In a weird last-minute announcement, Apple announced this morning that it will ship its $29 Mac OS X service pack, called "Snow Leopard," on Friday.

Apple today announced that Mac OS X v10.6 Snow Leopard will go on sale Friday, August 28 at Apple’s retail stores and Apple Authorized Resellers, and that Apple’s online store is now accepting pre-orders. Snow Leopard builds on a decade of OS X innovation and success with hundreds of refinements, new core technologies and out of the box support for Microsoft Exchange. Snow Leopard will be available as an upgrade for Mac OS X Leopard users for $29.

To create Snow Leopard, Apple engineers refined 90 percent of the more than 1,000 projects that make up Mac OS X.

Curiously, there are no major new end user features worth noting, which explains the "service pack" claim above. (Yes, it supports Exchange, but that won't impact most Mac users.) I've been using this thing all year, including the final version for the past week or so, and I have to say ... there's just not much there. It makes my "Windows 7 vs. Snow Leopard" series somewhat ponderous to write because I can't focus on what's new but must instead just compare the two OSes more generally. In case it's not obvious, users expect things to improve somewhat with each OS release, that's the minimum, but Snow Leopard doesn't go beyond that at all. This stands in sharp contrast to Windows 7, which does indeed change the overall Windows experience in useful ways. Snow Leopard is just simple refinements. Sorry, but it's just not that interesting.

And while Snow Leopard is indeed priced right for those up-to-date Mac users who paid $129 each year to upgrade to the latest OS release, or even more to just buy a new Mac, it's going to cost the hold-outs a lot more: $169 for a package that also includes iLife 09 (which is good) and iWork 09 (which is pointless). That's the only way that previous-generation ("Tiger") Mac OS X users can get Snow Leopard. And that's only for those on Intel-based Macs. You didn't upgrade yet? Sorry, Luddite, you can't get Snow Leopard.

I raise this issue because there's been a lot of talk lately about how Microsoft won't support direct upgrading of an 8-year-old operating system (XP) to Windows 7, though it does support a very useful migration process. Apple, meanwhile, isn't supporting upgrades from machines that were sold as recently as two and a half years ago. I think this distinction is important, and doesn't get enough attention.

Anyway. I'll put up a short Snow Leopard article this week and then get back to work on the Windows 7 vs. Snow Leopard series.