tcopy tape to tape WAY too slow

[Dan Nelson]

In the last episode (Mar 30), Jesse Guardiani said:
> I'm copying 35G/90G AIT-1 tapes on FreeBSD from tape drive to tape
> drive (nrsa0 and nrsa1) using the tcopy -c command and it's taking
> WAY too long. Over 12 hours including the verification process. (not
> sure exactly how long as it finished when I was sleeping)
> 
> Is there something I can do to speed this up?

I don't think tcopy is double-buffered; if you only have one file on
that tape and know the blocksize, dd if=/dev/nrsa0 bs=##k | dd
of=/dev/nrsa0 bs=##k should be much faster.  If you have multiple files
or unknown blocksizes, the cptp command from the MAG package at
http://www.cs.vu.nl/~dick/mag.html will preserve filemark and blocksize
info through pipes, so you could do a cptp | cptp pipe.

-- 
	Dan Nelson
	dnelson at allantgroup.com