Newsgroups: alt.folklore.computers From: eric@fudge.uchicago.edu (Eric Fischer) Subject: Spacewar in Decuscope X-Nntp-Posting-Host: fudge.uchicago.edu Message-ID: Sender: news@midway.uchicago.edu (News Administrator) X-Newsposter: Pnews 4.0-test51 (15 Jan 97) Organization: The University of Chicago Date: Fri, 18 Dec 1998 15:44:09 GMT Lines: 41 Path: chonsp.franklin.ch!pfaff.ethz.ch!news-zh.switch.ch!news-ge.switch.ch!news.maxwell.syr.edu!newsfeed1.earthlink.net!uwm.edu!uwvax!uchinews!not-for-mail PDP-1 PLAYS AT SPACEWAR by D. J. Edwards, MIT J. M. Graetz, MIT [Decuscope, vol. 1, no. 1, April, 1962, pp. 2-4] If, when walking down the halls of MIT, you should happen to hear strange cries of "No! No! Turn! Fire! ARRRGGGHHH!!," do not be alarmed. Another western is not being filmed -- MIT students and others are merely participating in a new sport, SPACEWAR! Planned and programmed by Stephen R. Russell under the auspices of the Hingham Institute Study Group on Space Warfare, SPACEWAR is an exciting game for two players, many kibitzers, and a PDP-1. The game starts with each player in control of a spaceship (displayed on PDP's scope face) equipped with propulsion rockets, rotation gyros, and space torpedoes. The use of switches to control apparent motion of displayed objects amply demonstrates the real-time capabilities of the PDP-1. Also displayed on the scope is a central sun which exerts a gravitational influence on the spaceships. The entire battle is conducted against a slowly moving background of stars of the equatorial sky. The object of the game is to destroy the opponent's ship with torpedoes. The computer follows the targets and participants have an opportunity to develop tactics which would be employed in any future warfare in space. Your editor visited the MIT Computer in Room 26265 and can verify an excellent performance. She learned that the best "Aces" had only a 50% chance of survival. Enthusiasm nevertheless ran high and the battle continued while young Mr. Russell tried to explain his program. "The most important feature of the program," he said, "is that one can simulate a reasonably complicated physical system and actually see what is going on." Mr. Russell also said that symbolic and binary tapes were available. Please contact Mr. Russell for additional information. ###### From: jlp2@tiac.net (John L. Pearlman) Newsgroups: alt.folklore.computers Subject: Re: Spacewar in Decuscope Date: 18 Dec 1998 17:25:41 GMT Organization: The Internet Access Company, Inc. Lines: 28 Message-ID: <75e36l$iq3@news-central.tiac.net> References: NNTP-Posting-Host: sunspot.tiac.net X-Newsreader: TIN [UNIX 1.3 950726BETA PL0] Path: chonsp.franklin.ch!pfaff.ethz.ch!news-zh.switch.ch!newsfeed-zh.ip-plus.net!news-nyc.telia.net!news.idt.net!newspeer.monmouth.com!news-feed1.tiac.net!posterchild2!not-for-mail Eric Fischer (eric@fudge.uchicago.edu) wrote: : PDP-1 PLAYS AT SPACEWAR : : by D. J. Edwards, MIT : J. M. Graetz, MIT : : [Decuscope, vol. 1, no. 1, April, 1962, pp. 2-4] : : If, when walking down the halls of MIT, you should happen to hear : strange cries of "No! No! Turn! Fire! ARRRGGGHHH!!," do not : be alarmed. Another western is not being filmed -- MIT students : and others are merely participating in a new sport, SPACEWAR! : : Planned and programmed by Stephen R. Russell under the auspices : of the Hingham Institute Study Group on Space Warfare, SPACEWAR : is an exciting game for two players, many kibitzers, and a PDP-1. (snip) Does anyone know how I could contact Steve Russel? If he's who I think he is, I knew him in the early/mid 50's in the Boston area. -- John L. Pearlman -- or If one man calls you a donkey, pay him no heed. If two men call you a donkey, get yourself a saddle. (ancient Rabbinic saying) ###### From: bernie@fantasyfarm.com (Bernie Cosell) Newsgroups: alt.folklore.computers Subject: Re: Spacewar in Decuscope Date: Sat, 19 Dec 1998 15:18:30 GMT Organization: Fantasy Farm Fibers Lines: 40 Message-ID: <367bc06c.577437@news.infoave.net> References: NNTP-Posting-Host: pem05-23.swva.net Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit X-Trace: news3.infoave.net 914080460 16575 208.140.224.87 (19 Dec 1998 15:14:20 GMT) X-Complaints-To: usenet@news3.infoave.net NNTP-Posting-Date: 19 Dec 1998 15:14:20 GMT X-Newsreader: Forte Agent 1.5/32.452 Path: chonsp.franklin.ch!pfaff.ethz.ch!news-zh.switch.ch!newsfeed-zh.ip-plus.net!news-nyc.telia.net!newshub.northeast.verio.net!news-pen-3.sprintlink.net!news-east1.sprintlink.net!news-peer1.sprintlink.net!news-backup-west.sprintlink.net!news.sprintlink.net!news3.infoave.net!news.infoave.net!not-for-mail