[HECnet] DU11 vs. DUV11

On 2013-01-06 21:04, Steve Davidson wrote: -----Original Message----- From: owner-hecnet at Update.UU.SE [mailto:owner-hecnet at Update.UU.SE] On Behalf Of Johnny Billquist Sent: Sunday, January 06, 2013 14:57 To: hecnet at Update.UU.SE Cc: Steve Davidson Subject: Re: [HECnet] DU11 vs. DUV11 On 2013-01-06 20:35, Steve Davidson wrote: -----Original Message----- From: owner-hecnet at Update.UU.SE [mailto:owner-hecnet at Update.UU.SE] On Behalf Of John Wilson Sent: Sunday, January 06, 2013 14:29 To: hecnet at Update.UU.SE Subject: Re: [HECnet] DU11 vs. DUV11 From: "Lee Gleason" <lee.gleason at comcast.net> I'm even more curious what a PDT-11 optimization is doing in an RSX driver...was there at one time an RSX product product planned for the PDT family? I've never met a PDT-11/110 in person. The docs say they were downline-load-only -- so what DID they run? MRRT11? RSX11S would certainly make sense. Also, DEC dumped a lot of the PDTs to their own employees, so maybe someone made a few tweaks to the RSX code for their own evil purposes at home. John Wilson D Bit The main target for the PDT-11 was RT-11. It was slow. The floppies spent a great deal of time seeking. They were the size of a small microwave oven. In software services we would use it to test patches to RT-11 and some of the layered products. I had one for a time that I used at home over a 300 baud connection. Tough to say whether the dial-up or the floppies were slower... :-) You must be talking of the PDT-11/150 then. The /110 and /130 sat inside a VT100 shell. Extremely similar to a VT103 (I actually never figured out what the difference between a VT103 and a PDT-11/130 is.) If I remember right, the /110 and /130 were TU58 based and the backplane was a 4x4 18-bit configuration. I think only the 11/130 had the TU58. The /110, as John mentioned, supported only downline loading of the system from somewhere else. I know I've seen the manuals... Hmm, hang on... Ah! Found it. The PDT-11/150 documents sits under pdp-11 on bitsavers. The PDT-11/110 and /130 sits under terminals on bitsavers. That's why I didn't find it at first... Anyway, yes, only the /130 have the TU58. They both can boot using MOP over serial line. It's all in the manuals. The difference (I suspect) to the VT103 would probably be the network booting capabilities. In the RT-11 group I seem to remember one (or more) of those 4x4 18-bit backplanes swapped out for the 22-bit variant. At least one of those machines used a DSD for a "real" system disk! :-) It either emulated an RL01 or RL02, and an 8-inch floppy. At that point the TU58's became data "storage" devices. The PDP-11/23+ that I had in my office used the DSD for RT-11 and RC25's for RSX-11M. Wow does that bring back memories... :-) :-) I've also read about people modifying the backplane for 22-bus Qbus, and then you could throw in an 11/93 CPU, a SCSI controller, and then you'd have a system that really rocks. However, the power supply is apparently a bit marginal. Johnny -- Johnny Billquist || "I'm on a bus || on a psychedelic trip email: bqt at softjar.se || Reading murder books pdp is alive! || tryin' to stay hip" - B. Idol