Short for Network File System, but there are others. Invented at Sun. Supports a large fraction of UNIX filesystem semantics (larger than the other networked FSes) but definitely not complete.
Tcl and NFS
One issue, at least up until 8.5a1, is that a fair number of tests in the core test suite fail when run in an NFS-mounted directory. This is because of the fact that NFS only supports a subset of the classic semantics.
LV On what platforms? Nearly all testing I have done since Tcl 6 has been done on NFS mounted directories - and I get less than 6 failures. Of course, I've been using SPARC SunOS machines.
DKF: I have problems persistently with (IIRC) both Sol9 and Linux. Perhaps it also depends on the configuration of the NFS server? If so, we've got a total imponderable and a set of tests that are simply non-portable. :^/
[Other issues?]
Network Block Device (NBD) is a network protocol for accessing block devices over the network. Block devices are hard disks and things that behave like hard disks such as disk images and virtual machines.
nbdkit is both a toolkit for creating NBD servers from “unconventional” sources, and the name of an NBD server. nbdkit ships with many plugins for performing common tasks like serving local files.
nbdkit is different from other NBD servers because you can easily create new Network Block Device sources by writing a few glue functions, possibly in C, or perhaps in a high level language like Tcl.
nbdkit-tcl-plugin is an embedded Tcl interpreter for nbdkit, allowing you to write nbdkit plugins in Tcl.