Tape backup performance on 386 ISA/EISA systems

[Keith Ericson]

In article <1060 at sixhub.UUCP> davidsen at sixhub.UUCP (bill davidsen) writes:
<In article <1990May30.132457.6117 at virtech.uucp> cpcahil at virtech.UUCP (Conor P. Cahill) writes:
<| 
<| 2. The performance of the disk due to optimizations will probably have
<| little performance effect on the overall perforance on the tape write, since
<| the tape write is the limiting factor.
<
<  I'm sorry, this is just totally wrong. You must never have had a
<fragmented disk. I have seen transfer rates as low as 300kBytes/sec with
<a fragmented disk and streaming tape which ran in fits and starts. I see
<about 4MB overall (from the time I hit return to the time the tape is
<rewound) on a non-fragmented f/s.

By far and away the biggest difference I've ever seen in disk<->tape
transfers is the size of the buffer uses in the cpio command: I generally
use cpio -[i,o] [???] -C 1048576 -[I,O] /dev/tape  for screaming, if not
streaming, tape I/O.

kEITHe