<?xml version='1.0' encoding='utf-8'?>
<?xml-stylesheet type="text/xml" href="compare-ml.xsl"?>
<!DOCTYPE comparison SYSTEM "comparison.dtd">
<!--
TODO:

* Add intelligent merging of renamed paths.
* Add IDE integration.
* Add Speed (?)
-->
<comparison>
    <meta>
        <implementations>
            <impl id="cvs">
                <name>CVS</name>
            </impl>
            <impl id="aegis">
                <name>Aegis</name>
            </impl>
            <impl id="arch">
                <name>Arch</name>
            </impl>
            <impl id="bitkeeper">
                <name>BitKeeper</name>
            </impl>
            <impl id="cmsynergy">
                <name>CMSynergy</name>
            </impl>
            <impl id="co-op">
                <name>Co-Op</name>
            </impl>
            <impl id="darcs">
                <name>Darcs</name>
            </impl>
            <impl id="monotone">
                <name>Monotone</name>
            </impl>
            <impl id="opencm">
                <name>OpenCM</name>
            </impl>
            <impl id="perforce">
                <name>Perforce</name>
            </impl>
            <impl id="subversion">
                <name>Subversion</name>
            </impl>
            <impl id="superversion">
                <name>Superversion</name>
            </impl>
            <impl id="svk">
                <name>svk</name>
            </impl>
            <impl id="vesta">
                <name>Vesta</name>
            </impl>
            <impl id="vss">
                <name>Visual SourceSafe</name>
            </impl>
        </implementations>
        <timestamp>
            $Id: scm-comparison.xml 61 2005-04-06 17:09:28Z shlomif $
        </timestamp>
    </meta>
    <contents>
<section id="main">
    <title>Version Control System Comparison</title>
    <expl>
        This is a comparison of version-control systems. It is split
        into several categories and sub-categories under which the
        systems are checked.
    </expl>
    <section id="repos_operations">
        <title>Repository Operations</title>
        <section id="atomic_commits">
            <title>Atomic Commits</title>
            <expl>
                Support for atomic commits means that if an operation on the
                repository is interrupted in the middle, the repository will
                not be left in an inconsistant state. Are the check-in
                operations atomic? Are the check-in operations atomic, or can
                interrupting an operation leave the repository in an
                intermediate state?
            </expl>
            <compare>
                <s id="cvs">No. CVS commits are not atomic.</s>
                <s id="arch">Yes. Commits are atomic.</s>
                <s id="darcs">Yes. Commits are atomic.</s>
                <s id="subversion">Commits are atomic.</s>
                <s id="superversion">Commits are atomic.</s>
                <s id="svk">Commits are atomic.</s>
                <s id="aegis">Commits are atomic.</s>
                <s id="bitkeeper">Yes (but need to verify)</s>
                <s id="monotone">Yes.</s>
                <s id="opencm">Yes. Commits are atomic.</s>
                <s id="perforce">Yes. Commits are atomic.</s>
                <s id="vesta">Yes. Commits are atomic.</s>
                <s id="co-op">Yes. Commits are atomic.</s>
                <s id="vss">No. VSS commits are not atomic.</s>
                <s id="cmsynergy">Yes. Commits are atomic.</s>
            </compare>
        </section>
        <section id="move">
            <title>Files and Directories Moves or Renames</title>
            <expl>
                Does the system support moving a file or directory to
                a different location while still retaining the history
                of the file?
            </expl>
            <compare>
                <s id="cvs">
                    No. Renames are not supported and a manual one
                    may break history in two.
                </s>
                <s id="subversion">Yes. Renames are supported.</s>
                <s id="superversion">No. Renames are not supported.</s>
                <s id="svk">Yes. Renames are supported.</s>
                <s id="arch">Yes. Renames are supported.</s>
                <s id="darcs">Yes. Renames are supported.</s>
                <s id="bitkeeper">Yes. Renames are supported.</s>
                <s id="aegis">Yes. Renames are supported.</s>
                <s id="monotone">Yes. Renames are supported.</s>
                <s id="opencm">Yes. Renames are supported</s>
                <s id="perforce">
                    Not directly (you copy and then delete but it manages to
                    keep track of the branch; the item below allows for this
                    very feature)
                </s>
                <s id="vesta">
                    Yes.  The unit of checkout/checkin is a directory
                    tree.  Files and directories can be added,
                    deleted, and renamed between versions.
                </s>
                <s id="co-op">Renames of files are supported.
                    Renaming a directory requires creating a new one,
                    moving the files and deleting the old one.
                    Moved file histories are preserved.
                </s>
                <s id="vss">
                    Affects the whole history, it's like renaming a
                    file in the CVS repository. There is a kludgy workaround
                    using "share-rename,move,delete" that gets what you
                    want.
                </s>
                <s id="cmsynergy">Yes. Renames are supported.</s>
           </compare>
        </section>
        <section id="copy">
            <title>File and Directories Copies</title>
            <expl>
                Does the version control system supports copying
                files or directories to a different location at the
                repository level, while retaining the history?
