Large hard disks will likely cause problems though less so with SCSI disks. At a minimum the C drive partition can not be larger than 2GB for any version of Windows NT before 5.0/2000. This is because the text-mode part of the installer is only capable of creating FAT partitions and NT can't handle FAT partitions larger than 2GB. If you selected to format C drive as NTFS it will be created as FAT and after the initial file copy and reboot it will then be converted to NTFS. You can apparently get around this by partitioning and formatting the disk on another NT box so you don't have to do it at install time but I've never bothered. A large disk may also cause other issues - perhaps the SCSI driver may have issues, etc. I don't think I've ever tried on anything bigger than around 4GB.

NT 3.51 is only about 3 months older than Windows 95 (NT 4 is about a year newer than 95) and overall I've never had much trouble getting it to work on mid-90s hardware. Probably with a smaller disk it will work fine on your machine. NT 3.50 should be similar. NT 3.1 is more problematic and requires a SCSI CD-ROM drive for one (IDE CD-ROM drives weren't really a thing in 1993).

davidrg wrote on 2022-07-12, 21:11:

Large hard disks will likely cause problems though less so with SCSI disks. At a minimum the C drive partition can not be larger than 2GB for any version of Windows NT before 5.0/2000. This is because the text-mode part of the installer is only capable of creating FAT partitions and NT can't handle FAT partitions larger than 2GB. If you selected to format C drive as NTFS it will be created as FAT and after the initial file copy and reboot it will then be converted to NTFS. You can apparently get around this by partitioning and formatting the disk on another NT box so you don't have to do it at install time but I've never bothered. A large disk may also cause other issues - perhaps the SCSI driver may have issues, etc. I don't think I've ever tried on anything bigger than around 4GB.

The C: partition for Windows NT 3.51/4.0 can be 4GB. Its version of FAT can create up to 64KB clusters. Through it might be unrelated to NT 3.51; unofficially, if you use some sort of imaging tool, you can successfully boot off of an 8GB C: drive after NTFS conversion has completed with NT 4.0. I never tried larger, though.

Have you tried a different SCSI controller? What about a different disk? Have you tried fiddling with LBA in the BIOS?

OSkar000 wrote on 2022-07-12, 15:32:

I just started to play around a bit with a Pentium Pro (Dell Optiplex GX pro) but its not without problems. […]
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I just started to play around a bit with a Pentium Pro (Dell Optiplex GX pro) but its not without problems.

I have tested it with Windows 98SE on a IDE-disk without any problems. Everything works as expected.

Memtest runs without problems and it seems stable.

A real Pentium Pro should of course have scsi hard drives so I added an Adaptec 2940UW and a 36gb 10krpm disk from hp/compaq.

Started the Windows NT install from the floppy disks and inserted the CD and got the right drivers for the scsi-card. It detects the harddrive and I can make partitions and format them. However, all formaring attemps ends up with an error message that the disk couldn't be formatted.

Some ideas:
To large hard drive for WinNT 3.51? Tried to make a 4gb partition and then a 2gb.
Wrong drivers?
To large disk for the computer?
It doesn't like scsi at all
Its july, I'm not supposed to do anything like this when I have vacation...

Things to test:
Check drivers
Format the hard drive from the scsi-card
Test a smaller scsi-disk
Test a smaller ide disk

any ideas? 😀

I'm not sure which SCSI driver you're using... from what I remember the default WinNT drivers only supported CHS. You probably need to refer to your driver's manual to see if it does have LBA support.

Have you tried UniATA? It should probably work with a lot of hard disk controllers as well as proper LBA. You may try the official 0.46e8 version. That one works with NT3.51.

I changed to a smaller disk (9.1gb) and another scsi-card and was able to install without much problems.

So there are probably some compability issue with the disk and/or scsi card.

Lets se what goes wrong next 😀