Editing Sharp Zaurus (section)

== 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 Palmtop Environment|GPE]] [[graphical user interface]]s 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,<ref>{{cite web|url=http://my-zaurus.narod.ru/cacko.html |title=Cacko ROM - English Qtopia ROM for Sharp Zaurus C7x0/C860 |publisher=My-zaurus.narod.ru |access-date=2012-10-21}}</ref> 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 (operating system)|Ubuntu]] for the clam-shell models C3x00 et al., SL-6000 was started in 2008.
* Arch Linux ARM has been ported in 2015 on the C3x00 models.

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 was a port of [[OpenBSD]] for several Zaurus models.<ref>{{cite web|url=http://www.openbsd.org/zaurus.html |title=OpenBSD/zaurus |publisher=Openbsd.org |access-date=2012-10-21}}</ref> 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.<ref>{{cite web|url=http://mail-index.netbsd.org/port-arm/2006/11/19/0000.html |title=port-arm: NetBSD/zaurus |publisher=Mail-index.netbsd.org |date=2006-11-19 |access-date=2012-10-21}}</ref> In early September 2016, the OpenBSD Project ceased support for the Zaurus port of their operating system.<ref>{{cite web |url=http://undeadly.org/cgi?action=article |title=Error |website=undeadly.org |access-date=22 February 2022 |archive-url=https://web.archive.org/web/20161106182320/http://undeadly.org/cgi?action=article |archive-date=6 November 2016 |url-status=dead}}</ref>