On 2013-01-06 22:06, 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 15:54 To: hecnet at Update.UU.SE Cc: John Wilson Subject: Re: [HECnet] DU11 vs. DUV11 On 2013-01-06 21:47, John Wilson wrote: I still can't find where it says "8085A" in the 110/130 manual, but page B-3 gives I/O page timings and mentions an "I/O microprocessor" and the fact that word I/O takes 90 usec but byte I/O takes 180 usec. So that certainly explains the difference in the DUV driver. Plus the manual specifically says that RSX11S is available for the /110, so I guess it was even supported! Sweet. Also mentioned on page 4-6, but pretty much with the same level of detail. Byte writes cause a read-modify-write. Time of 180 usec. And there is an (unmentioned) 8-bit microprocessor acting in between the PDP-11 and any peripherials. 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 I just found my VT103 LSI-11 Video Terminal User's Guide. The beast looks like a VT100 but has dual, count them dual, TU58's in the front and a 4x4 18-bit backplane in the back. Typical configuration (slot-wise) is: 1 - LSI-11 Processor 2 - MSV11-DD memory 3 - DJV11-J (4-channel serial line interface) Or 1 - LSI-11 Processor 2 - MVX11-A memory and serial in/out The bus slots are numbered from 0-7. I will look for my PDT documentation a little later. I am cleaning up that part of the basement now anyway. I actually have a couple of VT103, but I've never laid my hands on any PDT-11, which is why I (obviously) don't know enough about them. 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