Wrt Termination on the cdrom, https://th99.infania.net/r/M-O/60108.htm will help

It seems to be a 1x cdrom, so I doubt it will do any synchronous or disconnects on the scsi bus, and while such things should be "automagically".
Try disabling them using
DEVICE=C:\SCSI\ASPI2DOS.SYS /D /C- /U- /Q10
in stead of the aspi2dos line you have in your config.sys

weedeewee wrote on 2023-07-17, 17:36:

Wrt Termination on the cdrom, https://th99.infania.net/r/M-O/60108.htm will help […]
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Wrt Termination on the cdrom, https://th99.infania.net/r/M-O/60108.htm will help

It seems to be a 1x cdrom, so I doubt it will do any synchronous or disconnects on the scsi bus, and while such things should be "automagically".
Try disabling them using
DEVICE=C:\SCSI\ASPI2DOS.SYS /D /C- /U- /Q10
in stead of the aspi2dos line you have in your config.sys

Thanks very much weedeewee
- Good to know about the termination switch. I have it set to "on" since this is what the Adaptec manual wants.
- Sadly, the new arguments cause the machine to hang up during boot, but it resumes normally if I power off the CD-ROM
- I also tried with termination off, in case that somehow caused the hangup, but no dice
(There is a disc inside and it does spin when powered on, lights normal)

I tried several combinations of the arguments. With parity checking disabled, the drive apparently loads successfully, but `DIR` always returns a "Not Ready" error. I'm not sure if the drive should have parity checking or not.

I had one of those drives back in the day. It was quite finicky.

As I recall, I had to power up the drive just before starting the computer to catch the initialization routine just right.

alphaharris wrote on 2023-07-17, 18:42:

I tried several combinations of the arguments. With parity checking disabled, the drive apparently loads successfully, but `DIR` always returns a "Not Ready" error. I'm not sure if the drive should have parity checking or not.

Is it possible the disc cannot be read? Have you tried another CD?

sangokushi wrote on 2023-07-17, 19:22:

Is it possible the disc cannot be read? Have you tried another CD?

I have tried a few 90's CD-ROMs. Notably the behavior is exactly the same if the door is just left open.
The "busy" light barely goes on but the "not ready" is returned right away, which in any other device would make me check jumpers.. but there isn't anything other than the switches noted above.

"Finicky" is probably right. I have tried powering on and off at several points before and after boot.

alphaharris wrote on 2023-07-17, 19:45:

I have tried a few 90's CD-ROMs. Notably the behavior is exactly the same if the door is just left open.
The "busy" light barely goes on but the "not ready" is returned right away, which in any other device would make me check jumpers.. but there isn't anything other than the switches noted above.

"Finicky" is probably right. I have tried powering on and off at several points before and after boot.

Since the drive can be used as audio CD player. When it's not connected to SCSI bus, it plays audio CD without problem?

sangokushi wrote on 2023-07-17, 21:19:

Since the drive can be used as audio CD player. When it's not connected to SCSI bus, it plays audio CD without problem?

Good question..
I think it requires software to play audio CDs. The only control is a volume knob, like some internal drives.
When I put in an audio CD it just spins .. no sound from the headphone jack (both connected and disconnected from SCSI).

alphaharris wrote on 2023-07-17, 18:42:

I tried several combinations of the arguments. With parity checking disabled, the drive apparently loads successfully, but `DIR` always returns a "Not Ready" error. I'm not sure if the drive should have parity checking or not.

Termination should stay on on both ends of the chain/cable,
sometimes it's the host as one of the outer ends, with the other end being a device or seperate terminator, or
it can be two devices, either internal or external, though most likely the internal one being at the end of the cable and the external one being at the end of the cable.

With parity checking disabled it at least finds the drive .?
ie aspicd does not show "CD-ROM driver not loaded:..."
you already showed a picture once of aspi2dos, aspicd, mscdex & ... being loaded, can you post that again with the parity disabled switch ?

weedeewee wrote on 2023-07-17, 22:47:

With parity checking disabled it at least finds the drive .?
ie aspicd does not show "CD-ROM driver not loaded:..."
you already showed a picture once of aspi2dos, aspicd, mscdex & ... being loaded, can you post that again with the parity disabled switch ?

