Installing Oct ’91 NT from CD

With VirtualBox 4.3, it is possible to install the oldest known pre-release of Windows NT directly from CD, the way Microsoft intended. This is the Fall ’91 Comdex preview which only supported the x86 architecture and a very short list of hardware devices. The pre-release was available only on CD-ROM and although it was possible to install it more or less manually from DOS, there was a graphical installer on the CD-ROM.

NT 10/91 GUI Setup

However, the hardware support being as limited as it was, the only supported storage controller was Adaptec AHA-1540 or compatible with a SCSI CD-ROM attached. Fortunately this is adequately emulated by the BusLogic SCSI HBA device in VirtualBox.

Successfully getting through the NT setup isn’t as trivial as it ought to be, so here are a few hints:

  • The SCSI CD-ROM should use ID 2 so that the default device selected by boot floppy can be used without any intervention.
  • The hard disk may be either SCSI or IDE. Smaller is better (about 500MB IDE, 1GB SCSI).
  • The VM must have a serial port enabled, otherwise NT will refuse to boot.
  • The VM must have at least 12MB RAM assigned, and preferably 16 or more, or NT will crash or hang in various interesting ways. Yes, NT was bloatware, requiring much more RAM than its closest competitor, OS/2.
  • Most importantly, NT will crash if the hard disk isn’t formatted—this is probably a bug in the installer. NT insists on creating a swap file, even when the system has plenty of RAM. If there’s no C: drive with a FAT partition, NT will print an error message and then get into a bugcheck loop and finally crash.

If everything is to NT’s satisfaction, the graphical installer will start and present a nice step-by-step installation wizard. It would be interesting to know why Microsoft used a fully graphical install in the pre-release and a partially text-mode installer in the finished product.

The choices are quite limited, and the pre-release nature of this NT version clearly shows—for example in the filesystem selection dialog, FAT is the only available choice.

NT 10/91 Filesystem Setup

Another sign is the debugging support dialog; while released NT versions supported kernel debugging, debug support was not a user-visible choice in the standard installer user interface and so-called checked build were available separately.

NT 10/91 Debugging Setup

That said, despite the very limited choices, the October 1991 pre-release of Windows NT is a fairly complete system with a GUI and optional networking. The hardware support was extremely limited, but the system was not intended for general consumption.

NT 10/91 Networking Setup

Once the installation completes and the system is rebooted, a familiar user interface is presented:

NT 10/91 Desktop

The GUI is a clone of Windows 3.x, with a mix of elements from Windows 3.0 and 3.1 (Windows 3.1 was released approximately half a year after the Oct ’91 NT pre-release).

Curiously, the installation disc also functioned as a kind of a live CD, a concept unheard of in 1991. All it takes is exiting the setup, which lands the user in an empty desktop with an empty Program Manager… from whence it is possible to start CMD.EXE and other programs. Unfortunately the installation CD was clearly not intended for this and the environment (especially PATH) needs to be manually adjusted.

The October 1991 pre-release of Windows NT is historically significant as the first semi-public version of NT. It significantly predates the eventual July 1993 release of Windows NT 3.1, and shows how far along the OS was after nearly 3 years of development, but also how much was still missing relative to the final product.

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19 Responses to Installing Oct ’91 NT from CD

  1. Yuhong Bao says:

    “Yes, NT was bloatware, requiring much more RAM than its closest competitor, OS/2.”
    I think even MS never intended “NT OS/2” to replace OS/2 2.x at least initially.

  2. slipstream says:

    I assume this means you can install Dec91 with the graphical installer aswell?

    And use cdinstall.img in later builds, without modifications?

    (I already patched the NT 3.1 RTM text setup so cdinstall.img would work with the Aztech NT 3.1 IDE CD-ROM driver: see here )

  3. Michal Necasek says:

    Yes, the Dec ’91 build works too. It’s not all that different.

