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When Computers Go Wrong
Barence writes "PC Pro's Stewart Mitchell has charted the world's ten most calamitous computer cock-ups. They include the Russians' stealing software that resulted in their gas pipeline exploding, the Mars Orbiter that went missing because the programmers got their imperial and metric measurements mixed up, the Soviet early-warning system that confused the sun for a missile and almost triggered World War III, plus the Windows anti-piracy measure that resulted in millions of legitimate customers being branded software thieves."
Due to the imperial-metric mash-up, the sums were so far askew that when Ground Control initiated boosters to secure the pod in orbit, all they succeeded in doing was firing it closer to the planet, where it burnt up in the atmosphere.
When I see the Imperial-Metric confusion shit, I just want to slap the shit out of someone. That waste because some engineers are incapable of using Metric or some vendor just doesn't want to spend the money to modernize their machinery. I know of an aerospace contractor that is using machinery from the 50s - yep, they're constantly being recalibrated and sometimes they don't notice - ooopsie!
And when I see that we, the US, are one of two countries still on Imperial - one is some Third World non-industrial country, I want to barf.
And then, when I have to buy two sets tools to work on a car, I wish for the entire US auto industry to go bankrupt and be replaced with some modern companies.
I love Metric. It makes measurements and calculations much easier - quick! What is the mass of 329 mL of water? You'd need a calculator to do something similar in Imperial.
The "Switchboard meltdown" problem sounds like the incident which led to the creation of the EFF.
Basically, someone forgot to include a ";" in a C program, which led to the problems at ATT. Originally, they thought it was due to "hackers", and called in the Secret Service.
The Secret Service in turn busted a gaming outfit called "Steve Jackson Games". Who was completely innocent, of course, but that has never mattered to the Secret Service when they need to look like they are actually useful. The SS confiscated the computers, all illegally.
The ACLU refused to get involved, so John GIlmore (formerly of Sun, and who worked with Richard Stallman to get out an open Operating System around that time) created the EFF to fight the unconstitutional raid on Steve Jackson Games. The EFF trounced the Secret Service in Court, and was thus born. I believe if you google for "Steve Jackson Games", you can still find the original story around.
So, in a way, you can say that the EFF was created due to the single misplacement of a semicolon in a C program. Would that all of our bugs have such results. :)
(See title.)
:per directory (more or less equivalent to /dev on a *nix box) on a Data General mainframe machine running AOS/VS. While hundreds of users' processes disappeared off the system (which took about 90 minutes), I found it expedient to simply make my confession to the boss.
Any of us who have been in a sysprog or sysadmin role for a significant amount of time (by which I mean double-digit years) will often have at least one anecdote of some monumental cockup we've perpetrated.
My worst case in point is where I managed (IIRC after a long liquid lunch) to delete the
Fortunately, in this case, the escapade was more or less written up as "Shit Happens", which I thought was generous...
"Computers don't make mistakes. They do, however, execute yours VERY carefully."
That's a good way of phrasing it. But it does miss the fact that not all "computer errors" are due to software mistakes.
One example, of course, is the Pentium FDIV failure. That was a hardware failure, "programmed" into the CPU by Intel's experts in solid-state hardware design. There wasn't a whole lot that any software developer could do to defend against that failure.
Another, more subtle one, came up when I was a grad student back in the 1970s. At that time, most of the campus research computing was done on the big mainframe in the campus Computer Center. After discovering a number of (published ;-) results that turned out to be wrong, some researchers investigated, and found that they were due to undetected overflows in the calculations. Yes, the hardware could and did test for overflows, and set a status bit when they occurred. Almost all this calculating was done in Fortran, and the Fortran compiler had a run-time flag that could turn the status-bit checking on or off. It defaulted to OFF. They did a bit of analysis, and concluded that about half the runs of Fortran programs on that machine produced output that included numbers that were incorrect due to undetected overflow.
So why didn't they make the overflow-detection flag default to ON? Well, they did a little survey of the users. They found that the overwhelming response was that, if enabling overflow checking made the program run slower, then overflow checking shouldn't be done. Somewhere around 90% of the people asked said this. They weren't mathematically ignorant people; they were the people using the Fortran compiler for the data in their professional publications.
This told us a lot about the way such things are done. Since I left academia and worked in what passes for the Real World, I've found that this is a nearly universal attitude. Faster and cheaper is always preferable to correct. This is still true even when we have computers in commercial aircraft and hospital operating rooms. And you can't call this sort of thing a "human error". People don't decide to disable overflow checking by accident; they do it knowing full well what the effect will be. When the computer fails in such cases, it wasn't executing a human's mistake; it was doing what the human wanted it to do.
Those who do study history are doomed to stand helplessly by while everyone else repeats it.
"Units are parts of variables" usually comes along with systems in which there is no escape. Dimensional analysis is fine up to a point, but when you get into weird quantities like dBm/sqrt(Hz) (seriously: ten times the log-base-10 of a quantity measured in milliwatts, over the square root of another quantity measured in hertz), the systems that enforce units tend to fall apart, and often it turns out that they simply lack the notation you need. (By the way, "dBm per root hertz" was a unit that I used in daily work at an earlier time in my life. And I still use weirdness like neper-coloumb per square micron.)