My next question is: Is there any way to get DOS and Windows 3.11 to mount the partitions of both the SD and CF card and have them both accessible? Seems like DOS only wants to use one HDD at a time, though Adaptec's SCSI interrogator can see the other drive. It would be nice to be able to use the front-accessible CF card to transfer data.

At present, the CF card and SD card contain identical information. They have two 2 GB partitions each, thus C:\ is MS-DOS 6 with Win3.11, and D:\ is Temp.

I tried to go into FDISK to set drive 2 as active, but it won't let me.

I have a hypothesis to solve the first question. I currently have the SD set as ID0 and the CF as ID1. The CF is easily ejectable. If I set the SD to ID1 and the CF to ID0, then when the CF is inserted, the Adaptec host controller will boot from the lowest ID first, so it will boot the CF. If I eject the CF, the Adaptec will naturally boot the SD.

Still, I thought it was possible to set the boot ID on the SCSI BIOS? Perhaps an updated firmware has this feature?

Also, which do you think will have faster HDD benchmark results on an SXL-40? The CF-to-SCSI or the SD-to-SCSI. My CF card is 200x and the SD card is class-10 at 90 MB/s with version 6 of SCSI2SD.

On my 1520B the bootable disk has to be on ID 0. Why don't you put the CF adapter on ID 0?

yawetaG wrote:

On my 1520B the bootable disk has to be on ID 0. Why don't you put the CF adapter on ID 1?

It is on ID1. Did you miss this photo that I posted?

I actually need to put the CF on ID0 and SD on ID1. See my hypothesis above.

My hypothesis was correct. The Adaptec 1540CP SCSI card does not try to boot from the Bridge: Null when the CF card is removed, and will boot the SD Card on ID #1. I'd still like to know if there is another more direct way to tell the SCSI card which ID to boot from.

Now, is there any means to use both the CF and SD cards in Win 3.11 when they are both inserted? I can only see 2 drives when there should be 4:

CF: C:\ and D:\
SD: E:\ and F:\
CD-ROM G:\

I've noticed that with my plan, there is about a 45 second delay for the ACARD to timeout. The extra 45 seconds is too long to wait on every boot. If I hard reset, the ACARD immediately goes to NULL, so there is no wait. So I'd like to exclude the ACARD CF card from being searched by the BIOS at boot. Is this possible? Setting the option for ID 0 (the CF Card on ACARD) to "exclude from SCSI scan" doesn't seem to have any effect, that is, I still have to wait the 45 seconds for the ACARD to timeout. How to tell the Adaptec host controller not to check for ID 0 on the SCSI chain?

Getting a more advanced SCSI controller might be a good idea...

Do you know of an ISA SCSI controller with this feature?

If you exclude ID0 from BIOS scan, neither it will try to boot from it, nor it will assign a drive 'letter' (80h/81h).
However, you can add ASPIDISK.SYS to mount it in DOS anyway.

Try to compare the performance between native BIOS only and with ASPI driver loaded.

Disruptor wrote:

If you exclude ID0 from BIOS scan, neither it will try to boot from it, nor it will assign a drive 'letter' (80h/81h).
However, you can add ASPIDISK.SYS to mount it in DOS anyway.

Try to compare the performance between native BIOS only and with ASPI driver loaded.

For the normal instance of when a CF card is not inserted into the ACARD adapter (in which case I am booting from the SCSI2SD), excluding ID0 from the BIOS scan still has the SCSI BIOS sitting around waiting (~45 s) for the ACARD to timeout, thus returning BRIDGE:NULL. So the SCSI adapter still wants to report what is on ID0 even though I said to exclude it. Why is this?

I have found a work around to the 45 second delay. If I enable PnP SCAM support in the Adaptec BIOS, the ACARD+CF does not appear in the SCSI scan. I'm not exactly sure why this works, but I suspect the ACARD has some logic indicating that there isn't an IDE device plugged in, so it disables SCAM. PnP SCAM support is a feature which lets the SCSI card automatically assign ID's to devices which support SCAM. If SCAM is disabled, then the device won't appear on the BIOS scan, hence no delay!

Here's the BIOS option to use:

By the way, the option to "dynamically scan SCSI bus for BIOS devices" is what lets ID's other than 0 to be booted from.

Without a CF card inserted, only the SD card shows up:

When a CF card is inserted, SCAM decides that the ID 0 is appropriate (perhaps because this is the ID I've jumpered it to? Or perhaps because it wants there to be a bootable ID 0? Nonetheless, it boots with the CF card when one is inserted, and boots from the SD card when a CF card is absent, and without the 45 second delay. This is what I was after.

Hopefully this will help someone other than just me. There is a nice (complete?) list of all Adaptec's SCSI BIOS options here:
https://storage.microsemi.com/en-us/support/s … _user_guide.htm

EDIT: Oh, and the SCSI BIOS supports multiple disk drive assignments, and so the reason I could not view both SD and CF at once in DOS/Win was due to something simple - I still had LastDrive=E in config.sys. I changed E to H and now I can access both cards.

Performance comparison of SCSI SD, CF, and HDD on this system can be found here, SCSI2SD - Comparison of SCSI SD, CF, and HDD performance

feipoa wrote:

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Unrelated to your question, but where did you pick up that beige CF card drive? Everything I've seen on the net is black and thought I'd have to resort to painting one.

Addonics made these beige metal CF adapters. The stopped appearing online around 2012.

Thanks, and yeah you're right, they're all black. Can't find a single beige one at all.

feipoa wrote:

My hypothesis was correct. The Adaptec 1540CP SCSI card does not try to boot from the Bridge: Null when the CF card is removed, and will boot the SD Card on ID #1. I'd still like to know if there is another more direct way to tell the SCSI card which ID to boot from.

Cool. This might mean that it could be sufficient to install a switch on the front plate, so that the first drive is either ID 0 (->boot from first drive) or ID 2 (->boot from second drive).
Will try this out soon.