SUMMARY: tape-to-tape copy

Date: Tue Aug 27 1991 - 14:11:35 CDT

I asked:
> Does anyone have a HIGH performance tape-to-tape copy utility? I tried Sun's
> tcopy, and only got ~35 Kbytes/second copying from a dat drive ( 184
> kbytes/second) to a High density Exabyte (500 Kbytes/second). Right now, it
> takes 15 hours to copy a 1.2 Gig tape, which is just too long! Naturally, I'd
> like the copy program to produce an exact copy, including record block sizes
> and file marks. I've also tried tapecv but it wasn't any faster.
> I think that by doing some async. I/O, and reading/writing groups of records
> that it should be possible to get much higher performance. suggested taper, from (, which is usable locally or over a
network by using rsh.
        taper rf /dev/dat0 | taper wf /dev/smt0 suggested "copytape", which he uses to copy Sun
distribution tapes, which is a stress test for most tape copy programs.
A version of copytape is available from sun-source/copytape.c

If I knew the format of the tapes in advance, I could use
"buffer" (a tape buffering utility ) from celit!hutch@UCSD.EDU
 "block" (somewhere on comp.sources)
"ddd" a two process version of dd available from Location: /Comp.sources.unix/Volume15
      FILE -rw-r--r-- 17915 Sep 20 1988 ddd

Glen Dudek ( supplied me with tpcp, which does reads and writes
in sep. processes to speed up I/O, and preserves file marks and blocksizes.

I haven't had time to benchmark these tools yet, but I certainly appreciate
all of your responses!

Thanks again. I'll be happy to make any of these utilities that I now have
available to anyone who requests them.

        Joe VanAndel
        NCAR - ATD/RSF
        P.O Box 3000 Fax: 303-497-2044
        Boulder, CO 80307-3000 Voice: 303-497-2071

Status: OR

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