I have O/S 5.0.7 MP3 on an IBM server running hardware RAID 0 (mirroring) using the ips driver on bus 0 of the adapter.

On bus 1 of the adapter is a DLT VS160 tape drive.

The above has worked for close to a year however a while ago BackupEdge (tape backup software) was reporting verification failure after the backup. A manual run of the verification worked fine. Lately however the verification fails with a tape read error.

I've told the customer to clean the drive and use new tapes but the problem persists.

The good people at Microlite (they wrote BackupEdge) said that you should never put a tape on the second bus of a RAID controller (SCO seems to think doing that is ok) and that I should add a another host adapter for the tape which I'm willing to do.

However, I'm not 100% sure how to go about doing that. I have an Adaptec AHA-2940UW Rev. C I was hoping to use but I know there's more to it that just plugging in the card and running mkdev tape.

Browsing the SCO Knowledge Base I found an article http://docsrv.sco.com:507/en/man/html.HW/alad.HW.html that talks about configuring an Adaptec 2940 by editing space.c but I have no idea what values to supply for the various options. The examples in the document mean very little to me. For example for the SCIS ID the docs say:

Set the SCSI ID for the host adapter.

aha_change alad_hba_id[ha_number]={1,1};

This ID must be changed if another device (such as another host adapter) already exists on this ID.

Now, does another adapter mean 'another alad adapter' or 'any other scsi host adapter'? Does 1,1 the first adapter or the second adapter?

In space.c the line looks like:

#ifndef SCSI_NALAD
#define SCSI_NALAD 2
#endif

#if SCSI_NALAD == 0
#undef SCSI_NALAD
#define SCSI_NALAD 1
#endif
int alad_num_adapters = SCSI_NALAD
|
|
|
aha_change alad_hba_id[SCSI_NALAD];

So, what should this line be changed to?

What I need is a step by step cookbook recipe for adding the adapter. Currently the un-installed 2940uw is set at irq 15 and address F800. When I run hwconfig I don't see anything else using that irq. The other thing that concerns me is will the machine still boot after I do this? This is a production server and I don't trust the tape backup so I don't want to go experimenting with this.

Thanks.

Just install the adaptec 2940 and attach the tape drive to it.
Then run mkdev tape
when asked what host adapter the tape is attached to, answer alad
then enter the rest of the scsi arguments.

The article(s) that you refer to apply to changing the boot controller to an adaptec 2940

I feel like an idiot.

It was just that simple.

All the worries about juggled irq's, installing the alad driver and worrying about SCO booting after the adapter was install were needless.

It just worked.

Thank you.