            </expl>
            <compare>
                <s id="cvs">No. Copies are not supported.</s>
                <s id="subversion">Yes. And it's a very cheap operation (O(1)) that
                    is also utilized for branching
                </s>
                <s id="superversion">No. Copies are not supported.</s>
                <s id="svk">Yes. Same as subversion.</s>
                <s id="arch">No. Copies of files and directory structures are
                    not supported.
                </s>
                <s id="darcs">No. Copies of files and directory structures are
                    not supported.
                </s>
                <s id="bitkeeper">
                    Yes. Copies are supported.
                </s>
                <s id="aegis">No. Copies are not supported.</s>
                <s id="monotone">Yes. Copies are supported</s>
                <s id="opencm">No. Copies are not supported.</s>
                <s id="perforce">Copies are supported (though, because
                    of its architecture, I don't know how well)
                </s>
                <s id="vesta">
                    Yes.  A new package/branch can be based on any
                    existing version without affecting the past
                    history.  (This is also an O(1) operation.)
                </s>
                <s id="co-op">Copying doesn't retain history, moving does.</s>
                <s id="vss">Yes. Copies are supported up to a point.</s>
                <s id="cmsynergy">Yes, and it's a very cheap operation (update the target
					directory to include the new file/directory).
				</s>
           </compare>
        </section>
        <section id="repos_clone">
            <title>Remote Repository Replication</title>
            <expl>
                Does the system support cloning a remote repository to get
                a functionally equivalent copy in the local system? That
                should be done without any special access to the remote
                server except for normal repository access.
            </expl>
            <compare>
                <s id="cvs">No.</s>
                <s id="subversion">Indirectly, by using Chia-Ling Kao's SVN::Mirror
                    add-on or Shlomi Fish' svn-push utility.
                </s>
                <s id="superversion">Yes.</s>
                <s id="svk">Yes.</s>
                <s id="arch">Yes.</s>
                <s id="darcs">Yes.</s>
                <s id="bitkeeper">Yes.</s>
                <s id="aegis">Yes.</s>
                <s id="monotone">Yes.</s>
                <s id="opencm">No.</s>
                <s id="perforce">Yes. Via the Perforce Proxy (P4P) tool.</s>
                <s id="vesta">Yes.  Replication is a fundamental part of the design.</s>
                <s id="co-op">Repositories are always replicated on local machines.
                    There is no central server.
                </s>
                <s id="vss">
                    Not directly possible with the included GUI or
                    command line tools; ssarc and ssrestor might be useable
                </s>
                <s id="cmsynergy">Yes, as long as you have the (more expensive) Distributed package.</s>
            </compare>
        </section>
        <section id="push">
            <title>Propagating Changes to Parent Repositories</title>
            <expl>
                Can the system propagate changes from one repository to
                another?
            </expl>
            <compare>
                <s id="cvs">No.</s>
                <s id="subversion">Yes, using either Chia-Ling Kao's SVN::Mirror
                    script or the svn-push utility by Shlomi Fish.
                </s>
                <s id="superversion">No.</s>
                <s id="svk">Yes.</s>
                <s id="arch">Yes.</s>
                <s id="darcs">Yes.</s>
                <s id="bitkeeper">Yes.</s>
                <s id="aegis">Yes.</s>
                <s id="monotone">Yes.</s>
                <s id="opencm">No.</s>
                <s id="perforce">Unknown. Probably Not.</s>
                <s id="vesta">
                    Yes.
                </s>
                <s id="co-op">It's a peer-to-peer system,
                    which keeps all replicas of the repository in sync.
                </s>
                <s id="vss">
                    Not directly possible with the included GUI or
                    command line tools; ssarc and ssrestor might be useable
                </s>
                <s id="cmsynergy">Yes, as long as you have the (more expensive) Distributed package.</s>
            </compare>
        </section>
        <section id="permissions">
            <title>Repository Permissions</title>
            <expl>
                Is it possible to define permissions on access to different
                parts of a remote repository? Or is access open for all?
            </expl>
            <compare>
                <s id="cvs">
                    Limited. "pre-commit hook scripts" can be used to
                    implement various permissions systems.
                </s>
                <s id="arch">
                    Yes. It is possible to define permissions on access to
                    different parts of a remote repository based on the
                    permission systems of the underlying protocol.
                </s>
                <s id="darcs">
                    No.
                </s>
                <s id="aegis">
                    Yes. Aegis relies on the UNIX permissions system to
                    implement permissions for files in the repository.
                </s>
                <s id="bitkeeper">
                    FILL IN
                </s>
                <s id="subversion">
                    Yes. The WebDAV-based service supports defining HTTP
                    permissions for various directories of the repository.
                </s>
                <s id="superversion">
                    No.
                </s>
                <s id="svk">
                    Same as subversion.
