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- Newsgroups: comp.sys.sgi
- Path: sparky!uunet!decwrl!sgi!classic.asd.sgi.com!jeremy
- From: jeremy@classic.asd.sgi.com (Jeremy Higdon)
- Subject: Re: 8mm and dd
- Message-ID: <p9qeri8@sgi.sgi.com>
- Sender: jeremy@classic.asd.sgi.com
- Organization: Silicon Graphics, Inc. Mountain View, CA
- References: <715275893@anthrax.cs.duke.edu> <1992Aug31.192332.26751@nsisrv.gsfc.nasa.gov>
- Date: Tue, 1 Sep 1992 06:27:02 GMT
- Lines: 33
-
- In article <1992Aug31.192332.26751@nsisrv.gsfc.nasa.gov>, merritt@climate.NoSubdomain.NoDomain (John H. Merritt) writes:
- > In article <715275893@anthrax.cs.duke.edu>, jwt@duke.cs.duke.edu (Jeffrey W. Tannehill) writes:
- > |>
- > |> We have an 8mm tape drive attached via a scsi cable to our SGI IRIS 4D.
- > |> It seems to work as expected with the SGI backup and restore utilities and
- > |> with the BSD dump and restore commands. However, whenever I try the dd
- > |> command to write I get:
- > |>
- > |> > dd if=/etc/motd of=/dev/tape
- > Well, you were on the right track with the block size specification
- > in your later examples. In my layman's term, the "Invalid argument"
- > comes from the mismatch of the block size of the 'dd' statement and
- > the block size of the output device; I could not produce this error
- > message for the variable block 8mm device.
- >
- > I have noticed that if the input file has an odd number of bytes and
- > you output to the variable block device, that the entire file will
- > not be written; the last byte will be missing. If, however, you use
- > "bs=1" you will get the desired results (for the variable block 8mm device).
- > I would expect "Invalid argument" when you try to write the wrong
- > amount of bytes for the device -- fixed block device perhaps when the
- > 'bs' is not correct. I always see "No space left on device" when the
- > 'bs' is too small or you are trying to read a high density tape on a
- > low density drive.
-
- "No space left on device" also occurs when you get to end of data on
- the tape, which is what the previous poster is doing. When using the
- fixed blocksize device, you must give a blocksize arg to dd that
- is a multiple of that blocksize. You must also successfully write
- something before you can read anything from a tape.
-
- jeremy
-
-