eric@fudge.uchicago.edu (Eric Fischer) wrote: } PDP-1 PLAYS AT SPACEWAR } Planned and programmed by Stephen R. Russell under the auspices } of the Hingham Institute Study Group on Space Warfare, SPACEWAR } is an exciting game for two players, many kibitzers, and a PDP-1. What is not as well known [except for folk who've seen the source code] is that Space War was an amazing coding job.. it is arguably one of the first "object oriented" programs. Inside spacewar, there is a list of 'objects', each object being a bunch of pointers-to-subroutines together with some data. The inner loop involved cycling through each object and calling its 'move' subroutine, then calling its 'display' subroutine. If an object exploded, its 'object' was just replaced by the "explosion object". When you came back from hyperspace, it just created a new object, added it to the list, and continued... It would be a jewel of good programming -today-, but for its being done 35 yrs ago it is an absolutely astoundingly clean and clever bit of code. For example, the inner loop to display things looks like: mq4, lac i ml1 / routine for calculating spaceship dap . 1 / or other object and displaying it jsp . mb1, lac . / alter count of number of instructions add _mtc dac _mtc mq1, idx mx1 / end of comparison and display loop The 'mb1' stuff is to tune the size of the loop so taht the speed of the program is constant [basically it finesses out whether it was hard or easy to display a particular shape]. /Bernie\ -- Bernie Cosell Fantasy Farm Fibers bernie@fantasyfarm.com Pearisburg, VA --> Too many people, too few sheep <-- ###### From: jcmorris@mwunix.mitre.org (Joe Morris) Newsgroups: alt.folklore.computers Subject: Re: Spacewar in Decuscope Date: 19 Dec 1998 23:17:28 GMT Organization: The MITRE Corporation Lines: 33 Message-ID: <75hc68$7jf@top.mitre.org> References: <367bc06c.577437@news.infoave.net> NNTP-Posting-Host: mwunix.mitre.org Path: chonsp.franklin.ch!pfaff.ethz.ch!news-zh.switch.ch!newsfeed-zh.ip-plus.net!news-nyc.telia.net!howland.erols.net!netnews.com!newsswitch.lcs.mit.edu!news-f.std.com.MISMATCH!world!blanket.mitre.org!news.mitre.org!mwunix!jcmorris bernie@fantasyfarm.com (Bernie Cosell) writes: >eric@fudge.uchicago.edu (Eric Fischer) wrote: >} [1962 article about _Spacewar_] >What is not as well known [except for folk who've seen the source code] is >that Space War was an amazing coding job.. it is arguably one of the first >"object oriented" programs. [...] >It would be a jewel of good programming -today-, but for its being done 35 >yrs ago it is an absolutely astoundingly clean and clever bit of code. And all of this was packed inside a program sized to fit a machine that had 4K memory (at 18 bits/word). This included not only the functional code for the game, but also Pete Sampson's background of (correctly laid out) stars -- which would move in the background, with a complete cycle every four hours of real time IIRC. Although the object-oriented-before-the-term-was-invented design was very nice, one thing that the Spacewar developers didn't do was include lots of comments. Some sections (for example, the constants block at the front of the listing, and Pete's star list) are well-peppered with commentary, most of the listings have only a few comments per page and only a couple of subroutines have header comments documenting the calling sequence. And no, I'm not trying to put down the developers since I was guilty of exactly the same offence at the time. I had a couple of lines in the code (which probably didn't survive the next revision) but which 36 years later I'm completely unable to locate in the listings. Joe Morris ###### From: dicks@math.ohio-state.NO.SPAM.edu (Ethan Dicks) Newsgroups: alt.folklore.computers Subject: Re: Spacewar in Decuscope Date: 20 Dec 1998 00:52:01 GMT Organization: Department of Mathematics, The Ohio State University Lines: 18 Message-ID: <75hhnh$sac$1@mathserv.mps.ohio-state.edu> References: <367bc06c.577437@news.infoave.net> <75hc68$7jf@top.mitre.org> NNTP-Posting-Host: math.mps.ohio-state.edu X-Trace: mathserv.mps.ohio-state.edu 914115121 29004 128.146.111.30 (20 Dec 1998 00:52:01 GMT) X-Complaints-To: usenet@math.ohio-state.edu NNTP-Posting-Date: 20 Dec 1998 00:52:01 GMT X-Newsreader: trn 4.0-test68 (29 August 1998) Originator: dicks@math.ohio-state.edu (Ethan Dicks) Path: chonsp.franklin.ch!pfaff.ethz.ch!news-zh.switch.ch!news-ge.switch.ch!news.maxwell.syr.edu!news.cis.ohio-state.edu!math.ohio-state.edu!not-for-mail