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kenjennings

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Posts posted by kenjennings

  1. Posted

    Remarkably, I have an answer.. . He was pretty nice about the interruption and provided a lot of interesting facts:

     

    Hi Ken,

    The Graphics Symbiosis System (GRASS) was written in PDP-11 assembler and only ran on the PDP-11 and Vector General Display. I stopped working on it in the late 1970s. The Zgrass language was written in Z-80 assembler and ran only with a Bally Arcade chipset for graphics. J. Fenton and Nola Donato and I wrote it, and we stopped working on it in the early '80s. In the mid-80's, I started working on the C version of Zgrass called RT/1. It ran on several platforms (IBM PCs and the like, and Apple Macs) mainly with Truevision Targa graphics frame buffer cards, and we kept it going until the early '90s when I switched my attention to virtual reality on SGI computers.
    GRASS had lists of x,y,z endpoints that defined lines to be drawn by the graphics hardware (it was a caligraphic or stroke display, not a pixel display). Zgrass was a 2D pixel-based system, as was RT/1.
    GRASS was backed up on then standard 9-track mag tape. I have one of these, but how to read it, and if it is readable are unknowns. I don't have any media with Zgrass code preserved. I have one Mac 3/5" floppy with RT/1 on it, but I don't know if it has source code or just the executable.
    All these languages had BASIC-like syntax, with the addition of pretty sophisticated string manipulation so that one could craft and execute program segments with programs. And, of course, they had high level primitives optimized in assembler that made the languages operate as real-time instruments with a keen sense of timing, like video games and musical instruments. The sense of time, of course, never really existed in standard graphics languages which pretty much built up complex frames in orders of magnitude slower than 30fps.
    If I run into any more documentation, I will contact you. Whatever I have is stored in my cabin in Wisconsin, and I don't get there often, typically going only mid-summer.
    Thanks for your inquiry.

    ..tom..

     

     

     

    Not a lot of good news. Looks like the business end of *grass could be largely lost unless someone else who worked on it retained the related media. Perhaps when summer comes around he'll be able to recover something.

     

    • Like 1

  2. Posted

     

    Outside of the Wikipedia article, I have never heard of "RT/1." Who made this? When was it released? Could you please provide any non-Wikipedia link(s) to some of the information about "RT/1" that you have found?

     

     

    The text on the Wikipedia page appears to be taken from Thomas A. DeFanti's page on EVL about GRASS.

     

    https://www.evl.uic.edu/entry.php?id=1935

     

    "The last version of GRASS was RT / 1, a port of GRASS to other platforms that seperated the language from the display model and allowed it to be ported to other platforms. Versions existed for DOS, Windows, SGI platform using OpenGL, HP-UX, AIX, Macintosh and Amiga."

     

    I sent an email to Tom DeFanti inquiring about the ports. This took a few tries. Invalid email addresses. The last one I sent hasn't bounced so far. We'll see how this goes.

  4. Posted

    I read in a couple places that ZGRASS was ported to PC, Mac, and Amiga as "RT/1". Does anyone have any of these? I haven't been able to find a download for Amiga, and the applicable occurrences of ZGRASS and RT1 on Google are so few that I have little hope of this existing.

     

    Is there original source code available for ZGRASS on the astrocade? I haven't found that either.

     

    Has anyone considered porting ZGRASS to other platforms, say something comparable in the 8-bit world, like the Atari 8-bits??

  6. Posted

    Anything reading from a CIO device should safely deal with the fact that fewer bytes were read than requested.

     

    But, what should happen if the request is for one (or more) bytes and zero bytes are returned?

    Should the reader recognize length of zero? (I think so).

    Or should the device behave like an end of file had occurred? (probably not ideal).

     

    We are talking about the dragon network cart, right? So, as a special device never conceived of for the Atari in 1978 I think you have some lattitute for deciding appropriate behavior for the CIO user.

  7. Posted

    Driving controller only uses the lowest 2 bits (Grey Code), and from what I just searched through it's 16 changes per rotation. It was also mentioned in places that more than one sample per scanline is desirable.

    Trakball - there are at least 2 modes with these. There's joystick emulation which is just that, movement will emulate a joystick which will require no extra software processing. There's also a movement code mode where a directional delta is generated for H/V such that the bitpair meanings are

    00=no movement

    11=move left

    10=move right

    Trakball in mouse mode (verification needed) - does this exist? I was just about sure Missile Command works equally with an ST mouse or right sort of trakball.

