I had qualified my use of the term client previously when I said, "When I say client, I mean client as in client/server".
I liked your first post. However, to demostrate that the transformation is unambiguous, you need to generate [Oa, Ob'] and [Ob, Oa'] and show that they give the same result. There is no need to talk about the federation protocol to answer the question. The ambiguity that the OP talks about can only ever happen on the client (meaning the client that the user interacts with), so what the servers do amongst themselves is irrelevant. I feel this conversation is getting nit picky and off topic now. Dan Brett Morgan wrote: > On Dec 3, 12:42 pm, Daniel Paull <[email protected]> wrote: > > Brett - let's just take a step back here. All this conversation is to > > answer this question: > > > > "On the server a piece of text is lets say "15" and two clients alter > > the same piece in "16" and "17" respectively. What would be the > > outcome of the transforms? There is no unambigeous way to cope with > > this edit I think." > > I showed that there is an unambiguous way to cope with that scenario > when I posted code using wave's BufferedDocOps, Composer and > Transformer. > > > There is no need to talk about federated servers to answer the > > question. > > I disagree, as server federation uses this code extensively in dealing > with the above scenario, amongst others. > > > The FedOne client, to my understanding of where it is at now, does not > > wait for acknowledgements from the server (nor does the server send > > acknowledgements to clients) and does not perform any OT. It is a > > completely differnent animal that what is described in the Google OT > > white paper and is not, at this stage, a sensible reference for anyone > > trying to understand how to implement a Wave client or understand how > > clients/servers interact. Am I wrong with my understanding of where > > the FedOne client is at? > > Again, you are using the term client without qualification. I told you > there are two separate client/server relationships in the FedOne code > base, yet you continue to talk as if there is only one. > > > Dan > > > > Brett Morgan wrote: > > > The problem here is that there are two separate client/server > > > relationships. > > > > > Firstly there is a client/server relationship amongst the federated > > > servers, where in the server that is hosting the document acts as a > > > server to the relying federated wave servers that act as clients. > > > > > Secondly, there is a client/server relationship between a wave server > > > and it's ui clients, be they web applications or otherwise. > > > > > Yes, the client server terminology has been overloaded with the need > > > to understand the context of the communication in question. This is > > > unfortunate, but it is a natural result of the complexities of > > > building a real system. Real systems are not the simple things they > > > write about in academic papers. Here in the real world we have to deal > > > with the very real physical limitations of things like hard disks and > > > routers. > > > > > The reason I am talking about the federation protocol is that it is a > > > real example of a client server protocol that uses OT. It can be used > > > to inform the discussion of how web clients could interact with their > > > wave server using OT. > > > > > Stating that FedOne doesn't implement a sensible client/server > > > protocol at this point is incorrect. > > > > > On Dec 3, 11:19 am, Daniel Paull <[email protected]> wrote: > > > > When I say client, I mean client as in client/server. I dislike the > > > > overloading of the word client that has been used in this thread and > > > > it has caused much confusion, and I am sure, misinterpretation. In > > > > what way is an upstream or downstream wave provider a "client"? They > > > > should be described as caches and proxies respectively. > > > > > > I also don't understand why the federation protocol is being discussed > > > > here as the OP was asking about how concurrent operations from two > > > > clients are handled when the transform clearly results in an > > > > ambiguity. > > > > > > I also don't understand all the references to the FedOne code base as > > > > FedOne does not implement anything the remotely