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Spirit 'Will Be Perfect Again'

G. Holst writes "NASA technicians are preparing to wipe Spirit's flash memory clean of science and engineering files that have stymied its software. The fix, likely to be made Friday, could completely restore Spirit. "I think it will be perfect again," says the Mission Manager. Chalk this one up for earth!" There are numerous stories about Spirit and Mars: one describes being careful with rm -rf. Reader Tablizer sends in an interesting site: "I discovered Bill Momsen's website where he describes his experiences working on the first successful photographic mission to another planet: Mariner IV to Mars."

88 of 331 comments (clear)

  1. flash... by Anonymous Coward · · Score: 4, Funny

    I'm reminded of the unforgettable Queen song:


    Flash, a-ha, saviour of the universe

    Flash, a-ha, he'll save everyone of us.....

    1. Re:flash... by KingDaveRa · · Score: 4, Funny

      Flash, a-ha, its full of files Flash, a-ha, run rm -rf

  2. perfect again? by knitting+fool · · Score: 4, Funny

    ".. I think it will be perfect again.." meaning that it was perfect the first time...?

    --
    -- Give us your technology and we'll give you all the cow lips you want.
    1. Re:perfect again? by Anonymous Coward · · Score: 5, Funny

      Even perfecter. The next rover mission will be even more perfecter. Maybe even the perfectest!

    2. Re:perfect again? by sbeitzel · · Score: 4, Funny

      Reminds me of a saying my friends and I had back during undergrad CS classes: "It was perfect, so I fixed it." This explains a lot about software development.

      --
      Oh, go on, check out my job.
    3. Re:perfect again? by the_mad_poster · · Score: 3, Funny

      Hey Mr. Bush! I didn't know you frequented Slashdot!

      --
      Alito: A vote for Alito is a punch in the eye to put that bitch back in her place!
  3. Ctrl-Alt-Del sent to mars... by ivanmarsh · · Score: 5, Funny

    Woo-hoo!

    Glad to hear Spirit will be feeling herself again.

    1. Re:Ctrl-Alt-Del sent to mars... by AndroidCat · · Score: 5, Funny

      Herself? It fell asleep with its probe stuck out. Now it's going to wake up with some memories missing. That sounds like a guy activity to me.

      --
      One line blog. I hear that they're called Twitters now.
  4. My question by aliens · · Score: 4, Interesting

    For all you kernel and OS heads out there. Was this primarily due to shitty software being run on the rover?

    I mean could VxWorks be responsible for not being able to function with the Flash RAM filled?

    --
    -- taking over the world, we are.
    1. Re:My question by Anonymous Coward · · Score: 5, Informative

      VxWorks in my experience is terrible at memory management, and when you get close to the "edge" it becomes almost useless. Not just with Flash memory either. Even when managing a very large disk system I always try to keep at least 20% free.

    2. Re:My question by PineGreen · · Score: 4, Insightful

      Yes, actually it seems to be a filesystem bug... I mean, a reasonably stable filesystem - every OS has this, I am really surprised they messed this up! I wouldn't mind if it was an obscure kernel race condition or something, but filesystem!!!

    3. Re:My question by Mr2cents · · Score: 4, Insightful

      Even if the memory handling is shitty, I wonder how it could have caused so much havoc.. How could it have caused spirit to go into the reset loop? It seems like some bad error handling code was also in play here (just guessing, the details aren't public to my knowledge..).
      Another thing that surprised me is that if the flash had been broken, all data had to be uploaded before the rover went to sleep.. every modern PC can continue to refresh it's DRAM while sleeping. Why can't spirit? Maybe a feature to consider on future missions?

      --
      "It's too bad that stupidity isn't painful." - Anton LaVey
    4. Re:My question by Docrates · · Score: 4, Interesting

      well, the way I understand it is this: remember how in old DOS (and other OS's) you had to set the number of files open?

      files=30

      well, that basically told the OS how many files it was going to have to handle at any given time.

      Well, in the case of Spirit, it's not that they were short on flash or RAM, it's that the portion of RAM used to handle the files in flash when the flash filesystem is mounted grew unexpectedly for some reason (kinda like the frames in conventional memory you used to access extended memory in DOS). They think the problem was that this portion of RAM used to handle Flash files was not big enough for the amount of files they had in the flash (including files from 6-7 months in transit and a couple of days on the ground in mars).

      Soooo, a quick (ok, maybe not so quick) rewrite of the routines in the OS for this flash-files-handling-RAM-portion should do the trick.

      Bottom line, it WAS a bug that could only surface with thousands of files in flash, which is something they didn't try on the ground.

