Summary Box: Apple previews Mac OS update

COMING SOON: An update for the Mac operating system, dubbed Mountain Lion, that will copy more features and apps from the iPhone and iPad to the Mac.

TIMETABLE: Apple released a developer preview on Thursday. The new software is due on sale this summer, a year after it released the latest update, Lion. Apple didn’t say what Mountain Lion would cost.

TRENDS: Apple started the trend of making its Mac operating system more like its phone and tablet operating system, iOS, with the release of Lion.