page 199 (2026) (accessed 2026-10-16)

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