Sharp Zaurus - Operating Systems

Operating Systems

These are frequently called 'ROMs' in the community because the Zaurus' OS is usually stored in embedded flash memory, and are installed using a flashing tool. There's also a special "rescue" mode NOR flash (or P2ROM in newer models) in all Zauruses since the 5xxx series which allows recovery from a corrupted OS.

• OpenZaurus, which uses the OPIE or GPE graphical user interfaces and is designed for the power user. OpenZaurus does not include the proprietary software that comes with Sharp's distribution. OpenZaurus development has been dropped in favour of Ångström which is also based on the OpenEmbedded build environment, but supports a larger range of devices, not limited to Zauri.
• Ångström distribution, the replacement for OpenZaurus. OpenZaurus no longer is being developed for, as its developers now work on Ångström distribution. Ångström is an OpenEmbedded build system based Zaurus distribution with its current images being console and an X11 GPE based ROM.
• pdaXrom, a distribution based on the X graphics system and the matchbox/openbox user interface.
• Cacko, an alternative to the original Sharp ROM, it is based on the same Qt graphics system with as many underlying parts of the OS upgraded as possible yet still maintains full compatibility and allows the proprietary Sharp applications to be run.
• In August 2007 a port of Gentoo Linux was started which offers some promise.
• Zubuntu, based on the ARM port of Ubuntu for the clam-shell models C3x00 et al., SL-6000 was started in 2008.

For the Sharp and Cacko ROMs, there are third party and somewhat experimental kernels such as "Tetsu's" (a Japanese Zaurus expert) which offer interesting optimisations and drivers for unusual hardware. It is possible to replace only the Linux kernel which can give better performance while maintaining compatibility and retaining installed software that comes with a "stock" ROM.

As well as the choice of GUI (qt/qtopia, X11 + matchbox, X11 + E17 etc.), one key difference is the choice of whether the kernel was built with using ARM standard EABI or not, and whether it uses software or hardware floating point (code using hardware floating point is actually slower because the hardware doesn't support it, so those instructions cause an exception which then has to be handled by the kernel, with noticeable overhead).

There is a port of OpenBSD for several Zaurus models. The port is available on the SL-C3000, SL-C3100, and SL-C3200 with development continuing in order to expand support to the C860 and C1000. This port of OpenBSD does not however replace the original operating system entirely, nor is it made available as a ROM image, instead it uses the original Linux install as a bootloader and installs the same as OpenBSD would on any other platform. There is also a NetBSD port is in development, based on the work from OpenBSD.