Microsoft .Net runs in Windows, x86, x64 and IA64. But there is another implementation called mono with a broad support for platforms and OS:
OS:
- Linux
- Mac OS X, iPhone OS
- Sun Solaris
- BSD - OpenBSD, FreeBSD, NetBSD
- Microsoft Windows
- Nintendo Wii
- Sony PlayStation 3
Platforms:
- s390, s390x (32 and 64 bits): Linux
- SPARC (32): Solaris, Linux
- PowerPC: Linux, Mac OSX, Wii, PlayStation 3
- x86 Linux, FreeBSD, OpenBSD, NetBSD, Microsoft Windows, Solaris, OS X, Android
- x86-64: AMD64 and EM64T (64 bit): Linux, FreeBSD, OpenBSD, Solaris, OS X
- IA64 Itanium2 (64 bit): Linux
- ARM: little and big endian: Linux (both old and new ABI), iPhone, Android
- Alpha: not maintained. Linux
- MIPS: Linux
- HPPA: not maintained Linux