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From: pnessutt@dmshq.mn.org (Bob Monio)
Newsgroups: comp.unix.i386
Subject: Re: Archive Tapes
Message-ID: <7804@dmshq.mn.org>
Date: 3 May 90 02:53:39 GMT
References: <29490@cup.portal.com> <1990May2.113532.26951@msuinfo.cl.msu.edu>
Reply-To: pnessutt@dmshq.mn.org (Bob Monio)
Organization: Death Fleet Command
Lines: 36

In article <1990May2.113532.26951@msuinfo.cl.msu.edu> jhl@frith.uucp (John Lawitzke) writes:
>From article <29490@cup.portal.com>, by Dante_A_Nicolello@cup.portal.com:
>> Problem two:
>>         When the tape reaches the end of the cartridge, not the end of the
>> current track, unix produces a "write() error" instead of prompting
>> me to switch tapes.
>
>tar and cpio have no idea how long or how dense your tape is. They
>assume you will not attempt to write more to tape than it can hold. If
>you use the backup program you can specifiy density and length so the
>program knows when it needs to prompt for a new tape.

Some vendors have modified their tar and cpio programs to support 
multiple volume archives.  NCR has done this with their cpio
implementation.  But, not all vendors do this.  This is unfortunate
since some people don't have the luxury of large capacity tape
devices.

>One solution is find the source to pdtar and hack it to prompt for a new
>tape at the necessary point.

Or, use afio.  Afio is a cpio lookalike with the capability to write
tape volumes of varying sizes and blocking.  We have used it
extensively at different user sites that do not have backup tools with
multiple-volume support.  

Afio was posted on comp.sources.unix a while back.  I can mail the
shar file to anyone that would like it.

 -Bob

-- 
 Robert A. Monio                     "I've learned all my heroes and wanted
 Level I Systems, Inc.                the same/To try out my hand at the
 pnessutt@dmshq.mn.org                Patriot Game..."
 ..amdahl!bungia!dmshq!pnessutt            -- Robby Jackson, 'Patriot Games'