By contrast, Vista has no strong sense of personality.
This is not a revolutionary idea - and Microsoft is planning a vaguely similar function for Vista - but Time Machine's UI (user interface), which involves windows flying through space, is quirky and fun. The first major Leopard feature demoed at Steve Job's WWDC keynote was Time Machine, a backup utility that lets you step back to earlier versions of your system and files. Leopard looks to be idiosyncratic and entertaining in a way it's hard to imagine a Microsoft product being. The two major service packs for XP have been relatively feature-light. The difference is that XP is still the current version of Windows, while Apple followed up Puma with Jaguar, Panther and Tiger – Apple has a lots-of-incremental-upgrades philosophy, compared with Microsoft's big-upgrade-once-in-a-blue-moon approach. Both Apple and Microsoft released OSes in the autumn of 2001 - Apple's was OS X Puma Microsoft's was Windows XP. Implementation strategies Leopard is an upgrade to Mac OS X, whereas Vista replaces Windows XP almost entirely.
