ok, this is more clear now...
to QNO1)
there is a command xlock
[fp@admin6] % man -M /usr/openwin/share/man xlock
Reformatting page. Please Wait... done
User Commands
xlock(1)
NAME
xlock - locks the local X display until a password is entered
to QNo2)
what you call session is a shell on another host, in this shell you execute commands, the only think I know is bg and fg (as Ken already mentioned); If your client (the machine you are sitting at) and the network has no restrictions about connections you can start as many commandtools/xterms/etc as you like, some of them offer somathing like session1 and session2, but afaik, these are independant shells running on the host being connected in one managed window (I have never seen this under Solaris, but I know it from RedHat/SuSE Linux)
does this answer your question or is this even more confusing? HTH...
Regards
-- Franz
Sorry I'm not a native spaeker, I'm from Munich, Germany - "Home of the Whopper", oh no, "Home of the Oktoberfest" ;-)
Solaris System Manager; I used to work for Sun Microsystems Support (EMEA) for 5 years