1 03/01/88  Extended Access
 2 
 3 Message segments make use of an additional field of access modes, listed
 4 below.
 5 
 6     a (add) process can add a message.
 7     d (delete) process can delete a message.
 8     r (read) process can read any message.  If this mode is given,
 9        s access must also be given.
10     o (own) process can read or delete its own messages.
11     s (status) process can find out how many messages are in the
12        segment.
13     w (wakeup) process can send a normal priority wakeup.  If this mode
14        is given, a access must also be given.
15     n (null) process cannot access the segment in any way.
16     u (urgent) process can send "urgent" messages to the user
17        accepting messages on the mailbox.  If this mode is given,
18        a access must also be given.  (Urgent messages are not
19        currently implemented.)
20 
21 
22 Default extended access for a mailbox:
23 
24     adrosw          User.*
25     aow             *.SysDaemon.*
26     aow             *.*.*