That was my thought, also. ApacheWavers, please respond with some avails calibrated to UT+1 for this week and next week. Time to get this party started! My L,A. project is waiting for the funder to come through, but my Nkommo project is gaining steam - hopeful that we'll have some exciting announcements fairly soon. Time to change the world with Wave!!!
All the best, John Blossom email: jblos...@gmail.com phone: 203.293.8511 google+: https://google.com/+JohnBlossom On Tue, Jul 16, 2013 at 1:58 PM, Joseph Gentle <jose...@gmail.com> wrote: > I've had a busy few weeks - gearing up to launch our product at work. > We should organize another hangout sometime. > > -J > > On Sat, Jul 13, 2013 at 7:24 AM, John Blossom - Shore Communications > Inc. <jblos...@shore.com> wrote: > > Soo...how is this initiative going? How may I help to move it forward? > > > > Best Regards, > > > > John Blossom > > President > > Shore Communications Inc. > > > > where content, technology and people meet. (Salesmark of Shore > > Communications Inc.) > > > > web: shore.com > > blog: contentblogger.com > > email: jblos...@shore.com > > phone: 203.293.8511 > > fax: 203.663.8259 > > twitter: jblossom <https://twitter.com/jblossom> > > google+: google.com/+JohnBlossom > > LinkedIn: John Blossom <http://www.linkedin.com/in/johnblossom> > > facebook: John Blossom > > skype: jblossom > > > > > > > > On Mon, Jul 8, 2013 at 9:43 AM, John Blossom <jblos...@gmail.com> wrote: > > > >> Ingenious, Torben, certainly adds efficiency. John > >> > >> On Mon, Jul 1, 2013 at 4:38 AM, Torben Weis <torben.w...@gmail.com> > wrote: > >> > >>> 2013/6/25 Joseph Gentle <jose...@gmail.com> > >>> > >>> > > >>> > >> When peers connect, they send each other missing ops. Figuring out > >>> > >> which ops are missing can be surprisingly tricky - but we'll > figure > >>> > >> that out later. New ops must be ingested in order, so we always > >>> ingest > >>> > >> an operation after ingesting all of its parents. > >>> > > >>> > Just use a Merkle Tree that is at the same time a prefix tree with > >>> respect > >>> to the hashes of the ops (explanation below). > >>> The bandwidth usage is O(1) if both clients are in sync and O(log n) if > >>> they have one or few different ops and O(n) in the worst case, where n > in > >>> the number of ops. > >>> > >>> Constructing the tree is simple. > >>> Let the hash function output 20 bytes and let's encode this in hex. > This > >>> results in a hash-string of 40 hex-characters for each operation. > >>> Each node hashes over the hashes of its children. Leaf-nodes > correspond to > >>> operations and thus use the hash value of their respective operation. > >>> The tree-invariant is that all siblings on level x share the same > prefix > >>> of > >>> x hex-characters. > >>> The tree is not sent over the network. Instead, clients start comparing > >>> the > >>> hashes at the root. > >>> > >>> Two clients compare their root hash. If it is equal, the entire tree is > >>> equal and therefore they are in sync. > >>> If not, they download all direct children and repeat the procedure for > >>> each > >>> sub-tree rooted by one of these children. > >>> For example, if child number 3 has a different hash, but all others > share > >>> the same hash, then we have learned that there are one or more ops > with a > >>> hash of 3xxxx... that are different and need syncing. > >>> > >>> Typically we can limit the depth of the tree to few levels. 8 levels > >>> already yield a tree that could store 16^8 possible ops. So in the > worst > >>> case two clients need to wait for 8 round-trips to determine a missing > op. > >>> > >>> In addition, each client sends a time stamp. So when syncing we report > the > >>> last time stamp received from this client and ask for all ops this > client > >>> received later. If these are few, then simply get them (even if we know > >>> some of the ops already, because we got them from another client). If > >>> there > >>> are too many ops, fall back to the merkle tree. With a good > approximation > >>> of RTT and bandwidth, it is easy to calculate which algorithm is the > best > >>> to sync two clients. > >>> > >>> Greetings > >>> Torben > >>> > >> > >> >
