Daily Archives: September 26, 2007

EXCELlent arithmetic?

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Hmmm…. Some people are claiming that Excel has difficulty with multiplication. (See image above.)

Over the weekend members of the microsoft.public.excel newsgroup reported a serious bug in calculations made by Excel 2007. Initially it just seemed that Excel Can’t Multiply. The bad news is, Excel can’t do other operations correctly either. The good news is, this is only true when the results are within a very specific range of numbers. And the better news is that the Excel team has mapped out the nature of the problem and is feverishly working on an update.

So what went wrong? It all boils down to the fact that you can’t represent an infinite group of non-integer numbers using a finite number of bits. In fact, Excel can store “only” about nine quintillion distinct values. The numbers going into your calculations may be infinitesimally different from the number displayed, and for two calculations that nominally have the same answer the result may be infinitesimally different. Excel generally manages just fine in dealing with these tiny differences, but in exactly 12 instances out of the nine quintillion possibilities it goes completely bonkers.

The Excel team discovered that it wasn’t just calculations involving 65,535 that were affected; those that should come out to be 65,536 were also sometimes wrong (returning 100,001 instead). And they discovered it wasn’t just multiplication. In truth, the operation didn’t matter, only the result. When they work up a fix it will still have to “make its way through our official build lab and onto a download site”, but they expect it to happen soon.

Useful fact: a quintillion is 1 followed by 18 zeroes.

The funny thing is that my copy of Excel does not make this mistake (see below).

But then, I’m running Excel 2004 for Mac.

Virgin unplugs its subscribers

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Here’s an interesting insight into Digital Restrictions Management, aka DRM.

Virgin has closed Virgin Digital, its Windows Media-based alternative to Apple’s iTunes. It stopped selling one-off downloads on Friday, though subscribers will still have access to their collections until their next monthly payment is due.

After that, their songs will no longer be playable, thanks to the limitations placed on playback by the DRM technology built into each track.

Virgin announced the move this weekend in an email sent out to all its customers, all of whom have presumably been busy backing up their tracks or – in the case of subscribers – burning them to CD so they can be re-imported as MP3s.

The service will formally close on Friday, 28 September – coincidentally the day Apple’s new iPod Touch is due to arrive in the UK – and finally shut down on Friday, 19 October.

Translate that into non-digital terms. You buy an album from a record store, and play it happily on your CD player. And then, one day, it won’t play any more. Why? Because the store from which you bought it has — for some reason decided upon by the store’s owners — closed.

All your iPhone are belong to us

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From The Register

Apple has issued a notice that unlocked iPhones could suffer permanent damage when they update the firmware, and reminded customers that such damage is not covered by the warranty.

The process of unlocking an iPhone is complicated, and involves code running at a pretty low level in the OS. Users may feel confident that they can always re-flash their iPhones using iTunes, but even that requires a working kernel (minimal OS) on the phone – damage that and you’ve got a Jesus doorstop.

Such damage is unlikely. Far more probable is that every time an update is installed users of unlocked iPhones will have to unlock them again, but Apple felt the need to remind people of the risk they take when unlocking the handset or installing third-party applications.

Engineers inside O2, the UK operator deploying the iPhone in November, are under the impression that Apple will be able to re-lock phones to their network when they’re updated, but that will depend on the unlock process used and if Apple can be bothered to apply the resources needed to reverse it.

The assumption among many iPhone buyers seems to be that no matter what Apple does, the hackers will make everything work. The faith in techno-anarchism is touching, but may be misplaced if Apple just reverses everything with each update…

Footnote: readers puzzled by the grammatical infelicities in the headline are respectfully directed to here.

Iran invades US

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Lovely column by Maureen Dowd on the tempestuous US visit of the fruitcake who is now President of Iran.

First, we break Iraq and hand it over to the Shiites, putting in a puppet who leans toward Iran and is aligned with the Shiite militias bankrolled by Iran. Then, as Peter Galbraith writes in The New York Review of Books, President Bush facilitates “the takeover of a large part of the country by an Iranian-backed militia,” with the ironic twist that “there is now substantially more personal freedom in Iran than in Southern Iraq.”

And on top of all that, we help build up the self-serving doofus Iranian president, a frontman with a Ph.D. in traffic management, into the sort of larger-than-life demon that the real powers in Iran — the mullahs — can love.

New York’s hot blast of nastiness, jingoism and xenophobia toward its guest, Mahmoud Ahmadinejad, only served to pump him up for his domestic audience. Iranians felt that their president had tied everyone in knots, including the “Zionist Jews,” as Iranian state television said. The Times reports that Mohsen Rezai, a former head of the Revolutionary Guards, was on TV criticizing the rude treatment his president received: “It is shocking that a country that claims to be civilized treats him that way.”

Ms Dowd also solves a problem that had been baffling me: how to remember (and pronounce) the name of the Iranian Prez. Solution: Just say “I’m a dinner jacket”.