I am definitely interested. I will check my schedule for next week. ~Michael
On 7/16/13 11:02 AM, "John Blossom" <jblos...@gmail.com> wrote: >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 >> >>> >> >> >> >> >>
