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Thread: Help needed with early-'80s computer specifics for fictional story (screenplay)!

  1. #31

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    I download segments of Landsat 4 imagery to my Xerox-820-II CP/m computer using a 1200baud modem in 1981 or so. 8-bit pixels, filled the 320KByte double-sided/double density 5.25" floppies. Developed image processing algorithms to segment the image and find objects in it. This was 1981 or so. Used Microsoft FORTRAN-80, a Fortran 66 compliant compiler. I rewrote the multiply and divide routines in the FORTRAN library to use the extended Z80 instruction set, got a 2x speed-up over the original library routines. Even made my routines call the same error handlers. The computer that I dialed into was an $8M Texas Instruments Advanced Scientific Computer that was about the same size as WOPR. Filled a warehouse, took three AC units for chilled water, and had 22 16-bit TI 980B minicomputers to handle peripherals. I miss heavy metal.

    By 1985 (1984?, I forget) or so I bought a Leading Edge Model M with a 20MByte hard drive, did lots of color graphics and image processing, I forget the modem speed. 9600baud modems were coming around. The 8087 floating point processor made things faster.

    This was a fast-evolving period. By the time the 80386/80387 came out, I could do almost everything on the PC that used to require a VAX. A few years either way for the storyline makes a big difference for hardware selection and capability.
    Last edited by BrianS; August 4th, 2020 at 02:22 PM.

  2. Default

    Quote Originally Posted by BrianS View Post
    I download segments of Landsat 4 imagery to my Xerox-820-II CP/m computer using a 1200baud modem in 1981 or so. 8-bit pixels, filled the 320KByte double-sided/double density 5.25" floppies. Developed image processing algorithms to segment the image and find objects in it. This was 1981 or so. Used Microsoft FORTRAN-80, a Fortran 66 compliant compiler. I rewrote the multiply and divide routines in the FORTRAN library to use the extended Z80 instruction set, got a 2x speed-up over the original library routines. Even made my routines call the same error handlers. The computer that I dialed into was an $8M Texas Instruments Advanced Scientific Computer that was about the same size as WOPR. Filled a warehouse, took three AC units for chilled water, and had 22 16-bit TI 980B minicomputers to handle peripherals. I miss heavy metal.
    Similarly, when the Mandelbrot set hit, what, Scientific American?, we were all playing with it (naturally, who wasn't).

    In the end, it was faster for us to run sets on the university mainframe, and download the results (at 1200 baud...), than it was for us to generate them locally on the PC or machines we had at the office. The mainframe tore through them in a flash. The process was still slow, make no mistake, just...less slow!

  3. Default

    Quote Originally Posted by Ecto_Jedi View Post
    --------------------------------------------
    | WELCOME TO "THE FISSION HOLE" |
    --------------------------------------------

    PROVIDING YOU ALL THE INFO
    YOUR GOVERNMENT HAS BEEN KEEPING FROM YOU SINCE 1945

    THERE ARE CURRENTLY 53,454 ARMED NUCLEAR WEAPONS
    ON ACTIVE ALERT IN THE WORLD AT THIS TIME.

    ENJOY YOUR DAY!
    There's nothing wrong with having that come out on a generic terminal, no reason to wait for 300 or 1200 baud, not for a movie. You might be surprised how usable 1200 baud is, 2400 more so, but no reason to get picky. No reason to waste movie time, or, worse, audience time, waiting for a screen to paint.

    Just add a flashing cursor, and few beeps and boops, put some dust on the terminal, make the characters bright and a little fuzzy, and you'll be good to go

    Let me add.

    There was a show past few years called "Halt and Catch Fire" which was presented as being done in the early micro days, early 80s, etc.

    For me, I couldn't watch it. I found it unwatchable for a bunch of reasons, one of which was how fast and loose it was with the technology.

    But this was a show that's ostensibly about not just that era, but computers in that era, so I found the "creative license" particularly egregious.

    Computer folks like to kibitz computers in media, just like car folks, or gun folks harping on about "12 shot revolvers" and what not. But, again, I'm assuming your movie is not about early 80's computer, rather it takes place in the early 80's and has light contact with era computing.

    Wargames got it right. As right as it can get, frankly. Use that as a model and you can't go wrong.
    Last edited by whartung; August 4th, 2020 at 08:16 PM.

  4. #34
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    I was thinking if you wanted some nice (but somewhat blocky) colour graphics streaming onto a screen from a period-era modem, take a look at the Prestel / Minitel services that were available at the time.
    Here in Australia our big telco had a knockoff of Prestel called Viatel but it didn't make much of an impact I recall, probably too expensive.
    Regarding Videotex systems I had a quick look and went down a small rabbit hole to learn about the 'Teleputer' that offered online shopping and more, back in 1980: http://www.aldricharchive.com/teleputers.html

  5. #35

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    Quote Originally Posted by whartung View Post
    Similarly, when the Mandelbrot set hit, what, Scientific American?, we were all playing with it (naturally, who wasn't).

    In the end, it was faster for us to run sets on the university mainframe, and download the results (at 1200 baud...), than it was for us to generate them locally on the PC or machines we had at the office. The mainframe tore through them in a flash. The process was still slow, make no mistake, just...less slow!
    I used the Floating Point Systems FPS-120b attached to the 11/780 for the Mandelbrot set and other Chaotic algorithms, the "horseshoe" comes to mind. I ended up using the Intel Sugarcube with four Sky array processors to use fractals to generate cloud models. Displayed using the IBM PGC, with its 640x480 256 colors.

