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History's Worst Software Bugs
bharatm writes "Wired has an article on the 10 worst sofware bugs.. From the article 'Coding errors have sparked explosions, crippled interplanetary probes -- even killed people. Here's our pick for the 10 worst bugs ever, but the judging wasn't easy.'"
July 28, 1962 -- Mariner I space probe. A bug in the flight software for the Mariner 1 causes the rocket to divert from its intended path on launch. Mission control destroys the rocket over the Atlantic Ocean. The investigation into the accident discovers that a formula written on paper in pencil was improperly transcribed into computer code, causing the computer to miscalculate the rocket's trajectory.
1982 -- Soviet gas pipeline. Operatives working for the U.S. Central Intelligence Agency allegedly (.pdf) plant a bug in a Canadian computer system purchased to control the trans-Siberian gas pipeline. The Soviets had obtained the system as part of a wide-ranging effort to covertly purchase or steal sensitive U.S. technology. The CIA reportedly found out about the program and decided to make it backfire with equipment that would pass Soviet inspection and then fail once in operation. The resulting event is reportedly the largest non-nuclear explosion in the planet's history.
1985-1987 -- Therac-25 medical accelerator. A radiation therapy device malfunctions and delivers lethal radiation doses at several medical facilities. Based upon a previous design, the Therac-25 was an "improved" therapy system that could deliver two different kinds of radiation: either a low-power electron beam (beta particles) or X-rays. The Therac-25's X-rays were generated by smashing high-power electrons into a metal target positioned between the electron gun and the patient. A second "improvement" was the replacement of the older Therac-20's electromechanical safety interlocks with software control, a decision made because software was perceived to be more reliable.
What engineers didn't know was that both the 20 and the 25 were built upon an operating system that had been kludged together by a programmer with no formal training. Because of a subtle bug called a "race condition," a quick-fingered typist could accidentally configure the Therac-25 so the electron beam would fire in high-power mode but with the metal X-ray target out of position. At least five patients die; others are seriously injured.
1988 -- Buffer overflow in Berkeley Unix finger daemon. The first internet worm (the so-called Morris Worm) infects between 2,000 and 6,000 computers in less than a day by taking advantage of a buffer overflow. The specific code is a function in the standard input/output library routine called gets() designed to get a line of text over the network. Unfortunately, gets() has no provision to limit its input, and an overly large input allows the worm to take over any machine to which it can connect.
Programmers respond by attempting to stamp out the gets() function in working code, but they refuse to remove it from the C programming language's standard input/output library, where it remains to this day.
1988-1996 -- Kerberos Random Number Generator. The authors of the Kerberos security system neglect to properly "seed" the program's random number generator with a truly random seed. As a result, for eight years it is possible to trivially break into any computer that relies on Kerberos for authentication. It is unknown if this bug was ever actually exploited.
January 15, 1990 -- ATT Network Outage. A bug in a new release of the software that controls ATT's #4ESS long distance switches causes these mammoth computers to crash when they receive a specif
Something about their latest toy... ahm, ship that had to be towed back to port because Windows NT they used to run everything on the ship keep blue screening.
ELOI, ELOI, LAMA SABACHTHANI!?
The term predates computers. In the original usage, any sort of mechanical device or system could have bugs.
2 4657,10005407,00.htm
http://www.silicon.com/software/webservices/0,390
My UID is the product of 2 primes.
Jeuss Christ. I'd somehow never heard of this bug, and I've been developing for Windows machines for years.
How on earth was such a basic and low-level bug ignored for so long? It doesn't seem like rocket-science to fix it with a small bounds-checking if statement!
Everything in moderation, including moderation itself
Do people just open an article, do a Ctrl+F and type microsoft to find something 'juciy'? If you would have RTFA you would have seen that the 'Ping Of Death' was mentioned which did impact Windows machines.
- what is the definition of simultanagnosia?! I've been meaning to look it up!
if you subscribe (I don't any more) you can probably find it by searching for "random".
I think the last line is actually something like
Dilbert: That isn't very random though.
Some guy: That's the trouble with randomness - you can never tell.
Its intent was not to cause terror, but to inflict economic damage. I heard about a similar incident where a Japanese shipbuilder was stealing blueprints from a UK shipyard tendering for a contract and undercutting them. The UK shipbuilder deliberately designed a ship that would capsize on launch, which the Japanese duly stole, built, and launched. I don't know if anyone was killed, but ethically it's a tricky one.
http://www.alexisparkinn.com/photogallery/Videos/A irbus320_trees.mpg/
(Let the slashdotting begin! (poor servers))
All things considered, I don't know if the pilots survived.
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Any problem can be made unsolvable if there are enough meetings made to discuss it.
Because it was actually implemented as microcode and stored into the CPU, whether as mask rom or some other means of storing, but it was indeed software either way you look at it.
