From mboxrd@z Thu Jan 1 00:00:00 1970 From: bqt@update.uu.se (Johnny Billquist) Date: Wed, 26 Feb 2003 14:04:39 +0100 (CET) Subject: [pups] (no subject) In-Reply-To: <001c01c2dd92$2c23e9b0$77b95b8b@ics.forth.gr> Message-ID: On Wed, 26 Feb 2003, Christos Papachristou wrote: > A few questions from a newbie: > I have installed 2.9BSD on a microPDP11/73 with an RD52, using the MSCP > version of Jonathan Engdahl. After startup the kernel > indicates 160kb of memory .I am not familiar with such an old unix to > find out the details but I understand it as 256k minus the kernel. The memory > is M8067-LF i.e. 512k Qbus. Does this mean that the system can't see the > rest of it and that I have configure/recompile the kernel? > The system seems anyway to run fine. Are you sure it's reporting bytes, and not words? > I haven't seen an operational PDP with UNIX before this, > so I can't judge its speed. When in single user mode it seems to > me that it runs "fast". However upon entering multi user mode the speed > drops dramaticaly. I have not yet compiled in the 8 port multiplexer > (DHV11-A), so only the console is functional and thus no gettys are > loaded. So ,why is there such a change in speed? Does the multiuser mode > just rise the nice value of the console tasks? There shouldn't be a big difference in speed. Are you starting some heavy demons? > Some information on the system. It is a KDJ11-B (M8190 -no suffix) i.e. an > 11/84. So, the label on the system says microPDP11/73 (in an BA23 enclosure) > the cpu is an 11/84 (if the FPU socket is the DIP-40 slot then it is > unused), and the 2.11BSD second stage boot (version from vtserver) I > have tried indicates 11/83. The memory is after the CPU and is Qbus (M867-LF). > If I have understood what I have read in the list, this must be a mixed > system that could use PMI memory, but just uses Qbus?? What exactly is my > system? There exists a specific 11/73 CPU card, but we'll ignore that for now. The 11/73, 11/83 and 11/84 all use the same CPU card. The differences are in other areas, and cannot always easily be detected by software. The difference between an 11/73 and 11/83 is if the system have Qbus memory or PMI memory. The difference between an 11/83 and 11/84 is if the system have the KT84 (or whatever the card is called, my memory fails me at the moment) Unibus map, which is a Q-bus to Unibus converter along with the Unibus map required. The CPU is always on a Qbus, but in the 11/84, nothing but CPU and PMI memory is on this bus. > Moreover the MSCP controller (M8639 YP i.e. RQDX1) > the serial port multiplexer(M3104 i.e. DHV11-A) and the memory are Qbus while > the cpu board is indicated as Unibus in the field guide. Can these two bus type > s be mixed? (If yes , i would be tempted to abuse the dead VAX11/780 in the > basement. Can this be done?). No. As stated above, the CPU card is actually always Qbus. In the 11/84 you have a bus adapter to connect the Unibus. > Anyway, I thought that the best choice of > a UNIX for it since it only has an RD52 woulbe 2.9 BSD with MSCP support. > Was this a good guess? Yes, since you probably don't want to pay a lot of money to Mentec for one of their OSes. 2.11 is much nicer, but you'll want more memory and disk space for that. Johnny Johnny Billquist || "I'm on a bus || on a psychedelic trip email: bqt at update.uu.se || Reading murder books pdp is alive! || tryin' to stay hip" - B. Idol