Windows NT 3.1 October 1991 build

October 1991 release of Windows NT 3.1 was compiled for the COMDEX Trade Show in 1991-10. Interestingly, this build does not have a build number, unlike both earlier and later builds. Instead, Winver displays "Version VERSION" in place of the actual version number. It is speculated this build was rushed to completion so it was ready in time for the show, which could be the reason for the lack of a build number and MIPS port.

It is also one of few Windows NT builds before Longhorn to have a fully graphical setup, a feature which has not returned until Longhorn build 4001 with its WIM-based setup.

Password authentication doesn't work in this build yet.

Under emulation and, presumingly, on real hardware with the Adaptec AHA-154x SCSI adapter, there is an issue with CD-ROM media changes that make the File Manager and/or Command Prompt to hang. Notably, this build already had long filename support, but only under HPFS partitions.

GUI setup

 * Adaptec AHA-1540 or compatible SCSI bus
 * (adequately emulated by the BusLogic SCSI HBA device in VirtualBox and in 86Box)


 * SCSI or IDE hard disk, connected to SCSI port 0 if using SCSI
 * SCSI CD drive connected to SCSI port 2
 * COM1 port enabled
 * At least 16 MB of RAM
 * Hard disk pre-partitioned and preformatted in MS-DOS

Text mode setup (from MS-DOS)

 * 16 MB of RAM
 * COM1 port enabled
 * Prepartitioned and preformatted disk in MS-DOS

GUI Setup
In order to use the GUI setup, the system of choice must have a CD-ROM drive connected to the SCSI bus. As of now, it has been confirmed to work in VirtualBox and 86Box. VirtualBox instructions
 * 1) Make a virtual machine with 500MB hard disk and 24 MB of RAM. Use the NT4 profile.
 * 2) Go to VM settings and open the Storage tab.
 * 3) Remove the CD drive from the IDE bus and add an SCSI bus.
 * 4) Add a CD drive this time to the newly created SCSI bus, mount the 10-91 ISO file. It's recommended to set the SCSI port to no. 2, as it's the default boot option on the NT boot floppy.
 * 5) Add a floppy bus and add a floppy drive. Mount an MS-DOS boot disk with FDISK and FORMAT.
 * 6) Go to the Serial Port tab in VM settings and enable the COM1 port.
 * 7) Save the settings.
 * 8) Start the VM. MS-DOS should boot. Run FDISK and partition the drive. Then format it with the FAT filesystem.
 * 9) Mount the boot.img image file and press Right Ctrl+Del
 * 10) OS Loader boot menu should be displayed. Choose the SCSI port of your CD drive you configured in VM settings.
 * 11) Follow the on-screen instructions.

Demo applications
This build includes several demo applications for demonstrating the new operating system abilities.

Win Bez
Demonstrates the Windows NT Graphics Device Interface (GDI), the API responsible for rendering graphical objects on the screen.

Performance Meter
Measures the performance of the then-new NT kernel.

PlayIt
Illustrates the sound and music abilities of Windows generally. A version was allegedly available for Windows 3.1x Enhanced Mode aswell.

Mltithrd
Demonstrates the multithreading abilities of Windows NT.

NT desktop
Accessories and Games bundled with this build