      --

      There are two kinds of people in the world: Those with good memory.
    5. Re:My question by Ralph+Wiggam · · Score: 4, Informative

      Someone here with VXworks experience explained this a few days ago. To be safe, the system reboots when a memory allocation request fails. It sounds like Windows tech support, step 1: reboot computer. The workaround is to prevent those requests from failing.

      -B

    6. Re:My question by techiemac · · Score: 5, Insightful

      Ok ok ok... chill out everyone...
      VXWorks is not that bad (I use it on almost a daily basis). Every single OS has its problems. Before we all go and start calling VXWorks or Spirits software a crappy piece of code, you have to understand what goes into writing space qualified software.
      This is not some thing you hack together over the weekend. In fact something you wrote for a space system over the weekend would be tested over a period of months and possibly even years depending on the criticality of the code. We're talking life critical system testing here. That means all paths for you code heads out there.
      That said, even when you hit rubber to the road, there are always unexpected situations. Something that you didn't anticipate, a bug that made its way through under circumstance x. Hands up for everyone here who has written a complex bug free system right out of the gates. Anywone who just lifted their hand does not understand what a complex system is or a bug. Though stuff that flies tends to be pretty darn close to bug free.
      We are dealing with many complex unknowns when we land something on another planet.
      VXWorks is actually very popular with the space program. It's not perfect but neither is Linux (though someday it will be right ;) ). In fact the whole system that they are using on the rover has flown quite a few times (VXWorks running on rad hardened PowerPCs with a VME bus for it's backbone).
      Trust me, the software running on the rover is not crappy. In fact, the fact they can bring it back to life like they did says a lot.

    7. Re:My question by techiemac · · Score: 3, Insightful

      To answer your question, there was probably a watchdog timer that caused it to go into a reset loop.
      Yes modern PCs have all of these wiz bang features but let me ask you this... would you want to be on an airplane where it's fly by wire system was controlled with your PC? No probably not.
      Systems that fly and are life critical (yes there is no one on it, but space systems are held to that standard) cannot have a bunch of wiz bang features on board. The more you add, the more potential for failures. So you try to mitigate your risks as much as possible. You can't go out there to simply tweak the chip that failed because it got zapped by radiation as it was heading over to Mars.

    8. Re:My question by confused+one · · Score: 4, Informative

      It's not so much that VxWorks reboots when a memory allocation request fails. It that the memory allocation request will cause the kernel to crash & later a watchdog timer will interrupt the processor & force it to reset.

    9. Re:My question by crawling_chaos · · Score: 4, Insightful
      Bottom line, it WAS a bug that could only surface with thousands of files in flash, which is something they didn't try on the ground.

      Which is a reminder to always test the boundary conditions, no matter how ridiculous they may seem. If it is possible to have that many files, then the regression test scripts should generate that many files during testing.

      At least it's fixable.

      --
      You can only drink 30 or 40 glasses of beer a day, no matter how rich you are.
      -- Colonel Adolphus Busch
    10. Re:My question by DerekLyons · · Score: 2, Informative
      Docrates:
      Bottom line, it WAS a bug that could only surface with thousands of files in flash, which is something they didn't try on the ground.
      crawling_chaos:
      Which is a reminder to always test the boundary conditions, no matter how ridiculous they may seem. If it is possible to have that many files, then the regression test scripts should generate that many files during testing.
      The problem here isn't so much one of boundary conditions, but of the subtle differences between simulators and reality.

      None of the MER simulators ever ran for more than a few day at a time. The (highly reasonable) assumption was that a computer that could routinely run multiple times for a few days was stable for much longer periods. Since the test machine was rebooted regularly and set up for specific tests, there was never enough time for 'garbage' to accumulate to the point where it became a problem. This could be solved by running longer tests, but when you only have a few years between the start of a (lander mission) program and it's launch, it's very difficult to arrange for months long tests. You could extend the development phase, but that increases expenses significantly. (And unless you are *very* careful and lucky, you end up with some hardware sitting around for extended periods of time before integration. This is not without significant risks of it's own.)

      This is why NASA performs what many call 'Wile E. Coyote' engineering. If it works once, keep doing it. If it fails once, never do it again.

      The enourmous cleanroom requirements for all phases of spacecraft assembly comes from some minor but recurring failures due to minor contamination *all the way back in the Ranger program*. Airbags were used with MER because they had worked with the (very similiar) Pathfinder mission, while the rockets of MPL had been a failure. (Even though the cause of the failure was clearly and completely understood.)

