The launch of Apple Inc's latest operating system, Leopard, was its best ever, a research group said on Monday.
Apple, maker of the Macintosh computer, the iPod digital music player and the iPhone smartphone, started selling Leopard on Oct. 25, after a four-month delay due to the company's work on the iPhone.
The new version of Apple's OS X software costs $129 for a single user and $199 for a "family pack" that can be installed on as many as five computers in a single household.
New features include a file back-up feature called "Time Machine," improvements to e-mail and instant messaging, and the ability to preview documents or files without starting up a separate program, as well as quick access to other computers on a home or an office network.
Leopard is the sixth version in as many years, a fact the Cupertino, California-based concern is quick to contrast with Microsoft Corp, which went more than five years between new versions of its Windows operating system.
Microsoft's Windows Vista became broadly available early this year and comes in several versions that cost between $100 and $260, according to the company's Web site.