18 Apr
2019
18 Apr
'19
4:11 p.m.
On Apr 18, 2019, at 3:06 PM, Warner Losh <imp at
bsdimp.com> wrote:
On Thu, Apr 18, 2019 at 12:41 PM Dan Veeneman via cctalk <cctalk at classiccmp.org>
wrote:
On 4/18/2019 2:27 PM, Paul Koning via cctalk wrote:
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
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...