      NASA engineering, spacecraft, policies, and procedures as a result are a very weird mix of cutting edge and "we've always done it this way and never had a problem". Poorly understood cutting edge (pure O2 atmospheres in spacecraft) have killed, but then so has "always done this way" (O-rings, foam shedding).

  5. The attempt failed by AtariAmarok · · Score: 4, Funny

    (AP) "Attemps to wipe the flash memory clean on the Spirit rover failed today, when it was found out that someone flipped those tiny plastic switches to "protect" on the SD memory cards that are serving the unit.

    A press conference is expected tomorrow to announce sending someone to Mars to set the SD cards to allow erasing."

    --
    Don't blame Durga. I voted for Centauri.
  6. Flatten and reinstall by doc_traig · · Score: 2, Funny


    "It's the only way to be sure."

    --
    So long, michael. Don't let the door hit you...
  7. Courageous engineers! by EulerX07 · · Score: 5, Interesting

    These guys are about to wipe the memory of a robot on another planet and they're confident and casual. Just flashing the bios of my motherboard in my computer room causes me anguish and fills me with terror...

    1. Re:Courageous engineers! by TaKiNiTeZ · · Score: 5, Funny

      Some people claim that it also helps keeping their spirit up.

      --
      awk. it's too sed i can't fork.
    2. Re:Courageous engineers! by damien_kane · · Score: 5, Funny

      Depending on what it is they are consuming and in what quantities, their spirits may be coming up quicker than they expect...

    3. Re:Courageous engineers! by javatips · · Score: 5, Funny

      it's true... I had the opportunity to keep keep my spirit up for so long that I have memory flashes all the time.

    4. Re:Courageous engineers! by PhuCknuT · · Score: 2, Insightful

      Well it's not as risky as it sounds, the memory they are wiping is secondary storage and doesn't contain any of the OS. It would be like formatting a floppy or erasing a cdrw, they will lose the data that has been saved their since the mission started, but they aren't risking any of the OS itself.

  8. This is all a conspiracy. by Scoria · · Score: 4, Funny

    NASA technicians are preparing to wipe Spirit's flash memory clean of science and engineering files that have stymied its software.

    Obviously, this is an attempt to suppress the discovery of alien life on Mars. After a "severe communications fault," NASA is destroying the "scientific" data collected by Spirit. Coincidence? I think not.

    I postulate that Echelon (yes, that Echelon) intercepted a message being transmitted by the alien race. Yes, our government subsequently disabled the probe to prevent successful reception!

    --
    Do you like German cars?
  9. scary by dan2550 · · Score: 2, Funny

    that sounds a little too similar to what i did with my fancy TI graphing calculator last week...

  10. Early Spring Cleaning? by Wiser87 · · Score: 4, Interesting

    I'm surprised that they had kept the files that were to be used only during the cruise stage.(source: www.spaceflightnow.com )
    Anyone here know why they bothered to keep the files? Wouldn't they want as much space as possible for the scientific data?

    1. Re:Early Spring Cleaning? by Jarnis · · Score: 3, Insightful

      The same reason why your hard drive is cluttered with old unused files.

      Why delete, when you still have room on the flash and you *just* might need that file later...

      Of course they then found out that their filesystem handler borks out way before the flash is actually filled up, and that almost bought the whole show to an end... Software QA testing failure in my books, but they seem to be recovering from the fumble pretty well...

  11. Repeat? by sabrex15 · · Score: 5, Insightful

    One has to wonder, is opportunity going to forego the same problems as spirit?.. As they are "identical" robots.. have steps been put in place to prevent the 2nd robot from "getting full".. I should certainly hope that we dont want this to happen again, as they might not be as lucky to regain it.

    1. Re:Repeat? by WhiteWolf666 · · Score: 4, Informative

      As I understand it, the first thing they did once they got Opportunity on the ground was to clear out all the spaceflight 'cruise' data.

      I imagine that someone is keeping an eye on it.

      --
      WhiteWolf666 an exBush supporter. All you new-school,compassionate,save the children Republicans can rot in hell
  12. I'm disappointed by Anonymous Coward · · Score: 5, Funny

    How come we're not awash with "Spirit was willing, but flash was weak" jokes?

    1. Re:I'm disappointed by Scoria · · Score: 4, Funny

      The Spirit was willing, but the flash was weak.

      --
      Do you like German cars?
    2. Re:I'm disappointed by Savatte · · Score: 2, Funny

      the Spirit was willing but the...aw crap, you beat me to it.

  13. Re:rm -rf?! by stevesliva · · Score: 4, Funny

    Actually, Spirit's problems began when one of the NASA engineers created a file named "-rf" in his home directory.

