Actually a PDP-11/84 uses a Q-Bus CPU in an adapter of some sort, same with the memory. My concerns with what I see listed above are if the memory will work with the CPU (did it come out of the same system?), I don't have time to check the part number. The other concern is, since you're wanting to run 2.11BSD, is the disk controller supported? Zane

On Wed, 10 Dec 2003, John Allain wrote: An 11/84 is an 11/83 CPU board with Qniverter extender for Unibus, so he can just use the /83 board in his box to make a nice 11/83 system. Right? Nope, that uses the memory interconnect stuff. For the /83, you can use either standard (slowish) Qbus memory boards, or the faster PMI-based boards.. not impossible to get, but not easy either. Fred -- Fred N. van Kempen, DEC (Digital Equipment Corporation) Collector/Archivist Visit the VAXlab Project at http://www.pdp11.nl/VAXlab/ Visit the Archives at http://www.pdp11.nl/ Email: waltje(a)pdp11.nl BUSSUM, THE NETHERLANDS / Sunnyvale, CA, USA

Possible Classiccmp parity error detected. Inconsistent information. In another source KDJ11-A_UsersManual.pdf. page.73/2-18, the M8192 is the J11, which is the 11/73 CPU. I tend to trust the Field Guide, and the list too, for that matter. But trust then verify. John A.

Patrick Finnegan wrote: the 11/73 is a double, the 11/83 is a quad size board, 11/83 has also PMI, and was at the beginning a 15 MHz. OH, and the 11/83 has a very nice verbose Boot-PROM ;-)

Information that wasn't lost on me. I would like to know more about that qinverter, in time. Wasn't there an 11/93~4 too... Was this a J11 with more clock speed again? John A.

All the talk about Qbus PDP11's is getting me a little anxious. I have a bunch of *almost11* parts, but no machine. Does anyone want to sell/trade either: 11/53 PROM images 261E5.hex and 262E5.hex -or- a M7506/M7458/M7558/? MSV11 memory board I've got chassis,CPU,O/S,controllers,drives,a drive formatter, comm boards,terminals (whew) but just need one of the above. John A. probably should wait till next month.

On Friday 12 December 2003 16:12, Eric Smith wrote: Looks like I got my information wrong or something... Anyhow, so can the M8190 act as either an 11/83 (QBUS) or 11/84 (UNIBUS-ish) cpu? If so, the FIELD GUIDE should probably still be updated to indicate this, IMHO. Pat -- Purdue University ITAP/RCS Information Technology at Purdue Research Computing and Storage http://www.itap.purdue.edu/rcs/

Yes... J11-based, but an entirely different board. It has either 2Mb or 4Mb on-board. And yes, the same board was the heart of the 11/93 and the 11/94. Although I have not put one together (yet), I think it is essentially the same box as the 11/84 (qbus for the CPU, q-u converter and unibus devices. Megan Gentry Former RT-11 Developer +--------------------------------+-------------------------------------+ | Megan Gentry, EMT/B, PP-ASEL | email: mbg at world.std.com | | Member of Technical Staff | megan at savaje.com | | SavaJe Technologies, Inc. | (s/ at /@/) | | 100 Apollo Drive | URL: http://world.std.com/~mbg/ | | Chelmsford, MA 01824 | "pdp-11 programmer - some assembler | | (978) 256 6521 (DEC '77-'98) | required." - mbg KB1FCA | +--------------------------------+-------------------------------------+

