Jeff and all -
I am currently doing a Master Thesis here at RIT about persistence and
shared objects using 3-tier solutions, VRML front ends, and Oracle servers
as a backbone. Maybe I could be of some assistance ? I don't have a
completed project to showcase yet but I do have a working model of the
underlying technology to store a Txyz, Rxyz, Sxyz and Crgb for shared
objects, as well as some nice mechanisms to support the propagation of these
changes to multiple clients...
(Steve Guynup is somewhat familiar with what I've been up to but I lost
track of him...)
Anyway, in answer to his question about saving position before crashing,
that is precisely the goal of what I've been working on. Instead of using
the server layer as the mechanism of communication, my system uses the
database itself as the means in which one users actions get forwarded. The
server is essentially a middle layer to allow the client access to the dbms.
Why did I do this ? In a more traditional mu environment you might
multicast. The problem with multicast when storing values for persistence
is: What happens if the user makes a change, and that change gets to other
users, but not to the database ? You have an inconsistent state, which is
problematic. By using the dbms itself as the relay mechanism you loose some
speed (although Oracle has some excellent structures for decreasing user
transaction time). If every action that is received by oracle can survive
system failure (which is a claim of most dbms packages) then at most the
client will be one step behind where they were when they died...
Now my system needs a **lot** of work yet, but I'd be happy to help.
Persistence is my big thing as far as research right now, particularly the
importance of persistent objects in mu storytelling... You can see some of
my stuff at http://www.rit.edu/~amp5315/aweb5/papers/
And some more at http://www.rit.edu/~amp5315/mystery/ (an interactive Clue
like game which should be up by the end of the month).
Oh, and if you want, I'll submit your site to over 50 different search
engines for the low price of <strangle...choke...gasp......>
Andy
RIT
