Shared system routines

[mike.rice at rand-relay]

From:  Mike.Caplinger <mike.rice at rand-relay>

Anybody ever heard of shareable images under VMS?  There's no
additional overhead once a process's address space is mapped in because
tha shared routines are just magically mapped in virtual memorywise.  I
think there were once plans to put such things in 4.2 BSD, but they
seem to have been abandoned.  They are nice in VMS, and can save lots
of disk space.  Also, if you change something you just reinstall the
sharable library - nothing need be relinked (if you're clever and use a
vector table, anyway.)  I don't like too many things about VMS, but
this seems to be a major win.