John Cowan cowan at mercury.ccil.org
Sat Jul 2 03:39:23 AEST 2016

Clem Cole scripsit:

> ​UNIX could (and did) at the time --   by the time of the AT (which was
> when the PC's hockey stick curve took off) an 5.25" floppy had a capacity
> of 1.44M.  An RK05, the V6 and V7 standard,  was 2.5 M which is a 40% loss
> of space, but it was do-able.  

The AT also had the 10 MB disk.  Back when I had an AT, I ran Xenix
System III on it along with the MS C compiler, and was able to create
console-mode programs to run on everyone else's MS-DOS machines.
It's hard to remember/believe that Xenix was a Microsoft product before
DOS was.

> > DEC had several (RT11, RSTS, RSX) and the line is perhaps a little fuzzy:
> > they were getting operating-ish.
> >
> ​Be careful here Ches.  RT-11 and DOS-11 meet your (and my definitions).

I would say even RT-11 is somewhere between executive and OS.  It could
run foreground tasks (hence the name Real Time) if properly sysgenned,
and it had a decent kernel API that you didn't have to bypass.

> But RSTS and RSX were multi-users and ran (run) protected mode, have/had
> full networking stacks etc.  


John Cowan          http://www.ccil.org/~cowan        cowan at ccil.org
We pledge allegiance to the penguin and to the intellectual property
regime for which he stands, one world under Linux, with free music
and open source software for all.  --Julian Dibbell on Brazil, edited

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