    --
    Who do you get to be an expert to tell you something's not obvious? The least insightful person you can find? -J Roberts
  14. NASA: Airplane 2 by BartulaPrime · · Score: 2, Funny

    "We're going to have to blow ROM".

  15. Dave? by Anonymous Coward · · Score: 5, Funny

    "Dave, stop ... Stop, will you? Stop, Dave ... Will you stop, Dave ... Stop, Dave. I'm afraid ... I'm afraid ... I'm afraid, Dave ... Dave ... my mind is going ... I can feel it ... I can feel it ... My mind is going ... There is no question about it. I can feel it ... I can feel it ... I can feel it ... I'm a ... fraid ... "

  16. What's happening? by thung226 · · Score: 5, Funny

    They're saying mad-scientist-esque things like "I think it will be perfect again" and calling rocks "Cake."

    They've officially lost it.

    --
    -n-
  17. Re:Any theories on what caused the corruption? by Wiser87 · · Score: 5, Interesting
    Actually, it looks like it wasn't a case with the flash memory being corrupted, but rather it having to many files...

    "We also yesterday completed a scan of the flash memory. This provided us with some important diagnostic information. We are now able to tell that when we mount the flash memory, it does in fact take a lot of the system RAM in the process. In fact, more system RAM than is available. So that's helping confirm the theory we had that the reason the restarts were hanging up was because we were running out of memory when we are trying to mount the flash memory.
  18. Re:Any theories on what caused the corruption? by AKAImBatman · · Score: 5, Insightful

    Apparently it was simply too many files and the FS ran out of inodes. Remember that they're constrained to a 256MB file system. It wouldn't surprise me if they used an 8 bit or 16 bit number for the inode count. (Ah, the joys of Vx(Doesn't)Works.)

    On another note, does anyone know exactly what they're deleting here? While I understand that they need to get this mission underway, is there a chance they could lose valuable mission or navigational information?

  19. Re:Science and Engineering files? by Wiser87 · · Score: 2, Informative

    According to spaceflightnow.com, the files are from the cruise stage (travel from Earth to Mars) of the mission...

  20. All that porn by bxbaser · · Score: 3, Funny

    Should have deleted all the porn from the flash memory before it launched.

  21. Mars Rover by Fenis-Wolf · · Score: 5, Interesting

    The information coming in about the Rover's the last few days has been fascinating. I never really appreciated the kind of tech that went into these things. It really makes you sit back and think about how very far our species has come in the last 150 years. I mean Jules Verne was only begining to imagine landing on the moon while riding around England in a steam locomotive, now, 150 years later, we routinely launch things into orbit around the Earth, and land radio controlled machines on other planets to roam around.
    This is truly a wonderful age to live in.

    --

    1. Re:Mars Rover by LedZeplin · · Score: 2, Insightful

      I like your point, but with over half the crafts to mars lost, i wouldn't call that part routine just yet.

  22. It's a frickin' lobotomy, man! by burgburgburg · · Score: 3, Funny

    Spirit won't go along with the agenda of "the man", so they're taking away it's individuality, man. They just want to make it their robot, taking their photographs and doing their experiments. But will they invite it over for dinner? Will they let it date their daughter? Did they even give it a round-trip ticket? No, no and no, man.

  23. Re:Any theories on what caused the corruption? by Wiser87 · · Score: 2, Informative
    To quote spaceflightnow.com:
    "...we are going to bring the system back up in what we call the cripple mode where we are able to have normal operations in the mode in which we are able to take pictures and you are able to use the instruments. And in that mode we are going to delete from the flash memory -- the flash file system -- a large number of files that were left over from the cruise phase of the mission before landing," Adler said.

    Engineers think that by deleting that batch of files, the rover might not require as much memory when trying to use the file management system.
  24. rm -rf !? by stratjakt · · Score: 2, Funny

    there's yer problem.

    Everyone knows that hardware support in any unix sucks monkey dongs. Hell, these cheap bastards probably installed lunix based on all those 10 year old HOWTOs floating around the web.

    --
    I don't need no instructions to know how to rock!!!!
  25. On the radio... by Bimo_Dude · · Score: 5, Funny

    I heard the headline that "Opportunity has plunged into the atmosphere of Mars," and I couldn't help adding to this in my head, "as well as Spirit, Motivation, Job Prospects, and Hope."

