Summary: 4mm tape drive on a SunOS 4.1.4 system (fwd)

From: Steven Sakata (
Date: Wed Apr 01 1998 - 17:04:44 CST

Thanks to all of you who responded to my question for the correct arguments
for the SunOS 4.1.4 "dump" command on a 4mm tape drive. The attachment
basically describes the answer very well.

                                    - Steven.

---------- Forwarded message ----------
Date: Wed, 1 Apr 1998 15:45:04 -0500
From: "Button, Daniel (SOM400A)" <>
To: Steven Sakata <>
Subject: RE: 4mm tape drive on a SunOS 4.1.4 system


        Take a look at this.



        -----Original Message-----
        From: Steven Sakata []
        Sent: Wednesday, April 01, 1998 1:25 PM
        Subject: 4mm tape drive on a SunOS 4.1.4 system

        I'm trying to back up a SunOS 4.1.4 system on a 4mm tape drive
with the
        dump command. However, looking at the man page, there's no
mention of
        what arguments to use for a 4mm tape drive. Does anyone know
the correct

        Thanks, Steven.

                  Symptoms and Resolutions article 10688
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SRDB ID: 10688

SYNOPSIS: Dump parameters for 4mm dat


What are the dump parameters for 4mm DAT drive for 4.1.3U1?


Here are the dump parameters for 4.1.3U1.

Native (non-compressed) mode:

  dump 0ubdsf 96 54000 5200 /dev/rst0 /dev/xxx

     The 96 specifies a blocking factor of 48 which is optimum for DAT/Loader
     The 54,000 is the same density factor used for the 8mm drives
     The 5,200 is used for size instead of 6000, because the DAT has a
     capacity of 2GB rather than the 2.3GB capacity of 8mm drives.
     The rst0 specifies non compression mode (this is very important)

compression mode:

    The DAT drive supports compression. However, it is not possible to
    determine how much data will fit on a tape. A typical value is twice
    non-compression mode, but in some cases the data won't fit on the
    tape and in many cases the data is muchmore compressible and tape
    capacity will be wasted.

    To be on the safe side, doubling the capacity is recommended. It should
    be noted however that in some cases even this may not be conservative
    enough, and that the only way to guarantee that the dump will not run
    out of tape is to not use compression.

    Doubling the size option (5200 in non-compressed mode) results in the
    following command:

        dump 0ubdsf 96 54000 10400 /dev/rst8 /dev/xxx

   The 10400 specifies an anticipated capacity of 4Gbytes. Note the
   use of /dev/rst8 instead of /dev/rst0.

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PRODUCT: Device config

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