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Re: [midatlanticretro] 50 years of Computer Games

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  • Jeffrey Brace
    From: Evan Koblentz Sent: Monday, December 05, 2011 10:28 PM To: midatlanticretro@yahoogroups.com Subject: Re: [midatlanticretro] 50 years of Computer Games
    Message 1 of 25 , Dec 5, 2011
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      From: Evan Koblentz
      Sent: Monday, December 05, 2011 10:28 PM
      To: midatlanticretro@yahoogroups.com
      Subject: Re: [midatlanticretro] 50 years of Computer Games

      >We have a Vectrex but it doesn't work

      Is anyone willing to take a look at it during the Festivus party ? My
      wishlist is to fix the Apple II & Commodore PET that are in the museum
      rooms, but will add the Vetrex !
    • Mike Loewen
      ... We had some real-time games on the SAGE computer, such as Baseball, but I don t know when they were written. Mike Loewen mloewen@cpumagic.scol.pa.us Old
      Message 2 of 25 , Dec 5, 2011
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        On Mon, 5 Dec 2011, B Degnan wrote:

        > In Steven Levy's book they talk about some sort of paddle flipping
        > game (as in front panel "paddles") tennis or something that was
        > played in real time before Space War.

        We had some real-time games on the SAGE computer, such as Baseball, but
        I don't know when they were written.


        Mike Loewen mloewen@...
        Old Technology http://sturgeon.css.psu.edu/~mloewen/Oldtech/
      • Dan Roganti
        ... oh, I neglected to mention, I think I mentioned it to you already. The intent was to have this running on an o-scope for display. And I intend to bring an
        Message 3 of 25 , Dec 5, 2011
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          On 12/05/2011 10:28 PM, Evan Koblentz wrote:
          >
          >
          >> I proposed to Evan about the next workshop the other day - something which is in line with the proposed them for the next VCF East. A kit in which you can build a vector graphics card that you can connect to any of your vintage computers.
          > Yup, I was talking with Bill on the phone just now, told him that.
          >
          > We don't have the bandwidth for an o-scope session next year.

          oh, I neglected to mention, I think I mentioned it to you already. The
          intent was to have this running on an o-scope for display. And I intend
          to bring an Atari vector monitor for larger viewing, a 19" monitor :)
          It's still not really an o-scope 101 class but it'll help.


          >> But which ones are Vector based. I remember the version which is on
          >> Vectrex console.
          > We have a Vectrex but it doesn't work

          mine's broke too :/ one of many on the repair list.


          >> I have a copy of SpaceWar which is made to run on a 8080
          > That's another thing we have in the museum -- an original Cromemco
          > Spacewar tape.


          That game is the raster version, which runs using the Dazzler color
          video graphics card. There was a demo with this running on a SOL20 at
          VCF East 6.0 - I think it was Bill S. Because I brought in my Cromemco
          JS-1 to compare with his replica.

          =Dan
        • Dan Roganti
          ... You might be thinking of the video game by Higinbotham at the Brookhaven Lab - it was an analog video game. I have an ol classmate that still works there.
          Message 4 of 25 , Dec 5, 2011
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            On 12/05/2011 10:34 PM, B Degnan wrote:
            > In Steven Levy's book they talk about some sort of paddle flipping
            > game (as in front panel "paddles") tennis or something that was
            > played in real time before Space War.
            >

            You might be thinking of the video game by Higinbotham at the Brookhaven
            Lab - it was an analog video game. I have an ol' classmate that still
            works there. Remember that demo you had running on your Heathkit [?]
            analog computer a couple of years ago in your basement, where it traced
            a curve across the screen - it's the same principle.

            =Dan
          • Evan Koblentz
            ... Right. Tennis for Two .
            Message 5 of 25 , Dec 5, 2011
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              >> In Steven Levy's book they talk about some sort of paddle flipping game (as in front panel "paddles") tennis or something that was
              >> played in real time before Space War.
              >>
              > You might be thinking of the video game by Higinbotham at the Brookhaven Lab - it was an analog video game.

