Why isn't dump maximally efficient with TK70 tapes?

[Steve Campbell]

In article <12420 at cbmvax.commodore.com> grr at cbmvax (George Robbins) writes:
>Mostly that dump doesn't document the -b switch to let you specify a more
>efficient block size and restore doesn't support it, which makes it a
>pain to restore tapes with non-standard block sizes.

It sure is a pain.  Still you can use the -b option on dump and then let
dd do the unblocking on restores.  For example:

	dump 0fdb /dev/rmt0h 6250 64 /dev/rra1a

and then for restores:

	dd if=/dev/rmt0h bs=64k | restore if -

This works and gets much better performance out of a TU81.  In one case the
elapsed time dropped by about 35%.  I haven't tried it on multi-volume dumps.

Would someone familiar with version 4.0 care to comment on whether the -b
option will be documented and supported by restore in that version?

						Steve Campbell
						Dartmouth College