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Compaq Portable III: Using multiple drives/storage devices on IDE controller possible?

T-Squared

T-Squared

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All right. I have had success in using XT-IDE on the Compaq Portable III, thanks to a patched BIOS ROM from VOGONS: https://www.vogons.org/viewtopic.php?f=46&t=62482

The problem I am having now is that I have a dual-plug cable, but it only reads and accepts one CF card. The other one is read as well, but when I mean that it only accepts one card, I mean it. The other is read at the exact same time, causing a conflict. There are primary/secondary jumper selectors on each CF adapter, but those don't seem to change anything..

Were the Compaq Portable IIIs meant only for one IDE drive? (It seems unlikely, since the SETUP/INSPECT CMOS program indicates that there is a primary and secondary IDE controller.)
 
T-Squared said:
Also, what I meant by dual-plug, is that there are 3 plugs. (One from the motherboard, two for primary-secondary/master-slave configuration.)
Click to expand...
Three connectors on the IDE cable, one that plugs into the motherboard, one for master, one for slave.
And a 'standard' cable, not one of those shown at [here], which are for a 'cable select' configuration.

When I look at a photo of the Portable III motherboard, I see only one IDE connector. That will correspond to the primary IDE controller. The primary IDE controller will support up to two drives, one acting as master, and the other (optional) acting as slave.

I see quite a bit online about CF cards (well, at least some) not properly acting as a slave. Maybe someone here will elaborate.

T-Squared said:
There are primary/secondary jumper selectors on each CF adapter ...
Click to expand...
I have just now looked online at various CF-to-IDE adapters, and cannot see any with 'primary/secondary' jumper/s.
The adapters that house a single CF typically have a jumper to select whether the CF is to act as master or to act as slave.
The adapters that house up to two CF's typically have a jumper to select which of the two CF's is to act as master (with the other to act as slave).

Maybe the creators of your CF-to-IDE adapter should have printed 'master/slave' instead of 'primary/secondary'.
 
I was trying to be politically correct, since a lot of people might now take offense at "master/slave" connotations. (Probably makes it worse.) But yes, they do have "Master/Slave" jumper setting markings on them.

Anyways, the point is that any CF card on the slave plug does not get detected by XT-IDE, and both of the adapters' drive-activity lights illuminate and blink in-unison, making me think that they are being accessed at the exact same time, as if both plugs are being used as the master device.

I didn't have this problem with my first XT-IDE Deluxe card, which has two ports: CF and IDE (both use a CF card, the master is on an IDE adapter.)
 
T-Squared said:
I didn't have this problem with my first XT-IDE Deluxe card, which has two ports: CF and IDE (both use a CF card, the master is on an IDE adapter.)
Click to expand...
The gist of what I am reading is that at least some CF cards will not function (or function correctly) when configured as slave. Maybe the CF cards used on your "first XT-IDE Deluxe card" are ones that work when configured as slave.
 
I have a PC/XT (IBM 5160) with a Glitchworks XT-IDE card, a 40 conductor cable, and two IDE-CF adapters, one configured as the master and one as the slave. One CF card works just fine as the C: drive, the other as the D: drive. I'm able to boot just about any DOS version I've tried simply by powering down the XT, swapping CF card in the C: "drive", and booting back up. Long story short, what you're trying to do is very doable. But in order to get to that state, I went through many cables, IDE-CF adapters, and CF cards which are supposed to be IDE compatible but often are not. You'll find that some CF cards, even some that work like a champ in a camera, simply cannot be set up as a PC boot device. My guess is that somewhere along the way, drive, cable, adapter, and CF card vendors got used to systems with only one "drive" and got really sloppy about the whole master/slave thing.

Some of the cables I had on hand were "cable select." You're lucky if they're marked or have the grey-blue-black connector color scheme. I found that 80 conductor cables are almost always "cable select" even if not marked as such. You may get lucky and get one of those to work. I didn't. As you found out, many IDE-CF adapters, even ones that have a Master/Slave option jumper, simply laugh at you while you're configuring them. I found that the simpler the device looks, the more likely you are to get them to "play well with others." IOW, avoid anything with any kind of logic chip. A true "pass through" device, which is what an IDE-CF adapter is supposed to be, doesn't need any "smarts" to do the job.

It isn't easy to find the info about how the master/slave business works. Lots of places will not so helpfully tell you all about how to set the jumpers, but not so much about what the jumpers are supposed to be doing, and/or how to troubleshoot things if they don't work as expected. Here is a page that summarizes it pretty well.

Using IDE Cable Select

unixwiz.net unixwiz.net

Essentially a well behaved IDE device that sees a ground on pin 28 acts as the master, otherwise it acts as the slave. That's the way it is supposed to work. But I have a couple of name brand hard drives that simply ignore the protocol. If they have power, they're gonna be the master. As you've already found out, once you get away from respected name brand devices, all bets are off.

Good luck.
 
The two drives that won't play nice with others are from Western Digital.

One CF card that refuses to be a DOS boot device is from SanDisk.

Pretty sure those are respected brands.

I "cheated" a bit when I bought a set on ebay consisting of an XT-IDE card, a short (6 inch?) 40 conductor IDE cable, an IDE-CF adapter and a pre-formatted pre-loaded CF card guaranteed to boot FreeDOS. The cable was waaaay too short but it gave me a place to start, I had a working single CF setup I could use as a base for testing components. I had to find a cable long enough to reach the right hand drive bay in my 5160 and another IDE/CF adapter that did the Master/Slave trick correctly, but after a lot of head scratching and some false starts I have a setup that just works AND (cherry on top) it looks like it might have rolled out of IBM Boca Raton equipped that way.
 
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