Google previously had offline mode for some of its services with Google Gears, but it retired that service a while back.

FORBES: Google Takes Gmail, Calendar, Docs Offline: A Big Plus For Chromebook

But instead of using Google's Gears, Jolicloud relies on Mozilla's Prism and Firefox to run various web-based applications.

ECONOMIST: Google goes in search of an instant operating system

Gears is built into Google Chrome but can just as easily be added to other browsers.

ECONOMIST: Google goes in search of an instant operating system

Microsoft has countered Adobe's AIR and Flex technologies with its own development tools called Live Mesh and Silverlight. (Sun Microsystems in May launched similar technology called JavaFX, and Google has a tool out called Gears.) Microsoft has 4 million software developers already using its .

FORBES: Magazine Article

To transform Chrome and Gears into a lightweight operating system, Google will have replaced the rest of Linux with a slimmed down windowing and application manager that integrates with Chrome and Gears for running applications on the web and with the Linux kernel for running the computer hardware.

ECONOMIST: Google goes in search of an instant operating system

Google has already developed the software, called Gears, that lets a browser run such web-based applications.

ECONOMIST: Google goes in search of an instant operating system