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From: bob@obiwan.uucp (Bob Willcox)
Newsgroups: comp.unix.bsd
Subject: Re: Tape on 386bsd...
Message-ID: <Bv474n.HKF@obiwan.uucp>
Date: 25 Sep 92 03:31:35 GMT
References: <q83o7rs@sgi.sgi.com>
Organization: Bob's Place, Austin TX
Lines: 29
In article <q83o7rs@sgi.sgi.com> rpw3@rigden.wpd.sgi.com (Rob Warnock) writes:
>randy@chinet.chi.il.us (Randy Suess) writes:
>+---------------
>| bob@obiwan.uucp (Bob Willcox) writes:
>| >it appears to be missing the first 2KB of each block read. (I was using
>| >a buffer size of 2MB as I recall).
>|
>| I am pretty sure this is a FAQ. Do NOT use any buffering.
>| just tar cf /dev/wt0 and cpio -oc > /dev/wt0. There is a
>| reason for this, but I can't find my notes. It is slow, but works.
>+---------------
>
>Well, you don't have to use *no* buffering, just keep it under 64 KB (I think).
>I have no problems with "cpio -B", which uses 5120-byte blocks, and it goes
>a *lot* faster than "cpio" without the "-B". ("Tar" defaults to 10240, which
>also works well.)
Thanks for the tip. Turns out I was able to get up to 485KB
(successfully) before encountering problems. I generally use afio for
backing up and was able to determine (imperically) that with a buffer
size of 5120 and a count of 97 (for at total of 485KB per block) my
reads of the tape worked okay. Beyond that I encountered problems
again. Note that writing 2MBs at a time seems to work just fine.
Bob
--
Bob Willcox ...!{rutgers|ames}!cs.utexas.edu!uudell!obiwan!bob
Phone: 512 258-4224 (home)
512 838-3914 (work)