The disc plague briefly defeated

I am clearly the calibration standard that disc makers use; the drive on my Mac Mini died a month after anything resembling a warranty that it might have had expired.

So I acquired a new drive of twice the size, and a 1GB memory stick because OSX 10.4 is much less happy in 512MB than 10.3 was, and went over to ewx's house to fit them, because he has a putty knife. It has to be a putty knife, it needs to be springy and really no thicker than a train ticket; I bought a paint-scraper but that was too solid and too thick.

Observations: open a Mac Mini by inserting the putty knife between plastic and metal casing on the underside at the front (where the CD-hole is) and inserting a normal kitchen knife to keep the case open once you've got it slightly open. The front left screw holding the hard drive in can be reached through an access hole if you have a really long jeweller's screwdriver, but it's easier to get at it by using a slightly larger normal screwdriver at an awkward angle from the top, then throw it away without worrying about putting it back in.

The three screws around the CPU fan are weird self-tapping ones and each has its favourite hole, so it is wise to label which one came out of which hole, though you can determine this by experiment since they do not go even with excessive force into holes they don't like. Drop the medium-length black screws that hold the hard-drive-and-CD assembly into the deep holes they come from before refitting the assembly, taking care that the one in the shortest hole doesn't spring out when you put the assembly back. Shut the Mac Mini starting at the back, otherwise a weird complex of catches at the back fails to engage.

You could save ten minutes of worry by bringing the PSU for the Mac Mini to the place where you're dismantling it, so that you can check it works before putting the top back on, wrapping it up and cycling home with it.

The wind blew with some vigour in an axis precisely from my house to ewx's.

Automated stupidity: the best kind of stupidity

Excel just marked a cell as 'contains possibly wrong formula' because I wasn't adding in the date.

In C1, there is a date; in C2:C10 there are a collection of sums of money, some positive and some negative; in C11 there is sum(C2:C10), and Excel has stuck a little green note in the corner of that cell suggesting that maybe I meant sum(C1:C10).

Dates are stored internally as a count of days since January 1st 1904, so if you look at them as numbers they're around 37000. Adding them to a collection of sums of money which are things like 'income tax deducted from salary this month' or 'pension contribution this month', so of the order of hundreds of pounds, screws up the calculation right royally.