> On Apr 18, 2019, at 3:06 PM, Warner Losh <i...@bsdimp.com> wrote:
>
> On Thu, Apr 18, 2019 at 12:41 PM Dan Veeneman via cctalk
> <cctalk@classiccmp.org> wrote:
> On 4/18/2019 2:27 PM, Paul Koning via cctalk wrote:
> > my memory is that DSM-11 is an operating system all its own, not just a
> > language processor running on top of a standard OS like RSTS.
>
> In the late 1980s and early 1990s, we used DSM running on VMS 4.7 for a
> nationwide (United States) mortgage credit reporting system.
>
> The big claim to fame for RSTS/e was I thought that it let you load
> 'foreign' executives so you could run RT-11 or RSX-11 or whatever binaries
> all on one system. I'd imagine DSM-11 images would be easy if it were a real
> OS. I'd always thought of RSTS/e as a poor-man's hypervisor. But maybe I'm
> misremembering how much it could do...
Poor man's hypervisor, I like that.
That's reasonably accurate. RSTS/E had "run-time systems", originally the
interpreter, support library, and user interface of the BASIC-PLUS language
machinery. Starting in, I think, RSTS/E V5B, it was generalized step by step
to become a collection of such things: a user interface, execution environment,
and other stuff. It might be very narrowly tailored, like the TECO run-time
system, it might be the interpreter library for a language, like the FORTH and
ALGOL run-time systems, or it might be a fairly complete emulation of a
different OS, like the RT11 and RSX run-time systems.
I first used a very primitive version of this feature in V5B around 1975, to
run an assembly language program before there was any general RSTS support for
doing that.
paul