                </s>
                <s id="monotone">
                    Yes. It is possible to restrict incoming changes
                    from certain sources to be performed only in certain
                    parts of the repository.
                </s>
                <s id="opencm">
                    Permissions are defined on a per-branch
                    basis.
                </s>
                <s id="perforce">
                    Yes. (more than half a dozen of permission levels that can
                    be set in a file by file basis)
                </s>
                <s id="vesta">
                    Yes.  Access permissions for each package (the
                    unit of checkout/checkin) can be different.
                    Access permissions for a branch can be different
                    from the basis package.
                </s>
                <s id="co-op">First access (joining the project)
                    requires administrator's approval.
                    Subsequent access to that project is not controlled.
                </s>
                <s id="vss">
                    Project specific permissions (read, write, delete, destroy)
                    can be set per user; but see "Networking Support":
                    this makes "Repository Permissions" a hindrance to
                    accidental damage but cannot prevent intentional damage.
                </s>
                <s id="cmsynergy">No, though a single server can serve many repositories.</s>
            </compare>
        </section>
        <section id="changesets">
            <title>Changesets' Support</title>
            <expl>
                Does the repository supports changesets? Changesets are a way
                to group a number of modifications that are relevant to each
                other in one atomic package, that can be cancelled or
                propagated as needed.
            </expl>
            <compare>
                <s id="cvs">No. Changes are file-specific.</s>
                <s id="subversion">Partial support. There are implicit
                    changeset that are generated on each commit.
                </s>
                <s id="superversion">Partial support. Changes are grouped into changesets,
                    but cannot be cancelled invididually yet.
                </s>
                <s id="svk">Same as subversion.
                </s>
                <s id="aegis">
                    Yes. Changesets are supported.
                </s>
                <s id="bitkeeper">
                    Yes. Changesets are supported.
                </s>
                <s id="arch">
                    Yes. Changesets are supported.
                </s>
                <s id="darcs">
                    Yes. Changesets are supported.
                </s>
                <s id="monotone">
                    Yes. Changesets are supported.
                </s>
                <s id="opencm">
                    Yes. Changesets are supported.
                </s>
                <s id="perforce">
                    Yes. Changesets are supported.
                </s>
                <s id="vesta">
                    Not exactly.  Vesta uses a related concept of
                    configurations instead, which some has similar
                    properties.
                </s>
                <s id="co-op">Yes. Changesets are the default.</s>
                <s id="vss">No.  Changes are file-specific.</s>
                <s id="cmsynergy">Yes.  Changesets (or tasks) are fundamental
                	to the way Synergy works.</s>
           </compare>
        </section>
        <section id="annotate">
            <title>Tracking Line-wise File History</title>
            <expl>
                Does the version control system has an option to track the
                history of the file line-by-line? I.e: for each line show
                at which revision it was most recently changed, and by whom?
            </expl>
            <compare>
                <s id="cvs">Yes. cvs annotate</s>
                <s id="subversion">Yes. (svn blame)</s>
                <s id="superversion">No.</s>
                <s id="svk">Yes. (svk blame)</s>
                <s id="bitkeeper">Yes. (bk annotate)</s>
                <s id="arch">Not in the command line client, but ViewARCH,
                a web-interface for Arch, has it.</s>
                <s id="darcs">Yes. (darcs annotate)</s>
                <s id="monotone">No.</s>
                <s id="aegis">Yes. aeannotate</s>
                <s id="opencm">Unknown. Probably not.</s>
                <s id="perforce">Yes, an annotation feature is present.</s>
                <s id="vesta">
                    No, but it would be easy to implement a tool that
                    did this, as the Vesta repository provides direct
                    filesystem access to all versions.
                </s>
                <s id="co-op">Not directly, but it's possible to compare
                    any two versions using a visual differ.
                </s>
                <s id="vss">Not directly, but it's possible to compare
                    any two versions using a visual differ.
                </s>
                <s id="cmsynergy">Probably, if you're a sufficiently proficient hacker with
					their scripting language.
                </s>
           </compare>
        </section>
    </section>
    <section id="features">
        <title>Features</title>
        <section id="work_on_dir">
            <title>Ability to Work only on One Directory of the Repository</title>
            <expl>
                Can the version control system checkout only one directory of
                the repository? Or restrict the check-ins to only one
                directory?
            </expl>
            <compare>
                <s id="cvs">Yes.</s>
                <s id="subversion">Yes.</s>
                <s id="superversion">No.</s>
                <s id="svk">Yes.</s>
                <s id="bitkeeper">No. All changes are made repository-wide.</s>
                <s id="arch">
                    It is possible to commit only a certain directory.
                    However, one must check out the entire repository as a
                    whole.
                </s>
                <s id="darcs">
                    It is possible to commit only a certain directory.
                    However, one must check out the entire repository as a
                    whole.
