A time to Jump!… and a time to refrain from jumping

January 25th, 2015

Here’s something to amuse and educate you over the washing-up: a fine episode of the Freakonomics Radio podcast, which manages to link Ecclesiastes, mediaeval trials, Van Halen, and the identification of terrorists.

What do King Solomon and David Lee Roth have in common?

Quite a lot of unanswered questions about the data here – I’d like to know more – but it’s definitely fun food for thought!

Thanks to Elaine, one of Rose’s former students, for the link.

UPDATE: A little historical knowledge is a dangerous thing. Rose points out that most such crimes in the English mediaeval court, at least, were capital ones, so there was little incentive to admit your guilt rather than take the ordeal, if given the choice! Other European courts, though, may have been different…

Tweet me nice

January 25th, 2015

I still (often) have doubts about whether Twitter is a valuable medium, but I see, looking at my archive, that I’ve now been tweeting for nearly seven years. Gosh. So it is at least a long-lasting one.

I’m far from a heavy user, though: over that period I’ve only averaged 1.3 tweets a day, with an average length of about 89 characters. Mind you, that’s still well over 40,000 words…

Good Vibrations

January 24th, 2015

TurntableNeedleAs a student, I was a bit of an audiophile, at least in the sense of making regular visits to the best local hi-fi shop, passing a lot of time there, and spending rather more of my limited funds than I probably should have on speakers, amps and the like. In later years, I started to realise that much of the stuff I was reading in audio magazines was complete rubbish, or overt sponsorship, or — more typically — both, and my attention drifted to other things. But I’m still interested in proper scientific analysis of what sounds good.

John Gruber linked to this article by Dave Hamilton, which explains why we record things on CDs at 44.1kHz and 16 bits. Quick summary: you may think you can hear higher resolution than that, but you almost certainly can’t. As part of the discussion, he linked to this nicely-done blind test on an audiophile site, where people were invited to download high-quality recordings of different pieces of music, play them back on the best gear they owned, and say which they thought was the 16-bit and which the 24-bit recording. After gathering data for two months, he published the results. Summary: you can’t hear the difference, even if you’re a musician and have very expensive gear.

Now, as Hamilton points out, there are good reasons for recording in higher resolution, because you want as much information as you can have in the recording, mixing, processing stages before you produce the final mix, in the same way that you should take RAW photos rather than JPEGs so that you can do more with them before producing your final image.

But when you actually come to distribute your final output, it’s fine to ship high-quality JPEGs, and it’s also fine to ship CD-quality audio. If it’s well-produced, then any more is completely unnecessary, whatever the sales guys may say! Unless you’re Superman, of course, in which case, thanks for dealing with that Luthor guy and still finding time to read my blog.

Guess I was just the last to know

January 24th, 2015

I learned today about an interesting local girl…

The Nobel-winning German physicist, Max Born, had a daughter named Irene. His wife was part-Jewish, so they left Germany before the war to escape the Nazis.

Irene married a Welshman who worked (as an MI5 officer) on the Enigma project at Bletchley Park. An interesting blend of family backgrounds.

They in turn had a daughter, who was born here in Cambridge. Her name?

Olivia Newton-John

Keep your Mac disks running smoothly

January 19th, 2015

Hard disks, and the filing systems that run on them, occasionally get confused. This can happen for all sorts of reasons: bugs, power cuts, software crashes, hardware glitches, to name a few. The advent of journalled filesystems make these hiccups much less of a problem than they used to be, but they still occur.

As with checking your car tyres, it’s a very good idea to be proactive about checking and fixing any small issues. Often your computer will continue to run just fine, so you won’t know there’s anything amiss, and, indeed, they may never cause a problem, but it’s much better to fix them before they do… otherwise that one broken link might just cause you to lose something important in the future.

That’s why I have an entry in my to-do system for each Mac that we have in the house, reminding me to run a check-and-repair on its main hard disk. These entries reappear automatically 6 months after I check them off. (If your to-do system can’t do that, you might want to think about getting Omnifocus.)

Anyway, on the Mac, you don’t need any special software to keep things ticking over nicely: you can use the standard Disk Utility program to run these checks, which lives in the Utilities folder within Applications. It’ve very easy: just fire it up, and on the left you’ll see your disks, and the partitions on each disk. Select one, and you can check (verify) or repair the disk layout itself, and the permissions of key files within the partition.