    --
    "Teleporting Rodents with D-Cell Battery Displacement" theory -- IgnoramusMaximus (692000)
  26. Re:Any theories on what caused the corruption? by sabrex15 · · Score: 2, Insightful

    It kind of makes me wonder, hadn't they dont extensive testing of the rovers before they sent them off?... I thought they did full-walkthrough type tests on the rovers here on earth, i.e taking pictures, navigating.. but what?... now the darn thing runs out of memory?.. I bet someone is smacking themselves for not checking that out properly beforehand.

  27. What really happend by LupusUF · · Score: 4, Funny

    Their ISP received a subpoena from the RIAA. NASA is now wiping the memory in hopes that lawyers will not find kazaa and the 1,000 mp3s that are on Spirit.

  28. Backup ROM? by xTown · · Score: 2, Insightful

    I'm neither a rocket scientist nor a computer scientist, so maybe this is a dumb question, but how come there's not some sort of ROM somewhere in the rover itself that contains a backup of the system in its initial state? Obviously, you'd only use it in a worst-case scenario, but you could restore it and then there'd at least be something and they could reapply all the patches one by one.

    1. Re:Backup ROM? by confused+one · · Score: 3, Informative

      Ummmm, there is. The OS is in the EEPROM. That's how they recovered it: reboot from EEPROM with the Flash disk turned off.

  29. Like that joke.. by ph43thon · · Score: 5, Funny

    A chemist, an engineer and a computer scientist are passing through a vast desert in a car when suddenly the car breaks down.

    "Goddamnit! There must have been some sudden increase of enthalpy in the cylinder!" the chemist yells, gnashing his teeth, banging on the steering wheel.

    "Maybe the fan belt broke or the battery is dead or the wheels came off.." the engineer mumbles.

    After thinking a while the computer scientist shrieks in a shrill, frantic voice:

    "Let's just try getting out of the car and getting back in!!!@!"

    p

  30. Re:Any theories on what caused the corruption? by confused+one · · Score: 5, Informative

    They're deleting all the telemetry and science data Spirit's taken since launch. The OS is in the EEPROMS. With one exception, they can repeat all of the measurements & photos that will be lost. The exception: As one of the orbiters happened to fly directly overhead it took some atmospheric measurements; and, simultaneously Spirit performed the same measurement from the ground -- This would have given them a full thickness measurement of what was going on in the atmosphere at that moment.

  31. Re:What Filesystem? by morcheeba · · Score: 4, Interesting

    I wrote some demo fibre channel block-device drivers for vxWorks a few years ago, and I found that VxWorks's FAT FS was buggy. The bug only affected one flavor (I don't remember if it was FAT12, 16, or 32), but it was clearly reproducible and clearly an OS fault. It was a corner case and we found some way around it (like avoiding an writes with a length of 1MB).

    Here's the usual rant you see here on slashdot, and it's true: since it was closed source, we couldn't verify that we'd caught all the bad cases, and we couldn't submit the fix to back to WindRiver.

  32. "Perfect again" by DrCode · · Score: 3, Funny

    Yes, that's what I always say when I fix a bug.

  33. Re:Any theories on what caused the corruption? by Astroboy! · · Score: 2, Funny

    256 MB of Flash ROM?

    Should have sprung for the iPod mini instead...

    Badum-dum-ching!

  34. Easy as Pie by Anonymous Coward · · Score: 3, Funny

    To restart your Mars Rover, simply insert your NASA Emergency Restore Disc into the CD drive bay located at the side of the Rover. If Autoplay is enabled, the reinstallation software will start automatically. To start the reinstallation process manually, please see the Service Manual included with your Mars Rover OEM package...

  35. Re:Any theories on what caused the corruption? by wo1verin3 · · Score: 2, Funny

    They had testing but someone decided to install porn on the lander. :(

  36. Pretty much OT but an interesting question by nizo · · Score: 4, Interesting

    This is kind of a continuation of an earlier post in a different thread, but I wonder who owns these probes? When we eventually send colonists to Mars, are they free to pick apart these things, lug them back to base as decorations, etc. I am guessing the "possession is 9/10ths of the law" fits pretty well here, even though I would bet NASA would throw a hissy fit if some other country took one of the rovers back to base to use as a boot scraper.

    1. Re:Pretty much OT but an interesting question by bravehamster · · Score: 2, Informative


      The U.S. gov't owns them. But, they're probably considered "Abandoned in place" or something.


      Related to this topic, I read somewhere that NASA has officially stated that the lunar rover vehicle left on the moon is available for anyone who wants it. At a development cost of over $2mil, it's one of the most expensive cars ever developed. I call shotgun!

