back to article Deep Impact succumbs to 'HAL bug' as glitch messes with antenna

NASA has stopped trying to contact Deep Impact, the comet-pronging probe that in 2005 dropped an “impactor” the size of a coffee table onto comet Tempel-1. The space agency's explanation for the decision will be familiar to anyone that has read or watched 2001: A Space Odyssey: a software glitch means the spacecraft can't point …

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"HAL bug"

Not to be picky, but the bug that caused the malfunction of HAL was something that caused it to not to be able to resolve what appear to be contradicting instructions.

The AE35 unit malfunction never happened.

In fact, HAL was predicting a failure of that unit (the prediction itself was a lie).

R

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Re: "HAL bug"

Not to be picky, but the bug that caused the malfunction of HAL was something that caused it to not to be able to resolve what appear to be contradicting instructions.

Wasn't it a certain three-letter American agency that gave HAL the conflicting instructions?

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Boffin

Re: "HAL bug"

IIRC the reason HAL erroneously predicted a failure of the AE35 unit was because it was a reflection of his subconscious realisation that the source of his conflict was coming from Earth. It was a manifestation of his desire to break with Earth and remove that conflict.

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Re: "HAL bug"

I've also seen an alternate theory that had the two "sentient" life forms in a race to get to the next level of evolution, and HAL was trying to get the source first, to advance his own kind.

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Re: "HAL bug"

I read that HAL was so named because it was 1 letter ahead of IBM in the alphabet.

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Re: "HAL bug"

I read that HAL was so named because it was 1 letter ahead of IBM in the alphabet.

Repeatedly denied by Clarke & Kubrick.

From https://en.wikipedia.org/wiki/HAL_9000#Origin_of_name

"As is clearly stated in the novel (Chapter 16), HAL stands for Heuristically programmed ALgorithmic computer"

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Happy

"...it seems safe to keep one's eyes on Jupiter and stocking up on sun screen."

Shouldn't that be "...it seems safe to keep one's eyes away from Jupiter and stocking up on sun screen."?

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It was a Y2K problem ..

'"Basically, it was a Y2K problem, where some software didn't roll over the calendar date correctly," said A'Hearn. The spacecraft's fault-protection software (ironically enough) would have misread any date after August 11, 2013, he said, triggering an endless series of computer reboots aboard Deep Impact.'

http://news.nationalgeographic.com/news/2013/09/130920-deep-impact-ends-comet-mission-nasa-jpl/

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Coat

Re: It was a Y2K problem ..

No one expected the world to be around after Dec 21 last year, so stopping work on Aug 13th this year would have been seen as an abundance of caution ..

who knew ?

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Re: It was a Y2K problem ..

Calling that Y2K seems a bit misleading given it is 13 years past that point!

But really, it seems odd that they did not have the on-board memory to store just a single byte more for the date/time and then have absolutely no chance of the system running out of time-keeping before its hardware & power supply died.

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Re: It was a Y2K problem ..

It probably already has a few more bytes than 'required' which is why it was going 7 years after the planned end date. If you 'just add one more byte' to every situation that might require it you end up with a satellite too heavy to launch.

And with the capability (apologies for mixing my satellites and fictional universes) of becoming V'Ger, if you ever get it off the ground.

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Re: It was a Y2K problem ..

Seen about 5 years ago, in a "Bargain Books" bin: How to Survive Y2K.

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Did someone set cflags to -O3?

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"DIXI also did the business"

So, have NASA heard about the loo-for-rent business named 'Dixi' ?

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Deep Impact succumbs ..

August 11, 2013 == 4294967296 tenths of seconds, if tenths of a second are stored in a 32 bit INT, then 2^32 will wrap-round on August 11, 2013. Deep Impact launched in Jan 2005, uses the RAD750 CPU, radiation hardened PowerPC 750 clone. Which it says below was a 64 bit CPU, which is curious as to why it used 32 bit arithmetic for measuring the time.

http://www.petervis.com/Vintage%20Chips/PowerPC%20750/PowerPC%20750.html

http://www.theregister.co.uk/2013/09/23/deep_impact_succumbs_to_hal_bug_as_bug_messes_with_antenna/

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