              Right. "Tennis for Two".
            • B Degnan
              ... This was a game that had to do with the lights on the front panel, but I don t remember for sure. I bet there was some sort of basic real time
              Message 6 of 25 , Dec 5, 2011
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                At 10:45 PM 12/5/2011, you wrote:
                >On 12/05/2011 10:34 PM, B Degnan wrote:
                > > In Steven Levy's book they talk about some sort of paddle flipping
                > > game (as in front panel "paddles") tennis or something that was
                > > played in real time before Space War.
                > >
                >
                >You might be thinking of the video game by Higinbotham at the Brookhaven
                >Lab - it was an analog video game. I have an ol' classmate that still
                >works there. Remember that demo you had running on your Heathkit [?]
                >analog computer a couple of years ago in your basement, where it traced
                >a curve across the screen - it's the same principle.

                This was a game that had to do with the lights on the front panel,
                but I don't remember for sure. I bet there was some sort of basic
                real time oscilloscope "move the square" kind of demo that involved a
                analog joystick-ish device, maybe a large potentiometer. Who knows.

                I wouldn't say the theme for VCF E is set in stone, or if it will be
                "50 years of Computer Games" exactly. We still have to determine how
                exactly to put all of this together, who will speak etc. I am sure
                we'll get more focus over the next 6 weeks or so. Most VCF's are a
                bit of an arcade anyway, we have to find a way to specifically cover
                the important milestones of computers in gaming (vs. consoles,
                etc)....but this causes me to wonder things like - what is more of a
                computer an Atari 2600 or a totally TTL Pong Game? How exactly do
                you differentiate between "computer games" and video games? Does the
                computer have to have a keyboard as the only distinction? Does it
                have to be played on a general purpose computer? What about arcade
                games that incorporated computing milestones? How about the computer
                systems that were used to write the video came cartridges? Anyone
                have one of those? Text adventures?

                On another tangent, exactly *how* does one hook an oscilloscope up to
                a PDP 8 to play spacewar anyway?


                Bill
              • Evan Koblentz
                ... Correct. This is very important! VCF never has an official theme . Some years it just works out on an informal basis. The 50 years idea came up when Dan
                Message 7 of 25 , Dec 5, 2011
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                  > I wouldn't say the theme for VCF E is set in stone, or if it will be
                  > "50 years of Computer Games" exactly.

                  Correct. This is very important! VCF never has an official "theme". Some
                  years it just works out on an informal basis.

                  The 50 years idea came up when Dan and I were discussing what to do for
                  next year's show t-shirt. We started thinking about milestone
                  anniversaries and we realized that Spacewar is one such milestone. So
                  are many others -- 35 years of 8-bit computing, 30 years for the Apple
                  IIe and C-64, and lots more. We concentrated on Spacewar because it will
                  make for a cool shirt. That's all.
                • Dan Roganti
                  ... while on the subject of the T-Shirt how about using fluorescent ink - so the Spacewar design glows in the dark ! using a black short of course
                  Message 8 of 25 , Dec 5, 2011
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                    On 12/05/2011 11:07 PM, Evan Koblentz wrote:
                    > We concentrated on Spacewar because it will
                    > make for a cool shirt. That's all.

                    while on the subject of the T-Shirt
                    how about using fluorescent ink - so the Spacewar design glows in the dark !
                    using a black short of course
                  • Dan Roganti
                    ... That one doesn t ring a bell yet. ... I haven t read about anything like this before - but you know there s always something done in the lab that never
                    Message 9 of 25 , Dec 5, 2011
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                      On 12/05/2011 11:01 PM, B Degnan wrote:
                      >
                      > This was a game that had to do with the lights on the front panel,
                      > but I don't remember for sure.

                      That one doesn't ring a bell yet.


                      > I bet there was some sort of basic
                      > real time oscilloscope "move the square" kind of demo that involved a
                      > analog joystick-ish device, maybe a large potentiometer. Who knows.

                      I haven't read about anything like this before - but you know there's
                      always something done in the lab that never gets documented cause it was
                      usually some random amusement or curiosity during the downtimes.