resembles a sensible > > > > client/server protocol at this point in time. > > > > > > Dan > > > > > > On Dec 2, 12:40 pm, Brett Morgan <[email protected]> wrote: > > > > > > > I just want to clarify here that by "client", you are talking about > > > > > the remote wave servers, not the traditional usage of the term client, > > > > > for example of web client that displays content from a wave server. > > > > > > > The many uses of the term client in this context are going to lead to > > > > > people becoming confused if we are not careful. > > > > > > > On Dec 2, 3:35 pm, Daniel Paull <[email protected]> wrote: > > > > > > > > The FedOne source does not implement server acknowledgements, nor > > > > > > does > > > > > > the FedOne example client perform any OT, so reading the FedOne > > > > > > source > > > > > > is not going to help at all. The only information that exists at > > > > > > this > > > > > > point in time on how the client and server interact is in the Google > > > > > > OT white paper. > > > > > > > > Dan > > > > > > > > Brett Morgan wrote: > > > > > > > Dan, > > > > > > > > > The basis of this is already in the published FedOne source. You > > > > > > > could > > > > > > > check what they have done instead of trying to figure out what > > > > > > > they > > > > > > > should have done. > > > > > > > > > brett > > > > > > > > > On Dec 2, 2:19 pm, Daniel Paull <[email protected]> wrote: > > > > > > > > Oops - forgot the important bit! The Google OT White paper > > > > > > > > states: > > > > > > > > > > "When a server acknowledges a client's operation, it means the > > > > > > > > server > > > > > > > > has transformed the client's operation, applied it to the > > > > > > > > server's > > > > > > > > copy of the Wavelet and broadcasted the transformed operation > > > > > > > > to all > > > > > > > > other connected clients." > > > > > > > > > > So, unless that is in error, transofrmed operations are sent > > > > > > > > from the > > > > > > > > server to the clients. > > > > > > > > > > It seems crazy to send to original, untransformed operation to > > > > > > > > the > > > > > > > > clients as the clients will have to repeat the transformation > > > > > > > > work > > > > > > > > that the server has already done! > > > > > > > > > > Dan > > > > > > > > > > Daniel Paull wrote: > > > > > > > > > Hi Tad, > > > > > > > > > > > What you have written here is more in line with what I > > > > > > > > > understood of > > > > > > > > > the federation protocal where servers act merely as proxies > > > > > > > > > and caches > > > > > > > > > for Waves that they do not own. So all servers should end up > > > > > > > > > with the > > > > > > > > > same state space as you have indicated. > > > > > > > > > > > As you note, this does still leave the question unanswerd - > > > > > > > > > what does > > > > > > > > > Google do in their wave client? The recently released Python > > > > > > > > > Wave > > > > > > > > > client code also offers no clues as there is presently a > > > > > > > > > bunch of > > > > > > > > > "TBD" markers in the code where the client would perfrom OT. > > > > > > > > > > > One thing that is clear is that clients will apply operations > > > > > > > > > is > > > > > > > > > different orders, so TP1 must be met. It will be interesting > > > > > > > > > to see > > > > > > > > > what the community comes up with on the client side as it is > > > > > > > > > much more > > > > > > > > > complex than what the server has to do. I wonder how long it > > > > > > > > > will > > > > > > > > > take before a correct implementation is developed! > > > > > > > > > > > Cheers, > > > > > > > > > > > Dan > > > > > > > > > > > Tad Glines wrote: > > > > > > > > > > I see the problem here. You think I'm still talking about > > > > > > > > > > site identifiers. > > > > > > > > > > > > My very first reply was about site identifiers. And we both > > > > > > > > > > ended up > > > > > > > > > > being correct. I was correct in that wave OT doesn't use > > > > > > > > > > explicit site > > > > > > > > > > identifiers. You where correct in that wave OT probably > > > > > > > > > > uses "implied" > > > > > > > > > > site identifiers (client and server). > > > > > > > > > > > > I then read your blog in which you state that the server > > > > > > > > > > sends > > > > > > > > > > transformed deltas to the client. My subsequent posts > > > > > > > > > > mostly focused > > > > > > > > > > on the fact that the server doesn't send transformed deltas > > > > > > > > > > (we'll > > > > > > > > > > ignore the "toy" client). Your blog is very well written > > > > > > > > > > and gives a > > > > > > > > > > good detailed description of how OT works. The only > > > > > > > > > > discrepancy is > > > > > > > > > > that the server doesn't send transformed delta's to the > > > > > > > > > > client > > > > > > > > > > (federation remote). It sends the original un-transformed > > > > > > > > > > delta. > > > > > > > > > > > > I just did another review of the FedOne code and cleared up > > > > > > > > > > another > > > > > > > > > > assumption I had made. The federation remote doesn't do OT > > > > > > > > > > the way we > > > > > > > > > > had assumed. When a delta originates from the remote > > > > > > > > > > (client), the > > > > > > > > > > delta passes through the remote (without OT) and is sent to > > > > > > > > > > the host. > > > > > > > > > > > > If we start with: > > > > > > > > > > > > Host [O1, O2, O3] > > > > > > > > > > Remote1 [O1, O2, O3] > > > > > > > > > > Remote2 [O1, O2] > > > > > > > > > > > > where: > > > > > > > > > > > > Remote1 has sent Oa > > > > > > > > > > Remote2 has sent Ob > > > > > > > > > > > > When Host gets Oa it will not do OT and will apply it > > > > > > > > > > directly then > > > > > > > > > > send it to Remote1 and Remote2. > > > > > > > > > > When Host gets Ob it will transform it against O3 and Oa > > > > > > > > > > then send Ob > > > > > > > > > > to Remote1 and Remote2. > > > > > > > > > > > > When Remote2 gets Oa it will notice that it is missing O3 > > > > > > > > > > and will > > > > > > > > > > request it from the Host. Regardless of the order in which > > > > > > > > > > O3, Oa and > > > > > > > > > > Ob arrive, Remote2 will optionally transform and apply them > > > > > > > > > > in the > > > > > > > > > > order specified in the "applied_at" version of each delta. > > > > > > > > > > In this > > > > > > > > > > example, O3 and Oa will be applied with out transformation > > > > > > > > > > and Ob will > > > > > > > > > > be transformed against O3 and Oa before being applied. > > > > > > > > > > > > If Remote1 gets Ob first it will store it and wait for Oa > > > > > > > > > > before > > > > > > > > > > applying Oa, transforming Ob against O3 and Oa and then > > > > > > > > > > applying Ob'. > > > > > > > > > > > > The resulting state space is: > > > > > > > > > > > > Host [O1, O2, O3, Oa, Ob'] > > > > > > > > > > Remote1 [O1, O2, O3, Oa, Ob'] > > > > > > > > > > Remote2 [O1, O2, O3, Oa, Ob'] > > > > > > > > > > > > This still leave the question of how Google handles OT in > > > > > > > > > > their client. > > > > > > > > > > > > -Tad > > > > > > > > > > > > On Tue, Dec 1, 2009 at 5:26 PM, Daniel Paull > > > > > > > > > > <[email protected]> wrote: > > > > > > > > > > > Hello Tad, > > > > > > > > > > > > > Following what you just wrote: > > > > > > > > > > > > > Remote1 will end up with [O1, O2, O3, Oa, Ob'], where Ob' > > > > > > > > > > > is IT( Ob, > > > > > > > > > > > Oa ), and, > > > > > > > > > > > Remote2 will end up with [O1, O2, O3, Ob, Oa'], where Oa' > > > > > > > > > > > is IT( Oa, > > > > > > > > > > > Ob ) > > > > > > > > > > > > > So, as per my previous message, for Remote1 and Remote2 > > > > > > > > > > > to converge to > > > > > > > > > > > the same document state, then [Oa, Ob'] must have the > > > > > > > > > > > same effect as > > > > > > > > > > > [Ob, Oa']. Note that this is exactly what TP1 states. > > > > > > > > > > > > > Please explain how convergence is possible without > > > > > > > > > > > resorting to site > > > > > > > > > > > identifiers (either explicit or implied) in the case of > > > > > > > > > > > inserts at the > > > > > > > > > > > same position, as per > > > > ... > > > > read more » -- You received this message because you are subscribed to the Google Groups "Wave Protocol" group. To post to this group, send email to [email protected]. To unsubscribe from this group, send email to [email protected]. For more options, visit this group at http://groups.google.com/group/wave-protocol?hl=en.
