Minor modes -- qustion

[Eugene C. Ciccarelli <ECC at MIT-AI>]

In ZWEI in Remote-File 10.0, LMFILE-Remote 17.1, MIT-Specific 9.0,
System 86.37, ZMail 45.1, microcode 136,  , on Lisp Machine Nine:

I have a couple of minor modes that don't get turned on
automatically by major-mode hooks, but that get turned on by the
user manually.  I have two kinds of action that I'd like to
be able to specify:

1. The mode is turned on and off globally, perhaps with an
override in certain buffers, but at the moment I don't much care
about that.

2. The mode is turned on and off per-buffer.

Are there variables that control such actions?  How do I use
them?