Multi-Taking MS-DOS
Beta Test Release 1.00
Release Notes
Enclosed you will find Microsoft's first beta release
of Multi-tasking MS-DOS. This version is based upon MS-DOS
Version 2 sources, we will be reimplementing the multi-
tasking enhancements on top of Version 3 sources shortly.
Although we have distributed a bootable disk for the
IBM PC, this package can be adapted to any MS-DOS machine.
Those manufacturers who are designing IBM compatible ROMs,
would be wise to keep multi-tasking in mind. Specifically,
this IBM PC implementation has had to hook out the entire
disk (both floppy and hard disk) ROM code because after he
IBM code set's up the DMA transfer it simply loops in ROM
waiting for the interrupt to occur (routine WAIT_INT).
Problems you may wish to avoid within future ROMs are:
1) loading ES with the physical video RAM location
(label M3)
2) Looping in ROM on Cntrl-NumLock (label K40)
3) No way to add special detecting special key
strokes which a jump out into RAM after reading
the keystroke at KB_INT would avoid
4) Not being able to hook the loading of DS to point
to DATA (EQU 40H) in numerous routines.
Other than these deficiencies the ROM code developed should
be very usable.
By implementing the above suggestions, the size of your
BIOS can be reduced since it will not be necessary to
duplicate functionality in RAM.
More detailed specifications of the device driver
formats will be forth coming. For the time being you will
have to make use of the sample source code for the IBM PC.
If you have further questions please contact Microsoft OEM
customer support through Technical Assist Requests (TAR).
* * * WARNING * * * WARNING * * * WARNING * * *
Each copy of this software distribution has been
individually serialized to facilitate tracing of
unauthorized duplication.
* * * WARNING * * * WARNING * * * WARNING * * *
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