SUMMARY: bar's incremental append switch

From: Jim Sisul (bmskc!moe!sisul@uunet.UU.NET)
Date: Thu Oct 15 1992 - 11:56:24 CDT

Keywords: bar QIC SunOS

My original question:

>The man page for bar(1) states that the "u" option,
>which would be useful for incremental archives, does
>not work with 1/4-inch tapes. Why is this? Are
>there any modifications or improved versions of bar
>or the /dev/rstX device driver (for SunOS 4.1.1 or newer)
>that support this feature on 1/4-inch tapes drives?

>Also, 3M is advertising QIC-150-size tapes that
>hold 1.5GB and drives that accommodate this new format.
>will these work with bar and existing SunOS (4.1.1 & up)
>device drivers? If not, what kernel modifications, etc.,
>are necessary to support the new drive?

The answer, from Matt Goheen (uunet!!matt):

The problem isn't bar, it's a hardware limitation on the current
implementation of QIC drives. The problem is that these drives
erase the tape in one pass while writing the first track. This
means that you cannot update a file in the middle of the tape
w/o erasing all of the other tape tracks.

Thanks to Matt and all those who responed to original posting.

As for the 1.2 GB 3M tapes, a representative whom I called said
they were still testing that format, and that IBM is the only vendor
committed to building a drive compatible with both the new format
and the older QIC-150 and QIC-24 formats. Oh, well.

Thanks for all your help,


James P. Sisul
Associate Software Engineer
Biomedical Systems Division
PPG Industries, Inc.
16505 West 113th Street
P.O. Box 15955
Lenexa, KS 66215-5955

VOICE: (913)894-7500, ext 7181
FAX: (913)894-7733
EMAIL: {...}uunet!bmskc!sisul OR sisul@bmskc.PPG.COM

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