                      > I wouldn't say the theme for VCF E is set in stone, or if it will be
                      > "50 years of Computer Games" exactly. We still have to determine how
                      > exactly to put all of this together, who will speak etc. I am sure
                      > we'll get more focus over the next 6 weeks or so. Most VCF's are a
                      > bit of an arcade anyway, we have to find a way to specifically cover
                      > the important milestones of computers in gaming (vs. consoles,
                      > etc)....

                      yes, this is important - a lot of great engineering went into this.


                      > but this causes me to wonder things like - what is more of a
                      > computer an Atari 2600 or a totally TTL Pong Game? How exactly do
                      > you differentiate between "computer games" and video games? Does the
                      > computer have to have a keyboard as the only distinction? Does it
                      > have to be played on a general purpose computer? What about arcade
                      > games that incorporated computing milestones? How about the computer
                      > systems that were used to write the video came cartridges? Anyone
                      > have one of those? Text adventures?

                      woah dude, your getting too deep ;)

                      > On another tangent, exactly *how* does one hook an oscilloscope up to
                      > a PDP 8 to play spacewar anyway

                      Basically you need a card which has a few channels of Analog to Digital
                      converters. I'm sure Dave G. can show us what he has on his system. I'm
                      looking towards doing this with McGuire's PDP-8 over here. You can see
                      an example of the S-100 card from Cromemco, D+7A. I'm getting mine setup
                      for this. You need an o-scope with a X-Y mode setting on the Horizontal
                      Timebase control. This lets you have direct access to the beam drivers
                      and create the images.

                      =Dan
                    • Evan Koblentz
                      ... Make it 3-D.
                      Message 10 of 25 , Dec 5, 2011
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                        >> We concentrated on Spacewar because it will make for a cool shirt. That's all.
                        > while on the subject of the T-Shirt how about using fluorescent ink - so the Spacewar design glows in the dark ! using a black short of course

                        Make it 3-D.
                      • Dan Roganti
                        ... And everyone has to walk around wearing the red/blue 3D glasses
                        Message 11 of 25 , Dec 5, 2011
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                          On 12/05/2011 11:26 PM, Evan Koblentz wrote:
                          >>> We concentrated on Spacewar because it will make for a cool shirt. That's all.
                          >> while on the subject of the T-Shirt how about using fluorescent ink - so the Spacewar design glows in the dark ! using a black short of course
                          > Make it 3-D.

                          And everyone has to walk around wearing the red/blue 3D glasses
                        • Dan Roganti
                          ... jeesh,
                          Message 12 of 25 , Dec 5, 2011
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                            On 12/05/2011 11:25 PM, Dan Roganti wrote:
                            >
                            > Basically you need a card which has a few channels of *Digital to
                            > Analog* converters.

                            jeesh,
                          • David Gesswein
                            ... With a display peripheral. With the 8/I I used the AX08 laboratory peripheral. It can draw points on the XY screen and also has A/D and digital I/O. On the
                            Message 13 of 25 , Dec 6, 2011
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                              On Mon, Dec 05, 2011 at 11:01:33PM -0500, B Degnan wrote:
                              >
                              > On another tangent, exactly *how* does one hook an oscilloscope up to
                              > a PDP 8 to play spacewar anyway?
                              >
                              With a display peripheral. With the 8/I I used the AX08 laboratory
                              peripheral. It can draw points on the XY screen and also has A/D and
                              digital I/O. On the 8/E I used the VC8E which is the point plot only.
                              Every model of the point plotting used incompatable instuctions for operation.

                              In theory the AX08 should work with my straight 8. With only 4k memory
                              the spacewar I used last time won't run but I have a simpler one which
                              should. End of this month is the next big push on working on the restoration.
                            • Bill Sudbrink
                              ... Yes, but not my Sol. I have an IMSAI chassis full of Cromemco cards. I have shown all of the Cromemco software I can locate, including Space War, Tank War
                              Message 14 of 25 , Dec 6, 2011
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                                Dan Roganti wrote:
                                >
                                >
                                > >> I have a copy of SpaceWar which is made to run on a 8080
                                > > That's another thing we have in the museum -- an original Cromemco
                                > > Spacewar tape.
                                >
                                >
                                > That game is the raster version, which runs using the Dazzler color
                                > video graphics card. There was a demo with this running on a SOL20 at
                                > VCF East 6.0 - I think it was Bill S. Because I brought in my Cromemco
                                > JS-1 to compare with his replica.

