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First post, by c0keb0ttle

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I have a 486 using the MS-4137 motherboard.

It has been working fine with a CF adapter connected to the primary IDE channel on my VLB I/O card.

Now I've been trying to install a CD-ROM, and I want to use the secondary IDE channel because of space and cable issues, but I can't get it to work.

If I connect the CF card (Master) and CD-ROM (slave) to the primary IDE channel everything works fine, but I move the CD-ROM to the secondary channel it is not detected at all.

I think both channels are enabled with the jumpers on the VLB card, and I've even tried another VLB card with two channels but I can't get that one to work either.

Anyone know if some 486 mobos simply can't handle two IDE channels?

Reply 1 of 25, by derSammler

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What OS? If DOS, which CD-ROM driver are you using? Did you try a different one? Maybe the one you're using doesn't scan the secondary port. The Oak CD-ROM driver is always a good option, it normally works with anything.

Reply 3 of 25, by TheMobRules

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The BIOS in your PC needs to have support for dual IDE controllers in order to use the secondary IDE connector on the VLB card. A simple way to check this is by using the BIOS HDD "auto-detect" option: if only "C" and "D" drives are scanned, it means a single channel is supported, while dual channel support would show "C", "D", "E" and "F" being scanned.

Another option is to use one of those IDE cards that have their own BIOS with dual controller support.

Reply 5 of 25, by derSammler

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The BIOS in your PC needs to have support for dual IDE controllers in order to use the secondary IDE connector on the VLB card.

That's not correct in this case. For a CD-ROM to work, the BIOS doesn't need to support secondary IDE. That's only needed for hard disk drives, since only these are accessed through int 13h.

Is the CD-ROM jumpered as master/single drive? It may not work as slave when no master is present.

Reply 6 of 25, by c0keb0ttle

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It's jumpered as Master currently.

Some progress has been made:

1. I can get it to work with VIDE-CDD when connected to my ESS soundcard's IDE as tertiary channel (port IE8 and IRQ 12).
2. it does REACT to SOMETHING when connected to the secondary channel on the VLB card. Trying several CD drivers the light on the CD does light up and it makes some slight clicking noises, but the drivers all report no drives found.

Maybe an resources conflict? IRQ 15 is used by SOMETHING according to SYSCHK, and my guess was the secondary IDE as it should be, but who knows? And how can I check which port my secondary IDE actually uses?

Reply 8 of 25, by Jed118

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They are extremely finnicky:

My compact flash AT integration - 1989 to 1996: A multi platform, multi O/S compatibility analysis

I've had nothing but problems with them - seems they don't play well with dual channels. Every one of them I've installed into a dual channel (Primary and Secondary IDE) yielded issues. I've resorted to using them as transfer media and for that purpose they work out very well.

*edit I should add that the 486 runs its CDROM off the soundcard - the Primary save is reserved for the CF card. The CDROM works well with the CF card in place, I was able to access the drive and run a game off it.

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Reply 9 of 25, by c0keb0ttle

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I also get the CDROM running fine off my soundcard, but I can't get it to work from the secondary IDE channel on any of my VLB cards. Running it as slave on the primary IDE works fine too.

Reply 10 of 25, by .legaCy

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on my 486 dx4 100 build my vlb controller was a bit finicky with the cd-rom, i had to test with some drives that i had laying around until it was detected, however it only worked as slave on the same channel as my HD.
it wouldn't even post properly with the cd-rom being the master on the secondary channel.
since i got it running i stopped messing up with and i really don't know why it wouldn't work properly being the master.

Reply 11 of 25, by Jed118

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I'm ghosting some drives right now and I'd like to add the following trick I forgot but now recall:

Pull the jumper out entirely, see if that helps the situation. I had just now a WD 22500 drive that would not be seen by BIOS when a Quantum 7.6AT was in there (both were able to be detected separately) but when you took the jumper out of the WD and set the Quantum as master, the WD would work in slave mode. The reverse is also true - Make the WD the master, take the jumper (set no jumper) out of the Quantum and they'll appear in BIOS and work properly.

Seems to be a poorly implemented CSEL, or some drives just don't like each other. Both those drives work with a Fujitsu 8.4 gig as well as a 540Mb (Quantum) I had lying around.

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Reply 13 of 25, by derSammler

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Moogle! wrote:

Some drives need to be in the correct orientation on the cable regardless of jumpers. HD at the end connector, CD in the middle.

If that happens, then you just made a big mistake by mixing cable select and fixed drive settings. Position only matters in a cable select environment. And cable select requires both drives set to CS and an IDE cable with master/slave ports (color-coded). Most people don't seem to be aware of that and using cable select wrongly by either using a color-coded IDE cable without setting devices to CS, or setting the devices to CS but using a standard IDE cable. That's not supposed to work.

Reply 14 of 25, by firage

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VLB being a 1992-1994 phenomenon and quickly dying out in 1995, several controllers don't yet support ATAPI for CD-ROM drives. The secondary connector usually has a separate ISA controller on my cards.

My own CD-ROM's always been hanging off one of my sound cards, though.

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Reply 15 of 25, by Malvineous

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Pretty sure IDE is just a "dumb" interface between the drive and the system, so controllers don't need to support ATAPI as they don't get involved with any actual communication, they just pass the bits along as fast as they can.

There's a dosdiags.zip floating around that includes a bunch of useful utils like HWInformer that will query the hardware directly and tell you what's there. My own experience was one of the IDE channels conflicting with the floppy controller (I/O port overlap) but moving it to be the 4th IDE channel fixed the problem. Can your VLB card be moved to the third or fourth channel? Do you have any other card (e.g. sound card with IDE) that might be putting resources in the way of the IDE2 channel? Presumably if you disable IDE2 then you should find IRQ15 shows up as free, and if not, that could well be the problem.

Reply 17 of 25, by bjwil1991

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Some CF-IDE adapters have issues where the CD drive won't work. My Socket 7 system with integrated PCI IDE controller card did that too, though. Use another adapter and see what happens. My Packard Bell Pack-Mate 28 Plus worked with the CF-IDE adapter and the CD drive connected to the Secondary adapter. Sometimes, setting the CD drive to Secondary Slave might fix it.

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Reply 18 of 25, by Darkscop

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Pibben wrote:

Whas this issue ever solved? I'm having the exact same issue (VLB-IO-card, CF-card on primary, CD on secondary).

Same here. Cdrom is never found on VLB IO Card secondary Port . Using a Sound Card IDE Port solves the problem.

Reply 19 of 25, by Anonymous Coward

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Sounds like there's possibly an issue with the VLB controller. The IDE port on a soundcard is normally tertiary, which shouldn't be easier to get going than a secondary controller.

Personally, I've had more issues with CD-ROM drives set as primary slave than secondary master. I used to run an ATAPI drive as secondary master in an old 486 with AMI colour BIOS and no support for secondary. It worked without a fuss, but this was with two ISA controllers...not VLB.

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