                </s>
                <s id="aegis">No. All changes are made repository-wide.</s>
                <s id="monotone">No. All changes are tree-wide.</s>
                <s id="opencm">No. All changes are made to a project as
                    a unit
                </s>
                <s id="perforce">
                    Yes. Changes to a sub-directory of the repository
                    are supported.
                </s>
                <s id="vesta">
                    Yes and no. The unit of checkout/checkin (called a
                    package) is a directory tree.  Most projects use
                    more than one.  Once created, a package must be
                    checked out/in as a unit.
                </s>
                <s id="co-op">No. All changes are made to a project as
                    a unit, but it's possible to access each file's
                    history separately.
                </s>
                <s id="vss">Yes.</s>
                <s id="cmsynergy">Yes and no.  Files and directories are checked out and in
					individually, however you have to work in the context of a project,
					which consists of one or more directories.</s>
           </compare>
        </section>
        <section id="tracking_uncommited_changes">
            <title>Tracking Uncommited Changes</title>
            <expl>
                Does the software has an ability to track the changes in the
                working copy that were not yet commited to the repository?
            </expl>
            <compare>
                <s id="cvs">Yes. Using cvs diff</s>
                <s id="subversion">Yes. Using svn diff</s>
                <s id="superversion">Yes. Local changes are detected and shown immediately. Changes can be
                  collected in a local buffer before being committed to the repository.</s>
                <s id="svk">Yes. Using svk diff</s>
                <s id="bitkeeper">Yes. Using bk diff.</s>
                <s id="arch">
                    Yes, using "tla changes".
                </s>
                <s id="darcs">
                    Yes, using "darcs whatsnew".
                </s>
                <s id="aegis">Yes. Using aediff</s>
                <s id="monotone">Yes. In a similar fashion to CVS.</s>
                <s id="opencm">Yes. Using cm diff</s>
                <s id="aegis">Yes. Using aediff.</s>
                <s id="perforce">Yes.</s>
                <s id="vesta">
                    Yes.  Intermediate immutable snapshots can be
                    taken during an active checkout (with vadvance).
                    These intermediate versions can be treated just
                    like checked in versions: they can be replicated
                    to other repositories and used as the basis for
                    branches.
                </s>
                <s id="co-op">Yes, using built-in visual differ/editor.</s>
                <s id="vss">Yes, using integrated diff tool.</s>
                <s id="cmsynergy">Yes, either using integrated diff tool or user-configured
					external diff tool</s>
            </compare>
        </section>
        <section id="per_file_commit_messages">
            <title>Per-File Commit Messages</title>
            <expl>
                Does the system has a way to assign a per-file commit message
                to the changeset, as well as a per-changeset message?
            </expl>
            <compare>
                <s id="cvs">No. Commit messages are per change.</s>
                <s id="subversion">No. There is no such feature.</s>
                <s id="superversion">Yes.</s>
                <s id="svk">No. There is no such feature.</s>
                <s id="bitkeeper">Yes. It is possible to have a per-file
                    commit message</s>
                <s id="arch">
                    No.
                </s>
                <s id="darcs">
                    No.
                </s>
                <s id="monotone">
                    Yes. It is possible to attach a comment to a certain
                    file at a certain revision.
                </s>
                <s id="opencm">
                    Unknown.
                </s>
                <s id="perforce">
                    No. Commit messages are per change.
                </s>
                <s id="vesta">
                    Not exactly.  The unit of checkin is a directory,
                    and commit messages are assigned at that level,
                    not to individual files.  Since configurations are
                    also versioned, they also have commit messages.
                </s>
                <s id="co-op">No. Commit messages are per change.
                    They go to all project members and update
                    their repositories.
                </s>
                <s id="vss">Since changesets are not supported, yes.</s>
                <s id="cmsynergy">Yes.</s>
           </compare>
        </section>
    </section>
    <section id="technical_status">
        <title>Technical Status</title>
        <section id="documentation">
            <title>Documentation</title>
            <expl>
                How well is the system documented? How easy it is to
                get started using it?
            </expl>
            <compare>
                <s id="cvs">Excellent. There are many online tutorials and
                    resources and an online book. The command line client
                    also provides an online comprehensive help system.
                </s>
                <s id="subversion">
                    Very good. There is a free online book and some online
                    tutorials and resources. The book is written in
                    DocBook/XML and so is convertible to many different
                    formats. The command-line client also provides a good
                    online help system that can be used as a reference.
                </s>
                <s id="superversion">
                    Fairly poor. There are two tutorials, but there is no
                    reference. Installing and getting started with the GUI
                    is very easy though.
                </s>
                <s id="svk">
                    Very poor at this moment.
                </s>
                <s id="aegis">
                    Medium. The documentation is given in several large scope
                    troff documents, that are only usable as not-so-PDFish
                    PDF documents, and as text documents that lack any
                    formatting. It is very hard to get started using
                    it with the online resources. The content is of good
                    quality, but otherwise not made very accessible.
