SCSI tape data loss

[Matthew Jacob]

> There are now a lot more things making sense
> because I've had other FreeBSD users report
> "unbelievable" output from a simple test program
> I have. I'll respond below, but with the latest
> test results, the problem seems to be generated
> from the simple sequence:
>
>   write()
>   ...
>   write()
>   ioctl(MTEOF)
>   ioctl(MTEOF)
>   ioctl(MTREW)
>
> is there any reason why writing two end of file marks
> followed by a rewind after a series of writes should
> create data loss?

No. That, in fact, whould flush data to the tape. Additional filemarks
should not be written even after you close here because the rewind would
clear SA_FLAG_TAPE_WRITTEN so a subsequent close won't write more.

I'm playing around with this some as we speak.

-matt