    The Sugarcube was $80K, much less than the FPS-120b with attachments at $130K.

  6. #36

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    Quote Originally Posted by whartung View Post
    There's nothing wrong with having that come out on a generic terminal, no reason to wait for 300 or 1200 baud, not for a movie. You might be surprised how usable 1200 baud is, 2400 more so, but no reason to get picky. No reason to waste movie time, or, worse, audience time, waiting for a screen to paint.

    Just add a flashing cursor, and few beeps and boops, put some dust on the terminal, make the characters bright and a little fuzzy, and you'll be good to go
    Quite close to my own philosophy. I won't sacrifice the pacing of the project on adhering EXACTLY to the historical speeds of a given modem -- but I do in fact like what you call "painting" the screen. WarGames does this well, with an added "beeper" on the incoming data stream (which no one ever did, but for movie conventions, is just one of those things that seems so natural).

    I just don't want anything we portray to be LAUGHABLY incongruous. Like using a late-'90s dial-up modem sound, for instance, if it's 1983.

    Here's that clip from WarGames again, when Matthew Broderick hacks the school system:


    The flow of data on his screen and the bleep-bloop sound works well. That's what I'll be aiming for as a rough guideline -- if it seemed roughly true-to-life in 1983, then like you said, no use wasting audience time obsessing over being absolutely 100% historical...especially if it means staring at a blank computer screen for ages while things load.

    There's a happy balance to achieve there, I think.


    (AS AN ASIDE: The tones the school sends to his telephone, around the 0:17 mark in the above clip -- does anyone recognize those as plausible tones for that answering computer to make? Or are they wholly the product of the film's sound designer, and just more-or-less "tech"-sounding bleeps?)
    Last edited by Ecto_Jedi; August 5th, 2020 at 09:06 AM.

  7. #37
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    Quote Originally Posted by Ecto_Jedi View Post
    (AS AN ASIDE: The tones the school sends to his telephone, around the 0:17 mark in the above clip -- does anyone recognize those as plausible tones for that answering computer to make? Or are they wholly the product of the film's sound designer, and just more-or-less "tech"-sounding bleeps?)
    Those don't really sound like any modem protocol I remember. Generally speaking the negotiation sounds of both 300 and 1200 baud modems have more of a "hissing" quality.

    Here's a possibly useful video. For 1983 either Bell 103 or V.22 would be reasonable for someone dialing in on a consumer-grade computer.



    (You might notice that everything V.22 and later starts off with a very similar "hiss-tick-tick" cadence, so only a stickler will probably catch it if you use a later flavor. The "Twang Twang" in the V.34 negotiation *is* kind of a 1990's giveaway, though, so don't use that. Pretty sure that sound actually appeared in AOL commercials at some point.)
    Last edited by Eudimorphodon; August 5th, 2020 at 02:40 PM.
    My Retro-computing YouTube Channel (updates... eventually?): Paleozoic PCs

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    Quote Originally Posted by Ecto_Jedi View Post
    (AS AN ASIDE: The tones the school sends to his telephone, around the 0:17 mark in the above clip -- does anyone recognize those as plausible tones for that answering computer to make? Or are they wholly the product of the film's sound designer, and just more-or-less "tech"-sounding bleeps?)
    So, (pedant hat on), yea, those modem sounds are Wrong(tm). The other video is much more accurate.

    He dialed 18 numbers to dial the school computer. Must be an international call, maybe he's really in Canada!

    Also, if you notice, during the login sequence, the text comes back much too fast for that modem. (Of course, maybe that's how the PDP-11/270 worked back then... )

    They slow it down later (but it's still too fast) when doing the grades.

    Finally, I'm pretty sure that IMSAI doesn't just show solid LEDs when it's operating. Maybe (I know that Altair, the LED are programmable when running -- a fellow put one online and you could control, at least some of, the LEDs using a simple BASIC program). So, that COULD be legit IMSAI, but I don't know.

    All that said, "nobody cares". It certainly didn't bother me when I watched it back in the day, I don't itch now.

    This, on the other hand, makes me itch.


  9. #39
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    Here's an article that touches on some of the details of the Wargames computers, including pointing out some of the technical discrepencies. If we really want to beat the whole modem thing to death, well, we do see a modem sitting atop his monitor, and it's a slightly relabeled Cermetek 212A... which is a direct-connect 1200 baud modem. Nobody seems to know the provenance of the acoustic coupler we see on screen, I wouldn't rule out that it's something from a telephone tape recorder setup or the like. But, yes, it's definitely only there for cinematic reasons.

    Re: the front panel lights, I'm pretty sure at least the bottom row should be flickering if the computer was actually running. Apparently the terminal interaction was actually being generated by another computer offscreen and the IMSAI was just a prop.
    My Retro-computing YouTube Channel (updates... eventually?): Paleozoic PCs

  10. #40

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    Quote Originally Posted by Eudimorphodon View Post
    (You might notice that everything V.22 and later starts off with a very similar "hiss-tick-tick" cadence, so only a stickler will probably catch it if you use a later flavor. The "Twang Twang" in the V.34 negotiation *is* kind of a 1990's giveaway, though, so don't use that. Pretty sure that sound actually appeared in AOL commercials at some point.)
    I rather like the "blee-bloo-bloop" sounds in V.32 myself. That's the one that has the most interesting flavor, to my ear. (Even, if the video is accurate, it was only sold in 1988 and cost two thousand bananas.)

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