InfiniBand (IB) is a high-speed (2–96 Gbit/s) low-latency (140–2600 ns) switched-fabric interconnect, developed primarily for HPC, but as of now widely adopted where its properties are in demand.
Note: this article is a very quick and dirty stub. Please add and edit as you see fit.
InfiniBand is supported on most major operating systems: Windows, Linux, (Open)Solaris, AIX, HP-UX, z/OS, among others. OpenFabrics Alliance (founded in 2004 as OpenIB Alliance) is developing a cross-platform IB/RDMA stack for Linux and Windows. The stack is released as OFED (OpenFabrics Enterprise Distribution) under both GPL and BSD licenses.
There are currently no publicly available InfiniBand stack or drivers for FreeBSD. Kip Macy imported basic RDMA infrastructure in May 2008, but the effort seems to have stalled since. However, proprietary IB/FreeBSD stacks are known to exist. Three major storage appliance vendors, NetApp, Isilon, and Panasas, ship products based (to some extent) on FreeBSD and all of them use InfiniBand for high-speed interconnects. Isilon has voiced its desire to rewrite their stack from scratch and open-source it.
Jeff Roberson has been working on the FreeBSD port of OFED for most of 2010:
There are rumors that Mellanox, a major IB HCA vendor is planning to port OFED to FreeBSD.