                </s>
                <s id="arch">
                    Medium. There are two online tutorials and a
                    comprehensive online documentation. The command line
                    client also supplies a reference page. However, some of
                    the documentation is out of date or incomplete.
                </s>
                <s id="darcs">
                    Good. The manual contains a brief tutorial and a solid
                    reference.  Every sub-command can print its usage.
                    Because the command-set is small and the model is
                    simple, many users find it easy to get started.
                </s>
                <s id="bitkeeper">
                    Very good. There is a comprehensive help at the BitKeeper
                    site. Each command is documented in its own man page,
                    and the client contains a help tool that offers
                    an integrated help system.
                </s>
                <s id="monotone">
                    Good. There's an overview and tutorial written in Texi,
                    and a man page. The client supplies documentation for
                    every command.
                </s>
                <s id="opencm">
                    Well documented.
                </s>
                <s id="perforce">
                    Very Good (html and command line help)
                </s>
                <s id="vesta">
                    Quite thoroughly (HTML, man pages, published
                    papers, a book-length research report).
                </s>
                <s id="co-op">Very good. Step-by-step tutorial and HTML help
                    is included.
                </s>
                <s id="vss">Medium.  Help file which is sometimes useful.
                	However, the interface is reasonably intuitive so
                	documentation isn't needed as much.
                </s>
                <s id="cmsynergy">Medium.  Lots of books, plus somewhat
                	clunky set of HTML pages, but has some radical concepts
                	which can cause real problems really quickly.  They recommend
                	a day's training for basic users, more for more advanced users.
                	Took a while to become fluent.
                </s>
            </compare>
        </section>
        <section id="ease_of_deployment">
            <title>Ease of Deployment</title>
            <expl>
                How easy it is to deploy the software? What are
                the depenedencies and how can they be satisfied?
            </expl>
            <compare>
                <s id="cvs">
                    Good. Out of being the de-facto standard,
                    CVS is available on most systems and is easy
                    to deploy.
                </s>
                <s id="arch">
                    Excellent. An arch service is nothing but a
                    filesystem-space hosted by any of its supported
                    protocols (FTP, SFTP, WebDAV, etc.). The arch client
                    is written in C, and is portable across UNIX systems
                    (and on Win32 only with a UNIX emulation layer).
                </s>
                <s id="darcs">
                    Very good. darcs requires few external libraries,
                    however you need the Glasgow Haskell Compiler if you
                    cannot find a binary. To start working, just "darcs
                    init".
                </s>
                <s id="bitkeeper">
                    Good. All that is required is downloading a binary
                    for the system and installing it using the installation
                    script. The package is self-contained and is easy to
                    set up.
                </s>
                <s id="aegis">
                    The Aegis binary should be installed as SUID-root, and
                    so requires root privileges to install. It also not very
                    portable to Win32 systems. Other than that, Aegis supports
                    an easy autoconf or RPM/apt-based installation process.
                </s>
                <s id="subversion">
                    A Subversion service requires installing an Apache 2
                    module (if one wishes to use HTTP as the underlying
                    protocol) or its own proprietary server. The client
                    requires only the Subversion-specific logic and the
                    Neon WebDAV library (for HTTP). Installation of the
                    components is quite straightforward, but will require
                    some work, assuming Subversion does not come prepackaged
                    for one's system.
                </s>
                <s id="superversion">
                    If Java 1.4 is installed, deployment of Superversion
                    usually takes two clicks.
                </s>
                <s id="svk">
                    In addition to installing subversion, users are required
                    to install the subversion perl bindings and a few modules
                    from CPAN.
                </s>
                <s id="monotone">
                    Excellent. It is possible to copy or compile the executable
                    to the user's machine, without any configuration or
                    external dependencies.
                </s>
                <s id="opencm">
                    Very good. Install the RPM, or build from tarball and
                    install the init script.
                </s>
                <s id="perforce">
                    Very good. Perforce is very easy to deploy.
                </s>
                <s id="vesta">
                    Medium to Good.  There is a detailed installation guide
                    for setting it up using a binary kit.  RPMs and
                    Debian packages have been recently released.
                    There are no dependencies on other software.
                    Vesta, however, is required to build itself.
                </s>
                <s id="co-op">Very easy to deploy, since there is no central
                    server. Can be configured to use e-mail or LAN (or both) for
                    synchronization. For e-mail, requires MAPI-compliant
                    e-mail client.
                </s>
                <s id="vss">
                    Very good - an installation package which does the work.
                    When you create a repository it installs the exe's in a
                    directory and you can run them from there if you need to.
                </s>
                <s id="cmsynergy">
                    Medium.  There is a detailed install guide for
                	setting it up using a binary kit and a set of scripts.  However
                	it still took several tries to get it properly installed and
                	configured.  The Windows client is a slightly clunky Windows
                	installer.
                </s>
           </compare>
        </section>
        <section id="command_set">
            <title>Command Set</title>
            <expl>
                What is the command set? How compatible it is with
                the commands of CVS (the current open-source defacto
                standard)?
