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Technology

The Apollo 11 Guidance Computer 154

Posted by CmdrTaco from the i-bet-it-gets-lost-in-boston dept.
wiredog writes "Dr. Dobbs has an article on the Apollo Guidance Computer with a jpg of a source code listing. Some specs: 70-lb box , Approximately 20 instructions, 16 bit word, ROM (rope core) 36K words; RAM (core) 2K words, Basic machine cycle: 2.048 MHz"
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The Apollo 11 Guidance Computer More

The Apollo 11 Guidance Computer

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  • the American Computer Museum there actually HAS an Apollo guidance computer, along with a lot of other neat stuff. Very cool. No, they don't let you use it. :-)
  • Maybe he actually got off his ass and went to a real, physical library, instead of being lazy and trying to get other people to do his research for him.

    Oh yeah, I forgot, NASA have a library in the UK don't they?

  • ...to avoid infighting and chaos.

    "Oh my GOD, she is so stealing my scarf look!" And plus they'd waste 3 hours a day with makeup.

    Ok, I'm done with that. But if you think that's unfair, then those male generalizations are unfair, too. I mean, they obviously aren't going to have the wrasslin' beer swilling types of folks, and they aren't going to have those women I described. The current astonauts they have work fine.

    saving $3m isn't so much compared to the (guessing) $700m for a shuttle mission. Also, where did you get that 100 lbs average for female astronauts? That sounds kind of low. (And possibly unhealthy depending on their height).

  • No, it wasn't. Bear in mind that even now, RTL logic is the only way to go for fast, small-system gates. Of course, now you're talking tens of GHz.

    But certainly, by the mid-sixties, there were industrial-spec RTL devices that would operate to 5MHz and beyond.

  • Well, that's pretty much all the injection controller is doing...
  • I wouldnt call this device computer: it is rather complex electronic device. Everything, including CPU was optimised for its purpose.
    Sometimes it is much better to do stuff electronicaly, rather than by the means of software: that simple, software is not reliable enough

    exT
  • Their fail safe systems were pretty simple, mostly consisting of duct tape.

    Seriously, their systems were simple enough, and targeted towards specific tasks, that they probably just had duplicates/triplicates of the systems themselves. If one goes wrong, the astronaut pulls it out and puts another one in.

    As simple as it was, you couldn't have tons of spare equipment laying around. They tested that equipment a lot as best they could.

    The big problems they had were external events/unpredictable events, such as the Apollo 13 explosion, etc. and you really can't design against that.

  • Cool! If I write an emulator for this machine will it let me go to the moon?

  • I think you're missing the point. In code that is controlling guidance on a space ship, you don't *want* lots of features. You want *one* feature - getting from point A to point B on the right route. The more parts and code you throw at that problem, the more likely it is that the guidance will fail. We have bloated software because people want all kinds of features that they will never use. How many features of of Word do you actually *use*. If you stripped it down to that, I'd bet it would crash a whole lot less...

  • Apollo Guidance Computer Manual (Score:5)

    by dbremner ( 16330 ) on Monday February 05, 2001 @08:30AM (#456029)
    A Google search found this site [apollosaturn.com]. It lists all the commands and has an ASCII drawing of the display.
  • Michael Collins (Apollo 11 CMP) wrote a memoir of his years with NASA, titled "Carrying the Fire," in which he mentioned Luminary as the LM guidance program and Colossus IIA ("I felt flea-like in its presence") as the corresponding CM program.

    He said that at an Apollo 11 mission debrief, he registered his complaints about the number of times (850, IIRC) he had to command the computer; the point being that if he fell behind or some emergency intervened, he could easily have made fatal mistakes.
  • Heavy spacesuits? ROFL, like that matters in zero gravity *NOT*

    Uh... like it matters YES. *MASS* my friend. Weightlessness doesn't mean masslessness. You may not have to "hold" up a heavy suit, but you do have to move it.

    You might want to know your stuff...

  • ... (Score:1)

    by Anonymous Coward
    If ($altitude == 0) then croak("You're dead...\n");
  • No, I can only bench about 130lbs

  • Re:Use of GOTO?!? (Score:3)

    by Qoud ( 202153 ) on Monday February 05, 2001 @08:33AM (#456034)
    Yes, they should have used GOSUB, they'd have stood a much better chance of RETURN'ing.
  • They would be far less likely to suffer from depression...

    You must never have listened to The Smiths. ;)

    Peace.
  • The average woman weighs 100 lbs and man 150 lbs? Not hardly.

    Yeah, that does seem a little high. I suppose if we're only sending up really tall people, it's a reasonable weight. But for average height men, 150 lbs makes you a fatty. Or an American. Your choice.

  • If we are to have a viable space exploration program, with happy and committed astronauts, we must put what I have recomended into practice. It will do our space exploration program the world of good, and improve its success rate.

