Fig R-1: w11a running on a Digilent
board with XC3S1000. The rlink connection is via the RS232
port and a
cable. The DBB1 kludge card contains a test setup for a
Fig R-2: Two of four processors of the 11/74 prototype PHEANX,
which was used up to the 90's for RSX builds. Earlier the
machine was used under the name CASTOR by DEC RSX Engineering
in Maynard. Picture courtesy of Dave Carroll.
Long term goal is to re-create a PDP-11/70MP (aka 11/74) system.
This up to 4 CPU
symmetric multiprocessor system
was developed in the
late '70's by DEC, but was never marketed. See article
The Never 11's
A few prototypes were build, see
for a picture of
PHEANX/CASTOR. Some documentation has survived, like the preliminary DEC
11/70MP system manual
, see also a
Full SMP support was added around 1980 to the RSX-11M-PLUS V2.0
see for example the set and remove affinity system calls in the
(STAF$ on p 5-193 and RMAF$ on p 5-128).
Worth to note in this context is that already in 1972 a 16 node SMP
system based on PDP-11 CPU's was build by
at Carnegie Mellon, the C.mmp
see their paper
for the Fall JCC 1972
- improve documentation, especially Tcl API
- improve verification, e.g. test benches
- resolve known issues
Short term (in work)
- support DDR memory on Arty and Nexys4 DDR
- fifo buffered implementation of character devices
(DL11,LP11, maybe PC11 too).
- DZ11: terminal multiplexer; classical multiuser operation.
- DEUNA: add loopback, chaining ect; support OS beyond 211bsd
- FPP Floating Point Processor:
The FPP will be asynchronous, with a more efficient coupling
than in the original KB11-C CPU plus FP11-C FPP combination.
- new cache system: now write-back, wider cache lines,
suitable to build a 11/70MP multiprocessor system.
In contrast to the original 11/70MP a state-of-the-art
cache coherence will be implemented.
- configurable CPU: make CPU features build-time configurable,
for example to generate stripped down w11a versions optimized as an
embedded console and IO processor in larger systems.
- stand-alone system: a system with an additional w11a CPU
acting as CIOP (console and IO processor) which can be operated
without a backend server.
- CPU throttling: some old code, especially tests with timing loops,
has problems on a fast machine....
Nice ideas, maybe they are realized, maybe not
- TOY clock: the time-of-year clock was never part of a 11/70
system, but it is very convenient to have.
- DMC11: the old way to interconnect nodes via point-to-point
connections. Can be used with 211bsd to transport ethernet frames.
- CR11: Card reader; pure nostalgia.
- DU11: Synchronous line interface. Use with
terminal emulation to link to a IBM
emulated by Hercules;
the purest nostalgia
Ports to new boards will be done when interesting products show up. Tempting
Release plan for w11a
|| Target Date
||Main release goals
||I/O complete (DEUNA, DZ11, buffered DL11,LP11)
||CPU complete (FPP, write-back cache,...)