                                Yes, but not my Sol. I have an IMSAI chassis full of Cromemco cards.
                                I have shown all of the Cromemco software I can locate, including
                                Space War, Tank War and Dazzle Doodle at (I think) two different VCFs.
                                Most recently (when you brought your JS-1 in), I had two IMSAI boxes,
                                my Cromemco and a second full of Processor Technology cards. I also
                                had my Sol on display. The point was sort of "don't judge a computer
                                by its box". The PT IMSAI is completely software compatible with the
                                Sol, while the "twin" (judging by the box) IMSAI is completely
                                incompatible. Anyway...

                                I will definitely be at VCF East 2012.

                                There, publically announced, now I can't back out.

                                Now I think I know the challenge I will set for myself for VCF12...

                                I have been having great fun with my most recent acquisition, the SWTPc
                                6800 but it is very "plain Jane". Just CPU, memory, diskette and serial
                                I/O right now. I'm going to try to add two cards:

                                1) an equivalent to the Cromemco D+7a
                                2) a display driver card (vector or raster?)

                                Then I will port Space War to the system.

                                The hardware shouldn't be too difficult, I don't know if there are vintage
                                cards, but I can build them if they don't exist or I can't get them.

                                Porting Space War may be a challenge. The Cromemco version is expecting
                                to run on a 4MHz Z80. I wonder if the 1MHz 6800 is up to the job? How
                                much "umph" does the PDP8 have in comparison? Which kind of display,
                                vector or raster, will take more CPU to drive it? Anybody have any SS-30
                                or SS-50 protoboards for sale/trade?

                                Bill S.
                              • Evan Koblentz
                                ... It will be a fun challenge, albeit unofficial, to see how many different systems we can get to play Spacewar -- and to see which system can do it with the
                                Message 15 of 25 , Dec 6, 2011
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                                  >>> I have been having great fun with my most recent acquisition, the SWTPc 6800 .... I will port Space War to the system.

                                  It will be a fun challenge, albeit unofficial, to see how many different systems we can get to play Spacewar -- and to see which system can do it with the least resources.
                                • David Gesswein
                                  ... The PDP-8/I fastest instruction is 1.5 us. 3 us min for memory access instructions. Looks like the minumum 6800 instuction takes 2 cycles immediate, 3
                                  Message 16 of 25 , Dec 6, 2011
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                                    On Tue, Dec 06, 2011 at 07:31:07PM -0500, Bill Sudbrink wrote:
                                    >
                                    > Porting Space War may be a challenge. The Cromemco version is expecting
                                    > to run on a 4MHz Z80. I wonder if the 1MHz 6800 is up to the job? How
                                    > much "umph" does the PDP8 have in comparison? Which kind of display,
                                    > vector or raster, will take more CPU to drive it? Anybody have any SS-30
                                    > or SS-50 protoboards for sale/trade?
                                    >
                                    The PDP-8/I fastest instruction is 1.5 us. 3 us min for memory access
                                    instructions. Looks like the minumum 6800 instuction takes 2 cycles
                                    immediate, 3 cycles for direct address so similar. PDP-8 is 12 bits and
                                    6800 8 bits so some advantage to PDP-8. 6800 instruction set is
                                    larger so more efficient (PDP-8 can't subtract, you have to negate
                                    the value then add). In the end the speed is probably similar.

                                    The relative speed would depend on how much the graphics board offloads
                                    of the work. Raster board with sprites or vector board with display lists
                                    would make CPU load less. Raw raster memory or D/A converters would
                                    make more work. The PDP-8 control is close to raw D/A converters.

                                    For a simple display raster is probably less load since it handles the
                                    refresh for you so you only need to write things that are to be changed.
                                    Vector without display lists you need to rewrite everything at 30+ Hz to
                                    prevent flicker.
                                  • Bill Sudbrink
                                    ... I m thinking a vector display with a display list. The SWTPc SS-30 bus provides a 4 byte interface per slot. I m thinking a of programming interface
                                    Message 17 of 25 , Dec 6, 2011
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                                      David Gesswein wrote:
                                      > Vector without display lists you need to rewrite everything at 30+ Hz
                                      > to prevent flicker.