In article <75hc68$7jf@top.mitre.org>, Joe Morris wrote: >...36 years later I'm completely unable to locate in the listings. There are sources to PDP-1 SPACEWAR available somewhere? It sounds like the perfect project to stick on Bob Supnik's PDP-1 emulator. All we need is some kind of D-A and and an oscilloscope off of, say, two parallel ports... -ethan -- Ethan Dicks http://www.infinet.com/~erd/ (dicks) at (math) . (ohio-state) . (edu) sellto: postmaster@[127.0.0.1] harvestbot fodder: president@whitehouse.gov fccinfo@fcc.gov root@[127.0.0.1] ###### Path: chonsp.franklin.ch!usenet From: Neil Franklin Newsgroups: alt.folklore.computers Subject: Re: Spacewar in Decuscope Date: 20 Dec 1998 20:07:16 +0100 Organization: My own Private Self Lines: 30 Sender: neil@chonsp.franklin.ch Message-ID: References: <367bc06c.577437@news.infoave.net> <75hc68$7jf@top.mitre.org> <75hhnh$sac$1@mathserv.mps.ohio-state.edu> X-Newsreader: Gnus v5.3/Emacs 19.34 dicks@math.ohio-state.NO.SPAM.edu (Ethan Dicks) writes: > > Joe Morris wrote: > >...36 years later I'm completely unable to locate in the listings. > > There are sources to PDP-1 SPACEWAR available somewhere? It sounds > like the perfect project to stick on Bob Supnik's PDP-1 emulator. Where does one find that? URL please. > All we need is some kind of D-A and and an oscilloscope off of, > say, two parallel ports... Why all that hardware? Rather modify the emulator to catch the instructions used to drive the scope and then plot the pixels onto the hosts screen. Of course one would have to store plot time and simulate pixels fading off if not regularly refreshed, else one would be emulating an storage tube. Without emulating the scope the PDP-1 emulator can not really be considered complete, as CRT output was one of the PDP-1s important features. -- Neil Franklin, Nerd, Geek, Unix Guru, Hacker, Mystic neil@franklin.ch.remove http://neil.franklin.ch/ "No, it was a JOKE! You can't RUN this!" Ken Thompson ###### From: cjt&trefoil Newsgroups: alt.folklore.computers Subject: Re: Spacewar in Decuscope Date: Sun, 20 Dec 1998 12:40:10 -0600 Organization: Prodigy Services Corp Lines: 58 Message-ID: <367D448A.2985@prodigy.net> References: <367bc06c.577437@news.infoave.net> Reply-To: cheljuba@prodigy.net NNTP-Posting-Host: dllsb206-02.splitrock.net Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit X-Post-Time: 20 Dec 1998 18:40:52 GMT X-Auth-User: 002709921/e373f7d00a0772f3 X-Problems-To: abuse@prodigy.net X-Mailer: Mozilla 3.04 (Win95; U) To: Bernie Cosell Path: chonsp.franklin.ch!pfaff.ethz.ch!news-zh.switch.ch!newsfeed-zh.ip-plus.net!news-nyc.telia.net!news.idt.net!nyd.news.ans.net!newsjunkie.ans.net!newsfeeds.ans.net!newscon05!prodigy.com!not-for-mail Bernie Cosell wrote: > > eric@fudge.uchicago.edu (Eric Fischer) wrote: > > } PDP-1 PLAYS AT SPACEWAR > > } Planned and programmed by Stephen R. Russell under the auspices > } of the Hingham Institute Study Group on Space Warfare, SPACEWAR > } is an exciting game for two players, many kibitzers, and a PDP-1. > > What is not as well known [except for folk who've seen the source code] is > that Space War was an amazing coding job.. it is arguably one of the first > "object oriented" programs. Inside spacewar, there is a list of 'objects', > each object being a bunch of pointers-to-subroutines together with some > data. The inner loop involved cycling through each object and calling its > 'move' subroutine, then calling its 'display' subroutine. If an object > exploded, its 'object' was just replaced by the "explosion object". When > you came back from hyperspace, it just created a new object, added it to > the list, and continued... > > It would be a jewel of good programming -today-, but for its being done 35 > yrs ago it is an absolutely astoundingly clean and clever bit of code. > > For example, the inner loop to display things looks like: > > mq4, lac i ml1 / routine for calculating spaceship > dap . 