Making Tape Backups
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Drive Formats

All beamlines support the following formats:
  • 4mm DAT systems, DDS2, DDS3, DDS4

    • Beamlines may support other formats, including:

  • X12-B supports DLT format.
  • X12-B and X12-C support DAT 4mm DDS1 format.
  • X12-B, X12-C, and X25 support Hot-Swap Removable Disks.

    The rest of this document is concerned only with the 4mm and 8mm systems.

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    • Operating the Tape Drive

    Many of the drives we use are "mirror" drives; they will make two identical copies of the tape at the same time.
    The front display of most of our mirror drives resemble this pattern:



    The lower most display window (bottom of drive 2 ) usually indicates "MIR" for mirror mode.

    If you would like to change the mode from mirror to independent mode (or vice versa):


    To copy data to tape, load two cartridges of the same type (if in mirror mode) into the drive, and open a terminal command window on the machine to which the drive is mounted.

    In the command window, change directory to your data directory.

    The device location and drive name should be posted on the drive. Use the command "tar cfv /device location/drive name ./your_data_dir"; and off it goes, almost. If you are making a tape on one of our Linux operating systems and want to read it on SGI at home specify a block size of 20 to make reading the tape a simple task. This is done by - tar cvb 20 -f/device location/drive name.

    If you want to verify the tape once it has been made, use the command "tar tfv /device location/drive name".

    If you are using DDS4 tape drive please note that compression of data can be done by adding 'c' after the drive name (for example tps1d1c)

    A hint in the use of tar:

    If a file name is preceded by -C, then tar will perform a chdir(2) to that file name. This allows multiple directories not related by a close common parent to be archived using short relative path names. This provides a method to get around the limitation of filename length; note that some care must be used when extracting a backup created in this manner.

    For example, to archive files from /usr3/x12cuser/rich/t1 and from /usr4/x12cuser/rich/t3, operating from computer node x12c-a, one might use 

              tar cvf /dev/st2     \
                 -C /usr3/x12cuser/rich  t1  \
                 -C /usr4/x12cuser/rich  t3

    There are a few things you should also be aware of:

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    Drive Locations

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    DDS4 drives can write and read tapes of type DDS2 ,3 and 4. It can not write type 1 tapes (60m or 90m). On the DDS4 drive the compression option is softwear controled. To create a compressed data tape you need to add 'c' at the end of the device name (for example tps1d1c).

    Last modified 02 November 2003 by Protein Crystallography Web Master