    Damn, there go our plans for prolonged manned missions which require several generations of astronauts... Whichever way you try, you still need a straight woman on board for it to work... :)

  • Scarcasim Alert! (Score:3)

    by Auckerman ( 223266 ) on Monday February 05, 2001 @07:05AM (#456038)
    Oh, come on! Everyone knows the moon landings were faked [8m.com] .
  • "Why do NASA try and make all their astronauts tall..."

    Actually, NASA has very specific height restrictions that mean anyone 6' tall or more had better not waste their time applying. It may be even lower. Check.

  • Re:But it worked (Score:3)

    by sphealey ( 2855 ) on Monday February 05, 2001 @07:06AM (#456040)
    "He then manually landed the craft, with only 4 seconds of fuel remaining on touchdown"

    I believe that was 64 seconds of fuel, with 60 seconds being needed to orient the descent module and fire the ascent module engine for a successful abort. The real question is whether Armstrong would have eaten into that 60 seconds to land. On the records he has always said no...

    sPh
  • Assuming, of course, that one could actually find a really clever MCSE guy...
  • "Actually, Windows wasn't in existence at the time"

    I know but it was too tempted to put a Windows joke in :-)
  • I really miss the days where software development and hardware engineering was really about being clever.
    And it's not even just clever in retrospect. The engineers knew that they had to be clever. Some of my favorite quotes:
    And in those days, many a clever programmer derived an immense satisfaction from the cunning tricks by means of which he contrived to squeeze the impossible into the constraints of the equipment.
    -- Edsger W. Dijkstra, "The Humble Programmer", 1972 ACM Turing Award Lecture

    Not written about software (or computers), but equally applicable:

    Perfection is achieved, not when there is nothing more to add, but when there is nothing left to take away.
    -- Antoine de Saint Exupery

    That explains why Microsoft software (and indeed most software) will never reach perfection. It's not even their objective.

    Today the art of making every byte of memory (and every gate of hardware) is nearly lost. It's still sometimes seen in very cost-sensitive embedded systems. But even there, in recent years there's been a tendency in recent years to say "screw it, let's just put in another 128K of flash memory and a faster processor."

    My day job involves embedded systems with fast RISC processors and hundreds of megabytes of RAM. There are occasional challenges, and I do take pride in my work, but when there are no resource limits it's just not fundamentally that interesting.

    In my spare time, I prefer to try to wring the "impossible" out of tiny microcontrollers:

    To someone who doesn't understand the concept of doing the most work with the least resources, none of these projects probably seem exceptional. But they were much more satisfying to develop than anything I ever do at a day job.

    In the old days, the only alternative to doing things cleverly was not to do them at all. If the engineers at Draper had been less clever in how they designed the AGC, the Apollo program might have had to be delayed by several years. The AGC is one of the finest examples of computer engineering (both hardware and software) ever. I imagine that some of the disparaging comments about how primitive it was (i.e., that it was obsolete at launch) were from people who either were trying to be funny, or have no conception of system design.

  • Care to explain?
  • Heavy spacesuits? ROFL, like that matters in zero gravity *NOT* :)

    Having never been in zero gravity myself, it still seems like a bulky spacesuit would increase the amount of mass you would be moving around, thus impairing/slowing your movement... It still requires force to move mass in space, even if the mass has zero weight. (right?)

    Still, I think women should be able to get around in the space suits just fine.

    Josh Sisk
  • Start DL'ing the source and hack some
    rockets.

    Vam
  • Yeah, but can it guide a missle as well as a PlayStation 2? Saddam wants to know...
  • LOL..women are less territorial than men? And less aggressive? Have you ever been near a woman on a mission to do something? hoo boy..not to mention the territory thing....
  • A jpeg here, a jpeg there. Can't somebody scan the whole thing and post it. I know that I could get a lot of people working on transcribing it. This software (whichever version, Apollo 11, 12, etc.) would be great to have.

    It would be awesome to run and emulation of the actual Apollo landing software!

    jlewczyk@speakeasy.net

    "To the Moon, Alice!" - plans to put the first American in space.

  • massively parallel human computers (Score:3)

    by peter303 ( 12292 ) on Monday February 05, 2001 @08:44AM (#456050)
    The current issue of Amerian Scientist has an
    article about a British meterologist who conducted
    the first finite-difference weather prediction
    calculation in the 1920s using a room full of
    people with adding machines. The motive for this
    was there were a few very dense measurements
    of weather data during the Great War,
    and Prof. Richardson wanted to see if it was predictable.

    Richard Feymann in "Surely you aren't joking"
    mentions a human calculation room for a-bomb
    modeling at Los Alamos in the 1940s.
  • thanks for the mirror
  • Simple, but unforgiving. You were peeking & poking directly into the computer's memory. I would hope nowadays that a little higher-level interface would be desired.

    Of course, if you need to patch around a bug in the software in the final few minutes before descent (which actually happened in one of the Apollo missions), there's no substitute for a good hex editor :)
  • What about the most important guidance computer of all? The astronauts? Were/are they as good as they could be?

