I popped into town just now to talk to my bank. Outside the bank was one of those ‘living statue’ performers – painted silver and with a pedestal to stand on.

I've seen plenty of those around before, of course, and they normally do nothing for me. But this one did – because he was off his pedestal, taking a break, and chatting to a passer-by while one silver-painted hand rootled enthusiastically in a bag of crisps.

The idea that statues need to take a snack break now and then really made me smile. Probably even Nelson comes down off his column every week or so, late at night, and goes looking for a kebab van.

‘My car should have passed that test!’ he said, seeking the mot juste.

My local printer at work, when you press the button on its control panel to cancel a queued print job, puts up a message box saying "This job will be cancelled. Continue?", with buttons marked "Continue" and "Exit".

Dear My Bank,

When you send me a letter, please either sign it with an actual person's signature, or do not bother at all. Printing somebody's name at the bottom of the letter in Brush Script where a signature ought to be is much, much worse than either.

No love,

Simon.

wildeabandon posted the other day about having gone through the ‘geek rite of passage’ of assembling a PC from parts from the first time.

I've never actually done that myself (I'm too lazy – I generally let the shop do it for me!), but I had a rite of passage of my own this week, namely my first ever full restore of a machine from backups. The firewall that died last Sunday is now running cheerfully again from its new flash card, with nothing lost beyond a week or so of logs I wasn't going to read anyway.

Of course, I couldn't do it the easy way. Oh no. Not for me the simple narrative of ‘flash card dies, haul spare out of drawer, format it, restore backup on to it, insert in firewall, boot up, away we go’. I didn't have the foresight to have laid in a spare card, so instead I restored the backup on to a spare corner of another computer's disk, then reconfigured the firewall (via some yak-shaving involving its kernel) to network-boot and NFS-mount its file system from there. It's been running happily in that configuration all week; the replacement card (and spare) arrived yesterday, so I've just transferred the file system back over, and it's now once again self-sufficient. While the machine was running diskless, I took the opportunity to upgrade its Debian installation (taking advantage of the unusual ease of making multiple copies of the filesystem to try things out), which I'd been meaning to get round to doing for far too long. As an added bonus, it now boots using GRUB (which was incompatible with its hardware last time I tried, but turns out to work fine in the latest version), so I no longer maintain any machine that runs the thoroughly irritating LILO. Hooray!

It's nice to have the lid back on the machine, and it's even nicer to know that the backups I've been religiously taking every week for a few years now really do work. (And with any luck they'll work even better next time: as a result of this exercise I've tweaked them a bit.)

The other day I mail-ordered two Compact Flash cards (one to replace the recently deceased one my firewall had been using as its hard disk, and one as a spare for when that one dies).

They arrived today. In separate jiffy bags.

It turns out my iPod wasn't defunct after all. It just needed turning back on!

Apparently, for the last three and a half years, every single time I thought I was turning it off or on, I was in fact putting it in and out of a state more akin to a laptop's ‘suspend’ function. On Monday it took it into its head, for reasons unexplained, to power itself off properly, which meant that pressing what I thought was the On button but was actually the Unsuspend button did nothing. To actually turn it on, one has to apply a Vulcan nerve pinch to two particular buttons and hold it for eight seconds, whereupon it spends a minute or so booting up before being willing to do anything.

I thought Apple were supposed to be masters of creating computing devices that a non-expert could use. If you can't even find the on switch without looking on the Internet, something is wrong!

(Unless, I suppose, any non-expert would have known to do that immediately, and I only failed to because my mind was too highly trained?)

I got home last night to discover that my firewall had gone on the fritz. It was too late in the evening to try fixing it, so I went to bed.

Up this morning and out to work, through what turned out to be 45 minutes of traffic jam for no discernible reason. Spent all day beating my head on an intractable problem, and didn't solve it. Went home via Sainsbury's, which was in utter chaos because its car park was full of bulldozers; also discovered on the way home that my iPod had quietly stopped working (it now refuses even to turn on).

I've now managed to emergency-reactivate my firewall (hence being able to post this), which is something, at least. But good grief. Can I have 24 hours of everything going right next, please?

That pedal a drummer presses to turn the closed hi-hat into an open hi-hat?

It occurred to me last week that it really ought to be labelled ‘Cymbal Shift’.

Rather late in the day compared to many people, I've recently been taking steps toward joining the DVCS generation.

For a year or two I've been an occasional light user of bzr, either to hold temporary branches off my main SVN repository (e.g. pre-commit polishing of a big patch somebody contributed to one of my public projects) or to hold projects too small, too experimental, too embarrassingly silly, or occasionally too private or legally encumbered to want to put into my public main SVN. A few weeks ago I managed to lose my long-standing fear of git, by dint of playing with test repositories and examining the output of git fast-export until I actually understood how its data structure fitted together and could work out everything else by reasoning about that. Having done so, I immediately migrated all my bzr repositories to git, because that kind of understanding is very valuable to me and bzr's documentation seems to place almost no emphasis on imparting it.

At the weekend, though, I actually did find the document which explains bzr's data structure – and, despite a superficially completely different user experience, it's actually very similar to that of git. As, I discovered after a brief browse on another website, is the data structure of Mercurial. The user interfaces can vary, but all three of these DVCSes have an essentially similar underlying data model.