1 / or other object and displaying it > jsp . > mb1, lac . / alter count of number of instructions > add _mtc > dac _mtc > mq1, idx mx1 / end of comparison and display loop > > The 'mb1' stuff is to tune the size of the loop so taht the speed of the > program is constant [basically it finesses out whether it was hard or easy > to display a particular shape]. > > /Bernie\ > -- > Bernie Cosell Fantasy Farm Fibers > bernie@fantasyfarm.com Pearisburg, VA > --> Too many people, too few sheep <-- Didn't that have a lot to do with the way the DEC graphics system worked? As I recall, you shipped it a list of "objects" and the hardware did a lot of the heavy lifting. ###### From: bernie@fantasyfarm.com (Bernie Cosell) Newsgroups: alt.folklore.computers Subject: Re: Spacewar in Decuscope Date: Sun, 20 Dec 1998 22:13:04 GMT Organization: Fantasy Farm Fibers Lines: 67 Message-ID: <367f746c.112210165@news.infoave.net> References: <367bc06c.577437@news.infoave.net> <75hc68$7jf@top.mitre.org> NNTP-Posting-Host: pem05-45.swva.net Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit X-Trace: news3.infoave.net 914191728 30219 208.140.224.109 (20 Dec 1998 22:08:48 GMT) X-Complaints-To: usenet@news3.infoave.net NNTP-Posting-Date: 20 Dec 1998 22:08:48 GMT X-Newsreader: Forte Agent 1.5/32.452 Path: chonsp.franklin.ch!pfaff.ethz.ch!news-zh.switch.ch!news-ge.switch.ch!news.maxwell.syr.edu!news-peer1.sprintlink.net!news-backup-west.sprintlink.net!news.sprintlink.net!news3.infoave.net!news.infoave.net!not-for-mail jcmorris@mwunix.mitre.org (Joe Morris) wrote: } bernie@fantasyfarm.com (Bernie Cosell) writes: } } >eric@fudge.uchicago.edu (Eric Fischer) wrote: } } >} [1962 article about _Spacewar_] } } >What is not as well known [except for folk who've seen the source code] is } >that Space War was an amazing coding job.. it is arguably one of the first } >"object oriented" programs. [...] } } >It would be a jewel of good programming -today-, but for its being done 35 } >yrs ago it is an absolutely astoundingly clean and clever bit of code. } } And all of this was packed inside a program sized to fit a machine that } had 4K memory (at 18 bits/word). This included not only the functional } code for the game, but also Pete Sampson's background of (correctly } laid out) stars -- which would move in the background, with a complete } cycle every four hours of real time IIRC. sorry, but it didn't run in 4K. Spacewar, itself, ran in the lower 4K and Sampson's star maps were in the next 4K. } Although the object-oriented-before-the-term-was-invented design was } very nice, one thing that the Spacewar developers didn't do was include } lots of comments. Some sections (for example, the constants block at the } front of the listing, and Pete's star list) are well-peppered with } commentary, most of the listings have only a few comments per page } and only a couple of subroutines have header comments documenting the } calling sequence. Exactly correct, but the program wasn't designed to be read by the hoise polloi, of course..:o) And even the comments that were there weren't all that much help in many cases. For example, the star field is a huge file that begins: ============================ /stars 1 <.> 3/13/62, pres. define mark X,Y repeat 8, Y=Y+Y 8192-X Y terminate 1j, mark 1537, 371 /87 Tur, Aldebaran mark 1762, -189 /19 Orio, Rigel mark 1990, 168 /58 Orio, Betelgeuze mark 2280, -377 /9 CMaj, Sirius mark 2583, 125 /10 CMin, Procyon mark 3431, 283 /32 Leon, Regulus mark 4551, -242 /67 Virg, Spica mark 4842, 448 /167 Boot, Arcturus 1q, mark 6747, 196 /53 Aqil, Altair ============================= Now you can try to guess what you would do if you, say, wanted to add another constellation or a nebula or the like..:o) Where would you put it in the list? What are those args to mark, anyway... RA and dec? what units? etc... Altogether a fun thing to try to sort out... [which I think was part of the initiation rituation at RLE anyway..:o)] /Bernie\ -- Bernie Cosell Fantasy Farm Fibers bernie@fantasyfarm.com Pearisburg, VA --> Too many people, too few sheep <-- ###### From: bernie@fantasyfarm.com (Bernie Cosell) Newsgroups: alt.folklore.computers Subject: Re: Spacewar in Decuscope Date: Sun, 20 Dec 1998 22:14:34 GMT Organization: Fantasy Farm Fibers Lines: 23 Message-ID: <36807677.112733663@news.infoave.net> References: <367bc06c.577437@news.infoave.net> <75hc68$7jf@top.mitre.org> <75hhnh$sac$1@mathserv.mps.ohio-state.edu> NNTP-Posting-Host: pem05-45.swva.net Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit X-Trace: news3.infoave.net 914191814 29728 208.140.224.109 (20 Dec 1998 22:10:14 GMT) X-Complaints-To: usenet@news3.infoave.net NNTP-Posting-Date: 20 Dec 1998 22:10:14 GMT X-Newsreader: Forte Agent 1.5/32.452 Path: chonsp.franklin.ch!pfaff.ethz.ch!news-zh.switch.ch!newsfeed-zh.ip-plus.net!news-nyc.telia.net!newshub.northeast.verio.net!news-pen-3.sprintlink.net!news-in-east1.sprintlink.net!news-peer1.sprintlink.net!news-backup-west.sprintlink.net!news.sprintlink.net!news3.infoave.net!news.infoave.net!not-for-mail dicks@math.ohio-state.NO.SPAM.edu (Ethan Dicks) wrote: } In article <75hc68$7jf@top.mitre.org>, } Joe Morris wrote: } >...36 years