Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!zaphod.mps.ohio-state.edu!samsung!uunet!ogicse!cvedc!mcspdx!adpplz!martin From: martin@adpplz.UUCP (Martin Golding) Newsgroups: comp.sys.dec Subject: Re: Digital PDT-11 ... what is it? Message-ID: <834@adpplz.UUCP> Date: 25 Jun 91 00:26:47 GMT References: <10923@plains.NoDak.edu> Distribution: usa Organization: ADP Dealer Services R&D, Portland, OR Lines: 78 In <10923@plains.NoDak.edu> blee@plains.NoDak.edu (Blaine Lee) writes: >First of all, thanks to everyone who helped out before on the sharing of >binarys on DEC's. >I was hoping someone has heard of a little box digital made about eight >years ago, the PDT-11. About 10, I think. The computer people found out what the terminal people were building, and made them stop. They offered us real PDP 11's as replacements at _4 times_ the cost, which is how we got started building computers. In 1981 I started working on the software for the second generation replacement for the PDT. Of course, being the thrifty types we are, we were reconditioning and reselling them up to a couple years ago. They got to be _so old_ that one prom (for unique serial number) was only available from military suppliers at $50 a pop. >I received one from a GM dealer that used it for comunications with GM's >main computers. >I believe I found one or two 8085's in it. Yep, more or less. See below. >Is this a common machine, or a special item made for GM? Nope. See more boring discussion below. >Does anyone have software for it? Your first problem will be finding anybody who can supply useful software on 8 inch floppies. Or, some nice person with dial up access and Kermit or the equivalent. >I do have the software that came with it, but all that is >just some very special stuff for GM. Not, exactly. The box you have was almost certainly distributed and software provided by ADP Dealer Services; we used to have tens of thousands of the damn things lying around. It sold with the RT11 OS, a special multi-user addon, and communications code to call various manufacturers (not just GM) using various obsolete communications equipment (202s), for ordering and inquiry. (Hey, it replaced a dual cassette Astronautics 301e, which replaced a tty ksr with paper tape reader/puch, ok? At the time, it was a good idea.) The PDT-11 (stands for Programmable Data Terminal) was a cute box with two 8 inch floppies, an LSI-11 (which isn't really a PDP-11) and a Q bus that isn't there: The LSI-11 was _really_ an 8 bit microcodable processor (rumors of P-code interpreters abound) coded to run the PDP 11 instruction set. The 8085 (if you say so, I haven't seen one lately) pretends to be portions of the bus, at least the DLV11 (terminal) interfaces. I'm not sure if it runs a theoretical disk controller as well. (The 11 starts a memory cycle, the 80xx gets an interrupt, figures out what the question is, does that, and completes the cycle. Up to a few _hundred_ microseconds for a read or write, but the software is compatible.) The PDT-11 runs the RT11 operating system, and any RT11 programs that are functional in the disk and memory you've got, which isn't much. (Some models were 32k, others up to _wow_ 56). At least the KED editor ought to be available, you may never have to vi again! If you can figure out how to move it onto your machine, I _may_ be able to email you hex copies of some of the tools. I don't know if they run on non-virtual RT11, though. We've been on TSX for years. More war stories on request- don't ask! Martin Golding | sync, sync, sync, sank ... sunk: Dod #0236 | He who steals my code steals trash. A poor old decrepit Pick programmer. Sympathize at: {mcspdx,pdxgate}!adpplz!martin or martin@adpplz.uucp