Problems with SCSI tape drives

You may encounter the following problems with SCSI tape drives:

• ``SCSI tape drive not recognized''

• ``Cannot access SCSI tape drive with /dev/rct0''

• ``Using the dd(C) command with Exabyte 8mm tapes''

• ``Waiting for DAT and Exabyte 8mm tape drives to initialize''

SCSI tape drive not recognized

For SCSI tape drives, a message similar to the following is displayed at system startup even if the tape drive is not present on the SCSI bus:

   %tape	-		-	-	type=S ha=0 id=2 lun=0

   NOTICE: ha: No controller response on SCSI adapter (ha=n id=n lun=n)
   NOTICE: Stp: Stp_call_oemtab - Inquiry failed on SCSI type n dev minor/n
   (ha=n id=n lun=n)
   /dev/rct0: cannot open

To correct the problem:

1. If the tape drive is external to the computer, check that it is powered on and that the SCSI bus is correctly terminated.

   If the tape drive is internal to the computer, check that it initializes a tape when you insert one in the drive.
   

2. Verify that the ID number for the controller of the device is correct and does not clash with the ID of any other device on the SCSI bus. The ID number is determined by the jumper settings on the controller. The valid range is 07 for SCSI-1 and 015 for a 16-bit Wide SCSI-2, Ultra-SCSI (SCSI-III), or Ultra2SCSI bus. tape drives are often configured for ID 2.

3. Make sure that the host adapter number is correct. The first SCSI host adapter of a given type is 0; the second is 1.

4. Check that the LUN (Logical Unit Number) is correct. In most cases, the controller is embedded in the same physical unit as the device and supports one device with LUN 0. If the controller is not embedded, it supports up to eight devices. If this is the case, the LUN is determined by the jumper settings on each device. The valid range is 07.

5. Verify that the host adapter itself is recognized at boot time.

6. Verify that the tape drive is supported. Refer to the SCO Certified and Compatible Hardware web page (CHWP) for a list of supported tape drives.

Cannot access SCSI tape drive with /dev/rct0

After an Upgrade installation, /dev/rct0 might no longer exist. When you try to access a configured SCSI tape drive, you might see the error:

   cannot open: /dev/rct0

If the device is correctly configured with mkdev tape, you can access the tape drive using /dev/rStp0.

Using the dd(C) command with Exabyte 8mm tapes

Do not use dd to put individual data files onto Exabyte 8mm tapes; extracting the files may cause extraneous characters to be appended to the original data. You can, however, use dd with Exabyte 8mm tapes to store and extract tar(C) or cpio(C) archives.

Waiting for DAT and Exabyte 8mm tape drives to initialize

You should wait for a DAT or Exabyte 8mm drive to finish its initialization sequence before attempting to access the device. This may take 30 seconds or more.