    This may seem a little startling, but what I have to say is of the utmost importance IMO, and has not been touched upon by our biased media representatives. It is a matter of scientific fact that male astronauts are better suited to the rigours of space exploration than are females. This is due to better water retention in men, better skills at navigating in 3D environments, an important skill on spacewalks, and highly superior hand-eye coordination and physical strength. Men are the clear choice for space missions.

    However, there are a number of problems involved in extended space missions for men. Amongst these is the loneliness and alienation involved. For this reason, it is my belief that gay men are far better suited for long term space exploration, being used to alienation and having a number of talents that heterosexual men do not, including better interpersonal skills. They would be far less likely to suffer from depression and the decrease in performance this would cause, as they would be able to love each other while on missions. As Human Beings are the most crucial elements in any space mission, equal opportunities regulation should not apply. We should find the very best men for the job, regardless of political and social motives.

    Unfortunately, NASA is beholden to the right wing Bush administration that runs our country, and so it will insist on choosing from men and women equally, without regard to performance.

    If we are to have a viable space exploration program, with happy and committed astronauts, we must put what I have recomended into practice. It will do our space exploration program the world of good, and improve its success rate.

    They fuck you up, your mum and dad.

  • In the early 90s, when the space shuttle
    were using computers designed around 1980,
    their specification sounded rediculously primitive, including core memory.
    Some of the astronauts were carrying laptops
    that were hundreds of times more powerful.

    The shuttle computers have been ugraded since.

    Core memory is considered more reliable than
    semiconductor memory in the space radiation
    environment.
  • Heh, I predict that Microsoft will announce that the source code to Windows is based on the Apollo 13 code... it avoids crashing by virtue of really clever MSCE guys..
  • Thanks for the correction. Yep, just a mistype. It was Apollo 14.

    QuantumHack
  • Right-O, I had a mistype there. Thanks for the correction.

  • Apollo guidance computer: 2.048MHz

    Intel 8088: 4.77MHz

    Intel 486: 66MHz

    Intel Pentium 4: 1.5GHz

    Intel Celeron A 300MHz running at 666MHz: priceless.

  • Women are better in space (Score:3)

    by Hairy_Potter ( 219096 ) on Monday February 05, 2001 @07:08AM (#456059) Homepage
    and it only takes a back of the envelope calculations to figure that out.

    • Women are smaller, and require less food, water and oxygen.

      The average woman astronaut, at 100 pounds, is 2/3 the weight of the average male astronaut at 150 pounds. With present day launch costs of 10,000 USD per pound, replacing a 6 person male shuttle crew with 6 females results in a cost savings of $3,000,000 dollars, or 300 extra pounds of equipment and payload. Factor in the reduced fod, water and oxygen requirements, and you might be able to loft 500 extra pounds into orbit.

    • Women are hardier.

      Woman live longer than men, and are healthier in general. When you are talking about expeditions lasting 3+ years (ala Mars), you want the healthiest people you can going.

    • Women are less aggressive and territorial than men.

      When you are talking about being locked in the space the size of 2 cubibles with 5 other people for 3+ years, you want low aggression, non-territorial people there, to avoid infighting and chaos. While Europe is making admirable strides towards breeding a complacent, passive population, for now, the best. most compatible crew would be woman.



    However, due to the stranglehold that the caucasian patricarchy has on the space program, don't expect this to be acknowledged, or to even see more than a token amount of women in space. Pity the Israelis don't have a space program, they don't have the resources for false pride and propping up insecure males, the would go for the gusto and have woman like Golda Meir in orbit.

    Thanks,

  • Mirror (Score:3)

    by tedtimmons ( 97599 ) on Monday February 05, 2001 @07:09AM (#456060) Homepage
    It's already loading VERY slowly. Feel free to use the following mirror:

    http://www.perljam.net/misc/apollo11-code.jpg [perljam.net]

  • I wonder what clock speed the HAL 9000 ran at?

  • But the hairspray would be a horrible fire hazard in a high-oxygen environment.

    Although, in a pinch, aerosol cans could provide a life-saving alternate means of propulsion, I suppose.
  • 1) "Gay can also mean big chip on shoulder you know"

    2) "I have been mistaken in the past for being gay, as a result of these idiotic sterotypes."

    so uh what you're saying is you have a big chip on your shoulder...?

  • Well a good look at the code would tell me.

    You'd be surprised how many 'professional' mapping / navigation packages upwards of $10K (US)per liscence have errors resulting from things like discontinuities across the international date line, small angles leading to divide by zero, etc.

    While most linux Joe Hacker's might not know much about navigation, In My Humble Experience many people that deal with 'real' navigation are pretty fair hardware/OS Joe Hacker's. Some even use ( Linux / Minux / BSD / Solaris / DRDOS / Forth / ... ) and peer exchange code / ideas.
    It's a funny old world.
  • You can GPL it, but are you prepared to incorporate the patches that people submit in the next version?

