The Origins of DOS

Jim Isbell, W5JAI jim.isbell at
Sat Oct 28 10:27:19 CDT 2006

TRS DOS market was prety big at the time.  To begin with it was the
ONLY desktop computer available in the mass marked....almost two years
if memory serves me well.  There were several "mini" computers around,
but nothing like the RS computer with 8k of memory and a tape system
for probgam loading/saving and BASIC.

On 10/28/06, Chandra Bajpai <cbajpai at> wrote:
> How big was the TRS-80 Market to support all thoses DOSes?
> I remember when NewDOS/80 and I just remember it being fast.  Any idea who
> wrote that?
> -Chandra
> -----Original Message-----
> From: cctalk-bounces at [mailto:cctalk-bounces at]
> On Behalf Of Fred Cisin
> Sent: Friday, October 27, 2006 10:24 PM
> To: General Discussion: On-Topic and Off-Topic Posts
> Subject: Re: The Origins of DOS
> On Fri, 27 Oct 2006, Warren Wolfe wrote:
> > [TRS-DOS]
> >     It was its own universe, Jim.  The links and questionable parentage
> > of the original version of DOS are tied directly to CP/M, which was the
> > first O/S for personal computers that any significant number of
> > businesses embraced.  And, Windows came out of the DOS world, and now
> > dominates as few products have dominated before.  (Note: I am NOT
> > claiming this is a GOOD thing.)
> >
> >     From what I can tell, TRSDOS was not a rip-off of anyone's software,
> > and nobody bothered to rip it off, so it's pretty much out of the world
> > of O/S scandal.
> There WERE several imitators of TRS-DOS (although still for TRS-80),
> including NEWDOS, DOSPLUS, and the semi-legitimate offspring LDOS.
> > It actually was pretty decent, and had a few ideas of
> > merit that didn't make it into the mainstream world for a while.  It was
> > just totally tied to Radio Shack computing, and suffered a mortal wound
> > when IBM came out with their PC.  No fault of its own.
> Rasio Shack AVOIDED expanding TRS-DOS into other semi-related hardware
> platforms.
> --
> Grumpy Ol' Fred                 cisin at

Jim Isbell
"If you are not living on the edge, well then,
you are just taking up too much space."

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