Jerome Fine replies: I just tested some real DEC PDP-11 Qbus systems. RT-11 reports (using RESORC.SAV) when the following are used: M8192-YB dual 15 MHz (KDJ11-AB) as: PDP 11/73A Processor always - PMI memory is not recognized M8190-AB quad 15 MHz (KDJ11-BB) as: PDP 11/73B Processor when used with normal memory or PMI memory below the CPU M8190-AE quad 18 MHZ (KDJ11-BF) as: PDP 11/73B Processor when used with normal memory or PMI memory below the CPU M8190-AB quad 15 MHz (KDJ11-BB) as: PDP 11/83 Processor when used with PMI memory above the CPU M8190-AE quad 18 MHz (KDJ11-BF) as: PDP 11/83 Processor when used with PMI memory above the CPU I have, at times in the past, had a PDP-11/93 board, but found it was too expensive to justify keeping one of my own since it was not much faster (only about 10% based on my own specific tests) than a PDP-11/83 system. I seem to remember that V5.06 of RT-11 was finally able to recognize the PDP-11/93 processor as opposed to V5.05 of RT-11 which was released in October 1989. As for the real advantage of the PDP-11/93, with all 4 MBytes of memory on board and 8 serial ports, it effectively replaced 4 quad slots with just ONE quad slot. What Megan Gentry has stated is correct, although I note that the letter "A" is present when the dual M8192-A boards are used. Also, I am not absolutely sure about "M8190-AE" for the KDJ11-BF CPU since the system is buried under a table and many cables and I could not get close enough. As for mention of a PDP-11/74 within this thread, no such system was ever built that was a parallel to the PDP-11/83 vs the PDP-11/84, i.e. using an M8190-AB (KDJ11-BB) in a backplane with a special Qbus AND a Unibus. In actual fact, there were a number of PDP-11/74 systems built which consisted of at least 2 PDP-11/70 systems running in "conjunction" with each other and sharing resources, probably memory. I believe there was even at least one additional instruction added or at least an enhancement of an existing instruction to allow "co-ordination" between the different PDP-11/70 CPUs within the PDP-11/74 configuration. It is said that none ever left DEC, but there have been rumours that one was sent to Ontario Hydro - I have never been able to confirm that rumour. John Wilson has speculated on the possibility of using a Pentium 4 with hyperthreading to emulate a PDP-11/74 under Ersatz-11 (see below). Six other points should be noted: (a) There are at least 4 and maybe a few more revisions to the actual J11 CPU chip. I have seen 04, 05, 08 and 09 if my memory serves me correctly. I am fairly confident that the KDJ11-BF boards currently "REQUIRE" at least the 08 rev and probably the 09 rev of the J11 chip to run at 18 MHz along with a 05 rev for the FPU chip on the KDJ11-BF. These rev numbers may be incorrect, but that is my best guess. Unless there is some incentive to actually pull the KDJ11-BF out to check those numbers (at great effort), that is my best recollection. No one else seems to have mentioned the large numbers of J11 rev levels and perhaps only a very few are aware of this fact? My most basic question is about the speed that the different rev levels of the J11 chip were able to be run? (b) The different rev levels for the J11 CPU chip were needed due to reasons which only DEC might wish to reveal, but some reliable stories are spoken of a bug with the floating point instructions using early rev levels with the KDJ11-BF and the 18 MHz clock speed. In addition, since the PDP-11/93 CPU boards were run at 20 MHz, these PDP-11/93 boards probably required a specific rev level as well? (c) I have also heard rumours that DEC (or a contract company) developed a much faster CPU, but it was never brought to market - possibly due to perceived competition against the MicroVAX II systems. A company by the name of Harris was mentioned in the mid 1980s. (d) A number of other companies developed MUCH faster CPU chips including QED (Quickware Engineering Design), Mentec and Strobe Data. The last company originally used the J11 within a PC and later developed their own. (e) It is possible to run PDP-11 code even faster. While the SIMH emulator which is written in C can run PDP-11 code much faster than a real PDP-11 and Charon-11 is likely also reasonable (although reports I hear are that it is not only very expensive, it also has a number of problems), Ersatz-11 is most likely the least expensive commercial version (as well as there being a free non-commercial hobby version) which can run at about 60 times faster than a real DEC PDP-11/93 on a 3.0 GHz Pentium 4 CPU under Windows 98 SE. In this respect for Ersatz-11, I have personally seen CPU speeds of about 15 times a real DEC PDP-11/93 on a 750 MHz Pentium III for the CPU and 50 times disk I/O when using ATA 100 EIDE hard disk drives as compared to RD53 disk drives. Obviously the disk I/O ratio is not as high when compared to much faster SCSI and ESDI drives. But using the newer SATA 150 drives would be able to improve that disk I/O ratio without any change to any of the emulators. See (b) above. Can Megan Gentry provide any information about a floating point bug for the KDJ11-BF? Also any information about the different rev levels of the J11 CPU chip? Or does anyone else know of the reasons for the different rev levels of the J11 chip, let alone what specific changes were made? With reference to your luck about putting the parts of a PDP-11/84 together with the correct memory, perhaps you had some help or maybe the memory was already inside the backplane. After all, it could not have been used anywhere else, so it might well have been just left in the backplane and been there when you "grabbed parts". Also, can you provide any insight as to why DEC stopped development on PDP-11 CPUs when other companies provided faster CPU chips much later than when DEC stopped? If there are any other questions, please ask! Sincerely yours, Jerome Fine -- If you attempted to send a reply and the original e-mail address has been discontinued due a high volume of junk e-mail, then the semi-permanent e-mail address can be obtained by replacing the four characters preceding the 'at' with the four digits of the current year.

I don't know what the performance figures were for the 11/74 either. However, the beast was deemed to be too hard to maintain. Too many cables, too much downtime. Having said that, the one that did reach a customer was supposed to have been so well received that they didn't want to give it back (or maybe refused to). Antonio -- --------------- Antonio Carlini arcarlini(a)iee.org

On Sun, 14 Dec 2003, Eric Smith wrote: That wouldn't have anything to do with it performing /too/ well, would it? -brian.