"Shoe-shining" with 60 meg Wangtek tape on Sys V 386 3.2.1

[Paul de Bra]

In article <1990Oct18.152955.14275 at uhura.neoucom.EDU> wtm at uhura.neoucom.EDU (Bill Mayhew) writes:
>I've been trying to figure out a way to prevent shoe-shining of the
>tape (repeated short back-and-forth movement) on a 60 meg
>Sperry/CMS Wangtek tape drive on my Sys V 386 3.2.1 system. I did
>
>find /usr/local -name "*" -print | cpio -oc -C1024 > /dev/rmt/c0s0

According to the manual the -Cn option gives you a buffer of
n BYTES, not n BLOCKS. There is a bug in the 3.2.1 cpio however
which makes cpio give you a buffer of 10xn BYTES. So you really have
asked for a 10k buffer.

You can safely use cpio -oc -C100000 to get a 1000000 byte buffer.
I always use -C131072 or -C262144 to get a multiple of 1024 bytes
after the 10x bug.

Paul.
(debra at research.att.com)