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I never actually bother with the ‘Verify’ buttons: I just hit ‘Repair’, since that will also do a check, and it won’t change anything if the disk or partition doesn’t need repairing. I start with Repair Disk, and then follow it with Repair Disk Permissions.

However, there’s a trick to this…

The system normally can’t do much in the way of repairs on the filesystem from which you’re actually running. So you’ll probably find that the ‘Repair Disk’ button is greyed out, as in the image above, and you’ll need to boot your Mac from another disk or partition in order to run them. Ah.

Fortunately, however, on recent versions of Mac OS X, this is trivial to do, because you also have a hidden ‘Recovery Partition’ on the disk, from which you can boot in order to recover from serious problems, reinstall the operating system, restore from backups, etc. And Disk Utility is available there. What’s more, it’s a good idea to run it from the Recovery Partition anyway, because you’ll have nothing running in the background and trying to do backups, sync with Dropbox, or whatever, while you’re doing the check.

So, reboot your Mac. Normally, if you hold down the Option/Alt key while it starts up, you’ll see a list of places from which you can boot. On Yosemite, however, this probably won’t show you the Recovery Partition, so you need to know a new keystroke: Cmd-R. Hold that while booting, and you’ll get a menu from which you can run Disk Utility. Run your checks, which normally only take a few minutes, then quit the utility and the parent menu, and you can reboot back into your normal, happy, healthy world.

One last wrinkle. If you use FileVault to encrypt your disk, which I’d recommend at least on a laptop, then you’ll need to give your FileVault password before Disk Utility can open the partition and run any checks on it. Just select the partition and click the Unlock button in the toolbar, type in your password and you’ll be ready to go.

Regular, scheduled, proactive checks will help keep your Mac happy and healthy!

Gateway to the past

January 7th, 2015

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A doorway at my old college, Gonville & Caius.

Farewell, Christmas

January 4th, 2015

We’re just taking the decorations down. We had them up for nearly two whole weeks this year! It’s been a fun Christmas: hope it was for you, too.

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Pyrotechnic devaluation

January 1st, 2015

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I’ve always liked fireworks. It seems delightful that, amidst our LED-illuminated high-tech world of lasers, giant displays and 3D computer graphics, the best way to make a large crowd of people all gasp in pleasure simultaneously is, still, to employ a Chinese technology more than a millennium old.

In my youth, Guy Fawkes’ Night was a treat, when we trudged across a couple of dark fields in our wellies to the local hill where, in the glow of an enormous bonfire, the town council put on a modest but very pleasing display; generally the one night of the year when fireworks would be seen.

Now, however, people seem to let them off on every conceivable occasion. There were some here last night, for New Year’s Eve, which is fair enough, and no doubt some of our neighbours will decide to pop some tonight to celebrate New Year’s Day. We had some near Christmas, too. And for this newfangled Halloween thing, now I come to think about it.

Then there are those who decide to let them off on some other night, perhaps the weekend closest to whatever date is being celebrated, so more people can attend. Since November 5th fell in the middle of the week last year, we had something going bang up above us most nights for a whole week. Random corporate, sporting or university events decide to include them occasionally throughout the year. And, of course, being in central Cambridge, where we are surrounded by the college May Balls, there is a week or so in mid-summer when there are fireworks going off every evening, usually from more than one venue at once.

All of this is exceedingly distressing for our rather nervous spaniel, and no doubt for most other animal life in the area. But it seems a bit sad to me, too. When they were something you could only see once a year at a special event – since very few people of our acquaintance would purchase them for a home display – it was, well, a bit more magical. Christmas comes but once a year, and rightly so. I can’t help feeling that Bonfire Night would benefit from the same self-restraint…

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Walking in a Wimpole Wonderland

December 31st, 2014

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The hill behind Wimpole Hall farm was beautiful first thing this morning.

I used to think that I’d use my wide-angle lenses for landscape photography, but I’m finding that many of the best shots come from my telephoto.

And the more experience I get with my little Fuji X-Pro 1, the less I feel the need to carry my big heavy full-frame DSLR. I also took five lenses with me this morning on a casual dog-walk; something I’d never be likely to do with my Canon kit!

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