Document 1609
Applications that Check the DOS Version Number

Description:
The DR DOS 6.0 Version Numbers

A few applications and device drivers have been encountered
which, when loading under the DR DOS 6.0 operating system,
display an error message that states the current version of
operating system is not supported. This can occur for several
reasons, which are outlined below.

Device drivers for disk drives or networks are sometimes
produced for specific versions of DOS or occasionally will use
specific configurations for different versions of DOS. The DR
DOS 6.0 operating system will appear to be COMPAQ DOS 3.31 to
applications and drivers. Usually, a DOS 3.3 driver works
properly. If you have been running previously with MS/PC DOS
4.x, the driver that you have been using might be designed
specifically for that version. Contact the manufacturer of the
driver to see if they have any specific configuration
information or drivers for DOS 3.3x.

When applications request the DOS version number from the
operating system, the DR DOS 6.0 operating system returns
version 3.31. The application then knows that it should expect
support for DOS 3.3-level calls and support for larger than 32
Mbyte partitions using the COMPAQ Extended Interrupt 25 and 26
convention. Most applications do follow these conventions and
therefore work without any difficulty. 

However, some applications have been designed to go beyond those
conventions and actually attempt to directly manipulate DOS data
structures or replace sections of the operating system code with
their own. These applications depend on having intimate
knowledge of each DOS version they detect and have been written
to react differently for each of those versions. If an
application uses this type of technique, the manufacturer will
have to design the application to take the DR DOS 6.0 operating
system into account as well. It is possible that the
manufacturer has already produced another version of your
application that runs under the DR DOS 6.0 operating system.
Contact the manufacturer to see if there is any information
about upgrades or specific configuration steps for the DR DOS
6.0 operating system. If the manufacturer is interested in more
information about the DR DOS 6.0 operating system, they are
welcome to contact Digital Research Inc. directly and we will
work with them on the situation.