Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!ames!sun-arpa!male!pitstop!texsun!texbell!sw1e!uucibg From: uucibg@sw1e.UUCP (3929]) Newsgroups: comp.editors Subject: Re: multi-user editors??? Message-ID: <1522@sw1e.UUCP> Date: 24 Apr 89 14:45:05 GMT References: <8531@xanth.cs.odu.edu> <1481@cfa.cfa.harvard.EDU> <764@manta.NOSC.MIL> Reply-To: uucibg@sw1e.UUCP (Brian Gilstrap [5-3929]) Distribution: usa Organization: Southwestern Bell Telephone Co Lines: 34 In article <764@manta.NOSC.MIL> budden@manta.nosc.mil.UUCP (Rex A. Buddenberg) writes: +But, how to do it. If we assume something about the construction, +then we can apply database analogy. Assumption: the text is broken +up into sentences and/or paragraphs that are recognizable by the +editor. Then have the editor simply record-lock the sentence/ +paragraph that you are working on so nobody else can touch it +until you move on and the lock is removed. Exactly like +record locking in a multi-user database management system. This solves the problem of changes to the existing contents of the file, assuming that you have some way of determining the scope of the changes that the user intends to make. That is, "Hmmm, is this guy(girl) going to change just this line or the whole paragraph?". Otherwise, gaining and relinquishing your locks could be expensive as all get out. However, this doesn't address the problem of deletion and insertion. In particular, what happens if two people try to insert a new paragraph at the same place? It's a solvable problem certainly, but synchronization becomes a bit more compilcated. I suppose you could have "hole locks" which would lock out other users from inserting new text between two given paragraphs. But that is not as nice as allowing multiple additions between paragraphs and assigning a particular semantics to such requests (though the first is a lot easier than the second, by a cursory examination). It would also be nice to have some sort of marker appear in the text of user A's display to let him know that user B is adding text between the two paragraphs. What other bells and whistles could we dream up? >Rex Buddenberg Brian R. Gilstrap Southwestern Bell Telephone One Bell Center Rm 17-G-4 ...!ames!killer!texbell!sw1e!uucibg St. Louis, MO 63101 ...!bellcore!texbell!sw1e!uucibg (314) 235-3929 ...!uunet!swbatl!sw1e!uucibg #include