Summary Box: Apple buys flash-memory co. Anobit

THE PURCHASE: Apple has bought Anobit Technologies, an Israeli maker of flash-memory technology already used in many of Apple’s gadgets.

WHAT’S FLASH?: It’s a type of memory used in digital devices, including Apple’s iPhone, iPad and MacBook Air, none of which have hard drives.

THE RATIONALE: Apple isn’t saying, though owning the manufacturer guards Apple against supply constraints in the industry and allows the company to customize the technology so it works more smoothly with the iPhone and other devices.