SUMMARY: Dubbing 8mm tapes

From: Paul Joslin (
Date: Wed Aug 11 1993 - 19:42:10 CDT

Thanks to all who responded.

My problem was:
> I have a user who has 256 8mm data tapes. He needs two copies of
> each. Management may say "Do it."
> Does anyone know of a hardware/software combination that would
> allow high speed copying between exabytes? We have an IGM automated
> tape library & varies single exabytes. The IGM offers a tape copy
> mode, but it's not that quick & and I wonder how much host
> intervention a copy would require.

1) There are no high speed ways to copy 8mm tapes. It will take
~1.5-2 hrs per tape. writes:

dominic> I presume you know about the tcopy command which, assuming
dominic> you have Exabytes on /dev/rst0 and /dev/rst1, allows you to
dominic> do a block-for-block, file by file, copy with
dominic> /usr/ucb/tcopy /dev/rts0 /dev/rst1
dominic> The bad news from your point of view is that it runs at
dominic> normal speed, so you can reckon on 90 minutes plus to copy
dominic> each tape. (I never heard of a high-speed Exabyte duplicator
dominic> -- or, indeed, of any high-speed helical-scan videotape
dominic> duplicator: even commercial videos are copied in real time.)
dominic> tcopy also requires processor intervention, although my
dominic> finding is that it uses very few cycles.

2) Several respondents recommended tcopy, which is included in SunOS
   4.1 (and possibly SunOS 5.X). Others recommended tprobe, tapecv,
   and copytape. One respondent had experience with a modified
   version of tcopy that used multiple buffering which was much faster
   that Sun's version. This version was created from Sun's source,
   and cannot be distributed. His numbers suggested that throughput
   dropped considerably when he had more than one tape per SCSI

3) Throwing hardware at the job may help.
"Patrick M. Landry" <> notes:
Patrick> This month I began seeing adds for a box from Contemporary
Patrick> Cybernetics (804-873-9000) which contains two 8mm tape
Patrick> drives. The add claims that the device can be used in a
Patrick> number of ways, one of which is to do offline dubbing of
Patrick> tapes. I have no idea whether the dubbing occurs at normal
Patrick> speed or not. All I have seen is their ad and I do not own
Patrick> any of their equipment.

If we are tapped to make the tapes, I'll need to verify that the Cont.
Cybernetics box does not tie up the SCSI bus during a tape-to-tape

4) FWIW, My preferred solutions are:
        1) Don't do it.
        2) Have user do it.
        3) Let operator do it, as a low level task.

    If it is done, the preferred way is:
        1) Use existing IGL 8mm jukebox to do tape to tape copy
        2) Buy dual 8mm box, add to machine with 8mm, and make copies
           in parallel. Since this machine has 2 SCSI controllers,
           this might be the best option.
        3) Buy dual 8mm box, and do tape to tape copy (within box)
        4) Copy from 8mm on another machine, across network, to IGL to
           make copies in parallel. Unfortunately, the other machine
           is not on the FDDI network. Also, the other 8mm is used to
           do backups.

Thanks to the following respondents:
  "Patrick M. Landry" <>
  Dan Stromberg - OAC-DCS <>
  Dominic Dunlop <> (Jay Scott) (Gary Richardson) (James Ashton) (Kevin W. Thomas) (Thomas Rigert) (Tommy Reingold)

Paul R. Joslin +1 513 255 1115

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