In Microsoft Windows NT version 3.51 or 4.0, you can use the Winnt.exe or Winnt32.exe file located in the /I386 installation directory on the CD-ROM to create a set of Windows NT boot floppy disks.
Both Winnt.exe and Winnt32.exe allow you to create boot floppy disks for installing Windows NT, or for using the Emergency Repair Disk (ERD).
Use the /O switch to create a set of boot floppy disks that can be used to perform either a Winnt.exe or Winnt32.exe installation. These disks are identical to the set created by a regular Winnt.exe or Winnt32.exe installation. Using this switch allows you to create the floppy disks without installing Windows NT.
Use the /OX switch to create a set of boot floppy disks to perform a CD- ROM or floppy disk installation. These disks are identical to the disks included with Windows NT in either the CD-ROM or floppy disk format.
The only difference between these two sets of disks is the Winnt.sif file on the second disk that is created when you use the /O switch. The Winnt.sif file contains an MsDosInitiated= entry. This is set to 1 when you use the /O switch. Deleting the file, or setting the value to 0, makes the set of disks equivalent to using the /OX switch. If the Winnt.sif file exists, and MsDosInitiated= is set to 1, Windows NT Setup looks for the installation files in the \$WIN_NT$.~LS temporary folder. If Winnt.sif does not exist, or MsDosInitiated= is set to 09, Windows NT Setup checks the CD-ROM drive, and then the floppy disk drive, for the installation files.
NOTE: Windows NT Small Business server (SBS) version 4.0 and 4.0a requires you to copy the Winnt.sif file from the first SBS CD-ROM \SUPPORT directory to the second installation diskette. Once this has been completed, the three diskettes are identical to the original diskettes that came in the SBS box. SBS 4.5 automatically copies this file to floppy disk 2.
Copied from https://support.microsoft.com/en-us/kb/131735
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Both Winnt.exe and Winnt32.exe allow you to create boot floppy disks for installing Windows NT, or for using the Emergency Repair Disk (ERD).
Use the /O switch to create a set of boot floppy disks that can be used to perform either a Winnt.exe or Winnt32.exe installation. These disks are identical to the set created by a regular Winnt.exe or Winnt32.exe installation. Using this switch allows you to create the floppy disks without installing Windows NT.
Use the /OX switch to create a set of boot floppy disks to perform a CD- ROM or floppy disk installation. These disks are identical to the disks included with Windows NT in either the CD-ROM or floppy disk format.
The only difference between these two sets of disks is the Winnt.sif file on the second disk that is created when you use the /O switch. The Winnt.sif file contains an MsDosInitiated= entry. This is set to 1 when you use the /O switch. Deleting the file, or setting the value to 0, makes the set of disks equivalent to using the /OX switch. If the Winnt.sif file exists, and MsDosInitiated= is set to 1, Windows NT Setup looks for the installation files in the \$WIN_NT$.~LS temporary folder. If Winnt.sif does not exist, or MsDosInitiated= is set to 09, Windows NT Setup checks the CD-ROM drive, and then the floppy disk drive, for the installation files.
NOTE: Windows NT Small Business server (SBS) version 4.0 and 4.0a requires you to copy the Winnt.sif file from the first SBS CD-ROM \SUPPORT directory to the second installation diskette. Once this has been completed, the three diskettes are identical to the original diskettes that came in the SBS box. SBS 4.5 automatically copies this file to floppy disk 2.
Copied from https://support.microsoft.com/en-us/kb/131735