Tape FAQ's

 

1. Q. How do I read a tape when I get the following message ?

2. Q. How do I get my DAT to work with IRIX 6.2, it used to work with IRIX 5.3 ?

3. Q

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Q. How do I read a tape when I get the following message?
 
tar: this appears to be a byte-swapped archive

A. You'll need to use the byte swapped tape device. To do this you will need two pieces of information. What SCSI controller your tape device is on and what SCSI address your tape device is at. To determine this information execute the following command, the output should be similar to the example:

The controller is 0 and the address is 7 from the above example. Now you can read your tape with the following command:

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Q. How do I get my DAT to work with IRIX 6.2, it used to work with IRIX 5.3?

A. You will need to modify the IRIX kernel. To verify that you have an IRIX kernel problem, execute the following command, your ouput should be similar to the example:

If it says DAT, then you have some other kind of problem.

Now you will need four pieces of information to modify the kernel. Execute the following command, your output should be similar to the example:

The Device line contains all the information you should need. In the above example, we need the manufacturer's name which is ARCHIVE. We also need the length of the manufacturer's name in this case it is 7. The next piece of information is the model number which is Python 28830 in the above example. Again we need the length of this string which is 12 for this example.

Now we need to modify the kernel files. First lets make a copy of the file before we modify it. Execute the following commands as root:

Now using your favorite editor (vi, jot, ed), modify the scsi file. Search through the file for DAT. You will find the following section:

{ DATTAPE, TPDAT, 7, 12, "ARCHIVE", "Python 25601" /*DDS1*/, 0, 0, {0},
MTCAN_BSF|MTCAN_BSR|MTCAN_APPEND|MTCAN_SETMK|MTCAN_PART|MTCAN_PREV|
MTCAN_SYNC|MTCAN_SPEOD|MTCAN_CHKRDY|MTCAN_VAR|MTCAN_SETSZ|
MTCAN_SILI|MTCAN_AUDIO|MTCAN_SEEK|MTCAN_CHTYPEANY,
/* minimum delay on i/o is 4 minutes, because when a retry is /
* performed, the drive retries a number of times, and then
* rewinds to BOT, repositions, and tries again. */
40, 4*60, 4*60, 5*60, 512, 512*512, 0, (u_char *)0 },
{ DATTAPE, TPDAT, 7, 12, "ARCHIVE", "Python 01931" /*DDS2*/, 0, 0, {0}, /
* note: this drive uses modeselect page 0xf for compression control;
* most of the other drives supporting compression use page 0x10 */
MTCAN_BSF|MTCAN_BSR|MTCAN_APPEND|MTCAN_SETMK|MTCAN_PART|MTCAN_PREV|
MTCAN_SYNC|MTCAN_SPEOD|MTCAN_CHKRDY|MTCAN_VAR|MTCAN_SETSZ|
MTCAN_SILI|MTCAN_AUDIO|MTCAN_SEEK|MTCAN_CHTYPEANY|MTCAN_COMPRESS,
/* minimum delay on i/o is 4 minutes, because when a retry is
* performed, the drive retries a number of times, and then
* rewinds to BOT, repositions, and tries again. */
40, 4*60, 4*60, 5*60, 512, 512*512, 0, (u_char *)0 },
 
If your DAT does not do compression, you will need to add a new portion that looks like the following:
 
{ DATTAPE, TPDAT, 7, 12, "ARCHIVE", "Python 28830" /*DDS1*/, 0, 0, {0},
MTCAN_BSF|MTCAN_BSR|MTCAN_APPEND|MTCAN_SETMK|MTCAN_PART|MTCAN_PREV|
MTCAN_SYNC|MTCAN_SPEOD|MTCAN_CHKRDY|MTCAN_VAR|MTCAN_SETSZ|
MTCAN_SILI|MTCAN_AUDIO|MTCAN_SEEK|MTCAN_CHTYPEANY, /
* minimum delay on i/o is 4 minutes, because when a retry is
* performed, the drive retries a number of times, and then
* rewinds to BOT, repositions, and tries again. */
40, 4*60, 4*60, 5*60, 512, 512*512, 0, (u_char *)0 },
 
If your DAT does compression, you will need to add a new portion that looks like the following:
 
{ DATTAPE, TPDAT, 7, 12, "ARCHIVE", "Python 28830" /*DDS2*/, 0, 0, {0},
/* note: this drive uses modeselect page 0xf for compression control;
* most of the other drives supporting compression use page 0x10 */
MTCAN_BSF|MTCAN_BSR|MTCAN_APPEND|MTCAN_SETMK|MTCAN_PART|MTCAN_PREV|
MTCAN_SYNC|MTCAN_SPEOD|MTCAN_CHKRDY|MTCAN_VAR|MTCAN_SETSZ|
MTCAN_SILI|MTCAN_AUDIO|MTCAN_SEEK|MTCAN_CHTYPEANY|MTCAN_COMPRESS,
/* minimum delay on i/o is 4 minutes, because when a retry is
* performed, the drive retries a number of times, and then
* rewinds to BOT, repositions, and tries again. */
40, 4*60, 4*60, 5*60, 512, 512*512, 0, (u_char *)0 },
 
If your DAT's information is different than the above example, make sure that you modify the first line correctly. For example, if the manufacturers name is Alpine and the model is ADAT 3742, the manufacturers length is 6 and the model length is 9. Therefore the first line would look like the following:
 
{ DATTAPE, TPDAT, 6, 9, "Alpine", "ADAT 3742" /*DDS2*/, 0, 0, {0},
 
Save the modified file. Then execute the following command, your output should match the example:

Now reboot your machine when you can. As soon as it comes up login and execute the following command, the kernel should recognize your DAT like the sample output:

Your tape should now work.

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