Operating systems always have been my favourite computer related topic, so I know and use many: * **Linux** -- I've been using several LinuxDistros extensively and I occasionally do minor packaging work for Fedora and Ubuntu. I've also put together and distributed a custom Linux distribution targeted at the AmigaComputer as part of the AmigaUnixCompendium project. * **NetBsd** -- I've been a NetBSD user since 0.9 and bacame an official developer with CVS commit access a little later. I made a custom NetBSD distribution on CD for the AmigaComputer called the AmigaUnixCompendium. See also OpenSourceDeveloperRole for some contributions I made. * **Sun Solaris** -- I've been using it since Solaris 7, but a few years ago I've lost interest in it because of lack of development. Besides building hundreds of GNU and other packages to replace almost all of Sun's userland, I successfully ported the early versions of KDE 1.x and 2.x to Solaris. * **MacOsX** -- I know this system quite well and have been using as a user and developer until mid-2006, when Apple started taking some steps back from their previous OpenSource commitment, showing lack of cooperation and disrespect for the OpenDarwin developers. * **AmigaOs** -- I've been programming a lot on the Amiga in early '90s, mostly as a freelance developer. I expecially prised its unique system and OS architecture, therefore I reused many of its best ideas in my EmbeddedDeveloperRole projects. * **MicrosoftWindows** -- I've been developing for Windows with little enthusiasm since Windows 3.1 upto Windows 2000. I'm familiar with most of the Win32 APIs and concepts, including GUI design with common controls and MFC, threading, overlapped I/O, events, COM, ODBC, DAO, VisualBasic, VBA, DirectMedia and DirectDraw. For new Windows development, today I recommend using portability layers and framwworks such as Cygwin, MingW and Qt.