    Anything created by the US Government is uncopyrighted. So sayeth 17 USC Sec. 105 [cornell.edu].
    --
    Ooh, moderator points! Five more idjits go to Minus One Hell!
    Delenda est Windoze

  • For anyone who wants to know MIT Intrumentation Laboratory changed the name of the company to The Charles Stark Draper Laboratory, Incorporated. We still do GN&C work for NASA and still do other projects for the goverment as a not for profit organization. To find out more about us try our web site at http://www.draper.com [draper.com] .
  • Gay can also mean (a) big chip on shoulder
    Hey, that's Chip with a capital C.

    I had a feeling you were going to say that.
  • The reason the computer are so lame on current space craft (shuttle or ISS) is that the electronic technology is not RAD hard like you alluded to in your last line. Since the memory is not total RAD hard they use multiple computers in parellel and poll for the right answer. Majority wins in a dispute between the computers. Did you know that the computer on ISS are merely 386 CPU machines because of heat removal problem with faster chips and a supply of RAD hard hard CPUs. I heard in the last shuttle mission one astronaut had to reinstall Windows 98 in the middle of a flight on one of their shuttle laptops. You gotta be disappointed with Microsoft reliability in this situation.
  • If you want to emulate something, emulate the DSKY. THAT is a great interface. See my other post.
    <p>
    QuantumHack
  • Remember, that little box wasn't doing the major navigational calculations. Most of that was done on the ground on mainframe computers.

    Incidentally, the panel from an Apollo guidance computer is in a display case in the Gates building at Stanford.

  • I agree with you, but I would like to add that managment doesn't help.
    I have told managers of projects(for embedded systems no less)that I need more time for code optimization, only to ne told don't worry about it, as long as it works at all, we can add more memory to the next hardware revision. sheesh.
  • If they sent macs back in time we would never get to the moon. In my experiance they are just about the most flaky machines around! If you must, send cak an Athlon 1.2Ghz DDR!

  • And then when you figure in the crates of KY jelly, cock rings, and "Hello Kitty" tote bags, you'd end up with a rocket that wouldn't be able to exceed the escape velocity of the moon, let alone Earth!

    Yeesh. I dunno what kind of fags you hang out with.

    The ones I hang out with are almost exclusively into Madonna and Men's Health magazine.

  • ...is that HAL was a Beowulf cluster?! :^)
  • Or you can just go here [compustory.com] and see a picture.
  • ... NASA has already faced this problem, because they use Win 95 laptops. How about 10 million lines. How about 20 M?

    Since when did anything Mikro$oft make have any bugs or faults? After all, wouldn't you trust your life to Windows?

    Astronauts should be smart people, right? And certain, much more stable OSes exist... say Unix, or Linux... So why not train Astronauts to use them?

    PS: I'd like to read the article, but I can't right now. *sigh* Slashdot effect...


  • If the P-level hits 254 during zero-G, it could cause an explosion in the oxygen tanks. Who should I report this bug to?
  • This seems like a legitamate post

  • A noble era which passed us long ago. (Score:3)

    by cje ( 33931 ) on Monday February 05, 2001 @07:17AM (#456080) Homepage
    I really miss the days where software development and hardware engineering was really about being clever. A lot of the work being done these days has been tainted by the Microsoft mindset: "If it's too slow, throw more CPU at it; if it's too big, throw more RAM at it." This is a luxury that we didn't always have, and it's something that I think a lot of people take for granted these days. Programmers are at their best when they take a machine with definite resource limitations and work with those limitations to develop an acceptable solution. This is, IMHO, a far more noble effort than simply throwing more resources at the problem until you've gotten to the point where the "lazy man's method" is acceptable.

    I can remember years back writing some assembly code on an Apple II; I had a routine that ended up being two bytes too long to fit between Page 3 and the keyboard buffer. In order to make it fit, I ended up resorting to self-modifying code that saved three bytes. Now, you might make the argument that self-modifying code is horrible style (and you'd be right), but at the time, that didn't matter to me; what mattered was that I'd come up with a solution that worked given the limitations I was stuck with. Coming up with something like that gives a person a far greater sense of accomplishment than does a solution that was attained simply by artificially throwing more resources at the problem.

    This type of mindset is for the most part dead. Oh, there are examples of it around in certain specialized arenas (for example, the current crop of Playstation 1 games has pretty much pushed that platform to its limitations.) But Moore's Law and dropping RAM prices have mandated that general software development should be quick and dirty rather than compact and elegant. And maybe, from a financial standpoint, that's how it should be; after all, it takes considerably more development time and effort (and therefore more money) to write the slickest code than it does to write acceptable code that works, given enough resources. However, that doesn't mean that we should not be able to lament the passing of the earlier era.

