Disk -> diskette (floppy diskette)

Disc -> obviously disc shaped (compact disc)

When GP said "That's disc, not disk." they were alluding to the fact that the storage medium being announced is a compact disc style format, not a hard or floppy disk style device.

In any event both terms are used in the context of computing e.g. "I'm going to burn these files from my hard-disk, to my compact disc."

Might I ask sir, exactly how cunning do you perceive yourself to be?

Is it just me or does this widely disseminated professional document contain a then/than error?

Let's hope that wasn't one of the coding challenges they faced.

if (x > y/2) than

{

'uh oh

}

(This post written assuming "the other one" = "the other part of the ray bundle")