Santa Cruz Operation settles Lotus lawsuit
Bill Mayhew
wtm at uhura.neoucom.EDU
Sun Jun 30 04:25:29 AEST 1991
Mircrosoft MS-DOS (formerly Seattle Ssytems QDOS) bears more than a
passing similarity to Digital Research CP/M-86 (Control Program for
Microprocessors). The -86 version of CP/M was designed for the
Intel 80x86 series of CPUs.
The FCB (File Control Block) methodology of accessing files in
MS-DOS was pretty much wholesale lifted from CP/M at the code interface
level. Basically you load a register with the function code, then
do a long jump to the DOS handler. This worked in both CP/M and
DOS at least up through DOS version 2.11. I don't know the level
of similarity of code internal to early DOS and CP/M-86.
I recall that to get CP/M-86 Wordstar 2.5 to run in MS-DOS, one
only had to patch one byte in the executable.
The other area of amusement is that the TOS+GEM interface on the
Atari ST computers is more than slightly reminiscent of MS-DOS
interrupt functions..
For Microsoft and Digital Research to be competitors, there seems
to be a surprising level of cross-fertilization in their products.
Bill
--
Bill Mayhew NEOUCOM Computer Services Department
Rootstown, OH 44272-9995 USA phone: 216-325-2511
wtm at uhura.neoucom.edu ....!uunet!aablue!neoucom!wtm
via internet: (140.220.001.001)
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