Remember when the LA air traffic control tower crashed, due to a bug in MS software after 49 days. I would think that this would make it up there. http://www.itgarage.com/node/459
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There are software engineers in Canada now. They can legally sign off on a software project. The problem is, is that you don't want to have every one of your programmers be licensed software engineers, all signing off on their own code. It would be too expensive to try and hire that many engineers, and managing all the signatures for all the code, when different people work on the same piece of code would be a nightmare to manage. Basically you'd have to have one engineer, or team thereof, overseeing the entire project to be sure that proper methods are being followed to ensure that there aren't any bugs. What you're asking for is more like saying that everyone who in building a bridge be licensed, and that they should all have to sign off on every rivet they put in.
The problem is, is that most companies producing software do not want to pay for an engineer to oversee their project. Also, the way most software operations are run, you wouldn't see an engineer, signing off on the projects. The engineer would force things to be much more tested in order to be ensure that things were actually worthy to be signed off on. There is lots of this kind of software being built for planes, and other situations where it really matters if there is bugs. I don't think this kind of situation will ever happen with off the shelf software. For one thing, software would cost too much, and most people aren't willing to pay $2000 to run an operating system on their home computer, and also because most engineers wouldn't sign off on a system, in which they didn't know the computer their software would run under. There's too many variables on a home computer to be able to garauntee, at that level, that your software will operate completely as expected.
Anthropic principle: We see the universe the way it is because if it were different we would not be here to see it.
Here is the Dilbert Strip... Enjoyj pg
http://www.geocities.com/raptorred42/Dilbert0001.
why?
Actually, you're confusing the title "P.E." (professional engineer) with the generally accepted term "engineer." One (the P.E.) is a licensed engineer, and others are used traditionally and arbitrarily with no legal recourse. For example, I and my co-workers are bona fide engineers, and most of us have engineering or engineering technology degrees. None of what we do requires a P.E. to sign off on anything, although there are other aspects of our business (and many other businesses) that do require a P.E.
Of course, there are all kinds of "engineers" that have that title but don't truly merit it -- customer service engineer; field service engineer; applications engineer; and so on. Most of these don't hold engineering degrees. For many of them, I don't begrudge them their title, either. But we also know that they're not P.E.'s.
--Jim (me)
That is correct -- Modern processors perform divides by having a reciprocal estimate lookup table.
This table produces an estimate with 12 or so good bits of precision. Iterative refinement (typically microcoded) then produces the rest of the bits. After that the reciprocal is multiplied in, and you get the result.
More recently this has been somewhat exposed, as most all modern processors have a reciprocal estimate instruction which executed in a single cycle. This is very useful if, for example, you want to normalize a bunch of normal vectors before passing them into the graphics pipeline. 12 bits is almost always enough for this purpose, and the reciprocal sqrt instruction is very much your friend here. So something that was dominated by the ~60 cycles of 1.0f/sqrt(sum_of_squares) becomes 1 cycle. Total speedup is about 10x -- and it's vectorizable -- the SSE unit will do a vector rsqrte.
My understanding of the pentium fdiv bug is that a section of the reciprocal estimate table had bad data in it.
This, in my opinion, counts as software, as would the microcode. If the bug had been in the multiplier, adder, or logic circuitry of the lookup table, then it would count as hardware.
Many, if not all the complex ciscy instructions are implemented in microcode -- so I believe that a bug in them would count as a software bug.
Ian Ameline
We've all seen it: the employee who's convinced she's doing a great job and gets a mediocre performance appraisal, or the student who's sure he's aced an exam and winds up with a D.
The tendency that people have to overrate their abilities fascinates Cornell University social psychologist David Dunning, PhD. "People overestimate themselves," he says, "but more than that, they really seem to believe it. I've been trying to figure out where that certainty of belief comes from."
Dunning is doing that through a series of manipulated studies, mostly with students at Cornell. He's finding that the least competent performers inflate their abilities the most; that the reason for the overinflation seems to be ignorance, not arrogance; and that chronic self-beliefs, however inaccurate, underlie both people's over and underestimations of how well they're doing.
I did not become a vegetarian for my health, I did it for the health of the chickens. --Isaac Bashevis Singer
The bug was about missing data in a lookup table. Intel said the problem was caused by a bug in the script designed to populate that table when the CPU was being designed, though legend has it that someone erronously "proved" that the data wasn't needed. So, I guess, either way you look at it, be it the script, the table, or the alleged logic flaw, it's a software, not a hardware bug (or at least, it's a bug caused by software.)
You are not alone. This is not normal. None of this is normal.
[the USSR's] murderous, oppressive grip on Eastern Europe and attempts at foisting their cheerful utopia on South America and Africa
As opposed to the US's murderous, oppressive grip on third world countries generally and attempts at foisting their cheerful utopia on the rest of the world.
It's fair to say the US's grip wasn't as thorough, but it sure was oppressive, and it encompassed more of the world than the USSR for more years. How many legitimate governments did the US overthrow because they didn't like them?
Terrorism is terrorism. Justifying the largest non-nuclear explosion in the name of fighting terrorism belongs in George Orwell's literature.
