A slightly better way, IMHO:

    String.instance_methods.grep /sub/

Oh, and if the pulse is actually one kilowatt instead of one
megawatt... the energy falls to 0.0001 joule... really, none
of these amounts are enough to cause any visual damage
to a steel plate.

One megawatt is one million joules per second. The pulse
lasts 100 nsec, or 0.1 millionth of a second. If you multiply
the two, you get the total amount of energy for the pulse... ... 0.1 joule.

That's about the same amount of energy as lifting a 100 g
chocolate bar 10 cm vertically in the air....

He tried to open a quarantined file, once with the 'cat' command
and once with vi, as root, and both times Sophos warned him and
prevented him from proceeding. Now, the code for the 'cat'
command is quite simple, it basically just does a open(2)
of the file and then issues a series of read(2). My question
is: Does Sophos actually intercept the system calls in order
to make sure no application opens an infected file? If so,
wouldn't that introduce a HUGE performance penalty on the
everything happening on the machine, since these system calls
are so crucial?

Well, you answered my question, then (in the other comment thread).

Thanks. And greetings.

Hey, are you Peter Seebach? If so, just a few comments above yours, I provided a link
to your insightful (and funny) Hacker FAQ. I've always recognized myself in it.

Have you ever considered reformating it to a more modern HTML document? It's simply
that in its present form, it really DOES look like a text from 1999... it shows
its age. :-)

See, for instance, section 2 (Productivity) of the Hacker FAQ.

Your computation actually has some errors in it. The amount of energy required to increase the earth's speed from what it is (about 30,000 m/s) by 1 m/s is not the same as the amount of enery needed to increase it from 0 to 1 m/s (which is what you computed, except that you also made a mistake by a factor of 2).

A better estimate (with same mass, but increasing the speed from 30,000 m/s to 30,001 m/s) yields
1.7921e29 joules needed. That's 5 orders of magnitude greater than your solution.

I once computed that to remove the top 1cm of topsoil or water from all the worlds land masses and oceans, and throw them out into outer space at escape velocity, we'd need to perfectly use the energy of 100 billions bombs like Hiroshima's. I wanted to see whether exploding a planet like the Death Star does in Episode 4 was realistic. It isn't. At escape velocity, the chunks of the planets would take 6 minutes to double the planet's volume (so the explosion would look very very slow).