The Origins of DOS

Fred Cisin cisin at
Fri Oct 27 21:20:26 CDT 2006

On Fri, 27 Oct 2006, Jim Isbell, W5JAI wrote:
> OK, where did TRSDOS fit in?  It was before MSDOS as far as sale to the public.

TRS-DOS, Apple-DOS, and CP/M were the three biggest players in
MICROcomputers before MS-DOS came along.

TRS-DOS was written, apparently as a "work for hire" by Randy Cook for
Randy loved to add new features, and was NOT into finishing anything.

TRS-DOS 2.0 (the first one released) was far from complete.
Randy Cook "finished" TRS-DOS 2.1 in a big hurry.

Apparat (among others) documented and fixed hundreds of bugs in TRS-DOS
2.1.  Then they released it, first as APR-DOS, and then NewDos.
Initially, they claimed that it was an all new product.
Then, when Randy's lawyer demonstrated that there was a hidden full screen
copyright message with "Randy Cook" credited, they then sold it as a
"patch" product, "requiring" that users already own a copy of TRS-DOS.
But, since there was no enforcement of that requirement, they had to pull
the product.  They rewrote a non-infringing version called NEWDOS-80.

Radio Shack got fed up with Randy's additions of more features than he
finished, and took over the product.  and dumped Randy.
For 2.2, the "Randy Cook" hidden copyright message was
patched to   "Tandy Corp"

Randy wrote a 3.0 release that he never finished.
The distributor of that refused to pay him.
Randy wrote a 4.0 release that he never finished.
The distributor of that refused to pay him.

Lobo drives NEEDED a patched and expanded version of TRS-DOS, because
their expansion interface used a 179x chip, and couldn't do all of
DAM patterns needed, and they wanted to expand to DS, 8" etc drives.

They hired all of the talent that they could find, such as Roy Soltoff, to
finish and document the product, to be called LDOS 5.0

The finished it!
They spun off a subsidiary company, LSI (Logical Systems, Inc.)
to market it.

Eventually, RS decided that their Model 3 TRS-DOS 1.3 wasn't cutting it,
so they licensed LDOS (as "TRS-DOS 6.0").  And Randy Cook started getting

Although Tim Patterson was familiar with it, TRS-DOS was NOT a significant
factor in the design of MS-DOS.

Grumpy Ol' Fred     		cisin at

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