Virtual Machine Boot

An important goal of OS/2 Version 2.0 is the ability to run past, current, and future DOS programs; indeed most DOS applications available today run unchanged in the MVDM environment.

However, it should be remembered that the "DOS" which runs in this case is highly optimized for (and specific to) an OS/2 Version 2.0 virtual 8086 machine. Because of this, there are fundamental internal differences between the DOS Emulation provided under OS/2 Version 2.0 and "real" DOS. Two problems may therefore arise:

  • Some programs may depend on specific DOS features such as internal control blocks, LAN Redirector hooks, or even undocumented functions, which are not present in MVDM's DOS Emulation.
  • Only DOS character device drivers can be loaded in MVDM's DOS Emulation. The user may own a block device (such as a special disk or tape drive) for which no OS/2 driver is available. (A block device is one accessed via a drive letter, such as E:).

    Virtual Machine Boot (VMB) solves both these problems. It allows the user to boot "off-the-shelf" DOS and use block device drivers in an OS/2 Version 2.0 virtual DOS machine, ensuring greater compatibility for DOS applications.

    Another possible use of VMB is to run DOS of a different National Language to that of OS/2 Version 2.0 itself. This may be useful in a multilingual environment.

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