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Re: A good open-source source version control system?

From: Colin S. Miller
Subject: Re: A good open-source source version control system?
Date: Mon, 25 Apr 2005 17:22:06 +0100
User-agent: Mozilla Thunderbird 1.0 (Windows/20041206)

Paul D. Smith wrote:
%% Rolf Magnus <address@hidden> writes:

  >> If by 'a "view" mechanism' you mean ClearCase's dynamic view
  >> capability, then you'll never find that in any open source tool, or
  >> indeed in any other proprietary tool either.  That capability is
  >> unique to ClearCase.

  rm> Just out of interest: What does it do?

ClearCase dynamic views use the MVFS, or Multi-Versioned File System, to
implement workspaces.  The MVFS basically provides a "live" mapping
between a UNIX (or, I guess, Windows if you go that way) directory
structure containing directories, files, etc., and the SCM data which is
implemented in a relational database.

Creating a workspace, then, just involves defining the mapping and takes
a second or two: no copying around is involved.  Changing the version of
the code you're looking at is similarly trivial, regardless of how far
you're moving in the codebase.

The downside is it takes a lot of horsepower in the client, server, and
network to make this fast enough to be usable.

In the 'dynamic' view, any changes committed by one engineer are
automatically propergated to others, unless they have also modified
that file (I forget how conflict resolving happens).

Also, the build directory can also be shared, so that when
you build, it can copy the object files from any machine
that has a copy.

This is fine if your machines are homogeneous. However,
it can cause subtle build errors if you are mixing the
tool chains between machines.

Colin S. Miller

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