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rvdbijl
May 17th, 2017, 08:50 AM
Hi Everyone!

I've been looking through this forum for a while now, as an owner of two IBM PC 5150's with varying levels of hardware. I also managed to put my hands on a Compaq Portable I system, which had a lot of trouble with its keyboard. Based on some threads here, I saw you can hook up a standard XT keyboard (instead of replacing all the foam pads), as long as you regulate the 12V supply down to 5. That's done, and working great now.

Next step on this machine is to a) install an XT-IDE adapter and b) install a network card.

So I'm on step a). To my surprise, the XT-IDE board will not show its boot menu / top bar at all, regardless of which ROM I flash on it. (xtidecfg does detect the card and has no trouble flashing the EEPROM). Doing some more digging -- turns out that Compaq Portables come in two flavors. One with a BIOS that doesn't support additional ROM's and one with a BIOS that does.. I guess I have the first flavor here. Question to the group - does anyone have an image of the second version of that BIOS ROM, so I can program a new EPROM and replace the one on the mainboard? Or is there another way to make the XT-IDE work?

I also noticed this beast will not take any MS-DOS version. I've only been able to get it to boot with a IBM DOS 3.0 floppy. Is that normal / common? Any tricks to get it to boot DOS 6.x?

rorypoole
May 18th, 2017, 04:56 PM
Can you still access the cf/hard drive after booting from floppy disk? I am slowly fixing my Compaq portable 1, my ROMs are rev c, when I get it working I could email a copy, I also plan to use a xt-ide card and am interested to know if I will have the same problem, other have used different versions of DOS on there Compaq portable, I would guess you need to clean the heads in your disk drive or test for a bad ram chip, what version of ROMs do you have?

rorypoole
May 18th, 2017, 04:59 PM
Have you tried booting from your 360k floppys on another computer?

Trixter
May 18th, 2017, 05:57 PM
Welcome to the forums. There are a few things going on here, and first I think you should verify that your xt-ide is working in one of your other vintage systems, and also verify the boot disks you're trying also work in your other vintage systems. With known good hardware/software, you can then start troubleshooting the Compaq.

There is no reason the Compaq would or wouldn't boot a specific DOS version. It should boot all of them, except for any OEM DOS versions that were built for a specific computer (for example, don't try to use AT&T 6300 DOS 2.11 on your Compaq; it will boot, but some of the utilities will hang). Any MS-DOS or PC-DOS version of DOS should work fine. So, if one of them isn't working, please describe how it is failing.

As for the BIOS not starting up the option ROMs, there are only two ways to fix that: Flash and use a BIOS that does, or try to use the hardware after DOS boots by using a driver. Because there is no driver for XT-IDE hardware, you must find and flash the later version of the Compaq BIOS.

There is actually a third option which I'm not sure anyone has explored yet: Write a custom boot sector that performs the option ROM scan/init, then proceeds to continue booting from floppy. This will require booting off of a floppy, but it will get the hard drive initialized before DOS loads so that the drive is visible from DOS. I'm not sure if anyone has written that, and unfortunately I don't have the time right now to do so, but thought I'd mention it in case it does exists and someone knows where it is.

SomeGuy
May 18th, 2017, 06:24 PM
Can you identify what ROM revision you have?

The REV. C bios is posted here: http://www.pcjs.org/devices/pcx86/rom/compaq/portable/ but it is in an odd format intended for their emulator. That site also has a list of the ROM part numbers for each revision. And I think the rev letter also appears in the BIOS itself. If I can dig it up, I can post a dump of mine, that is also REV C.

You aren't writing your disks with a 1.2mb drive are you?

The Compaq Portable will run any "vanilla" version of MS-DOS up to 6.22.

rvdbijl
May 18th, 2017, 07:17 PM
Thanks for all the replies!

So, I have gotten a little further -
1. My BIOS rev is B. It's actually on the chip. Looks like there is only one 8k EPROM on the board and 3 open sockets. That explains why the only ROM I saw was starting at F000:A000 or somewhere like that. I was expecting to see something at F000:0000... :)
2. Compaq DOS 3.31 runs, but anything newer loads for a while until it just freezes. I think it's when command.com loads. Floppy light stays on, ctrl-alt-del has no effect.
3. The XT-IDE works fine in my other 5150 system. No problem there. I think the BIOS on the Compaq just doesn't look for option ROM's, which I think I've read somewhere else is true for anything before Rev. C.
4. The floppies I'm using are fine. Written from another 5150 with 360K drive. No disk read errors at all on the Compaq or on the 5150.
5. I'll do a RAM test, just in case that's the issue. But I think I would have seen other symptoms too when I run programs in DOS. Suggestions on best programs to use? I suspect memtest86 won't work on this machine.. :)
6. I saw the website with the Rev C. BIOS, but I'm not sure how to convert the JSON into some type of HEX format readable by my programmer.... I did send the owner of the website a message asking if he has a .hex dump he could share.