    There’s one build which doesn’t work out of the box, but unfortunately I forget which. The older Adaptec 154x driver works on both Adaptec and BusLogic HBAs. In the NT 3.1 release, there are separate BusLogic (buslogic.sys) and Adaptec 154x (aha154x.sys) drivers and the Adaptec one no longer works on BusLogics. In one beta build, there’s the updated manufacturer-specific Adaptec driver but no BusLogic driver yet. It’s possible to use the buslogic.sys driver from the following build.

    There’s no need to modify the final NT 3.1 release, CD installation works with the original media using an emulated BusLogic SCSI HBA and a CD-ROM drive attached to it.

  4. Mess now emulates the 3c503, so you could NetBUI on this as well. I also recall the GUI had a checkbox to install the soundblaster driver (you could also fool the installer by copying the CD onto the hard disk, and running the install from under NT. This is how I managed to install the 1991 pre-releases on HPFS volumes…

    Before I went on my large trip, I ran the 1991 stuff on a Pentium, and even that was pokey. but I was able to have it mount a 3.51 fileserver well enough.

  5. Whistler says:

    Is there any chance that you would share the CD images? Would be interesting to add to my NT collection 🙂

  6. Peter says:

    It’s strange that they’d get rid of the GUI installer. If anything you’d think it’d be the other way around, with a text based installed in the early release and a GUI installer for the final release.

    I don’t think they came back to a GUI until Vista?

  7. Michal Necasek says:

    Yes, Longhorn/Vista was where the GUI installer came back. The only reason I can think of why they got rid of it is that it caused difficulties for floppy based booting/installation. Now that I think of that, I believe Vista (NT 6.0) was also the first version which could not boot from floppies at all.

  8. Calvin says:

    Windows FLP was an XP-based build with a Vista-esque installer: WIM images and a graphical installer. That’s about 2005.

  9. MiaM says:

    Is the GUI installer 16-bit win3.x code or 32-bit NT 3.1 code?

    IIRC the installer for Win95 ran in a minimal Win3.x-ish environment.

    Once NT were ported to other architecture the installer couldn’t reuse existing Win3.1 and dos and still beeing platform independent. Therefore I think it’s no surprise that the got rid of that specific gui installer.

  10. Michal Necasek says:

    The installer is all 32-bit. In fact I don’t think there’s NTVDM at all!

    That said, for portability reasons, it’s quite possible that Microsoft did not want to rely on VGA-compatible hardware being always present.

  11. TC1988 says:

    Probably not related to this, but related to the buslogic/aha154x there used to install NT here, but can you give me a sample of scatter/gather code with 3 arguments (like uint32_t, void *, int or size_t) for read/write access in emulation please? The one in VBox GPL seems too tighted to the kernel drivers.
    Also, how does VBox get the phase bus stuff right for the buslogic/aha154x implementation?

    Thanks 🙂

  12. Michal Necasek says:

    I’m afraid I don’t understand either question. I also don’t know what “tighted” means.

    If you’re asking about SCSI bus phases then VirtualBox does not care about that at all, it works on the SCSI command level, not SCSI bus level.

  13. TC1988 says:

    Ok thanks for the clarification.

  14. TC1988 says:

    Also, a thing that bothered me in my implementation of the aha154x (not buslogic though) for another emulator, the doc I have doesn’t mention where it does fetch/store the CDB. I know it is contained in the CCB + ID and LUN.

  15. Sean McDonough says:

    Is ye olde paranoide processor-detection code already present in the October 1991 builds?

  16. Michal Necasek says:

    No, it’s not. I’m not sure when they added it, but in Oct ’91 they most likely wouldn’t detect anything beyond the 486 I think.

  17. Sean McDonough says:

    One more question – at what point did the NT 3.1 betas switch from the full graphical installer to the one with the text-mode early setup?

  18. Michal Necasek says:

    I think only the 1991 pre-releases (Oct/Dec) had a graphical installer. The 1992 stuff looked much more like the released NT 3.1.

  19. Sean McDonough says:

    Ah, OK, thanx! 🙂

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