                                      I'm thinking a vector display with a display list. The SWTPc SS-30 bus
                                      provides a 4 byte interface per slot. I'm thinking a of programming
                                      interface something like:

                                      <low byte> vertex address
                                      <next byte> vertex X
                                      <next byte> vertex Y
                                      <high byte> vertex options

                                      vertex options would be something like:
                                      <low 4 bits> intensity to this vertex (0 is off)
                                      (do vector displays support intensity?)
                                      <next bit> 0 - no action
                                      1 - terminate (go back to vertex zero)
                                      <next 2 bits> unused
                                      <high bit> 0 - X,Y is absolute, X and Y are unsigned
                                      (vertex zero must be absolute?)
                                      1 - X,Y is relative to previous vertex, X
                                      and Y are 2's comp signed

                                      So, you poke a vertex address, then poke its three values.
                                      I'm not sure how "coarse" a 256x256 vector display would be.

                                      With relative vertexes (vertices?) moving the ships around the screen
                                      will require a fewer operations. Rotations will still be painful.
                                      I have no idea how realistic this will be to implement in hardware...
                                      I know it would be easy with a modern pic, but I think I want to try
                                      to go with a vintage design. Memory wise, it seems doable. It doesn't
                                      even require 1K. I could implement it with a pair of 2114 static RAMS.
                                      It might glitch during I/O. I could put 2K on the board and bank swap
                                      to commit the writes. Then I need something on the board, spinning
                                      through the RAM, driving three DtoA circuits? And a clock? I need to
                                      do some reading.

                                      Bill
                                    • Dan Roganti
                                      ... yes, the display list is necessary to avoid any lag, flicker, etc in the display - and offload the processing from the CPU. Much like in a raster video
                                      Message 18 of 25 , Dec 6, 2011
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                                        On 12/06/2011 09:30 PM, Bill Sudbrink wrote:
                                        > David Gesswein wrote:
                                        >> Vector without display lists you need to rewrite everything at 30+ Hz
                                        >> to prevent flicker.
                                        > I'm thinking a vector display with a display list. The SWTPc SS-30 bus
                                        > provides a 4 byte interface per slot. I'm thinking a of programming
                                        > interface something like:


                                        yes, the display list is necessary to avoid any lag, flicker, etc in the
                                        display - and offload the processing from the CPU. Much like in a raster
                                        video display.

                                        However for the next VCF workshop kit I'm planning, I intend to use an
                                        onboard 6502 for processing. Mainly for 2 reasons, this saves on parts
                                        and the firmware will be flexible for future hacks - and open source.
                                        I'm keeping it a vintage design - after all it's VCF and not Maker Faire
                                        ;) It's still fast enough when running 2mhz to maintain the screen
                                        refresh. The 6502 has the lowest instruction cycle count amongst all the
                                        other 8bitters - just as the 6800 but guess who's popular :)

                                        So then your host system would run the app software containing the game,
                                        graphics, etc. While the vector display board will contain all the
                                        graphics primitives in firmware, but then in vectors. It will save a
                                        host of hardware when you compare it to something like the Asteroids
                                        arcade game. And still have enough resolution, 1024x1024, this will
                                        also use 10bit DAC's as in that arcade - but not the same part# - after
                                        35yrs, they're still so friggin' expensive ($25). You can get modern
                                        DAC's that are much cheaper and quality as near as the AD561 used in
                                        that arcade.

                                        This kit will have options to connect via a parallel port or memory
                                        mapped I/O port - which most vintage computers can support. So then it
                                        can be compatible for most systems using one type of circuit board while
                                        not needing to make a card for each and every form factor, Apple II,
                                        S-100, SS-50, etc. It'll be a standalone box that sits beside your
                                        vector monitor.


                                        >
                                        > With relative vertexes (vertices?) moving the ships around the screen
                                        > will require a fewer operations. Rotations will still be painful.

                                        Rotations are doing using Matrix Math - it's less painful than in a
                                        raster graphics, as you only only to worry about the vertices. And you
                                        use Look Up tables for the Trig functions - to speed up the math. Just
                                        as they did on the PDP-1 SpaceWar.

                                        =Dan
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