Sidebar: An automounter Replacement

Not all UNIX systems ship with automounters, or if they do, it may be an expensive add-on product. Luckily, there is a freely available replacement, the Auto Mount Daemon (Amd). Amd is the BSD4.4 automounter and has been ported to many versions of UNIX. It seems that most of the ftp sites that carry amd do so in support of Linux, FreeBSD, and NetBSD, but it does run on AIX, HP-UX, SunOS, and many others. The documentation for Amd describes it as "a replacement for Sun's automounter." A better word than "replacement" might be "successor." Jan-Simon Pendry has taken the basic automounter, and added a richer map syntax (see Figure 2 for an example) and a more robust runtime environment. Amd is freely available, but as the author Jan-Simon Pendry points out, it is not public domain, nor does it appear to be GNU. If you have any doubts, read the license. My personal favorite feature is amd's use of logical "selectors." Amd maps use this rudimentary logic to allow mounts to be chosen based on which host the map is being interpreted on:

mount host1:/x/y on /pkgs/y unless you are host3

then

mount host3:/x/y on /pkgs/y

There is no way to do this directly in automounter. (See Figure 2 for example AMD map.)

For more information on selectors and everything else about Amd, see

ftp://usc.edu/pub/amd

and

ftp://ftp.cs.columbia.edu/pub/amd n