Microsoft wants PC makers to mount mobile-phone-like displays on the lids of laptop computers so users can check the time, battery status, appointments or see if new e-mail has arrived without having to open and start up their PC.

The software giant is including support for such displays in the next version of Windows, codenamed Longhorn, due out in 2006. Microsoft is developing software and reference designs for the displays, which it says will give users instant access to select data and save time and battery life because there is no need to open and boot up the PC.

The display on the lid of a laptop would be similar to a color cell phone display and powered by the notebook battery. Data pulled out of applications would be stored in a special memory cache so it is also accessible when the PC is turned off or in standby mode, said Sriram Viji, a program manager working on the "auxiliary displays" at Microsoft.

In a presentation at the VSLive and Windows Anywhere developer event in San Francisco on Wednesday, Viji showed a picture of an auxiliary display showing a menu of options that included calendar, contacts, tasks, inbox and media player. The picture also showed a set of buttons to allow users to navigate the menu.

In addition to displaying cached data, applications for the auxiliary display could be programmed to periodically wake up the PC, connect to the Internet, synchronize data and update that on the display, Viji said.

Besides the actual display, RAM and flash memory, the needed hardware for the auxiliary display would include a lightweight ARM processor and USB and system bus connections, Viji said. The display will run on the Smart Personal Objects Technology (SPOT) software, which is also used Microsoft's smart watches, he said.

Users will be able to customize the data displayed and virtually any application can take advantage of the screen, Viji said. Microsoft is calling out to developers to come up with applications. The software maker plans to provide developer guidance around the same time the first beta of Longhorn ships, some time in the first half of this year, he said.

Microsoft will support the auxiliary displays in all versions of Longhorn, including the server version. However, the company has put its weight behind the notebook application, Viji said. "We’d love to see that happen and we're definitely pushing to see that happen," he said.