    Finally, I should point out that I am not saying that current software developers are entirely devoid of creativity, because they're not. There are a lot of developers for a lot of different hardware platforms and operating systems that are doing some pretty cool things. I am claiming, however, that software development is rapidly becoming a field of endeavor that requires far less cleverness and wherewithall than it once did. Whether this is good or bad depends on your point of view, but I don't see how it can contribute to any increase in general software quality.
  • Missed a few points there. 1. Modern computers are far more liable to fail in space NO MATTER what software they run. This is due to increased radiation outside the atmosphere interfering with the CPU. Even if you run Linux! This is the reason why CPUs used in space vehicles are outdated, because they have gone through a vigourous hardening and testing procedure to check their suitability to space travel. i.e. the recent computer upgrade to the Hubble involved a processor (486, wasn't it?) many years obsolete by desktop standards. But it was a specially radiation-hardened chip and so less liable to fail in space.
    2. If an astronaut's laptop running email crashes, this is not a big deal. If the space shuttle's guidance computer crashes, this IS a big deal. This is why they've not upgraded the systems much over the years. This is why aerospace companies have very strict protocols of design - Rapid Application Development is NOT what they want! They want very slow and careful application development using formal methods. (IMHO, Open Source wouldn't work. Joe Hacker may be a linux whizkid but does he know about telemetry? Thrust vectors? Navigation? Do you trust him to?) The last programming problem was Ariane, as far as I know. and they fixed that by the time they launched the second one. The reason this Apollo Guidance Computer is designed like this is because it was the best they could do at the time, and as someone else commented, wasn't quite good enough as Neil Armstrong had to fly the LEM out of the programmed course to a safe landing.

    Hacker: A criminal who breaks into computer systems
  • An important issue when trying to move around in those very heavy spacesuits and when working on machinery that requires brute strength at times.

    If brute strength is an issue then why aren't we sending up 20 year old young bucks instead of thse middle-age PhDs?
  • No problem, just make it one the selection criteria that they don't have the problem.
  • Well, I have been incorrectly hit on my a gay man. It was as honest mistake. In context, my manner would easily have set off his gaydar. It wasn't until I started hanging out with some gay friends that my own gaydar developed better.

    But straight I am, and not in denial. It was just an honest mistake and I laugh about it with my gay friends. Some of my straight friends get all defensive about the idea that a gay person might hit on them, but it's not like the guy was being threatening. He was just a little more friendly than he probably would have been if he knew I was straight.
  • This article [planet.nl] is pretty detailed...
  • I know you're probably joking, but there's probably good reasons why they dont do that, otherwise, mini-me would have been up in orbit long ago, especially during appollo. My guess is that there are other health problems that usually go along with being a midget, and NASA is very strict about sending the healthiest people into orbit. (unless it's a publicity stunt, like John Glen)
  • Just think where the space program would be if a truck load of Mac Cubes, flatpanel displays, a bunch of those PPC-in-a-cdrom-size-box computers, and servers were sent back to 1955. Make sure they're loaded with Linux and all the right software, docs, etc. How much of a change would there be with a 45 year jump in computing technology?
  • Woe upon man for the curse that is woeman (read woman). And I'm not chicken enough to send it anonymously.
  • "Software Crisis". Ever notice that you don't hear that phrase too much anymore? (If you're too young to recognize that phrase, move along.) It used to mean the eternal 6- to 18-month delay to get new software written. Some large shops actually had development backlogs that stretched years. Then we got Structured Methods that made sure that we understood what we were supposed to be building. Reliability and usability went up some, but the backlog remained. Then, we got PCs, and OOP, and "Internet time", and 30G HDs for $100, and 256MB SIMMs for $100, and CPUs running in the gigaherz range and the "crisis" seems to have passed.

    I, too, miss clever programming tricks, and weighing the time/space tradeoff, and seriously bumming code, but I think overall we're better off that we at least have the option of throwing more hardware at the problem, or of designing something that won't run acceptably on state-of-the-art hardware because you know that a year from now when it's released, the state of the art will have advanced to the point where your design is feasible.
  • I wonder what clock speed the HAL 9000 ran at?

    HAL9000 ran at 24 frames per second. It was just a MOVIE, ya know.

  • Re:But it worked (Score:3)

    by ptomblin ( 1378 ) <ptomblin@xcski.com> on Monday February 05, 2001 @09:35AM (#456094) Homepage Journal
    Actualy, it didn't work.

    Actually, it didwork. Armstrong left the docking radar on when the procedure said to shut it off. This consumed processing cycles which meant that not all the events could be processed in the time allotted, which meant that some very critical calculations weren't getting done. The problem wasn't in the computer, it was in the astronauts not following procedure. The program was basically a big loop which had to be executed every 'n' milliseconds, and the engineers knew how many cycles they had to burn during those 'n' milliseconds, and designed and tested the procedures and programs accordingly. Once the astronauts deviated from the procedures, they were in unknown territory.

  • Re:Complexity Kills (Score:3)

    by arivanov ( 12034 ) on Monday February 05, 2001 @07:47AM (#456100) Homepage
    You are deeply misguided.

    They are not laptops. The laptops are only for austronauts personal use and sometimes for control of non-critical experiments

    The guydance and control computers are actually almost as simple as apollo 11. They were either 804(X=8,9)or 805(X=0,1). These were the highest ones certified for NASA use at the time the shuttle was designed. There is an overall of 5 of these extremely simple systems operating commands to the valves and the engine ignition system on a voting principle. The majority gets to execute the command. The idea is that there cannot be a simultaneous triple failure. This is actually described in detail in one of the articles on the shuttle ran by Scientific American in the eighties.

