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Compaq Portable II and XT-CF coexistence

geekdad

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Joined
Sep 20, 2022
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I'm in the process of retiring the Quantum LP10-5 in my Compaq Portable II and am looking to replace it with an XT-CF. I've been able to create a new CF card in another DOS machine by putting the Quantum in the 486 and letting boot from the it. A slave drive is the 486 that I was able to transfer all the files to.

I removed the drives and put the 486 back to normal with an IDE to CF adapter and as able to format new CF as a boot drive with all the original Quantum files.

Now the challenge....

I need to get the Portable II to accept a brand new XT-CF so I can use that as the boot drive and remove the Quantum. No luck as of yet. This Portable II has a multiufunction card that has the IDE controller, Floppy Controller, Serial and Parallel ports. I tried disabling the IDE controller I tried disabling the IDE controller via the dip switch on the board and that didn't work.

I also ran up the setup program for the PII and set hard drives to not installed. Still no luck.

I know AT class machines like the PII may have slightly different I/O settings and I'm sure the XT-CF isn't set to the right I/O and ROM Addresses. I just can't find the right settings for the PII.

Any guidance will help. I've built an XT-CF in the past and have two brand new pre-built ones I'm using. One is already in a Portable I. I have the ability to erase and reprogram the Flash.

What say the resident Guru's...
 
From the list/photos at [here], exactly which XT-CF are the "brand new pre-built" XT-CF's ? That information can assist.

Is the second "brand new pre-built" XT-CF, the one that you are trying in the Portable II, known to be working? If not, verify its status via your Portable I.

In the Portable II, remove the multi-function card for now, i.e. removing a potential (potential, not likely) source of interference. Surely it's not needed whilst you are working out what is going on with the XT-CF in the Portable II. Configure the CMOS SETUP for no hard drives (because the XTIDE Universal BIOS of the XT-CF does not use the hard drive information in CMOS SETUP). Yes, expect some sort of floppy related error, which I assume that you can acknowledge and continue the booting process.

Then, with a 'known working' XT-CF in the Portable II, what are the symptoms?
- For example, is it that you are not seeing the banner/splash text that the XTIDE Universal BIOS (XUB) displays - see [here] ?
- For example, is it that you are seeing the banner/splash text, but the XUB is not showing the make-model of the attached CF card - see [here] ?
 
What I'm currently using the pre-built Lo-Tech XT-CF-Lite Rev2 from Tex Elec. Initial tests were with the stock xt flash which didn't work and I realized I probably needed the AT version (ide_atl.bin . It's flashed in but I haven't had a chance to try it yet. Been pretty busy the past few days.

I did try removing the controller card and didn't see the splash. I figured the PII CMOS still had the existing HD settings and was getting confused.

I'm hoping to get some test time this afternoon after my yard work is done.
 
Since you’ve got an IDE-CF and you’ve got IDE in the portable II, have you tried using that instead? I would imagine you’d get better performance.
 
Since you’ve got an IDE-CF and you’ve got IDE in the portable II, have you tried using that instead? I would imagine you’d get better performance.

The plan is to retire the Quantum LP105 that's in the PII and use only the CF card. The Quantum is original to the PII so 37 years old.
 
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Well, I tried a few things. First was telling BIOS there's no hard drive. On boot up the PII complained the hard drive was missing. Makes sense... Next I removed the Multifunction board and tried again. It complained the floppy was missing which makes sense. I did start getting a missing or non-system disk error but that happens even if the XT-CF is in or out.

I'm pretty sure I need to configure the XT-CF BIOS settings because the PII just isn't seeing the card at all. No splash. I'm using the latest JUne 2022 build for ide_atl.bin and I believe I need to run xtidecfg to configure it. Problem is, I have no idea what settings to use for the PII since I need to retain the Multifunction card for acces to the serial port and floppy.
 
Made some progress. I was able to set up an IDE to CF adapter and the PII boots off the Quantum and sees the CF card without issue. The PII Setup detected the CF card for me so that was a pleasant surprise.

Not what I really want, but serviceable. Now I need a longer drive cable or an extension to allow the IDE-CF adapter to mount in card slot position but I still need to get the XT-CF going though. I can't count on how long the Quantum will last.
 
What I'm currently using the pre-built Lo-Tech XT-CF-Lite Rev2 from Tex Elec. Initial tests were with the stock xt flash which didn't work and I realized I probably needed the AT version (ide_atl.bin . It's flashed in but I haven't had a chance to try it yet.
Note that the 'XT' versions of the XTIDE Universal BIOS (XUB) also work on AT-class motherboards. That will be why XT-IDE and XT-CF suppliers put an 'XT' version of the XUB on their cards.

Just in case you are unaware, one can't simply grab the BIN file from the official download page and use an EPROM programmer to put it (unmodified) directly into the EEPROM. See note 3 at the bottom of [here].

I did try removing the controller card and didn't see the splash. I figured the PII CMOS still had the existing HD settings and was getting confused.
The XT-CF is 'special'. The hard drive portion of your Portable II's motherboard BIOS is unaware of it, and cannot communicate with it. The HDD settings in the CMOS SETUP are for 'normal' AT-class MFM/IDE hard drive controllers. Having a hard drive defined in CMOS SETUP will not confuse the XUB at all. The diagram at [here] might help explain the difference.

With the XUB's splash text not appearing, some possibilities I see are:
1. Faulty XT-CF (the ROM BIOS circuitry of it).
2. The XT-CF's EEPROM contains the XUB, but has an invalid checksum (which normally results in the computer's POST indicating a ROM problem).
3. The XT-CF's EEPROM does not contain the XUB.
4. The address range of the XT-CF' EEPROM is conflicting with something else in the computer.

Re point 4. For the 'Lo-tech XT-CF-lite rev.2', the default setting for the base (starting) address of the EEPROM is C8000. Per the information at [here], some VGA cards may conflict with that.

Re points 1 and 2 and 3. You can eliminate those possibilities quickly, by testing the XT-CF in your Portable I, noting that if the Portable I contains a hard drive controller (i.e. XT-class), the starting address of the EEPROM would need to be changed from C8000 (what the XT-class hard drive controller uses).

Are you able to run the RAYXTIDE tool at [here]? It may detect a problem.
 
Sorry for the late reply. I was traveling last week. I'll try the card in My P+. I've been meaning to swap out the original controller card and drive anyway.

If I keep the PII's original controller and drive along with the XTCF, I can get the PII to boot with it's own hard drive but depending on the jumpers, The PII either stalls at the ONTRACK splash (the PII drive has the Ontrack overlay) or RAYXTIDE doesn't see the XTCF or locks up looking for it. I did put the original flash image back into the XTCF EEPROM. It came with XT version 2.0.0.3 from October 2013.

I'm convinced it's an incompatibility based on I/O address, ROM Address, etc. There's something about the PII that is different. I have no idea where to look to see what space Compaq uses in their 80/40 Hi Res CGA adapter card.

Just to be clear, In order to configure the XUB BIOS Image I need to do that with the configurator *before* flashing it to the EEPROM. Right?

I should be able to do that from the PII by going back to the IDE-CF adapter and copying the files to the CF card. I'm just unclear of what settings to use.
 
I've decided to run the PII with the IDE to CF adapter for the time being. I know that configuration works. Once I know the XTCF cards are at least functional, I'll try it again.

Next is to put the XTCF in the the P+ and make sure it's really working. I have two to test.
 
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