Windows NT 4 - WORKING on ao486!

[alexoughton]

As I understand it the official minimum spec for 2000 is a Pentium although you "can" install it on a 486. With that in mind, the expectation of an FPU is not unexpected.

[Sorgelig]

I think Win98 doesn't use FPU in OS itself but requires it to secure the apps appeared at that time requiring FPU. Something like forcing to update HW.

[Caldor]

I think Win98 doesn't use FPU in OS itself but requires it to secure the apps appeared at that time requiring FPU. Something like forcing to update HW.

Yeah, sounds likely. A bit like what they are doing with Windows 11 now. You could run Windows 98 with a pre-Pentium machine, but usually it just did not make much sense to do so. It would not exactly be the full experience, since even without FPU you would need a faster CPU to do much with that OS. So I would agree that it was probably a bit of a hidden "you need a Pentium" nudge.

[alexoughton]

It seems that the most recent updates to the ao486 core have broken the keyboard under NT. I have raised a github issue regarding this:

https://github.com/MiSTer-devel/ao486_MiSTer/issues/102

Update: Sorgelig has reverted the change which broke keyboard. Updating to the ao486 and BIOS images released today will solve this problem.

[alexoughton]

I have found a solution for fixing NTFS conversion and have submitted the PR for it here: https://github.com/MiSTer-devel/Main_MiSTer/pull/557

Note that it's actually quite useful to keep the drive as FAT so that you can access it from DOS (maybe you need to do some troubleshooting, or copy something in from MisterFS). However, this provides you the option if you want it.

Update: Change has been accepted and merged into master. Should be included the next time there's a build of main.

[flynnsbit]

I have found a solution for fixing NTFS conversion and have submitted the PR for it here: https://github.com/MiSTer-devel/Main_MiSTer/pull/557

Note that it's actually quite useful to keep the drive as FAT so that you can access it from DOS (maybe you need to do some troubleshooting, or copy something in from MisterFS). However, this provides you the option if you want it.

Update: Change has been accepted and merged into master. Should be included the next time there's a build of main.

Unstable nightly from discord for those that want to test before the official release: https://github.com/MiSTer-unstable-nigh ... 226_1993d4

[alexoughton]

I just got NT to read a floppy disk for the first time. Someone put the NT kernel source code online a few years ago, and from there I've narrowed-down the problematic behavior to here:

https://github.com/ZoloZiak/WinNT4/blob ... py.c#L5095

There's a registry key which sets this "model30" variable. If you turn that on then it flips the behavior of the disk change detection. What seems to be happening now is my system has gone from reading the disk as always absent to always present. This means I can read a disk, but it doesn't properly detect if I change the image in the drive. This means it won't properly read the changed image, and could easily damage it.

While this isn't a solution, it's confirmation of what I've suspected for a while: That it's the media presence / disk change detection which is the cause of this problem. I'm seeing the same problem under Linux as well, and while I wasn't able to conclusively prove it there, there were definitely hints that this was nature of the issue.

Issue raised here with as much troubleshooting info as I can provide: https://github.com/MiSTer-devel/ao486_MiSTer/issues/103

[alexoughton]

I've fixed one of the problems around this, and the PR is here: https://github.com/MiSTer-devel/ao486_MiSTer/pull/105

NT can now read a floppy disk, but reading a second disk requires ejecting the image, trying to read the empty drive, and then mounting the second image. Just remounting a new image doesn't work as NT doesn't notice the image change. I know where the problem lies, but it will take some more time to fix.

[alexoughton]

Found a fix for the remaining issue with NT floppies. PR here: https://github.com/MiSTer-devel/Main_MiSTer/pull/560

I'm going to re-evaluate the NT setup steps now that floppies are working. This should give a much easier process, and I'm intending to make a post for that in the "guides" section.

[flynnsbit]

Super star level of effort to get this working! I'm excited to go through the process. Thank you for giving some love to the AO486 core. I know a lot of people these days steer clear of changes to it because of how full it is and how long it takes to build so a double thank you for your passion here.

[alexoughton]

Thanks for the kind words. It's been pretty exciting for me to learn how this thing works and actually make changes which fix things. I'd never even looked at Verilog before this thread, so I was particularly pleased when I was able to fix the main floppy issue in there.

[Neocaron]

Thank you indeed!

[alexoughton]

I've made some progress today on a single floppy image which does all the work for installing NT for you. You should just need this floppy, the NT install CD and a blank hard disk. I'd like to include the two necessary drivers directly within the floppy image, and am reaching-out to the authors of the drivers to ask for permission and pass-on thanks.

[MysteryScience]

This is some kind of dark magic, thanks for the amazing work!

[Inspector77]

This is great! Thanks a lot

[LamerDeluxe]

Congratulations on your achievements with this core! This was a really interesting story to read.

[RealLarry]

Great to read and was (is) an interesting thread to read, too. Personally I'm not interested in running NT4 on MiSTer - but doesn't this also mean that OS/2 would become possible now?

[alexoughton]

Unfortunately not. At least not the version I've tried which still crashes after first boot. I might try poking at that once the easy NT process is finished and posted. From my brief testing so far though, I found the failure messages of OS/2 to be even more cryptic than NT, so I don't have much hope that I can assist with that.