  • Contrary to what you seem to believe, the laptops carried aboard the shuttle serve no 'mission critical' (per se) functions. They're just laptops like you or I use, and Windows 95 is more than adequate for the purposes they serve.

    The actual guidance, life support, etc., systems run on the shuttles five redundant GPCs which, no, do not run Linux. The way in which the flight systems are coded is incredible -- every single line of code is audited dozens of times. Every single bug generates a binder of paperwork. And it's not just bureaucracy -- it works. Something like half a dozen bugs have affected the shuttle computers in the last decade.

    I wouldn't trust my life to Windows, but I sure as hell wouldn't trust it to Linux either. Anyone who says that they would is either suicidal or a damn fool.
  • NASA actually brings multiple laptops for guidance computer while in orbit. Only one computer is actually needed, but since they recognize the fact that windows is instable, they have a couple more for redundancy. While one is blue-screening, another one takes control of the system.
  • Not too shabby.

    not too shabby? did you ever a play a lunar lander from that period? that's outstanding! of course, I read the article and it doesn't say anywhere how many plays he had at it.

  • Alan Shepard was on Apollo 14. Alan Bean was on Apollo 12.
  • The astronauts didn't follow the procedure, because the procedure was flawed. If they'd had to abort the landing, it would've taken too long to reactivate the docking radar, so it was left on. However, this wasn't taken into account in the software design, so the system failed...
  • I wouldn't trust my life to Windows, but I sure as hell wouldn't trust it to Linux either. Anyone who says that they would is either suicidal or a damn fool.

    Don't act like the two are the same. I can test my Linux system and fix it because I have the source. My Windoze desktop is designed to fail by registry crap out and I can never be sure when or why it will blue screen. Any test performed today is valid only today and is not an indicator of future performance. A linux box can be striped down tested and quality assured. What it does today is what it will do until the hardware fails.

    Do you think the Wright brothers just lofted themselves into the air on an untried and unknown device? No they did not. They had a very good research, design and model program with wind tunnels, mock ups and the rest. Their fliers got off the ground because their behavior was as well known as possible at the time. They were not fools, they were brave men.

  • I got the impression that they made the decision to leave the radar on while on the mission. If there was a real problem activating the radar in time, rather than just a niggling fear that they might need to save some time in that eventuality, wouldn't they have discovered it in simulation? And if they'd simulated it, the computer would have had the same problem.
  • In my day we called our verb-noun interface "Zork", not 'DSKY'.

    go north

    look

    You see a mailbox here.

    open mailbox

    Inside the mailbox is a leaflet.

    take leaflet

    Taken.

    read leaflet

    etc.

    So that's how they made Zork work! I always wondered about that when I was a kid, I just assumed it was rocket science. Looks like I was right!

    omega_rob

  • Use of GOTO?!? (Score:5)

    by 2ndPersonShooter ( 235295 ) on Monday February 05, 2001 @07:34AM (#456126)
    I figured these NASA guys are crack engineers, so if I look at the code I might learn a thing or two. But then there it is, plain as day, the use of GOTO in line 470! I mean, come on, using GOTO in a guidance system? I couldn't believe my eyes!

    470 on BLASTOFF goto MOON

    Who do these guys think they are? Every 1st year CS student knows that GOTO is considered harmful. [acm.org]

    Let's do ourselves all a favor and never go to the moon again using a GOTO statement!

  • By comparison... (Score:4)

    by Gordonjcp ( 186804 ) on Monday February 05, 2001 @07:56AM (#456127) Homepage
    The fuel injection controller in most newish cars uses an embedded controller, usually with about 8k of ROM (most of which is lookup tables) and 256 bytes of RAM.
    They are usually based on 8032 family processors, and are clocked at a stunning 12MHz.
    Of course, I'm speaking for the Bosch Jetronic family, newer ones are more powerful (but not by much).

  • ...and now we do very little with so much.

    Or so it would seem, at least in the world of computing. And the scale of Apollo's computers suggests that going to the moon is predicated on will and desire, not technology.

    Of course, there is something to be said for the vastness of modern computing; we don't need to spend enless hours on the minutia, giving us the luxury of focusing on "the bigger picture".

    Still, I wonder what we could accomplish if we wrote put a historical level of effort into code optimization. Think of the bloat involved in Perl, Java, MFC, VB, scripting, and useless visual clutter. Sometime, bloat doesn't matter -- and sometime, the bloat is just a reflexion of laziness.

    Don't get me wrong; as my father (one of the first EEs) always said: "Use the right tool for the job." While C/C++ may be my tool of choice, it isn't the best or most efficient mechanism for every problem. I think our problem is the old saw about "a man with a hammer sees every problem as a nail." We are too myopic in our view of software developemnt, and we are often too lazy to use the right tool for the job.

    But I digress.

