Hi Mike,

> The user id. "root" on linux158 is not the user id. of the other system where this is mounted from.

yes, indeed - typically, you'll map the client user "root" to i.e. "nobody" or some other unprivileged user on the NFS server side ("root_squash" option, see "man 5 exports"). This is to protect the file system exported by the server - as the server admin, you cannot guaranteed that the "root" account at the NFS client is safe.