Transmeta, which sells low-power, Intel-compatible processors called Crusoe, previously referred to Midori as Mobile Linux. Transmeta has been working on the Midori additions to Linux for more than a year. Now it has released the software as an open-source project at VA Linux Systems' SourceForge site.
Transmeta expects Midori to be used in smaller Crusoe-based mobile devices, while Microsoft's Windows will continue to dominate laptops, the company has said. Midori is used in Gateway's Touch Pad, a product from which Gateway is retreating.
Several new products using Midori will be shown next week at the Cebit computer show in Germany, Transmeta said.
Linux developers along with competitors such as Microsoft and Red Hat have been waiting for months to see what improvements Midori would bring to the kernel of Linux. Now those details are starting to emerge. Additions include:
Support for power management hardware that reduces electricity consumption.
Support for the power-saving features of the Crusoe chip, including support for the LongRun technology that matches the chip's power consumption to how hard its working.
A file system that runs in flash memory rather than a hard disk. Flash memory, which unlike regular computer memory retains data even when power is switched off, is used in many gadgets.
A file system that lives in regular computer memory.
Dan Quinlan, a one of Transmeta's Midori developers, said Torvalds wrote the first version of "CramFS," a file system that compresses data to about half its original size before it's stored in flash memory.
In addition, Torvalds wrote software called RamFS that lets files be stored in regular memory, Quinlan said. Unlike previous file systems that could store information in RAM, this one lets file system size change automatically. That means the file system takes up just the right amount of space--not hoarding precious unused memory that could be used by higher-level software on the one hand, and not running out of space on the other.
Later improvements to Midori also are planned, Quinlan said. They include enhancements to the current support for the Advanced Configuration and Power Interface (ACPI) that enable a device to shut down everything except its memory to conserve power.
Quinlan, one of the six developers in charge of Midori, hopes outsiders will join the effort. "I think that for some number of projects, Midori will be an attractive place to do work," he said. There's even some potential that Midori might unify some of the disparate efforts at creating Linux for gadgets, he added.
Midori is designed to let devices turn on quickly, connect to the Internet and be personalized, Transmeta said. The software uses the Xfree86 graphics system, which some have complained is too bulky for small devices.
"It's not that bulky," Quinlan said. The newer version 4 of XFree86 is more modular, so that unneeded parts can be left out, he said. And using something else would be difficult, since Linux programs are designed to work with XFree86 or other versions of the X Window System standard.
"If you're using something other than X, you don't have any applications to start with, so it's totally worth the trade-off," he said.
The Midori Linux operating system, graphics system and basic software fits into about 8MB of memory, he said.
Unlike regular Linux--a clone of the venerable Unix operating system--Midori doesn't prompt for a username and password.
The name Midori, which means "green" in Japanese, was chosen to reflect Transmeta's emphasis on lower power consumption and therefore more environmentally sound computer systems, the company said.