    It is good for all programmers to be forced to get the most out of the least. I've been playing with my Lego Mindstorms kits, trying to build learning algorithms into limited program space, a few motors, and a couple of sensors. It's been a mind-stretching exercise, and I highly recommend such projects to programmers who want to hone their skills to a fine edge.


    --
    Scott Robert Ladd
    Master of Complexity
    Destroyer of Order and Chaos

  • I have to disagree with this, because I think part of any effective testing regimen is durability/lifetime testing. This is obviously something that doesn't happen very much with software testing because of all the little 'memory holes' that don't get noticed until a system 49 days old needs to be rebooted.

    We're right on the verge of sending out interstellar probes. Even if you could do rapid testing by automated means (AI calculated test types, etc... ), can you be assured that your system with last for dozens or hundreds of years necessary to cross the interstellar gap at sub-c speeds?
  • As a straight, heterosexual male, I have been mistaken in the past for being gay, as a result of these idiotic sterotypes.
    If you were mistaken for being gay by actual homosexuals, you might want to do some introspection.
    As a practicing homosexual, I can assure you that what is laughably called "gaydar" is damn near infallible.
    I have never once mistakenly hit on a heterosexual man - not once. Sure, sometimes I hit on latent homosexuals who were still in denial, but they've all been at the point in their lives where they were willing to expiriment.
    Of course if it's women or straight men that think you're gay, you've got nothing to worry about - they can't tell worth beens.
    Most of my hetero male friends think I'm straight.
    --Shoeboy

  • But it worked (Score:5)

    by sharkticon ( 312992 ) on Monday February 05, 2001 @06:48AM (#456135)

    Considering that today people seem to want to throw the latest technologies at every tiny little problem they encounter the fact that the Apollo 11 worked is a testament to the fact that more is not always better, and that complexity brings its own problems.

    Unfortunately, it seems as though people have gotten used to the idea that they require the latest technology, the latest "innovations" in order to be successful and cool. Hence the market for shoddy products that are rushed out quickly to customers, who can be guaranteed to solve their problems by getting the next release because it's newer and therefore superior.

    Whereas this machine, so simple compared to even the simplest of embedded processors today, did what it was supposed to, and did it well. Today, we see all kinds of computer problems due to technology being thrown at projects as a miracle cure without considering what is actually required! Just look at the Navy's debacle with NT for a prime example.

    Well done /. We need more stories to remind us that more technology isn't always good. Remember, 90% of everything is crap, and technology is no exception.

  • The problem with this sort of thinking is this: how long did it take NASA to build and program that computer? Back then they were programming in assembly language because they had no choice (for efficiency both of clock cycles and memory). Now, throw a couple gigs of memory and a few thousand MHz at the problem and it becomes a lot easier to handle, and you can use a nice friendly high-level language and accomplish way more than you ever could have before.

    The fact is that the average software engineer produces five lines of code per day of an efficient development cycle. In a project where lives will depend on the result (such as in space travel), the number is more like one or two lines of source code per day. That's regardless of what language they're using. So programming in assembly language you would produce way fewer features for the same time spent.

    This is just a fact of software development, there's no way around it. So don't tell me that computers that are more powerful are not a good way to solve problems. If that were true, we wouldn't have bloated software like Linux, Windows, and Microsoft Office. But bloated though they may be, they're pretty bloody useful!

    (BTW: I wasn't able to get through to the source code listing so I'm just assuming they were programming in assembly. My argument still stands, though, regardless.)

  • Complexity Kills (Score:5)

    by Bonker ( 243350 ) on Monday February 05, 2001 @06:54AM (#456143)
    Part of the beauty of this old, seemingly useless system was that it was simply designed, and almost perfectly optimized for the task.

    Now we have astronauts taking laptops into space and using MS software for email and networking while on board. The testing cycles for all this software is long because all faults have to be eliminated, but the simple fact remains that computer and software designs are becoming so complex that in the very near future, if not already, they are too complex for use in the space program.

    Hunting down a bug in a 100000 lines of code is one thing. Hunting down a bug and all the other bugs it causes in 4 million lines? NASA has already faced this problem, because they use Win 95 laptops. How about 10 million lines. How about 20 M?

    What about the computer processors that run the space shuttles. Frankly, they're all old technology, because upgrading to the newer stuff is just too damned dangerous. If the video processor that powers your HUD guidance systems crashes because of an obscure hardware bug that occurs only in freefall, you're screwed.

    Personally, I think that this sort of complexity is going to become the limiting factor in the advancement of technology. A point will come in the very near future when systems, be they processors or OS's, become so complex that the testing time necessary for critical use makes rapid development unprofitable.
  • I'm sure that if I was an astronaut I'd prefer the relative comfort and ease of use and reliability of modern ships compared to Apollo but there's something to be said for the single mindedness of that earlier gear. There was abolutetly NOTHING extra in that box, nada. I spent my formative years designing computational algorithms expressedly for limited resource, slow clock machines. The design goal specifically was "do xxxxxx in 25 ticks or less and using less than x K memory". It puts the fun back into orbital mechanics. By comparison I doubt you could run the diagnostic system that checks the indicator status lights on the space shuttle with one. Nor would you want to either.
  • Just one correction to an informative post -- right astronaut, wrong mission: Alan Shepard was on Apollo 14.
  • "Ground control, wtf are you doing the clocks only on 5 and we're off the ground."

