King

I do not know Delphi, but creating version control software anywhere near the level of SVN would be a large amount of work. Take a look at some of the features of SVN:
http://subversion.apache.org/features.html

What is the reason for creating your own source control application? If you just want something to help version control your source code, I would just use one of the source control applications out there.

If you are looking to do this just as a learning exercise, I would start with a much more limited scope. Maybe something that simply puts your code files into a database. If a new version of a file gets put in, it keeps the old one around so you can roll back to it. I would start with something like that, and then slowly add to it. It can very quickly because quite complex when you start dealing with branches and multiple people checking in and out files, and merging files and branches.

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