The launch of Apple Inc's latest operating system

Apple launch of Leopard system its best ever-group

The launch of Apple Inc's (AAPL.O: Quote, Profile, Research) latest operating system, Leopard, was its best ever, a research group said on Monday.

When comparing the first full month of sales of Apple Mac OS 10.5 "Leopard" (November 2007) to the first full month of sales for Mac OS 10.4 "Tiger" (May 2005), dollar volume for Leopard was up 32.8 percent and unit volume up 20.5 percent, NPD Group Inc said in a statement.

Apple, maker of the Macintosh computer, the iPod digital music player and the iPhone smartphone, started selling Leopard on October 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.

While the increases in dollar and unit volume can partially be attributed to going on sale during November -- a key month for consumer shopping -- and the growth in the number of Apple retail stores, NPD said the figures show that Apple has found the right formula for rolling out new versions of Mac operating systems.

Leopard is the sixth version in as many years, a fact the Cupertino, California-based concern is quick to contrast with Microsoft Corp (MSFT.O: Quote, Profile, Research), 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.