- Yes, that makes sense to me about termination. That is currently the case, with just the host adapter and external device.
- It does find the drive (:
- Certainly

Try disabling "Fast SCSI' on the 1510, those old drives were mated with a NCR 53c80 or NCR 53c90 (The Fushion CD had either the Spectrum Pro or PAS 16 SCSI and both used a 53c80 variant) which were SCSI-1 only capable 2Mb/s with max of 5Mb/s.
The 1510 is SCSI-2 FAST so may be trying to talk to the cdrom to fast.... just a suggestion. I have had to slow the adapter -> device speed on 2940's when working with old scsi drives...

Horun wrote on 2023-07-17, 23:30:

Try disabling "Fast SCSI' on the 1510, those old drives were mated with a NCR 53c80 or NCR 53c90 (The Fushion CD had either the Spectrum Pro or PAS 16 SCSI and both used a 53c80 variant) which were SCSI-1 only capable 2Mb/s with max of 5Mb/s.
The 1510 is SCSI-2 FAST so may be trying to talk to the cdrom to fast.... just a suggestion. I have had to slow the adapter -> device speed on 2940's when working with old scsi drives...

This is a promising direction, but I'm not sure how to set the speed.

It looks like the 1510 lacks the jumpers to do this (they are present on the 1520). http://download.adaptec.com/pdfs/user_guides/aha1520a_ug.pdf

ASPI4DOS has a command line switch for speed, but I'm assuming mine is only compatible with ASPI2DOS and I haven't found a complete listing for those switches: https://www.minuszerodegrees.net/manuals/Adap … ion%20Guide.pdf

I'll try the switch for the ASPI4DOS and see if it works on ASPI2DOS.. Maybe I need to find a SCSI-1 adapter.

ASPI2DOS gives me "invalid string" for /XFF and /X00 which would be the slowest settings, even though this indicates the 1510 might take a /X switch http://download.adaptec.com/pdfs/installation … /aha1510_ig.pdf
(It doesn't indicate what speed values you can give it)

Perhaps you can set your controller to negotiate asynchronous transfer mode (it is an option in the speed rates menu) to the cdrom device (SCSI ID 6) in the controller's BIOS.
If that works, we can look at the termination of your bus.

Can you show us a picture of your 1510A ? Some were just like a 1520A with many jumpers and BIOS.
But If it looks like this picture it is essentially a dumb card, like the 1505 designed for specific optical/tape drives/scanners and not a multi use scsi card.....many were included with Iomega drives or HP scanners iirc
No BIOS and most features disabled due to lack of support circuitry....

It's unknown to me if the software works but you could try http://www.6502.org/users/sjgray/software/sjg … jgplay_dos.html to play an audio cd.
See if that works.

edit : have you tried it ?

Which exact version of the host adapter do you have and do you have a terminator in the centronics connector that doesnt go to the computer?

Thanks for all the help folks (: I'll give y'all some pics and then address questions as I get time today.

Horun wrote on 2023-07-18, 02:57:

Can you show us a picture of your 1510A ? Some were just like a 1520A with many jumpers and BIOS.
But If it looks like this picture it is essentially a dumb card, like the 1505 designed for specific optical/tape drives/scanners and not a multi use scsi card.....many were included with Iomega drives or HP scanners iirc
No BIOS and most features disabled due to lack of support circuitry....

Disruptor wrote on 2023-07-18, 01:08:

Perhaps you can set your controller to negotiate asynchronous transfer mode (it is an option in the speed rates menu) to the cdrom device (SCSI ID 6) in the controller's BIOS.
If that works, we can look at the termination of your bus.

I "think" we are already doing these things with the current BIOS ASPI2DOS flags if I understand correctly. You can see the disabled value in one of the screenshots above.
Sadly I don't think this controller has a BIOS chip so I am limited to whatever the ASPI software can do with it.