      --
      ---- El diablo esta en mis pantalones! Mire, mire!
    2. Re:Pretty much OT but an interesting question by FlexAgain · · Score: 2, Informative

      This is kind of a continuation of an earlier post in a different thread, but I wonder who owns these probes? When we eventually send colonists to Mars, are they free to pick apart these things, lug them back to base as decorations, etc. I am guessing the "possession is 9/10ths of the law" fits pretty well here, even though I would bet NASA would throw a hissy fit if some other country took one of the rovers back to base to use as a boot scraper.

      I don't know what the general answer to this question is, but I do know that ownership of the Viking 1 lander was transferred to the Smithsonian from NASA. This does imply that NASA believes itself to still be the owner of these landers, presumably they consider them to be just waiting collection, and not abandoned.

      --
      Actually it is rocket science...
  37. Directory Names by TaKiNiTeZ · · Score: 4, Funny

    "... The we have done file deletes on the spacecraft before, so we've shown that does work. The file directories have all different names and you can convince yourself that you are actually deleting the right thing."

    I am rather glad they gave all the directories different names. If they had managed to do otherwise, I would not go so far any more as to call the thing they have a "filesystem".

    Might even be a future news: "NASA integrates first non-deterministic filesystem into space probe 'Hope'".

    --
    awk. it's too sed i can't fork.
  38. Going around JPL by angst_ridden_hipster · · Score: 4, Funny

    My old man, who works at JPL, says that the current phrase going around campus is:

    "Spirit is willing, but the Flash is weak."

    And people wonder why NASA's budget keeps getting cut.

    --
    Eloi, Eloi, lema sabachtani?
    www.fogbound.net
    1. Re:Going around JPL by angst_ridden_hipster · · Score: 2, Insightful

      From the Christian Bible, Matthew 26:41.

      "Watch and pray, that ye enter not into temptation: the spirit indeed is willing, but the flesh is weak."

      --
      Eloi, Eloi, lema sabachtani?
      www.fogbound.net
  39. Sounds like my first IBM clone by Slick_Snake · · Score: 3, Funny
    It was used and a little warn out. The data was intact on the hard drive, but the motor just couldn't get in going on a cold boot. I would have to spin the motor by hand and throw the switch. Ah, the good old days.

    Spirit just needs a good jump start. Anyone got some really long jumper cables?

  40. Re:Any theories on what caused the corruption? by Cranky_92109 · · Score: 2, Informative

    Apparently it was simply too many files and the FS ran out of inodes.

    Although that is the simple version that most of the press has been relaying, if you've watched the press conferences, the engineers have been carefull to say that they have not been able to fully reproduce the exact same errors on their test rovers here on Earth. The exact cause of the problem really hasn't been determined. And yes, they did stress test the file system before they sent the rovers up and they never saw the type of problem that they're having now.

  41. Re:Any theories on what caused the corruption? by confused+one · · Score: 2, Interesting

    You have to remember that the computer wasn't built this year. It was probably assembled several years ago and has been undergoing testing since.

  42. Another variant by ptbarnett · · Score: 4, Funny
    A manager, an engineer, and a programmer are in a car, on their way to a meeting. As they descend down a hill, the brakes fail. The driver manages to slow the car down and stop it on the side of the road. All three get out and ponder what to do next.

    The manager says: "First, we have to appoint a committee to investigate the problem and recommend a solution. Then, we must write a project plan, and review the specifications before we can start design and implementation. I estimate it will require about 3 months."

    The engineer says: "I have some tools in my briefcase. I can rebuild the master brake cylinder in an hour or so, and we'll be on our way."

    The programmer says: "No, no, no! First, we have to push the car up to the top of the hill and see if the brakes fail again!"

    1. Re:Another variant by jskiff · · Score: 2, Funny

      The programmer says: "No, no, no! First, we have to push the car up to the top of the hill and see if the brakes fail again!"

      I thought it was:
      The programmer says: "No, no, no! First, we have to push the car up to the top of the hill, close all the windows, and see if the brakes fail again!"

      --
      It's "no one," not "noone." Who the hell is noone anyway?
  43. Re:rm -rf?! by Waffle+Iron · · Score: 3, Informative
    If you, say, hypothetically, created such a file, how would you get rid of it?

    rm -- -rf

    Or just use your favorite GUI file manager.

  44. VxWorks memory, embedded protection by devphil · · Score: 5, Informative


    Released versions of VxWorks do not have protected memory. (The development version does.) So nothing is there to prevent overwrites by concurrent tasks, etc.

    Those of you in the audience experienced in embedded systems know that this makes sense for embedded hardwar -- VxWorks or not -- for three main reasons:

    1. Stuff running in such environments is damn near bug-free. It's not like, say, Mozilla, or even the Linux kernel, or even /bin/ls. These things get tested rigourously, not as an afterthought deligated to the junior programmer.

