SAB Diskette Utility uses IOCTL to copy the boot sector of your
C: drive when creating a system (bootable) diskette.  This is
done to make sure that the boot sector of the diskette is
compatible with the version of DOS that your are using.

Some hard disk device drivers do not support direct IOCTL
access.  If you are unable to create a system diskette because
of restricted access to the C: drive boot sector you can
create a file containing a copy of the boot sector of your
C: drive by using the following command:
             DEBUG < GETBOOTC.DBG

This will create a 512 byte file called SABDUSEC.DOS which
will contain a copy of the boot sector from your C: drive.
You can tell SAB Diskette Utility to use it by adding the
following line to the SAB.INI file in your \WINDOWS directory:
          BootSectorFile=d:\path\SABDUSEC.DOS
where d:\path\ is the drive and path that the SABDUSEC.DOS
file is in.

For example if you have installed SAB Diskette Utility in
C:\SABDU then do the following:
             C:
             CD \SABDU
             DEBUG < GETBOOTC.DBG
and add the following line to SAB.INI in your \WINDOWS
directory:
             BootSectorFile=C:\SABDU\SABDUSEC.DOS

You can also specify the name of the system files that will
be used to create the system (bootable) diskette:
             IOSysFile=
             MSDosSysFile=
             CommandComFile=

The first two specify the names of the two hidden files that
are part of the boot-strap loading process.  The third one,
CommandComFile specifies the operating system shell.