later I'm completely unable to locate in the listings. } } There are sources to PDP-1 SPACEWAR available somewhere? It sounds } like the perfect project to stick on Bob Supnik's PDP-1 emulator. I believe that the sources to SPACEWAR have already been reassembled at the MIT Computer Museum and are running there on a real PDP-1... } All we need is some kind of D-A and and an oscilloscope off of, } say, two parallel ports... And it has to have the right phosphors or else the trails won't be right..:o) /Bernie\ -- Bernie Cosell Fantasy Farm Fibers bernie@fantasyfarm.com Pearisburg, VA --> Too many people, too few sheep <-- ###### Newsgroups: alt.folklore.computers From: eric@fudge.uchicago.edu (Eric Fischer) Subject: Re: Spacewar in Decuscope X-Nntp-Posting-Host: fudge.uchicago.edu Message-ID: Sender: news@midway.uchicago.edu (News Administrator) X-Newsposter: Pnews 4.0-test51 (15 Jan 97) Organization: The University of Chicago References: <367bc06c.577437@news.infoave.net> <75hc68$7jf@top.mitre.org> <75hhnh$sac$1@mathserv.mps.ohio-state.edu> Date: Sun, 20 Dec 1998 22:31:30 GMT Lines: 14 Path: chonsp.franklin.ch!pfaff.ethz.ch!news-zh.switch.ch!news-ge.switch.ch!enews.sgi.com!uwvax!uchinews!not-for-mail Ethan Dicks wrote: > There are sources to PDP-1 SPACEWAR available somewhere? It sounds > like the perfect project to stick on Bob Supnik's PDP-1 emulator. Yep, the source is at http://lcs.www.media.mit.edu/groups/el/projects/spacewar/sources/ with a little documentation one level up from there. At the same place is a PDP-1 emulator in Java that's supposed to be able to play the game, though I haven't managed to get it to work myself. eric ###### From: dicks@math.ohio-state.NO.SPAM.edu (Ethan Dicks) Newsgroups: alt.folklore.computers Subject: Re: Spacewar in Decuscope Date: 21 Dec 1998 00:53:18 GMT Organization: Department of Mathematics, The Ohio State University Lines: 36 Message-ID: <75k65u$1a7$1@mathserv.mps.ohio-state.edu> References: <75hc68$7jf@top.mitre.org> <75hhnh$sac$1@mathserv.mps.ohio-state.edu> NNTP-Posting-Host: math.mps.ohio-state.edu X-Trace: mathserv.mps.ohio-state.edu 914201598 1351 128.146.111.30 (21 Dec 1998 00:53:18 GMT) X-Complaints-To: usenet@math.ohio-state.edu NNTP-Posting-Date: 21 Dec 1998 00:53:18 GMT X-Newsreader: trn 4.0-test68 (29 August 1998) Originator: dicks@math.ohio-state.edu (Ethan Dicks) Path: chonsp.franklin.ch!pfaff.ethz.ch!news-zh.switch.ch!news-ge.switch.ch!news.maxwell.syr.edu!news.cis.ohio-state.edu!math.ohio-state.edu!not-for-mail In article , Neil Franklin wrote: >dicks@math.ohio-state.NO.SPAM.edu (Ethan Dicks) writes: >> >> Joe Morris wrote: >> >...36 years later I'm completely unable to locate in the listings. >> >> There are sources to PDP-1 SPACEWAR available somewhere? It sounds >> like the perfect project to stick on Bob Supnik's PDP-1 emulator. > >Where does one find that? URL please. ftp://ftp.digital.com/pub/DEC/sim/sources/sim_2.3d.tar.Z >> All we need is some kind of D-A and and an oscilloscope off of, >> say, two parallel ports... > >Why all that hardware? > >Rather modify the emulator to catch the instructions used to drive >the scope and then plot the pixels onto the hosts screen. Of course >one would have to store plot time and simulate pixels fading off if >not regularly refreshed, else one would be emulating an storage tube. Exactly. Personally, since I _have_ an oscilloscope (a round-tube Tek 314, no less; almost period), I'd rather see real points of light on real hardware. IMHO, it's easier to modify Bob's emulator to drive external D-A's than to muck around in the graphical innards of most OSes, especially ones from Redmond. Plus, it would look *so* cool. -ethan -- Ethan Dicks http://www.infinet.com/~erd/ (dicks) at (math) . (ohio-state) . (edu) sellto: postmaster@[127.0.0.1] harvestbot fodder: president@whitehouse.gov fccinfo@fcc.gov root@[127.0.0.1] ###### From: dpeschel@u.washington.edu (D. Peschel) Newsgroups: alt.folklore.computers Subject: Re: Spacewar in Decuscope Date: 21 Dec 1998 09:07:44 GMT Organization: University of Washington, Seattle Lines: 21 Message-ID: <75l350$ucq$1@nntp1.u.washington.edu> References: <75hc68$7jf@top.mitre.org> <75hhnh$sac$1@mathserv.mps.ohio-state.edu> NNTP-Posting-Host: saul6.u.washington.edu X-Trace: nntp1.u.washington.edu 914231264 31130 (None) 140.142.17.39 X-Complaints-To: help@cac.washington.edu NNTP-Posting-User: dpeschel Path: chonsp.franklin.ch!pfaff.ethz.ch!news-zh.switch.ch!news-ge.switch.ch!news.maxwell.syr.edu!logbridge.uoregon.edu!news.u.washington.edu!dpeschel In article , Eric Fischer