Launching Next has discovered 5 operating system startups.
Founders' Book
#1 Platform for founders and early-stage startups.
Google Operating System (Unofficial Google Blog)
Unofficial news and tips about Google. A blog that watches the Google services that help you move your operating system online.
The GNU Operating System
Since 1983, developing the free Unix style operating system GNU, so that computer users can have the freedom to share and improve the software they use.
Debian -- The Universal Operating System
Debian is an operating system and a distribution of Free Software. It is maintained and updated through the work of many users who volunteer their time and effort.
www.centos.org - The Community ENTerprise Operating System
CentOS -- Community ENTerprise Operating System is a free rebuild of source packages freely available from a Prominent North American Enterprise Linux vendor.