            </expl>
            <compare>
                <s id="cvs">
                    A simple command set that includes three most commonly
                    used commands (cvs commit, cvs update and cvs checkout)
                    and several others.
                </s>
                <s id="subversion">
                    A CVS-like command set which is easy to get used to
                    for CVS-users.
                </s>
                <s id="superversion">
                    There is little need to memorize a command set because
                    all actions take place in a GUI. A part of the terminology
                    used in the application is borrowed from CVS.
                </s>
                <s id="svk">
                    A CVS-like command set which is easy to get used to
                    for CVS-users.
                </s>
                <s id="bitkeeper">
                    A CVS-like command set with some easy-to-get-used-to
                    complications due to its different way of work and
                    philosophy.
                </s>
                <s id="aegis">
                    A complex command set that involves many operations
                    just to get started. Not CVS-compatible. (albeit
                    support for such basic operations was contemplated)
                    Note that Aegis is a Software Configuration Management
                    system and not just a simple version control system,
                    which may justify this extra complexity.
                </s>
                <s id="arch">
                    Many commands are compatible with CVS or BitKeeper. However,
                    there are many other commands for it for different uses.
                    Aliasing of commands is possible so it it may be possible
                    to make it more compatible.
                </s>
                <s id="darcs">
                    The command set is fairly compact and the core commands
                    are easy to understand.  Follows CVS in a few places,
                    but since the model is different most commands are
                    unique.
                </s>
                <s id="monotone">
                    Tries to follow CVS conventions, but deviates where there
                    is a different design.
                </s>
                <s id="opencm">
                    A CVS-like command set that is familiar to existing CVS
                    users.
                </s>
                <s id="perforce">
                    Very extensive but not compatible with CVS.
                </s>
                <s id="vesta">
                    The command set is unrelated to CVS.  Most of the
                    time, users use about 5 commands.  Few ever need
                    to know more than about 20 commands.
                </s>
                <s id="co-op">Basic commands are compatible with CVS.</s>
                <s id="vss">
                    A bit of an afterthought.  It's possible to do basic
                	things, but it's really geared up for using the GUI.
                </s>
                <s id="cmsynergy">An extensive and powerful command set,
                	which has some CVS similarity, though the architecture
                	is so different that it quickly moves away for anything
                	but the basics.
                </s>
           </compare>
        </section>
        <section id="networking">
            <title>Networking Support</title>
            <expl>
                How well is the networking integration in the system?
                How compliant it with existing protocols and infra-structure.
            </expl>
            <compare>
                <s id="cvs">
                    Good. CVS uses a proprietary protocol with various
                    variations for its client/server protocol. This protocol
                    can be tunneled over an SSH-connection to support
                    encryption.
                </s>
                <s id="arch">
                    Excellent. Arch can utilize a multitude of protocols
                    for its service, which is nothing but a dumb remote
                    filesystem server. Currently supported protocols include
                    FTP, SFTP, WebDAV (remote file access over HTTP),
                    as well as any remote filesystem protocol (NFS, SMB).
                </s>
                <s id="darcs">
                    Good. Darcs supports getting patches over HTTP, and
                    getting and sending patches over SSH and email.
                </s>
                <s id="subversion">
                    Very good. The Subversion service can use either
                    WebDAV+DeltaV (which is HTTP or HTTPS based) as its
                    underylying protocol, or its own proprietary protocol
                    that can be channeled over an SSH connection.
                </s>
                <s id="superversion">
                    Good. Network support based on RMI is integrated
                    seamlessly. Encryption and HTTP tunnelling are planned
                    for the near future.
                </s>
                <s id="svk">
                    Very good. svk uses SVN::Mirror to retrieve remote
                    repository. There has been plans to add VCP support
                    to SVN::Mirror so it will be able to mirror from arbitary
                    remote version control systems.
                </s>
                <s id="bitkeeper">
                    Good. Repositories can be checked out from remote
                    over HTTP, and BitKeeper also sports its own proprietary
                    protocol for communicating between one repository and
                    the other.
                </s>
                <s id="aegis">
                    Poor. Aegis is filesystem-oriented and so can be networked
                    only via NFS (network file-system) or a similar protocol.
                    There exists some HTTP-functionality, but it is quite
                    limited.
                </s>
                <s id="monotone">
                    Good. Uses a custom protocol called "netsync".
                </s>
                <s id="opencm">
                    Good. Uses its own proprietary client/server protocol.
                </s>
                <s id="perforce">
                    Good. (single TCP/IP socket)
                </s>
                <s id="vesta">
                    Networking is inherent to the system.  The
                    repository exports both an NFS interface and an
                    RPC interface.  The checkout and checkin tools
                    automatically contact a remote repository when
                    required to perform an operation.
                </s>
                <s id="co-op">Uses the simplest LAN interface:
                    copying files between shared directories.