And, curiously, a thing that struck me about this model is that it's surprisingly similar to something I already know about: Usenet.

( may not be entirely serious )

I looked up at the beautifully clear night sky yesterday, and noticed that the stars actually looked to me as if they were different distances away.

Now I know perfectly well that human binocular vision can't possibly resolve distances of that magnitude. It therefore struck me as odd that I was perceiving something which I knew to be both an optical illusion, and true!

The other day I needed a lot of primes in a hurry, and I judged that it would be quicker just to sit down and write a simple Sieve of Eratosthenes program from memory than to faff about trying to google up one that somebody had already written and that wasn't in some unhelpful language.

So I wrote one; then I disposed of the obvious bugs by checking its output rigorously for numbers up to 10; then I ran it for numbers up to 100 and didn't see anything obviously wrong (though I didn't look that hard). Then I wondered whether there was any good way to be more confident of its correctness.

On a whim, I made it generate all the primes up to 2^32, and fed the output text file to md5sum (with Unix line endings). Then I pasted the resulting checksum into Google – and found a hit! Somebody else had generated the same set of primes, checksummed them in exactly the same way, and posted the MD5 on a web forum which was talking about prime-generating programs so that other people on the forum could use it as a test case. Just the confirmation I wanted.

The silly thing is that if I'd tried to google for things like ‘md5sum of primes up to 2^32’, it wouldn't have been remotely successful. But once you already know what you think the answer is (at least in cases where it's a mess of digits), googling for that will tell you whether anyone else agreed with you.

Last month I went to Borders, in Cambridge town centre, and bought a pile of paperbacks.

This evening I was sitting on my sofa reading one of them; I turned a page and found a receipt stuck between the pages. A receipt for the book I was holding – from WH Smith, in Cambridge town centre, dated February of this year.

What happened there then? Best explanation I can think of is that somebody bought it from Smiths and then managed to leave it behind somewhere in Borders – perhaps in the café – and when the Borders staff came to clear up they saw a pristine paperback, assumed it was part of their stock, and shelved it. How strange. I wonder if I ought to notify somebody.

You know the Internet has taken over your brain when you find yourself typoing ‘relolcation’. Or ‘allolcation’.

Underambitious fantasies. My back was itching in the pub last night, and I couldn't quite reach the right spot to scratch it. ‘If only,’ I heard myself think, ‘I had a slightly longer arm.’

Ridiculous! If I'm going to allow myself to fantasise counterfactually, why didn't I just fantasise ‘If only my back didn't itch in the first place’?

That well-known software design adage: ‘Make simple things simple, make difficult things possible.’

The implied word in the middle is ‘and’, not ‘or’!

Occasionally I feel just a little like Rimmer at work. This morning I sent an email response to a bug report from the support department, saying something along the lines of

Can you explain a little more about why you expect this to work? The C99 standard clearly states (section 7.19.7.3 clause 4) that…

and somewhere in the back of my head, Kryten is responding ‘Section 7.19.7.3 clause 4? No member of the support department shall raise a defect report while wearing a ginger toupée?’

crazyscot's recent LJ post about a factor-of-20 speedup of some code reminds me that I've never written down in here the story of my first summer job, despite it being a standard anecdote I use in real life when I get into those ‘the worst code I've ever encountered’ geek war-story conversations.

( some of the worst code I've ever encountered, and how I too sped it up by a factor of twenty )

The boss took one look at the speed test, and shook his head. ‘We can't ship that,’ he said, ‘it's far too embarrassing. We'll have to deliberately slow it back down again, and ship lots of incremental speed upgrades.’

I laughed.

He turned out not to be joking.

Blindness to the difference between positive and negative incentives. If there are two options, of which someone is currently choosing option A and you'd like them to choose option B instead, you can attempt to achieve this in two ways. You can increase the attractiveness of B to more than that of A, or you can reduce the attractiveness of A to less than that of B. Both of these have a good chance of changing behaviour, but the former makes the people it affects happier, while the latter makes them less so. Doing the latter when you could reasonably have done the former, or acting all surprised when you do the latter and people mysteriously don't seem to be happy about it, considered irritating.

Things that are simultaneously interesting and tiresome. Whether it's a potentially interesting topic of discussion but most people tend to focus on the boring bits, or whether it's interesting in principle but long since done to death, or whether the tiresomeness of the fact that it needs to be argued about at all is in opposition to the interestingness of some of the actual arguments, or whether the interesting and tiresome parts can't even be separated like that and the problem is just that my brain can't make up its mind whether it likes it, or (in extreme cases) all of the above. It's fair enough in this morally complex world that things can be both good and bad, but one might naïvely have thought it should at least be possible to reach a conclusion about whether any given thing was interesting or not. Gah.

Finally managed to get my music font up on the web this morning, after nearly a week of last-minute pre-release polishing. I swear, every time I publish something, it seems to take longer than the last time to sort out all the fiddly details like licences and distribution archives and READMEs and so on.

For anyone interested, I've put it up at http://www.chiark.greenend.org.uk/~sgtatham/gonville/.

Now I can have a rest, and then do something completely different.