Thanks for all the help so far! Looking forward to getting to the bottom of this.

rvdbijl
May 19th, 2017, 03:38 PM
Update:
I managed to pull that JSON type Rev C BIOS from the pcjs website and convert it with a little C# program into a BIN file and write it to my 28c64b EPROM. And woo-hoo! It worked when I popped it into the board!
Funny enough, it has no problem booting Dos 5.0 (the only one tested so far), while my Rev B BIOS would not boot anything newer than 3.31.... Amazing!

Unfortunately this was the EPROM that was on the XT-IDE board (I didn't have another one here), so I'll have to wait for my digikey order to come in to try the XT-IDE board. But based on the fact that it boots 5.0 now, there is clearly a difference. And I'm sure this version will scan for option boards!

Thanks for everyone's help!

PhilipA
May 19th, 2017, 04:17 PM
Sure the floppy drive/media is good? I found a Sony 3.5" drive that worked with the standard controller, crimped a plug into the wire and formatted a few discs 720k and mine will boot off that much more reliably than the original 5.25" drives/discs.

I've run msdos 3, 5 and 6 on mine and it works fine, as stated above.

Phil

Trixter
May 19th, 2017, 07:56 PM
The REV. C bios is posted here: http://www.pcjs.org/devices/pcx86/rom/compaq/portable/ but it is in an odd format intended for their emulator. That site also has a list of the ROM part numbers for each revision. And I think the rev letter also appears in the BIOS itself. If I can dig it up, I can post a dump of mine, that is also REV C.


If you could post yours, that would help me as well. I'm about to take possession of a Compaq Portable but I have no idea what ROM I'm getting.

SomeGuy
May 19th, 2017, 08:41 PM
Ok, the dumped Rev C ROM is attached. And yes, the two ROMs in the system have identical contents. That is a documented oddity of the earlier Compaq Portable and Portable Plus.
38678

Trixter
May 19th, 2017, 10:11 PM
Much obliged!

modem7
May 19th, 2017, 10:40 PM
Ok, the dumped Rev C ROM is attached. And yes, the two ROMs in the system have identical contents. That is a documented oddity of the earlier Compaq Portable and Portable Plus.
38678
Thank you. I have added them to the collection at [here (http://minuszerodegrees.net/rom/rom.htm)].

rvdbijl
May 20th, 2017, 10:07 AM
Thanks for all the responses! Like I said, I reconstructed the Rev C BIOS from the JSON on the web, and it worked!

For posterity, or for those of you who didn't believe me when I said that the Rev B BIOS didn't want to boot anything over DOS 3.31, attached is the image of the Rev B BIOS. :)
38686

I noticed there was some discussion about the # of ROMs on the mainboard, In my case, there is just one 8K ROM on the board, for rev B or C. I want to say my mainboard was Rev D, but the label on it isn't really clear as it looks like it says D/F or D1F. See picture below (with the 1 Rev B ROM still on it).

38688

modem7
May 20th, 2017, 02:52 PM
... attached is the image of the Rev B BIOS.
Thank you. I have added it to the collection at [here (http://minuszerodegrees.net/rom/rom.htm)].

rvdbijl
May 22nd, 2017, 04:39 PM
And thanks to everyone's help, my Compaq Portable I is now part of the networked family of PC's. With the XT-IDE working and a 3C503 card, it was more than happy to boot DOS 6.22 and log into my network share on a virtual WinXP machine on ESXi that has IPX enabled!

My next project is to get a PCjr there as well...

Trixter
May 23rd, 2017, 11:38 AM
Nice!

Is there a tutorial or something you followed to get your network drive to show up that you can post a link to? I'm mostly curious how much RAM the network redirector takes up.

rvdbijl
May 23rd, 2017, 03:16 PM
I'm not aware of a tutorial... But it's not too complex. You need to use Windows XP or earlier to share the drive, and make sure you add the IPX/SPX protocol in the network card properties. Then when you share a drive, it should be visible on your XT's with the DOS client.
As for how much memory it uses, I think on my Compaq, I had a little over 520K left with DOS and the client loaded. Not too bad.

I did have some trouble getting the 3c503 TP to work properly. The IRQ and IO address shuffle. Got it to work by turning on DMA.

If this is not clear enough, I can probably grab some screenshots this weekend and post them here (on the XT and on the WinXP machine).