XT-IDE on PCjr

Hardware questions and modifications

Re: XT-IDE on PCjr

Postby jmetal88 » Sun Mar 23, 2014 3:32 pm

Lutiana wrote:On the floppy is DOS 5, with JRConfig loaded in the config.sys, similar thing on the HDD. This seems to explain why I get a second "press esc..." prompt, but it does not explain why the system does not boot directly off the HDD till after the soft boot, since the hdd is definitely bootable.

So what is the ideal setup to get the system to boot DOS 5 on the HDD? Do I even need JRConfig?

Tell me, does your DOS 5 (and 6) patch for the Jr permanently modify the boot files, and would that mod be copied into new media when using either the sys.com command or a format /s command?


There's a version out there that supposedly modifies the FORMAT command to automatically perform the patch, but I haven't been able to get that to work. If you're using DOS 5, you probably will have to perform the patch again on the hard drive manually.

If you don't have two floppy drives but you're seeing two the second time the boot menu comes up, it's probably because your CONFIG.SYS has a line in it specifying there is a second floppy drive.
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Re: XT-IDE on PCjr

Postby Trixter » Sun Mar 23, 2014 7:48 pm

Each version of DOS past 3.x must be patched if it is to boot a PCjr properly, jrIDE or not. I wrote a generic patching utility that you can use against any disk you've just transferred DOS to (it's the boot sector that actually has to be patched, not the DOS files themselves). Patching utility is here: ftp://ftp.oldskool.org/pub/misc/Softwar ... TCHDOS.ZIP

Edit: It works for patching a hard drive too.
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Re: XT-IDE on PCjr

Postby Lutiana » Sun Mar 23, 2014 8:21 pm

Ahh, boot sector patch... Right, I'm willing to bet a million bucks the reason why my system is not booting directly off of the HDD is because of this, and that it is dropping into basic before I can see any error messages. JRConfig obviously does something at allows DOS to boot properly once it does that soft boot, it is also the reason why I suddenly get that second Floppy as an option (had it set for my other jr which has 2 drives).

I'll try your patching utility when I get a chance, but I suspect it will clear up my issue completely.
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Re: XT-IDE on PCjr

Postby Lutiana » Mon Mar 24, 2014 2:36 pm

Patching the boot sector worked like a charm. I still get the second "Press esc.." prompt, but from what I understand that is merely foible of JRConfig.

@Trixster - Your patch program would not work for me, it kept saying "a fatal error has occurred" with little else in the way of description, but the batch files I got from Mike's site did the job just fine.

Everything seems to be working perfectly on the system now!

Some other questions:

1. Does anyone have a list of the codes displayed on the 8 Segment? I'm just curious about what they mean, or could mean.
2. When I do a "dir" listing on the flash card, there is a very long wait at the end where it appears to be calculating the free space, in the order of a minute or so. Is this to be expected?
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Re: XT-IDE on PCjr

Postby jmetal88 » Mon Mar 24, 2014 2:49 pm

Lutiana wrote:Patching the boot sector worked like a charm. I still get the second "Press esc.." prompt, but from what I understand that is merely foible of JRConfig.

@Trixster - Your patch program would not work for me, it kept saying "a fatal error has occurred" with little else in the way of description, but the batch files I got from Mike's site did the job just fine.

Everything seems to be working perfectly on the system now!

Some other questions:

1. Does anyone have a list of the codes displayed on the 8 Segment? I'm just curious about what they mean, or could mean.
2. When I do a "dir" listing on the flash card, there is a very long wait at the end where it appears to be calculating the free space, in the order of a minute or so. Is this to be expected?


I'll let someone else answer 1, but as for 2, yes, you should expect a very long delay while it calculates the free space. With DOS 5 and 6, it'll be longer and more often than on earlier versions of DOS.
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Re: XT-IDE on PCjr

Postby Trixter » Mon Mar 24, 2014 8:16 pm

Lutiana wrote:@Trixster - Your patch program would not work for me, it kept saying "a fatal error has occurred" with little else in the way of description, but the batch files I got from Mike's site did the job just fine.


If it's not too much trouble, please try again with a fresh diskette, and if you get the error again please take a picture and send it to me so that I can try to debug what happened.
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Re: XT-IDE on PCjr

Postby alanh » Mon Mar 24, 2014 11:01 pm

If you make large partitions (more than a few tens of meg), the free space calc is pretty slow.

As far as the ROM codes, the BIOS source code is available in the PCjr Technical Reference manual. Through-out the boot process it outputs progressively decremented values to port 10h (normally 80h on a PC). So if anything hangs, you have good resolution in the code to figure out where. I don't have a complete list, but it has been useful to me when hacking around with the hardware to determine where BIOS gets unhappy.

-Alan
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Re: XT-IDE on PCjr

Postby Lutiana » Tue Mar 25, 2014 9:18 am

@Trixster - I think I can do that sometime in the next week or two.

@Alan - Oh, I had not realized the code was for the PCjr's BIOS, I thought it was specific to the jrIDE. Good to know!
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Re: XT-IDE on PCjr

Postby alanh » Wed Mar 26, 2014 12:13 pm

It's a similar circuit to a card like this for a regular PC:

http://www.computerhope.com/jargon/p/postcard.jpg

Also the decimal points on the 7 segment is actually the A7 address line and its inverted complement. I figured it would be useful CPU activity indicator.
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Re: XT-IDE on PCjr

Postby Maximillion95 » Sat Mar 29, 2014 10:07 pm

I just got mine and I am using it with a CF Card. It detects it properly and I can Fdisk/Format it as drive C, I can even store files on it. So I ran SYS.COM and it works, However when I run the DOS Patching utility it says it can't reed the boot sector on drive C. So when I reboot,DOS 6.22 hangs after "Staring MS-DOS" is printed to the screen. After that I tried to patch it manually, but it still hangs in the same way.
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