                </s>
                <s id="vss">
                    VSS uses a Windows network share which has to be writable
                    for the VSS users (since this means doubling maintenance
                    for new users). Add user in VSS and to share permissions.
                    the share is most often world-writable, as is the default
                    when creating a share) It does not perform well over a
                    slow network connection.
                </s>
                <s id="cmsynergy">Good (single TCP/IP socket)</s>
            </compare>
        </section>
        <section id="portability">
            <title>Portability</title>
            <expl>
                How portable is the version-control system to various
                operating systems, computer architectures, and other
                types of systems?
            </expl>
            <compare>
                <s id="cvs">Good. Client works on UNIX, Windows and Mac OS.
                    Server works on UNIXes and on Windows with a UNIX
                    emulation layer.
                </s>
                <s id="subversion">
                    Excellent. Clients and Servers work on UNIX,
                    Windows and Mac OS X.
                </s>
                <s id="superversion">
                    Excellent. Clients and servers work on any Java
                    1.4-compatible platform. There is official support
                    for Windows, Linux and OS/2.
                </s>
                <s id="svk">
                    Good. Clients requires subversion and its perl bindings.
                </s>
                <s id="bitkeeper">
                    Very good. Binaries are available for most common UNIX
                    systems and for Windows 98 and above.
                </s>
                <s id="aegis">
                    Medium. The source is portable across all UNIXes,
                    but the Windows version work only using cygwin, and even
                    then not entirely natively.
                </s>
                <s id="arch">
                    Good. The source is portable across all UNIXes,
                    but requires a UNIX emulation layer on Windows. (need to
                    verify). A service can be hosted on any platform
                    that sports a suitable Internet service.
                </s>
                <s id="darcs">
                    Very good. Supports many UNIXes, Mac OS X, and Windows,
                    and is written in a portable language.
                </s>
                <s id="monotone">
                    Excellent. Executable is portable across all UNIXes and
                    Win32.
                </s>
                <s id="opencm">
                    Good. Portable across all UNIX systems.
                </s>
                <s id="perforce">
                    Excellent. Runs on UNIX, Mac OS, BeOS and Windows.
                </s>
                <s id="vesta">
                    Good.  It should be portable to any UNIX system.
                    Currently it runs on Digital/Compaq/HP Tru64 UNIX
                    and Linux on several different CPU architectures.
                    Ports to Solaris and FreeBSD are planned but
                    haven't begun yet.
                </s>
                <s id="co-op">Windows only: starting with Win95.</s>
                <s id="vss">
                    The Microsoft Product is Windows only.
                    <a href="http://www.mainsoft.com/">MainSoft</a>
                    ships a version of it for some UNIX platforms.
                </s>
                <s id="cmsynergy">
                    Very good - various flavours of Unix,
                    Windows (only NT family for the server), VMS, and
                    possibly other systems.
                </s>
            </compare>
        </section>
    </section>
    <section id="user_interaces">
        <title>User Interfaces</title>
        <section id="web_interface">
            <title>Web Interface</title>
            <expl>
                Does the system have a WWW-based interface that can be
                used to browse the tree and the various revisions of the
                files, perform arbitrary diffs, etc?
            </expl>
            <compare>
                <s id="cvs">Yes.
                    WebCVS, <a href="http://viewcvs.sourceforge.net/">ViewCVS</a>,
                    and <a href="http://www.horde.org/chora/">Chora</a>.
                </s>
                <s id="bitkeeper">Yes. Its own built-in web-interface.</s>
                <s id="subversion">Yes.
                    <a href="http://viewcvs.sourceforge.net/">ViewCVS</a>,
                    <a href="http://freshmeat.net/projects/svnweb/">SVN::Web</a>,
                    <a href="http://websvn.tigris.org/">WebSVN</a>,
                    <a href="http://viewsvn.berlios.de/">ViewSVN</a>,
                    <a href="http://www.outoforder.cc/projects/apache/mod_svn_view/">mod_svn_view</a>,
                    <a href="http://www.horde.org/chora/">Chora</a>,
                    <a href="http://www.edgewall.com/trac/">Trac</a>, and
                    <a href="http://web-cpan.berlios.de/modules/SVN-RaWeb-Light/">SVN::RaWeb::Light</a>.
                    Aside
                    from that, the Subversion Apache service provides a
                    rudimentary web-interface.
                    </s>
                <s id="superversion">No.</s>
                <s id="svk">Yes. Same as Subversion.</s>
                <s id="arch">
                    There's <a href="http://arch.bluegate.org/viewarch.html">ViewARCH</a>, and
                    <a href="http://migo.sixbit.org/software/archzoom/">ArchZoom</a>
                    which are
                    works in progress.
                </s>
                <s id="darcs">
                    <a href="http://abridgegame.org/cgi-bin/darcs.cgi/darcs/">darcs.cgi</a>
                    is included in the distribution.