[held]

Congrats, was this a see if I can do it or did you have some specific memories attached to this archeology
Did you try win2k? Afaic remember it was rock solid and performance was almost identical.

[alexoughton]

Congrats, was this a see if I can do it or did you have some specific memories attached to this archeology

A bit of both. I was pretty young when NT 4 was current, but did enjoy using it when I could. My first job was with NT Server 4 so maybe I'll play with that version too.

Did you try win2k? Afaic remember it was rock solid and performance was almost identical.

Windows 2000 doesn't work. It will get past the first installation stages but then processes will die very quickly. It's likely due to the need for an FPU.

[held]

You could try nLite if that's still around. I remembered using something like that once.

[alexoughton]

OK, the easy setup process is now released. It evolved from being just a floppy image to being some floppies and a CD, but it's now as simple as a standard NT setup process.

There is one component missing from the driver floppy, which is the UniATA driver for the hard disk. While I was able to reach-out to the author of the video driver (who kindly granted me permission to include it in the image), I was not able to reach the UniATA author. He lives in Kyiv, Ukraine and so it's understandable that he would not be able to respond at this time. To work around this, the driver will need to be downloaded directly from his website. The install floppy will then automatically copy it from your "shared" directory. Details are in the readme.

Here's the github where I'm hosting everything: https://github.com/alexoughton/misternt. You can download the first version of the images from here: https://github.com/alexoughton/misternt ... gs/1.0.zip

I will write-up the "setup guide" forum post soon, but for now the github's readme file should be enough for anyone with familiarity of Windows NT setup. Note that MiSTer bugfix for floppies hasn't actually been released yet, so you will either need to jump through some eject/insert hoops, or use a nightly release for now: https://github.com/MiSTer-unstable-nigh ... 228_14ff77. I will likely wait until the fix is fully released before publishing the guide.

If anyone does have some time and interest to test out the process on their own MiSTer, then I would very much appreciate the feedback!

[NML32]

Thank you for the instructions and for putting together the install files.
I was able to follow your instruction and get NT 4 Workstation installed.
Is there a limit to the size of the VHD? I wasn't able to format a 1 Gig vhd, but no issues formatting a 500 Meg VHD.
I left the file system FAT.
I did a quick HyperTerminal test and was able to call a BBS.

[alexoughton]

Thanks for taking the time to test it!

Is there a limit to the size of the VHD? I wasn't able to format a 1 Gig vhd, but no issues formatting a 500 Meg VHD.

Most of my testing was with a 2GB VHD, with a little testing with a 400MB VHD. What happened with the 1GB which didn't work?

I did a quick HyperTerminal test and was able to call a BBS.

That's good to hear. I haven't tried connecting to a BBS yet, but I made some unsuccessful attempts to get PPP working.

[NML32]

With the 1 Gig VHD it appears to be in a loop where it tries to run FDISK then reboots with the same message tried to run FDISK again.

[alexoughton]

With the 1 Gig VHD it appears to be in a loop where it tries to run FDISK then reboots with the same message tried to run FDISK again.

Interesting. I'll take a look tomorrow to see if I can reproduce this. What's your method for creating the 1GB file? I want to try and follow your process as closely as possible.

[NML32]

Interesting. I'll take a look tomorrow to see if I can reproduce this. What's your method for creating the 1GB file? I want to try and follow your process as closely as possible.

Windows 10 Disk Management
Action Create VHD
Virtual hard disk size: 1 GB
Virtual hard disk format: VHD
Virtual hard disk type: Fixed size

Initialize Disk: MBR (Master Boot Record)
I tried formatting the volume as FAT from Disk management.
I also tried just Initializing Disk as MBR then letting the Boot First disk FDISK take care of setting up the partition and formatting.
Still ended up in a loop.

[alexoughton]

OK thanks, I will try a disk created that way. My method is to use PowerShell:

https://stackoverflow.com/questions/982 ... ows-system

[NML32]

OK thanks, I will try a disk created that way. My method is to use PowerShell:

https://stackoverflow.com/questions/982 ... ows-system

I didn't really understand that way.
I created a 1GB file using this process: https://tweaks.com/windows/62755/genera ... 1073741824
I still got the same looping. Then I booted from a DOS 6.22 disk and did FDISK and Formatted C: Then booted back to your disk and it recognized the partition and continued on with the install.

Hopefully, this helps.

Are you converting the File System to NTFS?

[alexoughton]

I created a 1GB file using this process: https://tweaks.com/windows/62755/genera ... n-windows/

OK good, that's actually the same way. There must be some bug which comes up specifically with a 1GB image rather than specifically with the method of creating the file. I'll take a look at this when I'm in front of my MiSTer tomorrow.

I'm curious are you converting the File System to NTFS?

Sometimes. I've lost count of how many times I've installed NT over and over again for the last few days to get this process working as smoothly as possible, and I've been testing it with both file systems. It seems to work just as well with either, although I suspect I may stick with FAT once I'm finished. It's pretty useful to be able to read it from DOS, especially if I want to transfer files in from MisterFS.