wrote: >with a little documentation one level up from there. At the same >place is a PDP-1 emulator in Java that's supposed to be able to >play the game, though I haven't managed to get it to work myself. If it's the one I've seen, it works for me. When I first saw it, there was a strange artifact -- one frame of a shit might not be erased until the next had been drawn, so double images showed up all the time. Did the real machine do that? I hope not. (I understand that the phosphors would leave trails, but that's a different thing entirely.) It's possible there's more than one emulator, or maybe they spiffed up the graphics routines, or maybe Java was slow the previous time. But thin bitmapped white lines in a square raster-scanned window don't really compare with thick smooth white (green? blue?) lines occupying an entire round vector-scanned 'scope. -- Derek ###### Newsgroups: alt.folklore.computers From: eric@fudge.uchicago.edu (Eric Fischer) Subject: Re: Spacewar in Decuscope X-Nntp-Posting-Host: fudge.uchicago.edu Message-ID: Sender: news@midway.uchicago.edu (News Administrator) X-Newsposter: Pnews 4.0-test51 (15 Jan 97) Organization: The University of Chicago References: <75hhnh$sac$1@mathserv.mps.ohio-state.edu> <36807677.112733663@news.infoave.net> <367D8E87.7383FE38@stoneweb.com> Date: Mon, 21 Dec 1998 16:42:11 GMT Lines: 48 Path: chonsp.franklin.ch!pfaff.ethz.ch!news-zh.switch.ch!newsfeed-zh.ip-plus.net!news-nyc.telia.net!howland.erols.net!vixen.cso.uiuc.edu!uchinews!not-for-mail Carl R. Friend wrote: > Was the PDP-1's 'scope a vector-plotter or a point-plotter? Please > forgive the (silly) question, but I've not got the doco to answer the > query. There's a copy of the PDP-1 manual at http://www.dbit.com/~greeng3/pdp1/pdp1.html From what it says there, it sounds like the standard display plotted points but a vector model was also available: | PRECISION CRT DISPLAY (TYPE 30) | | This sixteen-inch cathode ray tube display is intended to be used as | an on-line output device for the PDP-1. It is useful for high speed | presentation of graphs, diagrams, drawings, and alphanumerical | information. The unit is solid state, self-powered and completely | buffered. It has magnetic focus and deflection. | | Display characteristics are as follows: | * Random point plotting | * Accuracy of points +/-3 per cent of raster size | * Raster size 9.25 by 9.25 inches | * 1024 by 1024 addressable locations | * Fixed origin at center of CRT | * Ones complement binary arithmetic | * Plots 20,000 points per second | | Resolution is such that 512 points along each axis are discernable on | the face of the tube. | | One instruction is added to the PDP-1 with the installation of this | display: | | Display One Point On CRT | dpy Address 0007 | | This instruction clears the light pen status bit and displays one | point using bits 0 through 9 of the AC to represent the (signed) X | coordinate of the point and bits 0 through 9 of the IO as the (signed) | Y coordinate. | | Many variations of the Type 30 Display are available. Some of these | include hardware for line and curve generation. eric ###### Newsgroups: alt.folklore.computers From: mbg@world.std.com (Megan) Subject: Re: Spacewar in Decuscope Message-ID: Date: Mon, 21 Dec 1998 17:30:59 GMT References: <367bc06c.577437@news.infoave.net> <75hc68$7jf@top.mitre.org> <75hhnh$sac$1@mathserv.mps.ohio-state.edu> <36807677.112733663@news.infoave.net> <367D8E87.7383FE38@stoneweb.com> Organization: The World Public Access UNIX, Brookline, MA Lines: 26 Path: chonsp.franklin.ch!pfaff.ethz.ch!news-zh.switch.ch!news.belnet.be!newsfeed.wirehub.nl!btnet-peer!btnet!rill.news.pipex.net!pipex!ams.news.uu.net!uunet!in3.uu.net!world!mbg "Carl R. Friend" writes: > I'm given to understand that a version was produced for the PDP-8. >What hardware requirements were there on that version? I'm specifically >interested in the video hardware - i.e. "Will it run on a PDP-12?" There was also a version written by a friend of mine for the GT44. Instead of using the switch panel (actually, after the switch panel began exhibiting problems) we used some special boxes which we built which were attached to a DR11-C. The program could read the state of the switches by checking the bits of the input to the DR11-C. Plus, we could sit back comfortably (the cables were about 10 feet long). Megan Gentry Former RT-11 Developer +--------------------------------+-------------------------------------+ | Megan Gentry, EMT/B, PP-ASEL | Internet (work): gentry!zk3.dec.com | | Unix Support Engineering Group | (home): mbg!world.std.com | | Compaq Computer Corporation | addresses need '@' in place of '!' | | 110 Spitbrook Rd. ZK03-2/T43 | URL: http://world.std.com/~mbg/ | | Nashua, NH 03062 | "pdp-11 programmer - some assembler | | (603) 884 1055 | required." - mbg | +--------------------------------+-------------------------------------+ ###### From: bernie@fantasyfarm.com (Bernie Cosell) Newsgroups: alt.folklore.computers Subject: Re: Spacewar in Decuscope Date: Tue, 22 Dec 1998 02:51:34 GMT Organization: Fantasy Farm Fibers Lines: 14 Message-ID: <3680f388.210301450@news.infoave.net> References: <75hc68$7jf@top.mitre.org> <75hhnh$sac$1@mathserv.mps.ohio-state.edu> <75l350$ucq$1@nntp1.u.washington.edu> NNTP-Posting-Host: pem01-05.swva.net Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit X-Trace: news3.infoave.net 914294837 13865 208.140.224.5 (22 Dec 1998 02:47:17 GMT) X-Complaints-To: usenet@news3.infoave.net NNTP-Posting-Date: 22 Dec 1998 02:47:17 GMT X-Newsreader: Forte Agent 1.5/32.452 Path: chonsp.franklin.ch!pfaff.ethz.ch!news-zh.switch.ch!news-ge.switch.ch!news.maxwell.syr.edu!news-peer1.sprintlink.net!news-in-east1.sprintlink.net!news.sprintlink.net!news3.infoave.net!news.infoave.net!not-for-mail dpeschel@u.washington.edu (D. Peschel) wrote: } But thin bitmapped white lines in a square raster-scanned window don't } really compare with thick smooth white (green? blue?) lines occupying an } entire round vector-scanned 'scope. The standard Type-30 display on the PDP-1 had a phosphor that was pretty much white when it was hit, but then faded to yellow and faded gradually. /Bernie\ -- Bernie Cosell Fantasy Farm Fibers bernie@fantasyfarm.com Pearisburg, VA --> Too many people, too few sheep <-- ###### From: bernie@fantasyfarm.com (Bernie Cosell) Newsgroups: alt.folklore.computers Subject: Re: Spacewar in Decuscope Date: Tue, 22 Dec 1998 02:51:34 GMT Organization: Fantasy Farm Fibers Lines: 29 Message-ID: <3681f41b.210448392@news.infoave.net> References: <367bc06c.577437@news.infoave.net> <367D448A.2985@prodigy.net> NNTP-Posting-Host: pem01-05.swva.net Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit X-Trace: news3.infoave.net 914294838 13865 208.140.224.5 (22 Dec 1998 02:47:18 GMT) X-Complaints-To: usenet@news3.infoave.net NNTP-Posting-Date: 22 Dec 1998 02:47:18 GMT X-Newsreader: Forte Agent 1.5/32.452 Path: chonsp.franklin.ch!pfaff.ethz.ch!news-zh.switch.ch!newsfeed-zh.ip-plus.net!news-nyc.telia.net!news.maxwell.syr.edu!news-peer1.sprintlink.net!news-in-east1.sprintlink.net!news.sprintlink.net!news3.infoave.net!news.infoave.net!not-for-mail cjt&trefoil wrote: } Bernie Cosell wrote: } > } > What is not as well known [except for folk who've seen the source } code] is } > that Space War was an amazing coding job.. it is arguably one of the } first } > "object oriented" programs. Inside spacewar, there is a list of } 'objects', } > each object being a bunch of pointers-to-subroutines together with } some } > data. } } Didn't that have a lot to do with the way the DEC graphics system } worked? As I recall, you shipped it a list of "objects" and the } hardware did a lot of the heavy lifting. Nope. The hardware consists of a D->A that hit the deflectors of a fancy oscilloscope [and indeed, the PDP-1B I messed with actually had a vanilla oscilloscope hooked up as a "slave" to the main display]. You plotted everything a point at a time, one IOT per point. /Bernie\ -- Bernie Cosell Fantasy Farm Fibers bernie@fantasyfarm.com Pearisburg, VA --> Too many people, too few sheep <-- ###### From: jcmorris@mwunix.mitre.org (Joe Morris) Newsgroups: alt.folklore.computers Subject: Re: Spacewar in Decuscope Date: 22 Dec 1998 19:29:28 GMT Organization: The MITRE Corporation Lines: 66 Message-ID: <75oruo$ghg@top.mitre.org> References: <75hc68$7jf@top.mitre.org> <75hhnh$sac$1@mathserv.mps.ohio-state.edu> <75l350$ucq$1@nntp1.u.washington.edu> <3680f388.210301450@news.infoave.net> NNTP-Posting-Host: mwunix.mitre.org Path: chonsp.franklin.ch!pfaff.ethz.ch!news-zh.switch.ch!news.belnet.be!newsfeed.wirehub.nl!netnews.com!newsswitch.lcs.mit.edu!news-f.std.com.MISMATCH!world!blanket.mitre.org!news.mitre.org!mwunix!jcmorris bernie@fantasyfarm.com (Bernie Cosell) writes: >dpeschel@u.washington.edu (D. Peschel) wrote: >} But thin bitmapped white lines in a square raster-scanned window don't >} really compare with thick smooth white (green? blue?) lines occupying an >} entire round vector-scanned 'scope. >The standard Type-30 display on the PDP-1 had a phosphor that was pretty >much white when it was hit, but then