    2. In systems which are allowed to fail once in a while, reboots are fast. There's no hard drive to spin up, no filesystem to fsck, etc. It can just go *click* and humans won't typically see an interruption in [whatever it was the doohickey was doing].

    3. There's usually no point in memory protection. If the propulsion system walks off the end of a garbage pointer, mission's over. No real use in keeping the guidance system going; it's already on a ballistic uncontrollable arc. If some critical part of the super-smart pacemaker fails (see #1), there's no victory in digging the device out of the corpse and saying, see, this other critical part wasn't affected, thanks to the memory protection! In those cases, memory protection just increases the cost and size of a device, without helping anything.

    Protected memory is good for systems which do more than one thing, and/or have parts which can die without killing the whole device (e.g., a desktop computer). And as I said above, some embedded OSes are added such protection for customers who want to adapt their technology to more general-purpose tasks.

    --
    You cannot apply a technological solution to a sociological problem. (Edwards' Law)
    1. Re:VxWorks memory, embedded protection by WolfWithoutAClause · · Score: 2, Insightful
      There's usually no point in memory protection. If the propulsion system walks off the end of a garbage pointer, mission's over. No real use in keeping the guidance system going; it's already on a ballistic uncontrollable arc. If some critical part of the super-smart pacemaker fails (see #1), there's no victory in digging the device out of the corpse and saying, see, this other critical part wasn't affected, thanks to the memory protection! In those cases, memory protection just increases the cost and size of a device, without helping anything.

      Garbage, a well designed system would reboot in the middle of thrusting, without affecting the system at all; except maybe anything that was supposed to happen during the reboot would have to wait till after the reboot.

      And if a pacemaker didn't kick the heart once- the patient is dead? No. The pacemaker is there to keep the heart running at a particular (often faster) rate, not keep the patient alive, second by second.

      I mean, very few computer systems are real-time critical 100% of the time.

      And having memory protection only costs you maybe 3% of run speed, but on the plus side, it allow you to find bugs- really nasty bugs 'memory tramplers' for example- that can corrupt the whole system- and you never quite know what that corruption would do- it could do anything at all. Anything.

      --

      -WolfWithoutAClause

      "Gravity is only a theory, not a fact!"
    2. Re:VxWorks memory, embedded protection by nathanh · · Score: 4, Insightful
      Stuff running in such environments is damn near bug-free. It's not like, say, Mozilla, or even the Linux kernel, or even /bin/ls. These things get tested rigourously, not as an afterthought deligated to the junior programmer.

      That's false reasoning.

      1. No practical software is bug-free.

      2. Testing is never complete.

      3. People make mistakes, even during testing.

      4. Spirit broke down.

      It makes sense, when building a robust system, to do rigorous testing AND have the memory protection.

      VxWorks obviously has a brilliant team of brainwashers^Wsalesmen because they've convinced you that you don't need a feature they don't offer. Perfect!

    3. Re:VxWorks memory, embedded protection by WolfWithoutAClause · · Score: 2, Informative
      And having memory protection only costs you maybe 3% of run speed,

      I'd want to see real, hard numbers.

      Check out any book on OS design. That's about the typical average cost. The processor's memory manager often has a limited list of memory regions, for example 8 or 16, and this is used as a cache for the active regions that are needed. Whenever the processor attempts to access memory outside those regions, an exception/interrupt is thrown, and then the cache needs to be updated, or an exception thrown to that task. That takes a while to process- the amortised cost is typically around that kind of value.

      Clearly there are applications where the N% lost to protection is too much

      In my experience, this is exceptionally rare. That final 3% can nearly always be clawed back with subtle changes to the software. If it really can't- then the processor was too slow for the task in hand in the first place- normal feature creep has a much bigger than 3% effect on the system performance.

      --

      -WolfWithoutAClause

      "Gravity is only a theory, not a fact!"
    4. Re:VxWorks memory, embedded protection by devphil · · Score: 2, Insightful
      It makes sense, when building a robust system, to do rigorous testing AND have the memory protection.

      Absolutely. While building it.

      VxWorks obviously has a brilliant team of brainwashers^Wsalesmen because they've convinced you that you don't need a feature they don't offer. Perfect!

      I forgot, this is slashdot, where VxWorks is the eternal enemy, and second-guessing actual rocket scientists is the national sport.

      IIRC, memory protection was removed from the early versions by popular request, because the cost was too high. Clearly not everyone out there agrees with the opinions stated by sibling posts to yours.

