SCSI Termination Question

[GadgetUK]

Originally Posted by dalek

Are you trying to use the IDE interface on the A2091 with a CF card? If so it won't work:

(from here

Or if is the IDE interface on a separate card (in which case might be issues with scsi.device compatibility).

No! I am using a TF534 which provides the IDE. I think the TF534 IDE is clashing with the A2091 SCSI. If I boot the machine without a SCSI drive connected to the cable, it boots fine from IDE and in SysTest I see the A2091 ROM loaded as '2nd'. This leads me to think the scsi.device isn't the issue? But I am not using the IDE on the A2091 - that needs 8bit XT IDE which is pretty hard to come by these days anyway!

[dalek]

Ahh okay that's a bit different then - probably the issue mentioned by terriblefire that the 2091 scsi driver is requesting any type of RAM for buffers and getting allocated 32bit non-DMA'able RAM instead of chip ram.

Out of interest, do you have any RAM populated on the A2091? Maybe adding some if you don't would help things along. EDIT: and maybe, if anyone knows, the guru rom might be smarter about the ram it allocates if you can get a hold of one.

[GadgetUK]

Originally Posted by dalek

Ahh okay that's a bit different then - probably the issue mentioned by terriblefire that the 2091 scsi driver is requesting any type of RAM for buffers and getting allocated 32bit non-DMA'able RAM instead of chip ram.

Out of interest, do you have any RAM populated on the A2091? Maybe adding some if you don't would help things along. EDIT: and maybe, if anyone knows, the guru rom might be smarter about the ram it allocates if you can get a hold of one.

I have 2MB of RAM on the A2091 - but I've tried it both enabled / disabled and it behaves the same. I would like the guru ROM but from what I understand it comes with some additional address decoding or something and is not easy to find.

[brufnus]

Speaking of termination... here's a weird one:

I too upgraded my Amiga (CDTV) with a SCSI-controller; however, I installed an SCA drive with 50-pin to 80-pin adapter, and a CD-ROM drive as the last drive in the chain, thus locally terminated.
Now, the CD-ROM drive wouldn't show until I rebooted, and after trying different configs, I was actually able to make it work properly by adding a terminated 50-pin HDD in the middle of the chain, despite the fact that this is wrong.

I've had similar issues with MFM drives on my Myarc Geneve 9640 (successor to the TI-99/4A), so if nothing else works in the proper way, try doing it the wrong way and it might actually work! :-D
(Of course, the best and safest solution would be to find a way to terminate it properly, if possible...)