From mboxrd@z Thu Jan 1 00:00:00 1970 From: ggs@shiresoft.com (Guy Sotomayor) Date: Thu, 27 Nov 2003 22:16:13 -0800 Subject: [pups] Any SMP PDP11 platforms? In-Reply-To: References: Message-ID: <1070000173.3354.31.camel@nazgul.shiresoft.com> On Thu, 2003-11-27 at 19:09, Johnny Billquist wrote: > On Fri, 28 Nov 2003, Warren Toomey wrote: > > > Hi all, > > I stumbled across this reference to a 1975 Masters thesis: > > > > de Brito Meyer. W., and Hawley, J.A.. III. Munix. a multiprocessor version > > of UNIX. Master's thesis, Naval Postgraduate School, Monterey, Calif.. 1975. > > Description of dual processor Unix. > > > > Can anybody tell me what PDP11 platforms around 1975 had multi-CPU > > capability? Also, if anybody has further information about Munix, > > please let me know! > > > > Thanks in advance for any help. I've trawled thru the Unix Archive > > with no results. > > I remember that CMU built a MP system out of 11/40 systems... > Search for C.mmp (if my memory is correct). C.MMP was 12 11/40's and 4 11/20's. Each processor had 4KW of local memory + the 4KW I/O page. The rest of the memory (1.2MW) was accessible through a "cross-point" switch (ie it wasn't a common memory bus...think of it as 16 port memory -- there was no memory contention unless 2 processors wanted to access the same page (4KW) of memory). In addition to the cross-point switch there was special IPC (Inter-Processor Communication) hardware to allow the processors to interrupt and communicate with each other. The O/S that was run was Hydra a very radical capability based system (ie everything was represented as a capability -- files, programs, I/O, etc). If you didn't have a capability for something you didn't even know it existed. It was very cool! Somewhere I still have my "Hydra Songbook" which contains a bunch of details + kernel calls about Hydra. There was a predecessor (prototype) that supported either 2 or 4 11/40s. I remember seeing it in the same machine room as C. but don't remember what it being used for at the time as it was "discarded" from the C. project. > > I think they built some special hardware for this. And since these > machines don't have a cache, it makes life easier... > -- TTFN - Guy