Well, I was thinking that you have the (simplified) tuple (id, version). You can't write to an older version, since that's rewriting history. The kind of transparent branching like you're talking about seems a bit excessive, although I was thinking about "alias" vobjects that would just be a transparently reinterpreted pointed to another vobject, which could point to a specific version... This quickly starts to get complicated, though.
The way I see it, if you write to a vobject, one of three things can happen (when you replicate the vobject, it has flags telling you which one to use): (a) always send the request and wait for the reply before committing the change (b) send the request, apply the change optimisticly, but allow that the change could be rolled back (c) apply the change locally and don't send anything (these cases should look familiar, I think replication of value is basically the same as the replication of computation question) We do need to distinguish between local changes and "official" (digitally signed) changes. This is pretty easy, though, by clearing the digital signature or setting some sort of "dirty" flag. On Tue, May 08, 2007 at 06:13:21PM -0400, Reed Hedges wrote: > > > This means that if that version object is mutable, i.e. a not read-only > > > property, we need to also have branches in the version history, and any > > > reference to a past version of a vobjcet is really a reference to "the > > > most recent version in the branch rooted on this object, which if there > > > is only one version in the branch, is the same as the root object" [if > > > that makes any sense]. > > > > I don't understand. > > The example I was thinking of is this: > > Property P has versions P.1, P.2, P.3. If you have a normal reference > to P, you get P.3, though you know it just as P. If you write to P, it > creates a new version, P.4, but P (being the "current version") is > transparently changed to P.4. But if you have a reference to > P.2, and you write to it, resulting in a new version P.2.2, it appears > to you that the write didn't work, since you're still looking at P.2. > So P.2 needs to be an alias for "most recent version of P.2" in the same > way that P was. P.3 is then also an alias for "most recent version of > P.3", but P.3 doesn't have any derivative versions, so it's just P.3 (or > call it P.3.0 or something). > > Reed > > > _______________________________________________ > vos-d mailing list > [email protected] > http://www.interreality.org/cgi-bin/mailman/listinfo/vos-d -- [ Peter Amstutz ][ [EMAIL PROTECTED] ][ [EMAIL PROTECTED] ] [Lead Programmer][Interreality Project][Virtual Reality for the Internet] [ VOS: Next Generation Internet Communication][ http://interreality.org ] [ http://interreality.org/~tetron ][ pgpkey: pgpkeys.mit.edu 18C21DF7 ]
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