Perhaps the point was not merely regurgitation of facts but an analysis of your thought-process. It is almost impossible to have such an esoteric bit of trivia but you could have at least given them something:
"...Well I dunno but let's see...Filesystem Z(let's say reiserfs)...so this one's pretty good with really large files...its preferred to other ones(say ext2) for both support of larger files and better disk checking...at the time of distro x, version y, filesystem D(that you may be familiar with) hadn't even come out and was probably an improvement over Z, so I'd wager less bytes per block than filesytem D but more than...."
...or so could be a possible response...I hope I am getting my point through, though of course you're the one to have lived through the day and not me and I'm sure your reply was what you felt best, at the time.