13. They can be locking, merge-before-commit, or commit-before-merge.
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Editor's Notes
3rd point file operation vs file set operations In early VCSes, some of which are still in use today, checkins and other operations are file-based; each file has its own master file with its own comment- and revision history separate from that of all other files in the system. Later systems do fileset operations; most importantly, a checkin may include changes to several files and that change set is treated as a unit by the system. Any comment associated with the change doesn't belong to any one file, but is attached to the combination of that fileset and its revision number.
Everyone syncs and checks into the main trunk: Sue adds soup, Joe adds juice, and Eve adds eggs.Sue’s change must go into main before it can be seen by others. Yes, theoretically Sue could make a new branch for other people to try out her changes, but this is a pain in a regular VCS.
Ina distributed model, every developer has their own repo. Sue’s changes live in her local repo, which she can share with Joe or Eve.But will it be a circus with no ringleader? Nope. If desired, everyone can push changes into a common repo, suspiciously like the centralized model above. This franken-repo contains the changes of Sue, Joe and Eve.
On one end is a Subversion repository that holds all of your versioned data.On the other end is your Subversion client program, which manages local reflections of portions of that versioned data. Between these extremes are multiple routes through a Repository Access (RA) layer, some of which go across computer networks and through network servers which then access the repository, others of which bypass the network altogether and access the repository directly.DAV - DAV or to be specific webDAV. It stands for Distributed Authoring Version. mod_dav_svn - It’s a plug-in module for the Apache HTTP Server, used to make your repository available to others over a network.SVN - The command-line client program.svnserve - A custom standalone server program, runnable as a daemon process or invokable by SSH; another way to make your repository available to others over a network.
CHEAP COPY Subversion doesn't actually duplicate any data. Instead, it creates a new directory entry that points to an existing tree. If you're an experienced Unix user, you'll recognize this as the same concept behind a hard-link. As further changes are made to files and directories beneath the copied directory, Subversion continues to employ this hard-link concept where it can. It duplicates data only when it is necessary to disambiguate different versions of objects.[Hard-Link . . http://kb.iu.edu/data/aibc.html]