From: "George R. Gonzalez" Newsgroups: alt.folklore.computers Subject: TSS/8 and RTS8 ? Date: Wed, 26 Feb 2003 09:15:51 -0800 Organization: University of Minnesota, Twin Cities Campus Lines: 28 Message-ID: X-Trace: lenny.tc.umn.edu 1046279751 25733 160.94.172.8 (26 Feb 2003 17:15:51 GMT) X-Complaints-To: usenet@lenny.tc.umn.edu X-Priority: 3 X-MSMail-Priority: Normal X-Newsreader: Microsoft Outlook Express 6.00.2800.1106 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2800.1106 Path: chonsp.franklin.ch!pfaff.ethz.ch!news-zh.switch.ch!irazu.switch.ch!syros.belnet.be!news.belnet.be!cyclone.bc.net!snoopy.risq.qc.ca!msc1.onvoy!onvoy.com!lenny.tc.umn.edu!not-for-mail Xref: chonsp.franklin.ch alt.folklore.computers:130392 Way back, DEC came out with the "time share" option for the PDP-8. This was an amazingly RISCy way to virtualize the PDP-8. Basically if you enabled "time sharing" mode, all the dangerous instructions, like HLT, read switch register, and all the I/O instructions, would interrupt to the monitor, which would do the proper steps to make it look like the instruction executed. Since all the memory-bank switching instructions had been shoehowned into the I/O instruction space, this also allowed the monitor to do paging and virtual memory! Just like today, the basic DOS (OS/8) didnt do anything with this feature, but TSS/8 and RTS8 did! Looking thru the RTS8 source code, there was a big section that looked like it may have been bodily copied from TSS/8. I wonder if the cognoscenti in this NG can elaborate on what was the relationship between TSS/8 and RTS8. One might guess that they were pretty close cousins. Regards, George ###### From: John Everett Newsgroups: alt.folklore.computers Subject: Re: TSS/8 and RTS8 ? Message-ID: References: X-Newsreader: Forte Agent 1.9/32.560 MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Lines: 66 Date: Thu, 27 Feb 2003 15:24:58 GMT NNTP-Posting-Host: 209.86.101.145 X-Complaints-To: abuse@earthlink.net X-Trace: newsread1.prod.itd.earthlink.net 1046359498 209.86.101.145 (Thu, 27 Feb 2003 07:24:58 PST) NNTP-Posting-Date: Thu, 27 Feb 2003 07:24:58 PST Organization: EarthLink Inc. -- http://www.EarthLink.net Path: chonsp.franklin.ch!pfaff.ethz.ch!news-zh.switch.ch!news.imp.ch!news.imp.ch!snoopy.risq.qc.ca!newsfeed.news2me.com!newsfeed2.earthlink.net!newsfeed.earthlink.net!stamper.news.pas.earthlink.net!newsread1.prod.itd.earthlink.net.POSTED!not-for-mail Xref: chonsp.franklin.ch alt.folklore.computers:130542 On Wed, 26 Feb 2003 09:15:51 -0800, "George R. Gonzalez" wrote: >Way back, DEC came out with the "time share" option for the PDP-8. >This was an amazingly RISCy way to virtualize the PDP-8. > >Basically if you enabled "time sharing" mode, all the dangerous >instructions, >like HLT, read switch register, and all the I/O instructions, would >interrupt to the monitor, which would do the proper steps to make it look >like the instruction executed. Since all the memory-bank switching >instructions had been shoehowned into the I/O instruction space, this also >allowed the monitor to do paging and virtual memory! > >Just like today, the basic DOS (OS/8) didnt do anything with this feature, >but TSS/8 and RTS8 did! > >Looking thru the RTS8 source code, there was a big section that looked like >it may have been bodily copied from TSS/8. > >I wonder if the cognoscenti in this NG can elaborate on what was the >relationship between TSS/8 and RTS8. One might guess that they were pretty >close cousins. This cognoscente can't elaborate on the relationship between TSS/8 and RTS8, but as co-author of TSS/8 I can shed some light on the origins of that system and its supporting hardware. During the late '60s Gordon Bell had taken a "leave" from DEC and was a professor of computer science at Carnegie-Mellon. He had a Dutch grad student named Adrian Van Der Goor (sp?). Somehow between the two of them they came up with the idea that with some small hardware mods a time-sharing system could be built for the PDP-8. Gordon and Adrian visited Maynard sometime in 1967 or 1968 (I'm guessing) and made a presentation to some execs and also some of us in the (tiny) PDP-8 programming group. Gordon sort of just oversaw the meeting; Adrian made the presentation. The proposal was to create a "time-sharing option" which would create "user mode" and "exec mode" run states. In user mode all I/O operations, HLT, switch register reads, etc. would cause an interrupt. Of course at