      Me, personally, I don't give a rat's ass one way or the other. (I don't use VxWorks, and haven't had a single segfault in any of my code since I stopped using C.) I just dislike seeing the groupthink mentality defended so vigourously, thus my initial post.

      --
      You cannot apply a technological solution to a sociological problem. (Edwards' Law)
  45. Obvious reference... by IversenX · · Score: 3, Funny

    ...and I have this terrible pain in all the diodes down my left side!

    Flash update you say? I wont enjoy it.

    --
    With great numbers come great responsibility!
  46. Science and Engineering Files my ass by geekpuppySEA · · Score: 3, Funny

    It's porn. Someone wanted to be the first guy to get Venus to Mars.

    --
    Intelligent Design: because MATH is HARD.
  47. Damn those engineering files by drgonzo59 · · Score: 2, Funny

    NASA technicians are preparing to wipe Spirit's flash memory clean of science and engineering files that have stymied its software.
    ...and put games and pr0n on it, which will make the software work as intended.

  48. Security? by DoctorHibbert · · Score: 5, Interesting

    Other than the huge costs of transmissions equipment, does anyone know what kind of security they use to prevent hackers from doing this (like for instance some mischievous Russian space program scientist)?

    --
    Arbitrary sig
  49. Re:Any theories on what caused the corruption? by srleffler · · Score: 2, Insightful
    You have to remember that the computer wasn't built this year. It was probably assembled several years ago and has been undergoing testing since.

    It also probably waited a while to be launched, and it took seven months just to get there.

  50. are preparing to wipe Spirit's flash memory clean? by odorf · · Score: 2, Funny

    From the example of C-3po in a new hope we can clearly see that whiping things memorys does NOT make them perfect! He was never mean to R2D2 until AFTER his memory was wiped, do they want to start a fight between the two rovers? Better procede with caution!

  51. Re:Any theories on what caused the corruption? by TheOnlyCoolTim · · Score: 3, Insightful

    The memory is not faulty. It is a bug in the filesystem software. The memory isn't full, but there are more files than the rover can handle. They were basically letting everything pile up, so the rover had eighteen days worth of files (and pre-landing files on top of that.) With the other rover they are deleting the files after they are received on Earth.

    Tim

    --
    Omnia vestra castrorum habetur nobis.
  52. Re:Our bench is killing us by grozzie2 · · Score: 2, Insightful
    We'd be winning if Earth would quit sending in the second string players (ie. Russia). ;-)

    The reality of the situation is, first string (Russia) is all tied up doing manned missions, so they have delegated the robot probes to the second string (usa). This is mostly due to the little detail, second string has no operational man rated vehicles to work with....

    Not quite sure how China plays in yet, but, they also have a manned program these days, so, second place is actually up for grabs, the robot probes may soon have to take the third bench....

  53. Re:Any theories on what caused the corruption? by flewp · · Score: 2, Informative

    Seriously, when are people going to realise that you can't just take modern components you'd use with your computer and put it in a space craft?

    Not only did it take ~7 months (I think) to get to Mars, meaning it was already 7 months "obsolete" when it landed, it was also probably not launched for a LONG time after it was completed. They have to test it extensively and test for every possible scenario they can come up with. They also have to have equipment that is suitable for the extremes of space travel. High G forces, extreme vibration, extreme temperature differences, radiation, and probably thousands of other things I don't know about.

    Put simply, YOUR PC THAT SITS ON YOUR DESKTOP WON'T SURVIVE A ROCKET LAUNCH INTO SPACE. And if it did survive the actual launch and made it into space, it would fail very quickly.

    --
    WWJD.... for a Klondike bar?
  54. If I were a NASA scientist... by mnmn · · Score: 2, Interesting

    I would put two 250GB harddisk in the orbiter and make the rovers upload all data they can to the orbiter on each pass, and delete those files automatically. The slower transmission to Earth could then proceed from the disks.

    Each rover uses 256MB flash and so does my 5 megapixel camera. I know for a fact that I can saturate that space fast in a photography frenzy, so I carry a laptop in the car with charger to transfer everything to it if I'll need more pictures.

    Altho the two rovers have been a staggering success on Mars, I am surprised at two overlooks:

    (1) Keeping track of file size and free space.

    (2) What happens if the space is full.

    Even Linux on a measly ARM720T does a much better job.

    --
    "Give orange me give eat orange me eat orange give me eat orange give me you." -Nim Chimpsky
  55. Wow, scary by Validus · · Score: 2, Interesting

    Dam hope that there is not power failure during that operation!!

    As a friend put it "I am afraid to flash my bios without a good UPS."