As we stated earlier, only one person at a site needs to install PVM, but each PVM user can have his own hostfile, which describes his own personal virtual machine.
The hostfile defines the initial configuration of hosts that PVM combines into a virtual machine. It also contains information about hosts that you may wish to add to the configuration later.
The hostfile in its simplest form is just a list of hostnames one to a line. Blank lines are ignored, and lines that begin with a # are comment lines. This allows you to document the hostfile and also provides a handy way to modify the initial configuration by commenting out various hostnames (see Figure ).
# configuration used for my run sparky azure.epm.ornl.gov thud.cs.utk.edu sun4
Several options can be specified on each line after the hostname. The options are separated by white space.
[t80040000] ready Fri Aug 27 18:47:47 1993 *** Manual startup *** Login to "honk" and type: pvm3/lib/pvmd -S -d0 -nhonk 1 80a9ca95:0cb6 4096 2 80a95c43:0000 Type response:On honk, after typing the given line, you should see
ddpro<2312> arch<ALPHA> ip<80a95c43:0a8e> mtu<4096>which you should relay back to the master pvmd. At that point, you will see
Thanksand the two pvmds should be able to communicate.
If you want to set any of the above options as defaults for a series of hosts, you can place these options on a single line with a * for the hostname field. The defaults will be in effect for all the following hosts until they are overridden by another set-defaults line.
Hosts that you don't want in the initial configuration but may add later can be specified in the hostfile by beginning those lines with an &. An example hostfile displaying most of these options is shown in Figure .
# Comment lines start with a # (blank lines ignored) gstws ipsc dx=/usr/geist/pvm3/lib/I860/pvmd3 ibm1.scri.fsu.edu lo=gst so=pw # set default options for following hosts with * * ep=$sun/problem1:~/nla/mathlib sparky #azure.epm.ornl.gov midnight.epm.ornl.gov # replace default options with new values * lo=gageist so=pw ep=problem1 thud.cs.utk.edu speedy.cs.utk.edu # machines for adding later are specified with & # these only need listing if options are required &sun4 ep=problem1 &castor dx=/usr/local/bin/pvmd3 &dasher.cs.utk.edu lo=gageist &elvis dx=~/pvm3/lib/SUN4/pvmd3