OK, so much for that
All my random, scribbled-on-tiny-slips-of-paper sales "records" have been properly scribbled on large, well-ordered pieces of paper. I still need to go through and make an integrated customer list, but at this point I have enough information -- what was sold where, when and to whom -- to compute my sales taxes fairly quickly. I have a little under 2 weeks (including two whole weekends), so that's OK.
The fileserver still isn't dead, but I don't trust it yet. I'll probably upgrade to a Maxtor 500 just on general principles.
22:15 It died. There's a new disk in my immediate future. In fact, I may just start transfering to the PATA drive I bought Wednesday.
22:37 Hmm. I'm seeing write errors on the mirror drive (sdb). The easy thing to try would be disconnecting it first.