     

    I thought the driving controller needs more than one sample per frame not scan line. Similar to what a mouse requires as it is (in simple terms) just one axis of a mouse controller.

  8. Posted

    I know this is an old thread (hope this isn't a major breach of etiquette)...

     

    I see quite a few SP0256A-AL2 for about $7 shipped on US Ebay.

     

    I noticed last year that availability increased (and price decreased). I bought two (standard chip shipping cases), and a third in the original packaging.

  10. Posted

    Interesting topic.

     

    Related question -- Does anyone have an idea of what that Samsung MST phone feature could do?

     

    Reportedly, when the phone is near a point-of-sale card swipe it can broadcast a field strong enough that the magnetic stripe reader believes it read a physical card stripe. I would figure it must be pumping out a decent magnetic field to trick a read head from a distance without touching it.

     

    Does anyone know how to evaluate how strong this field could be? Would it nuke old school floppies?

    • Like 1

  13. Posted

    I pretty much skipped the NES and Super NES completely when they were current. At the time I was busy programming on my Atari and Amiga.

     

    I've had every Nintendo since the N64. I'm not much for blood-splatters-per-second gaming, so much of the PS and XBOX libraries are unappealing.

     

    I have a kid now, so the Wii U is getting more mileage than usual.

     

    Much of my gaming is on a PC with Steam doing cooperative, online, multi-player and sandbox-type games with my office friends.

  14. Posted

    Does anyone know where to find a reference manual for the GRASS, ZGRASS, or RT-1?

     

     

    The information on Wikipedia is lamely incomplete. The links on the page yield nothing useful. Google didn't find much more. I found a big Bally enthusiast site, but its mostly just pictures.

     

    i read that GRASS was ported to multiple platforms as RT-1, but I couldn't find anyplace where these could be downloaded..

     

     

    Anyone have anything better?

  17. Posted

     

    Decuir shows the very first block diagram (scribbled in his engineering notebook) of what the Amiga hardware architecture would look like.....a block diagram drawn while he was at Atari.

     

    For anyone looking, that hand-drawn block diagram occurs at 22 minutes in the video. (He says that diagram was done in 1979.)

  18. Posted

    Keatah: Atari did that on its own by ignoring the engineer's ideas. So, a lot of hardware and software folks packed their bags and set out to make a brave new world. That Atari talent is the same group that made the Amiga. Many here recognize the Amiga as the logical evolution from the Atari 8-bits.

     

    Atari succeeded on the momentum of those initial, great engineers. But I think the Atari 800 was the last good decision by Atari management and it looks to me to have been pure stinking luck. Atari was a slow motion train wreck most of the time until its death in 1984.

     

    What if Atari management had better listening skills?

     

    The engineers knew the 2600 had a limited lifespan and the Atari 400 should have been packaged as a VCS-style super system to replace the VCS instead of confusing the home computer line. That would leave a distinctive computer line with the Atari 800 "personal graphics workstation." :-)

     

    What if Atari let the engineers make the 68000-based system that they wanted? There could have been an updated, power-users' Atari graphics workstation using the 68000 released in 82 while Commodore's offering was the C64 videogame system. No contest. Commodore declares bankruptcy in 1983 and Jack Tramiel is later seen homeless, eating in a soup kitchen.

     

    Since a fictional, competent Atari would have been happy to support the engineers' ideas an Amiga-class system would not have been delayed by engineers leaving the company, finding investors, and struggling to run a company to develop their dreams. So, an Amiga (or better) could have been available at the same time as the Macintosh. RIP Apple. If it had run unix then Atari would have owned the world.

     

     

    We now depart from our retro fantasies and return to the leftover quart of eggnog.

    • Like 4

  23. Posted

    All the movements and animation sure seems like it is all character based.

     

    But I notice something .. when the player is walking between two passenger cars the player is partly visible through the accordion-like joint connecting cars. If that connector is not done by a sprite then they went to the extra effort to make a set of characters for the partly obscured player. hard working programmers that.

  24. Posted

    Is there a way to capture printer output? I'd like the text from an LPRINT or write to a channel open to a printer, but if it could capture all the real bytes sent by the Atari that would be cool. I tried several things in linux (diverting ouput to a file, an alleged "null" printer driver, etc) and the best I get is a short sequence of binary junk every time the printer is used.

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