                </s>
                <s id="aegis">Yes.</s>
                <s id="monotone">No.</s>
                <s id="opencm">No.</s>
                <s id="perforce">Yes, P4Web.</s>
                <s id="vesta">
                    Yes: <a href="http://www.scooter.cx/vestaweb/">Vestaweb</a>.
                </s>
                <s id="co-op">Since this functionality is always
                    available locally, there is no need for web interface.
                </s>
                <s id="vss">
                    It is possible to code one using the API, but no official
                    or third-party one exists.
                </s>
                <s id="cmsynergy">Possibly.</s>
            </compare>
        </section>
        <section id="availability_of_guis">
            <title>Availability of Graphical User-Interfaces.</title>
            <expl>
                What is the availability of graphical user-interfaces for
                the system? How many GUI clients are present for it?
            </expl>
            <compare>
                <s id="cvs">Very good. There are many available GUIs:
                    WinCVS, Cervisia (for KDE),
                    TortoiseCVS (Windows Explorer plug-in).
                </s>
                <s id="bitkeeper">Good. BitKeeper ships with several
                    GUIs for performing common tasks. I'm not aware
                    of any third-part GUIs.
                </s>
                <s id="subversion">Very good. There are many available
                    GUIs: RapidSVN (cross-platform),
                    TortoiseSVN (Windows Explorer plug-in), Jsvn (Java), etc.
                    Most of them are still under development.
                </s>
                <s id="superversion">
                    A GUI is integrated.
                </s>
                <s id="svk">
                    No GUIs are available.
                </s>
                <s id="arch">
                    There are
                    <a href="http://www.ibe.miee.ru/tlator/">tlator</a>,
                    <a href="http://www.hpl.hp.com/personal/Yasushi_Saito/octopy/">Octopy</a>,
                    and <a href="http://www.nongnu.org/archway/">ArchWay</a>
                    and possibly others under development.
                </s>
                <s id="darcs">
                    None to speak of.  (There is a modest graphical
                    interface to a few commands in the distribution, but it
                    is not being developed currently.)
                </s>
                <s id="aegis">
                    There is tkaegis.
                </s>
                <s id="monotone">
                    No GUIs are available.
                </s>
                <s id="opencm">
                    No GUIs are available.
                </s>
                <s id="perforce">
                    Yes, P4Win and others based on the available libp4
                    library.
                </s>
                <s id="vesta">
                    No GUIs are available, but the repository has a
                    C++ API, and it's not be hard to write one.  (At
                    least three different project-specific ones have
                    been written by users at Compaq and Intel.)
                </s>
                <s id="co-op">The system is GUI-based by design.</s>
                <s id="vss">
                    Standalone GUI comes with it, plus SCCI plug-in for
                    MS Visual Developer Studio. There is an Eclipse
                    plug-in.
                </s>
                <s id="cmsynergy">
                    A couple of GUIs.  A motif-based one
                    (even on Windows) allows most functionality but is clunky.
                    A nicer Java one allows developer work but not much
                    administrative stuff. Has an SCCI plug-in, though it
                    doesn't handle network problems well.
                </s>
           </compare>
        </section>
    </section>
    <section id="license">
        <title>License</title>
        <expl>
            What are the licensing terms for the software?
        </expl>
        <compare>
            <s id="cvs">GNU GPL (open source)</s>
            <s id="arch">GNU GPL (open source)</s>
            <s id="darcs">GNU GPL (open source)</s>
            <s id="bitkeeper">
                Proprietary, binary only license. Comes in
                two versions: gratis and pay per use. The gratis license
                is intended for development of free software only and is
                <a href="bk-license.html">problematic</a>. The pay
                per use license is free of most of its problems.
            </s>
            <s id="aegis">
                GNU GPL (open source)
            </s>
            <s id="subversion">
                Apache/BSD-style license. (open-source)
            </s>
            <s id="superversion">
                GNU GPL (open-source)
            </s>
            <s id="svk">Perl License. (open source)</s>
            <s id="monotone">GNU GPL (open source)</s>
            <s id="opencm">
                GNU GPL (open source), but moving soon to
                BSD or CPL (also open source).
            </s>
            <s id="perforce">
                A proprietary, binary only, commercial license.
                <a href="http://perforce.com/perforce/price.html">Price
                    starting at $750 per seat for the first year</a> and then
                $150 for continuing support for the subsequent years. Free for
                Open Source projects (no support in this case).
            </s>
            <s id="vesta">
                GNU LGPL (open source)
            </s>
            <s id="co-op">Proprietary, short text key. 30-day
                full-featured trial. Free to "observers"
                (members who don't make changes).
                $159 per workstation.
            </s>
            <s id="vss">
                VSS Ships with MSDN, and can also be purchased
                stanalone or with other tools.
            </s>
            <s id="cmsynergy">
                Prices negotiable with salesman.
                Server is typically roughly 20,000 British Pounds.
                Clients are 4,000 British Pounds.  Per-year costs of 18%
                of original.
            </s>
        </compare>
    </section>
</section>
    </contents>
</comparison>
