Determining Device Number and Device ID

In a tape library, each tape drive resides in a unique drive bay. The tape library drive bay is designated by the Device Number and the tape drive driver is designated by the Device ID.

This mapping between the drive bay and tape drive driver is critical for proper tape library operation.

Note. DPX requires that the first drive bay is designated with the number 0, not 1. If your tape library has only a single drive bay, the Device Number is 0.

Generally, the first drive bay (Device Number 0) is mapped to the first tape drive. So for Windows, the mapping would be as follows:

\\.\Tape0 is mapped to Drive Bay 0 (Device Number 0) \\.\Tape1 is mapped to Drive Bay 1 (Device Number 1) etc.

Similarly, for Solaris, the mapping would be as follows:

/dev/rmt/0cn is mapped to Drive Bay 0 (Device Number 0) /dev/rmt/1cn is mapped to Drive Bay 1 (Device Number 1) etc.

To confirm this, configure the tape drives in this manner, then try to load and unload a tape.

If you determine that it is not the case that the drive bays are mapped to the tape drives in order, do the following to manually map the device bays to the tape drives:

  1. Find out how the tape library numbers the drive bays internally. For example, top down, bottom up, or other. Consult the tape library documentation or manufacturer.

  2. Load the tape drives with tapes (preferably scratch tapes).

  3. Use the tapedump utility to acquire one of the tape drives and unload the tape. For example:

    $ ./tapedump tape /dev/rmt/0cn open rdonly unload

  4. Look inside the tape library and determine which tape ejected. Make note of:

    • The tape library drive bay number (Device Number) of the tape that physically ejects.

    • The Device ID you used to acquire this tape drive (/dev/rmt/0cn in our example)

    • The device server node for this tape drive.

  5. Quit tapedump and cycle through the device drivers on this and other device servers to map the tape library in its entirety.

Note. After opening a tape drive, you will have to quit tapedump to try another device driver. If the open operation fails, there is a rudimentary problem communicating with the tape drive via the device driver or the device driver is not valid. If necessary, consult the hardware manufacturer of the tape drive or Catalogic Software Data Protection Technical Support.

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