Status-Q

Our dear chancellor has decided to reduce VAT from 17.5% to 15%. This means that every business in the land has to reconfigure their billing systems, check the dates of their invoices rather carefully, and (in many cases) reprint lots of documentation to change their advertised prices.

In exchange, they'll will benefit from the wild shopping spree that can be expected when things costing £99 drop to a bargain £97! The queues of people in sleeping bags outside the department stores, waiting for opening time on Monday morning, will make all the changes worthwhile, and no doubt we will still be rejoicing in a year's time, when we have to change everything back again.

Actually, that's probably when the shopping crowds will turn out: the day before the prices go back up again, 13 months from now, in the post-Christmas sales at the end of 2009. I'm not convinced that's when it'll be most needed! In the meantime, the lost taxes will supposedly come to something like £12.5bn. Just the thing for a country plunging into debt. I rather suspect this is all really just a ploy to find useful consulting work for all those newly-redundant bank staff.

Still, I'm certainly no expert, and perhaps it'll all work out in ways I don't quite grasp. It does seem like a lot of bother to me, though.

We just need to make sure we don't come up with any other schemes for throwing money away, like, say, hosting the Olympics. Now that would be really silly.

Regular walking or running not really your thing? Or have you spent so much time at the gym that you've forgotten what it's like to run or cycle and actually move around at the same time?

You need SpeedFit!

Yes, they're serious...

Using paintballs to illustrate the difference between sequential and parallel processing.

Is this the world's biggest inkjet printing head?

I liked the Matt cartoon in the Telegraph this morning!

But since the British media, whenever it comes to America, almost invariably spout... well... the price of everything and the value of nothing, I was pleased also to see Anne Applebaum's piece, which quoted the most brilliant use of a hundred or so bytes that I've seen in a long time:

Early yesterday morning, black Americans were sending a short text message to one another:
"Rosa sat so Martin could walk. Martin walked so Barack could run. Barack is running so our children can fly."

It's easy to say that the honeymoon won't last, that things may not look so rosy in 4 years' time, etc. But it's been a very long time since America has had any good news. Now it's got some, and it has every right to be proud of it.

Exactly what you'd expect, of course, but I was surprised to see quite such a clear trend.

Beware of those email autoreplies - they can sometimes have unexpected consequences.

Many people travel regularly to another city. Not regularly enough to have an apartment there, but sufficiently often that the process of carrying a suitcase of clothes back and forth is a real pain. I think what is needed is a way to have a wardrobe in the places you visit most often. I'd like to create a business which does this and the great thing is that I can just piggy-back it on existing services. Here's how it works:

You go to a hotel, stay for a few days, and on departing you just leave behind any clothes that you'd like to stay in that city. The hotel laundry washes your clothes, and puts them in a specially design cardboard wardrobe, which is then picked up and put into storage. When you're next returning to that city, you just call up or log on and say where you'll be staying, and the clothes are hanging in your wardrobe when you get there. The cardboard wardrobe might have a special drawer for toiletries etc as well.

If you stop visiting that city, then for a modest charge, the wardrobe can be shipped back home, or to wherever your business is taking you now.

Neat, huh? Now, I was explaining this to a couple of lady friends of mine over lunch recently, and they pointed out that this was clearly a male-centric view of the world, because women would (a) want to have much more control over the precise clothing they had available for a particular trip and (b) wouldn't want to leave valuable outfits behind in some far-flung part of the world. I suggested that part of the storage process could include an automatic photographing of each of the items of clothing, so you could see on the website exactly what would greet you when you opened your wardrobe in San Francisco, but they still seemed unconvinced.

For the average travelling bloke, though, I think this could work quite well. What do you think? Anyone feel like investing in an exciting new globe-spanning venture?

A couple of people have told me how much they enjoyed James Randi's talks.

If you liked those, and you haven't yet seen it, you really owe it to yourself to watch Michael Shermer's TED talk, which is one of my favourites.

You can associate multiple email addresses with your Google account. Just edit your account info.

Then when people send you invitations to join calendars, share documents etc, at something other than your Google address, they will all be associated with your one Google account.

For some years I've been backing up my various Linux-based servers, websites etc using a custom script which makes incremental tar-based backups of key directory hierarchies, dumps some MySQL databases, and then copies the lot to a remote machine using scp or rsync. We run this each night using cron. It's worked well, but it's becoming rather spaghetti-like since we run some version of it on several machines, copying stuff to several other machines. And the process of pruning old backups to keep disk usage under control at both the sources and the destinations is somewhat haphazard.

So I've been looking at various other backup systems which may do a more manageable job. The big systems in the Unix world are the venerable Amanda and the more recent but highly-respected Bacula. I may do something based around Bacula in due course, but for now I needed something quick. Here's a quick rundown of some useful backing-up scripts. They all make use of rsync, or the rsync algorithm, in some way, but do more than just copy from A to B.

rdiff-backup

You can think of this as an rsync which keeps some history. The destination ends up with a copy of the source but also has a subdirectory containing reverse-diffs so you can get back to earlier versions. This is rather nice, I think, and it can pull the backups from or push them to a remote machine, though it does need to be installed at both ends. It's mostly Python and relies on librsync. The standard Ubuntu rdiff-backup package isn't very recent so I built and installed it by hand.

duplicity

This looks good and is being actively maintained. It's a bit like rdiff-backup but focuses on encryption, and uses incremental tar-based backups. For me, the downside was that it's push-only - you run it on one machine to send backups to another - and I was more keen on pulling from several machines under centralised control. Update: I later discovered that pushing can have some real advantages. One is that it can often be easier to manage the permissions of the backup user on the machine where the data exists. It might be a cron job run as root, for example. Another is that you may not always be able to install software or cron jobs on the machine where you want to store the backups. Also, duplicity has some interesting backends for things like Amazon S3. I'm using duplicity more now than when I first wrote this.

rsnapshot

In the short term, I think this is the one that will suit me best. You can create categories like 'hourly', 'daily', 'monthly', and specify how many of each you'd like kept. It creates complete copy directories for each copy of each one, but where the files haven't changed they are simply hard links to the previous ones, so it's pretty efficient on space. And a single configuration file can perform lots of remote and local backups. I suppose the downside is that the hard-link based architecture limits the range of filesystems on which you can store your backups, but if you're firmly in the Unix world this seems to work rather well.

Unison

Unison is a bit like rsync but does bi-directional synchronisation - it can cope with changes being made at either end. I hadn't really thought of it as a backup tool, but - perhaps because two-way synchronisation can sometimes do unexpected things - it does have the ability to keep backups of any files it replaces. One more option if you need it...!