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No equivalent for ide-scsi available with the new PATA drivers?

DISCUSSION Chuck Ebbert 4 participants 7 messages Jul 23, 2007 – Aug 7, 2007 libata

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People with IDE tape drives are complaining there's no ide-scsi driver available anymore with the new PATA layer. Is anyone working on one?

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Quoted 3 lines · On Mon, 23 Jul 2007 12:36:44 -0400 Chuck Ebbert <[email protected]> wrote:

People with IDE tape drives are complaining there's no ide-scsi driver available anymore with the new PATA layer. Is anyone working on one?

It would make no sense. The libata layer is already using the SCSI midlayer so compliant devices should already appear with the st driver.

We might need some tape detect logic, but I don't have any tape devices so its up to someone with a tape drive handy to help out...

Alan

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Quoted 9 lines · Alan Cox
Quoted 3 lines

People with IDE tape drives are complaining there's no ide-scsi driver available anymore with the new PATA layer. Is anyone working on one?

It would make no sense. The libata layer is already using the SCSI midlayer so compliant devices should already appear with the st driver.

We might need some tape detect logic, but I don't have any tape devices so its up to someone with a tape drive handy to help out...

I should have posted this earlier:

https://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=243568

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Quoted 5 lines · Chuck Ebbert
Quoted 4 lines · Alan Cox
Quoted 3 lines

People with IDE tape drives are complaining there's no ide-scsi driver available anymore with the new PATA layer. Is anyone working on one?

Quoted 7 lines
Quoted 5 lines

It would make no sense. The libata layer is already using the SCSI midlayer so compliant devices should already appear with the st driver.

We might need some tape detect logic, but I don't have any tape devices so its up to someone with a tape drive handy to help out...

I should have posted this earlier:

It looks like an error handling issue ... which command was being executed at the time the tape at ata2.01 went into the error state?

I haven't looked, but it's entirely possible that it's a simple timeout
issue: libata does some of its own error handling, but the tape commmands have to run with timeouts set to huge values (because it can take so long to rewind a tape or write a long block).

James

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In reply to Alan Cox
Quoted 7 lines · Alan Cox
Quoted 3 lines · On Mon, 23 Jul 2007 12:36:44 -0400 Chuck Ebbert <[email protected]> wrote:

People with IDE tape drives are complaining there's no ide-scsi driver available anymore with the new PATA layer. Is anyone working on one?

Quoted 5 lines

It would make no sense. The libata layer is already using the SCSI midlayer so compliant devices should already appear with the st driver.

We might need some tape detect logic, but I don't have any tape devices so its up to someone with a tape drive handy to help out...

I have a PATA tape drive here somewhere.
Does anyone out there want it, with the understanding that it be used to test/improve libata tape support?

One thing about ATAPI tape drives, is that they generally won't "stream" with the generic SCSI st code. Instead, many of them will do a *very* sluggish stop/start stop/start stop/start kind of action when reading/writing bulk data. To get them to stream continously requires more driver intelligence, *especially* when sharing a cable with some other device.

With an appropriate driver, tailored for ATAPI tape drives, they can run at full speed while sharing a channel with another active ATA/ATAPI device, both drives in use at the same time.

Cheers

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Quoted 1 line

I have a PATA tape drive here somewhere.

-EBUSY

Quoted 2 lines

Does anyone out there want it, with the understanding that it be used to test/improve libata tape support?

I'm happy to help someone else doing the work who needs info on libata etc but I've no time to work on whats a very obscure corner case.

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In reply to Chuck Ebbert
Quoted 3 lines · Chuck Ebbert

People with IDE tape drives are complaining there's no ide-scsi driver available anymore with the new PATA layer. Is anyone working on one?

You mean libata-pata? The SCSI tape driver, st (or the onstream osst driver), should just attach natively, shouldn't it ... or is there something missing in the sat layer?

James