Apple's new Macintosh operating system ships tomorrow. Visually stunning, OS 10.5--a.k.a. Leopard--is fast and stable, and it features a consistent set of powerful file-management tools familiar to anyone who has ever used iTunes. And unlike Microsoft Windows, which seems to grind slower with each successive release, OS 10.5 feels faster than 10.4 on the same hardware--provided that you have sufficient memory.
As I mentioned in my May 2007 review, Leopard's centerpiece technology is Time Machine, a revolutionary backup system that lets you take your computer "back in time" to find accidentally deleted files, address-book entries, photographs, and the like. Click "Time Machine," and the desktop drops off the screen to reveal a flowing star field with a sequence of windows progressing back toward the beginning of time (or at least to when you installed Leopard). Click on the timeline, and you can travel back to before you accidentally deleted a key paragraph in that annual report. You can then copy it and bring it back with you into the present.
Time Machine also has a clever disaster-recovery feature that lets you rebuild your Mac from a backup if the main hard drive fails. This feature is built into the MacOS installation process: once the operating system is installed, the computer asks you if you have a Time Machine backup to restore.
Yes, Time Machine's functionality is really no different than that of a traditional incremental backup system. But Time Machine is so much prettier and easier to use! Like the rest of 10.5, Time Machine's graphics and animations are smooth and pleasing but not excessive. The program needs just a tiny bit of configuration: turn it on and specify the hard drive where you want to keep your backups. The defaults are sensible but easily customized. And Time Machine is extensible, so that developers can incorporate it into their own applications. (For example, clicking the Time Machine icon while AddressBook is active allows you to restore individual address-book entries, rather than the entire AddressBook file.)
Unfortunately, Time Machine has a serious problem: there is no way (that I can find) to remove a file from a Time Machine backup. This is a pretty glaring omission. After all, Leopard has a "secure empty trash" feature that lets you throw away files so that they can't be recovered with forensic tools. What's the point of erasing a file on the hard drive and then overwriting the disk sectors seven times if Leopard is going to keep a copy of the file in the Time Machine backup?
Leopard's other big breakthrough is its Parental Controls, one of the best implementations of child-control technology I've seen. Parental Controls allows you to set time limits on your child's use of the computer (separate limits on weekdays and weekends), bedtimes, and wake-up times. The system gives a warning when bedtime is approaching; if your child is working hard on a paper for school, you can type in your username and password and lift the electronic curfew.
Parental Controls also allows you to specify websites that can't be accessed, the people with whom your child can exchange e-mails and instant messages, and even which applications your child can run. I was pleased to see that restrictions on websites and the like are actually built into the operating system, rather than built into Apple's Safari Web browser: I downloaded and ran a copy of Firefox, but the blocked websites remained blocked.