2010 question-Hal's "Destruct code"?

I’ll pop this question in a “spoiler” box, just to be safe…

In the movie “2010,” the sequel to “2001” (naturally), what was the code/equasion that Roy Scheider would have entered on his “pocket calculator” to activate the destruct mechanism he’d installed on HAL’s power supply?

Nine nines, take the square root, hit enter, if memory serves.

And it wasn’t a “destruct” code, exactly, but a means to disable HAL in an emergency.

I think it was nine 9s, square root, then the integer key.
(IMHO knowing this in no way spoils the movie)

Brian

It wasn’t so much a “self-destruct” as a “remote lobotomy” if HAL started getting…twitchy…again.

What is an “integer key”? Is that a fancy way of saying “equals” (which is what I intended to say instead of “Enter” – I’m such a goofball)?

I don’t remenber the code but it didn’t affect HAL directly, it activated a small guilhotine(?) that cut HAL’s main powerline.

“Integer” just extracts the whole (non-fractional) part of the result, i.e.:

sqrt(999999999) = 31622.776585872405015194191707146…

hitting integer yields simply 31622.