There's some confusion as to whether this is just a re-packaged
version of RT-11, or a time-sharing system layered on top of RT-11.
A repackaged RSTS. As remembered by Paul Koning, a former
CTS-500 is indeed repackaged RSTS. RSTS itself is a timesharing
system, you don't need to layer anything on top of it. The packaging
included, if I remember correctly, some stuff aimed at business
applications such as an indexed file system. (This predates the
support of RMS-11 in RSTS, and RMS-11 basically eliminated the
reason for having CTS-500.)
There were some PDP-11s with special paint jobs (blue rather than
maroon) and bezels, and also I think lower cabinets, as part of the
Written for the PDP-11/45 in 1972-1973 mainly by
Russ Atkinson, Roger Haskin and Perry Emrath, all of University of
Illinois Urbana, for a Chicago company named Datalogics (which was
consumed by Frame, and subsequently by Adobe).
Duress was similar to Dec's DOS to the outside user. The motivation
for writing the system was to take full advantage of the addressing
modes of the 11/45, and may indeed be the only working system to
use all three addressing modes. The system used K-space for the low-
level kernel, device drivers and task management; S-space (Supervisor)
for the disk file system; and U (user) for application code. Almost
all other systems ignored S-space and put the entire OS in K-space.
This implementation effectively doubled the amount of resident memory
available for the OS.
The system was used for a phototypesetting system for the State of
Wisconsin Legislature, and later was used for a variety of financial
and newspaper typesetting and editing systems.
FUZZBALL University of Delaware, David L Mills.
Used for TCP/IP, NTP, Packet Radio, Hello Routing
protocol research, complete with FAX facility, boots from an
RT11 system, uses DEQNA UNIBUS, PROTEON Unibus ethernet
cards. Some still hiding away.
RT-11-derived operating system
for Nuclear Medicine, supporting VT11 and VSV11 displays,
with image analysis software and ultimately sold by DEC
around 1985/6 to Philips Medical Systems.
Heathkit's hacked version of RT-11, wouldn't run on a "real" PDP-11.
Interactive Application System. Multi-purpose
multiprogramming system. This was a derivative of RSX11-D,
with additional features to make it more of a time-sharing
system. It also was specifically aimed at the 11/70, while
RSX11-D was for the 18-bit machines like the 11/45. There is
some suspicion that the intention was to make RSTS go away,
but RSTS started supporting more languages than just BASIC
and ended up outliving IAS.
A virtual operating system that could run Unix as
a process. Several machines at BTL ran MERTS.