    The good news was Windows couldn't run on it.

  • Re:But it worked (Score:3)

    by selectspec ( 74651 ) on Monday February 05, 2001 @06:56AM (#456154)
    Actualy, it didn't work. Fortunately, Armstrong noticed that Eagle was heading towards some jagged craters and turned the landing computer off. He then manually landed the craft, with only 4 seconds of fuel remaining on touchdown. Not too shabby.

  • The DSKY Rules! (Score:5)

    by QuantumHack ( 58048 ) on Monday February 05, 2001 @06:57AM (#456155) Homepage
    The Display/Keyboard interface (DSKY, pronounced 'diskey') to the Guidance/Nav computer (GNC) was a superb interface. I know an engineer who actually got to play with one. In a pre-GUI, pre-command-line age, the verb-noun interface was actually very intuitive. It's kind of like having a hardware interface that allows you to call various API methods or functions, which prompts you as to the various parameters, then displays the returned values.

    To the astronauts, the DSKY was the GNC; the GNC really was just a box stowed in the Lower Equipment Bay.

    The interface was so good, it was subsequently used on the F-8 fighter prototype. For more on the DSKY, see:

    http://www.dfrc.nasa.gov/gallery/photo/F-8DFBW/HTM L/EC96-43408-1.html

    To see it in action, watch the "From the Earth to the Moon" series from HBO. Most local video stores have 'em. The Apollo 12 one was my favorite for seeing the DSKY in action, when Al Sheppard helped upload new code (IN FLIGHT) to ignore a flakey ABORT button.

    Best to ya,

    Quantum Hack

    http://www.hamhud.net

  • Emulating this will be sweet and elite. The only problem is the 70 lbs box. Hurm...I bet if I strap together four old metal computer cases that will way nearly 70 lbs! Rock on!

    Hey...its the only thing I could think of besides saying "Can you imagine a Beowulf cluster of these things?"
  • I am tempted to ask "what heavy space suits"? I mean, it is not necessary, not even likely, than a Mars mission 15 years from now would require heavy space suits.

    As for the period, lots of women take Depo Provera, one common side-effect is that the period goes away. I'd say that problem is fixed.

    Actually, I think an all-women crew on a Mars mission deserves very serious attention. Also, I think it is important that recruitment of female astronauts gets more attention now, so that a high enough number of astronauts gathers enough experience for such a mission.

    Whether we should go at all, is a different issue...

  • Ha ha,
    Nothing's as funny as an offensive stereotype.
    Do you have any idea what it's like to be a homosexual in middle America?
    Violence, intimidation, ridicule, discrimination...
    It's not funny at all.
    You make me ill.
    --Shoeboy
  • IHBT, but...

    >I consider the average IQ on slashdot to be about 85.

    That very well might be the case now [resisting urge to flame]... the quality of discussion (especially on the science topics) has (obviously) dropped rather dramatically over time. As for myself, I don't have problems being that limited (the last IQ test had I had was quite some time ago, but I can assure you that it was nearly double the stated number... and of course, you should mention which IQ scale you are using, if you want to get picky).

    I was:
    A) Talking about males, not the general population, and
    B) Basing my personal views on the fact that *I* consider anyone substantially shorter than 6' tall 'short' and anyone a few inches taller than that 'tall'. It is a subjective measure. If I see a man who is 5'8" I think him 'short'. If I see a woman who is 5'8", I consider her 'tall'.

    While the 50th percentile (truly average) adult male on Earth is 5'9.1"(175.75cm) 172 lb (78.4 kg), that isn't representative of the society that I happen to reside in, where the average male is taller than that, statistically speaking. It probably has something to do with the large Scandanavian and German populations in the northern midwest (of the U.S.A.). The average height of the ~16 men in my department at work is about 6'1.5". Other parts of the country (like my hometown) had higher percentages of people of Italian and Slavic decent, and the average height was lower, but I am just speaking to my present situation. So take that enlightened age and guess, feel, and consider it all you like. Absolute truth without context isn't useful in many situations.

    (it's Monday, and I have a lot of pent-up anger today... thanks for the release)
    --

  • Re:Midgets are better in space (Score:4)

    by Sethb ( 9355 ) <bokelman@outlook.com> on Monday February 05, 2001 @08:12AM (#456167)
    Why not send dwarves/midgets? They're even smaller! You could build smaller vehicles, smaller spacesuits, pack less food, etc.

    Send Mini-Me to Mars!
    ---

  • Not practical. (Score:3)

    by BigBlockMopar ( 191202 ) on Monday February 05, 2001 @06:59AM (#456169) Homepage

    For this reason, it is my belief that gay men are far better suited for long term space exploration,

    Are you kidding? The Madonna CDs alone would make the launch weight prohibitive!

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