faded to yellow and faded gradually. That agrees with my recollection, although I can't find it in the PDP-1 manual. Here's the complete text of what the manual says about the display: **begin quote** PRECISION CRT DISPLAY (TYPE 30) This sixteen-inch cathode ray tube display is intended to be used as an on-line output device for the PDP-1. It is useful for high speed presentation of graphs, diagrams, drawings, and alphanumerical information. The unit is solid state, self-powered and completely buffered. It has magnetic focus and deflection. Display characteristics are as follows: Random point plotting Accuracy of points +/- 3 per cent of raster size Raster size 9.25 by 9.25 inches 1024 by 1024 addressable locations Fixed origin at center of CRT Ones complement binary arithmetic Plots 20,000 points per second Resolution is such that 512 points along each axis are discernible on the face of the tube. One instruction is added to the PDP-1 with the installation of this display: Display One Point on CRT dpy Address 0007 This instruction clears the light pen status bit and displays one point using bits 0 through 9 of the AC to represent the (signed) X coordinate of the point and bits 0 through 9 of the IO as the (signed) Y coordinate. **end quote** Some notes: * The PDP-1 was a word-oriented machine with two registers linked to the ALU: the AC (Accumulator) and IO (Input-Output). In arithmetic operations the IO served much the same function as the MQ in IBM's 36-bit binary machines. Memory words and the two registers were all 18 bits long; memory cycle time was 5 usec. * The PDP-1 used ones-complement arithmetic, with occasional hiccups when presented with negative zero (octal 777777). * DEC also marketed the "Ultra-Precision CRT Display" (Type 31) which had a raster size of only 3" square, but which offered 4096x4096 point addressing and 0.5% precision. * The "dpy" opcode took no arguments; the form shown in the quoted description above meant that the instruction was octal 720007, with the leading "72" being the generic "Input/Output Transfer" command and the "0007" being the address of the CRT. Joe Morris ###### From: dweber6940@aol.com (DWeber6940) Newsgroups: alt.folklore.computers Subject: Re: Spacewar in Decuscope Lines: 38 NNTP-Posting-Host: ladder03.news.aol.com X-Admin: news@aol.com Date: 23 Dec 1998 02:47:22 GMT Organization: AOL http://www.aol.com References: <367D448A.2985@prodigy.net> Message-ID: <19981222214722.24755.00000228@ng59.aol.com> Path: chonsp.franklin.ch!pfaff.ethz.ch!news-zh.switch.ch!newsfeed-zh.ip-plus.net!news-nyc.telia.net!newshub.northeast.verio.net!cpk-news-hub1.bbnplanet.com!news.gtei.net!portc02.blue.aol.com!audrey03.news.aol.com!not-for-mail >first > > "object oriented" programs. Inside spacewar, there is a list of >'objects', > > each object being a bunch of pointers-to-subroutines together with >some > > data. The inner loop involved cycling through each object and >calling its > > 'move' subroutine, then calling its 'display' subroutine. If an >object > > exploded, its 'object' was just replaced by the "explosion object". >When > > you came back from hyperspace, it just created a new object, added >it to > > the list, and continued... As I remember from the version of Space wars I did for the IBM 1130 in 73 or so, the object orientation as described was natural. My version did not have pointers attached to the objects, but they were exactly that. Delta ship, Tau ship, sun, exploding junk, torpedo. On the 1130 the tube had to be interrupt driven and the action of an object was to write its image as commands to the vector scope in a circular buffer. As each interrupt came in indicating that the last command had finished, the interrupt driver just pulled the next command out and issued it. Biggest hole was no semiphores to control this so every once in a while(a very long while, measured in games) the buffer would get out of sync. Mostly on pen up and pen down commands resulting in a negative image of the screen. The biggest design problem was the arithmetic. Floating point was all software and too slow. Hardware only supported 16 bits 2s complement. I somehow, and I would have to find the code to see how, got the code to do 16bit unsigned arithmetic and got just enough precision for it all to work. Got a very fast Newton's Square Root method to calculate gravity. Two ships, a few torps where no stress on the system. Turn the torp generation to machine gun mode and fill the screen with them would slow it all down alot, until someone got hit. Douglas Weber Douglas Weber