SUMMARY: 4mm tape drive nightmare

From: Marc S. Gibian (
Date: Tue Nov 11 1997 - 14:10:02 CST

I had asked about a problem with compatibility between tapes written on one
version of the Sun 4mm tape drive, being read by a very recent version of the
Sun 4mm tape drive. I recieved only one response suggesting that the solution is
to avoid the b/Berkeley version of the tape device. I have not had time in my
schedule to test this yet, though I have observered other tapes written on the
same drive with the non-Berkeley device name being read properly on the target
drives. It was also suggested that I should read without specifying a
compression selector in the device name.

Thanks to ...
Glenn Satchell - Uniq Professional Services <>

... for being the lone respondent to this question.


Marc S. Gibian
COMSYS Information Technology Services phone: (617) 377-6350
PRISM/TFS email:
                           or is it:
                        well, maybe:
              and if all else fails:

attached mail follows:

I am writting product install tapes on an old 4mm drive, a Sun (Archive) fast
narrow drive rated at 4g/tape on a SPARCstation 20 running Solaris 2.5. These
tapes have installed just fine for a while when read with the same drive,
installing to SPARCstation 20, 10, and Ultra 1,2 systems (Ultra 2-s always are
running Solaris 2.5.1, the others are a mix). When the Ultra workstations
arrived, they came with new fast wide 4mm drives that I am told are rated at
12g/tape. When I try to install with the same tape using these drives, I see
intermittent failures.

Today I isolated the failures to a "mt -f /dev/rmt/0hbn fsf 1" operation. On the
fast narrow drives, I can always perform the skip. On the fast wide drives, the
skip keeps missing the file mark and runs off the end of the data written to the
tape, finally terminating with a tape error. This of course results in a failed
install of the product.

I tried every tape command I could think of to skip forward the one file on the
fast wide drive. The only command that even reported the multiple files on the
tape was "tcopy /dev/rmt/0hbn". SO, to some degree the drive IS reading the
tape, but not acurately enough for it to be used as needed to install the
product. I should note that the data in the first file on the tape is read with
no problem on both tape drive types.

Can anyone please explain what is going on here?

Is there a command sequence I can use to RELIABLY skip forward a file for tapes
written on the fast narrow drive, reading on the fast wide drive?

Am I doomed to writting distribution tapes on fast narrow drives for use on fast
narrow drives and on fast wide drives for use on fast wide drives? What a
nightmare THAT would be!


Marc S. Gibian
COMSYS Information Technology Services phone: (617) 377-6350
PRISM/TFS email:
                           or is it:
                        well, maybe:
              and if all else fails:

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