interrupt the system would switch into exec mode. The proposed time-sharing monitor would reside in page 0, while user images and swappable parts of the monitor would reside in extended memory. It was proposed to give each user a 4k virtual (basic) PDP-8. The design of the monitor (as we then called operating systems) would be based upon a research system originally proposed (and perhaps actually built) for a PDP-4 or PDP-7. I can't now recall where the design came from, but it was described in detail in a computer science text of the period. The Time-Sharing Option was designed by a junior member of PDP-8 engineering who's name I've long since forgotten. Don Witcraft, who had worked on the PDP-10 monitor (later to be called TOPS-10) and I wrote TSS/8 based upon the suggestions made by Gordon and Adrian. BTW, the system was initially to be called TS-8, a name which persisted during most of its development. We changed it to TSS/8 when IBM announced TSS/360. It just seemed so right! One of the catch phrases around DEC at the time, "Man is going to the moon, and time-sharing on the PDP-8." jeverett3earthlinknet http://home.earthlink.net/~jeverett3 ###### Message-ID: <3E5E7F53.1959E4AA@earthlink.net> From: jchausler X-Mailer: Mozilla 4.72 [en] (Win95; I) X-Accept-Language: en MIME-Version: 1.0 Newsgroups: alt.folklore.computers Subject: Re: TSS/8 and RTS8 ? References: Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Lines: 58 Date: Thu, 27 Feb 2003 21:20:14 GMT NNTP-Posting-Host: 158.252.50.99 X-Complaints-To: abuse@earthlink.net X-Trace: newsread2.prod.itd.earthlink.net 1046380814 158.252.50.99 (Thu, 27 Feb 2003 13:20:14 PST) NNTP-Posting-Date: Thu, 27 Feb 2003 13:20:14 PST Organization: EarthLink Inc. -- http://www.EarthLink.net Path: chonsp.franklin.ch!pfaff.ethz.ch!news-zh.switch.ch!irazu.switch.ch!syros.belnet.be!news.belnet.be!uni-erlangen.de!newsfeed.arcor-online.net!news.tele.dk!news.tele.dk!small.news.tele.dk!newsfeed.news2me.com!newsfeed2.earthlink.net!newsfeed.earthlink.net!stamper.news.pas.earthlink.net!newsread2.prod.itd.earthlink.net.POSTED!not-for-mail Xref: chonsp.franklin.ch alt.folklore.computers:130562 John Everett wrote: > During the late '60s Gordon Bell had taken a "leave" from DEC and was > a professor of computer science at Carnegie-Mellon. He had a Dutch > grad student named Adrian Van Der Goor (sp?). Somehow between the two > of them they came up with the idea that with some small hardware mods > a time-sharing system could be built for the PDP-8. Gordon and Adrian > visited Maynard sometime in 1967 or 1968 (I'm guessing) and made a > presentation to some execs and also some of us in the (tiny) PDP-8 > programming group. Gordon sort of just oversaw the meeting; Adrian > made the presentation. When I came to CMU (then CIT) as a freshman in fall 1966, Gordon had a PDP-8 (and a Bendix G-15) in his anti office. The PDP-8 was just a "straight 8" with 4K core and an ASR 33. Some time shortly (that fall) a high speed paper tape reader/punch was added. Not much was being done with this machine (they let freshman play with it after all, that high speed reader was a blessing, reading in Fortran II on the ASR 33 was a pain :-) Rumor was that DECtapes were about to be purchased for it leading me to buy one from the bookstore (there were no other DECtape drives on campus then so I don't know why the bookstore would have been selling them). And then this big fixed head hard disk (very roughly a couple feet across, a single platter) arrived (in spring 67 or maybe fall 67) and all us "players" were banned from using the machine. I don't recall the vendor of the hard drive, it was not DEC. This pissed me off as that DECtape had cost about $15, serious money to an undergrad in the mid 60's. Fortunately, another group in the EE department shortly got a PDP-9 (for half of a hybrid computer, the other half being and EAI 680 or something close to that) and they allowed "players" when they weren't working on it, so my tape got used for the PDP-9 (still have the tape complete with printed directory listing). Anyway, I wonder if this disk drive was the first basis for this project? I didn't hear anything about it until the machine (same one) was moved to the computer center running TSS/8 several years later. Unfortunately, I never got a chance to try using it. I don't think the big hard drive was around anymore by that time either but I'm not sure. Chris AN GETTO$;DUMP;RUN,ALGOL,TAPE $$