Infuriate left and right
I used to work with the lead programmer on this software package from Multidata. We worked together at two different companies for a total of about four years.
Multidata's software allows a radiation therapist to draw on a computer screen the placement of metal shields called "blocks" designed to protect healthy tissue from the radiation. But the software will only allow technicians to use four shielding blocks, and the Panamanian doctors wish to use five.
This is also made very clear in the documentation. This isn't a bug at all, the dosimitrists misused the software.
The doctors discover that they can trick the software by drawing all five blocks as a single large block with a hole in the middle. What the doctors don't realize is that the Multidata software gives different answers in this configuration depending on how the hole is drawn: draw it in one direction and the correct dose is calculated, draw in another direction and the software recommends twice the necessary exposure.
Exactly. They tried to create a feature that the software did not support, and they did so in a manner that broke the software.
At least eight patients die, while another 20 receive overdoses likely to cause significant health problems. The physicians, who were legally required to double-check the computer's calculations by hand, are indicted for murder.
It's not a software bug, it's a user error. This isn't a bug any more than it's a "bug" that your Linux box stops working properly if you do sudo rm -rf /. The users of the product knew better.
To be fair, Multidata was not a great shop from a procedural standpoint - the guy who ran it was insane, but the software was rock solid. I actually worked with a number of former Multidata employees who jumped ship and went to a rival shop that builds similar software, and they were all fairly competant and intelligent.
"I have never won a debate with an ignorant person." -Ali ibn Abi Talib
Read the best of all of Slash: seenonslash.com
I think the two worst computer bugs of all time are the two that quite possibly could have wiped us all out. More inforation here.
(Copied from the article:)
* November 9, 1979, when the US made emergency retaliation preparations after NORAD saw on-screen indications that a full-scale Soviet attack had been launched. No attempt was made to use the "red telephone" hotline to clarify the situation with the USSR and it was not until early-warning radar systems confirmed no such launch had taken place that NORAD realised that a computer system test had caused the display errors. A Senator at NORAD at the time described an atmosphere of absolute panic. A GAO investigation led to the construction of an off-site test facility, to prevent similar mistakes subsequently. A fictionalized version of this incident was filmed as the movie WarGames, in which the test system is inadvertantly triggered by a teenage hacker believing himself to be playing a video game.
* September 26, 1983, when Soviet military officer Stanislav Petrov refused to launch ICBMs, despite computer indications that the US had already launched.
If it weren't for two humans who said "fuck what the computer says!", we might be in a very different place right now.
She loves me: 09F911029D74E35BD84156C5635688C0 She loves me not: 09F911029D74E35BD84156C5635688BF
I looked at this a while back because many millenia ago, I worked at the company that produced the telemetry/control system for the Trans-Sib pipeline. It was a specialised outfit based in Warwickshire, UK. It is very doubtdul that their systems could have nobbled by anyone. The network was closed, based on an X.25ish HDLC and the software was blown on to UV erasable EPROMs. The CIA may have modified the s/w at the pump stations, but again it is doubtful.
See my journal, I write things there
speaking of NASA foulups, Remember this one? "(CNN) -- NASA lost a $125 million Mars orbiter because a Lockheed Martin engineering team used English units of measurement while the agency's team used the more conventional metric system for a key spacecraft operation, according to a review finding released Thursday."
"How many light bulbs does it take to change a person?" --BMcC-->
I hate to be pedantic (well no, I love it), but according to the Jargon file's entry on "bug":
But then again, why expect more from Wired.
Actually engineers existed long before the steam engine. The title of Civil Engineer was created to differentiate the practioners from the Military Engineers - the most common and probably the oldest usage of the title of engineer.
...carrier dead.....
Some outside observers, however, said they are not convinced NT is blameless.
"It still boggles the mind that any divide by zero error on NT would cause a system to crash, let alone" 27 end-user terminals, said Gil Young, corporate network engineer for a systems integration firm in Orlando, Fla. "I don't care what operating system, computer or application I'm using, I should be able to type in a zero and expect the computer not to crash, especially if that zero is to represent a closed valve."
You mised one..
Item 0: Requirements reviews by peers and independants. If you don't have good requirements you obviously don't know things well enough to be building them. Sure you can catch some requirements issues in 1 and 2 but the longer you wait the costlier it is to fix.
A MSCS is NOT a Software Engineering Degree, so why WOULD you take courses in SE?I'd say that CS and SE are two different professions. There are places to get a MS SE (Texas Tech comes to mind) if you are interested.
The phone network bug was a misplaced { character in a nested if-else construct.
Is that what it was? I thought I'd heard that the AT&T outage was from a missing break; in a switch-case statement.
I found that more believable, because a missing { would cause a compiler error, where a missing break; is a valid way to purposely fall into the next case.
Though, really, I suspect both of us are just repeating rumors we heard.
This is my sig. There are many like it but this one is... Oops. Frank, I've got your sig again! Where's mine?