On Saturday 03 January 2009, Kent A. Reed wrote: >Gentle persons: > >I love these stories! > >I'm sorry, Gene, that you had such a bad experience. I can only protest >that a PDP11/23 wasn't a *real* PDP11. It came out nearly a decade after >the 11/20, had an LSI-based CPU instead of a boatload of M-series logic, >used the Q-bus instead of the Unibus, and (the most telling point for >me) didn't have a *real* front panel. All this is just rationalization, >of course. The truth is, you had to deal with a lemon at a time when DEC >was already beginning to reel from competition and market conditions. > >I (technically my advisor, since it was his grant money, but it was my >lab partner and I who made the case and wrote the requisition) took >possession of the third PDP11 sold out of DEC's Chicago office. As >affordable as it was, it was so expensive compared to our research >budget that we had to buy the CPU, ASR33 teletype, and power supply out >of one grant, the 4(yes, 4!)-Kiloword core memory module out of another, >and the high-speed paper tape reader/punch and relay rack out of a >third. The system pictured on the home page http://hampage.hu/pdp-11/ >might as well have have been my system. > And is about 15x the size of that 11/23, which wasn't much bigger than an old AT style desktop.
>The model line was so new that my escutcheon plate said "PDP11" and not >"PDP11/20" as it did on later machines. It was so early in the >production cycle that I got documentation in the form of a set of >E-sized drawings red-lined with the ECOs installed during manufacturing >and a bunch of prepublication drafts of manuals. Of course, all those >last-minute ECOs meant my backplane was chock full of colorful >wire-wrapped patches. With the exception of inevitable core-memory >issues (what minicomputer maker didn't have to run core-memory tests all >the time?), the only real problems I ever had over the years were >inevitably the result of forgetting to observe proper Unibus etiquette >or screwing up my wire wrapping. > >When I complained about the lack of software documentation, the DEC >Field Service Engineer surreptitiously passed me a number of source-code >distributions which I cheerfully pored through at night while my >experiments were running. It didn't take me long to discover that some >of the early software was actually PDP8 software mangled so a PDP11 >could interpret it, albeit slowly (not nothing did the PDP11 instruction >set include the EMT, or emulate trap, instruction). I was the best of >friends with the Chicago office after I showed them my version of >BASIC-11 running 4 times faster than theirs because I had replaced the >emulated instructions with native code. I didn't do it for them. Real >men wrote only in assembler or directly in machine code. I had to make >BASIC work well because my advisor was hopeless with anything else and >he had some experiments of his own to run. Chuckle, and I was one of those "Real Men" who wrote the stuff that ran unmolested for years, in assembly, without in the first case, an assembler, I simply looked up the nemonic in the book and punched it into a hex monitor. I wrote one for an RCA 1802 based machine that way, and it was still in daily use at that tv station a decade after I had gone on down the road. I did use Basic09 on a color computer 2, at WDTV to write an EDISK for a Grass Valley 300-3-A/B production video switcher, replacing a package Grass wanted $20k for with one that was 4x faster and used english filenames. That ran for 14 years, only discontinued because we couldn't get the custom stuff to keep the grass running any longer. And about 15 years ago I wrote a file verification plus swiss army knife for the color computer that is still being distributed by Cloud-9. In assembly. But thats all for a much simpler platform than a linux box, so I haven't done anything too earthshaking for linux other than updateing a C syntax checker I had cobbled up 20 years ago on the coco. I found one kernel bug with it, but someone else had submitted a patch a few hours before me that fixed that. Shrug. These kids are maybe not as thorough, but a lot faster than this old fart nowadays. >In defense of my taking up bandwidth on the EMC mailing list, the reason >we bought this PDP11 was to control and monitor a very large and >complicated experimental apparatus. Like a fly-by-wire aircraft, this >system would have crashed and burned if it weren't for computer-based >real*-time command, control, data acquisition, and processing. > >*I say "real" time, but keep in mind this was the early 1970s. I wrote >my software and meticulously counted cycles before RSX11M or its >country-cousin RT11 were available. Later, I got to spend some time >debugging an RSX11M program as a favor to a medical researcher at the >same university. Yikes. Drags up dusty memories I'd bet. I have a few too. :) >Regards, >Kent > > >---------------------------------------------------------------------------- >-- _______________________________________________ >Emc-users mailing list >[email protected] >https://lists.sourceforge.net/lists/listinfo/emc-users -- Cheers, Gene "There are four boxes to be used in defense of liberty: soap, ballot, jury, and ammo. Please use in that order." -Ed Howdershelt (Author) Dime is money. ------------------------------------------------------------------------------ _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
