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<sect><heading>CTM<label id="ctm"></heading>

<p><em>Contributed by &a.phk;.  Updated 16-Mar-1995.</em>

        <tt/CTM/ is a method for keeping a remote directory tree in sync with a
        central one.  It has been developed for usage with FreeBSD's source
        trees, though other people may find it useful for other purposes as
        time goes by.  Little, if any, documentation currently exists at
        this time on the process of creating deltas, so talk to &a.phk;
        for more information should you wish to use <tt/CTM/ for other things.

    <sect1><heading>Why should I use <tt/CTM/?</heading>
      <p><tt/CTM/ will give you a local copy of the ``FreeBSD-current''
        sources.  If you are an active developer on FreeBSD, but have lousy
        or non-existent TCP/IP connectivity, <tt/CTM/ was made for you.
        You will need to transfer up to four deltas per day (or you can
        have them arrive in email automatically), the sizes for which are
        always kept as small as possible.  This is typically less than 5K,
        with the occasional (one in ten) being 10-50K and every now and
        then a biggie of 100K+ or more coming around.

        You will also need to make yourself aware of the various caveats in
        running ``current'' sources, and for this it is recommended that
        you read <ref id="current" name="Staying current with FreeBSD">.

    <sect1><heading>What do I need to use <tt/CTM/?</heading>

      <p>You will need two things: The ``<tt/CTM/'' program and the initial
        deltas to feed it (to get up to ``current'' levels).

        The <tt/CTM/ program has been part of FreeBSD ever since version 2.0
        was released, and lives in <tt>/usr/src/usr.sbin/<tt/CTM/</tt> if you
        have a copy of the source online.

        If you are running a pre-2.0 version of FreeBSD, you can fetch the
        current <tt/CTM/ sources directly from:

        <url
          url="ftp://ftp.freebsd.org/pub/FreeBSD/FreeBSD-current/src/usr.sbin/ctm">

        The ``deltas'' you feed <tt/CTM/ can be had two ways, FTP or e-mail.
        If you have general FTP access to the Internet then the following
        FTP sites support access to <tt/CTM/:

        <url url="ftp://freefall.cdrom.com/pub/CTM">

        FTP the relevant directory and fetch the <tt/README/ file,
        starting from there.

        If you only have access to electronic mail or are otherwise blocked
        from using FTP then you may wish to get your deltas via email:

        Send email to <tt/&lt;majordomo@freebsd.org&gt;/ to subscribe to
        the list ``ctm-src-cur''.  (If you do not know how to subscribe
        yourself using majordomo, send a message first containing the
        word ``help'' - it will send you back usage instructions.)

        When you begin receiving your <tt/CTM/ updates in the mail, you may
        use the <tt/ctm_rmail/ program to unpack and apply them.  You
        can actually use the <tt/ctm_rmail/ program directly from a entry
        in <tt>/etc/aliases</tt> if you want to have the process run in a
        fully automated fashion.  Check the <tt/ctm_rmail/ man page for more
        details.

        <bf/NOTE/: No matter what method you use to get the <tt/CTM/
        deltas, you should subscribe to the <tt/ctm-announce@freebsd.org/
        mailing list.  In the future, this will be the only place where
        announcements concerning the operations of the <tt/CTM/ system will be
        posted.  Send an email to <tt/majordomo@freebsd.org/ with a single
        line of ``<tt/subscribe ctm-announce/'' to get added to the list.

    <sect1><heading>Starting off with <tt/CTM/ for the first time</heading>
      <p>Before you can start using <tt/CTM/ deltas, you will need to get a
        special ``base'' delta that provides the starting point for all
        deltas produced subsequently to it.

        You can recognize a base delta by the ``<tt/A/'' appended to the
        number (<tt/src-cur.0341A.gz/ for instance).  As a rule a base
        delta is produced every 100 deltas, the next one will be
        <tt/src-cur.0400A.gz/.  By the way, they are large!  25 to 30
        Megabytes of <tt/gzip/'ed data is common for a base delta.

        If you do have the 2.0-RELEASE <tt/srcdist/, you can instead
        retrieve the <tt/src-cur.0372R20.gz/ file, it's only 4Mb and it
        will take you to current from the 2.0-RELEASE sources.

        Once you've picked a base delta to start from, you will also need
        all deltas with higher numbers following it.

    <sect1><heading>Using <tt/CTM/ in your daily life</heading>
      <p>To apply the deltas, simply say
        <verb>
          cd /where/ever/you/want/the/stuff
          ctm -v -v /where/you/store/your/deltas/src-cur.*
        </verb>
        <tt/CTM/ understands deltas which have been put through <tt/gzip/,
        so you don't need to gunzip them first, this saves disk space.

        Unless it feels very secure about the entire process, <tt/CTM/ will
        not touch your tree.  To verify a delta you can also use the
        ``<tt/-c/'' flag and <tt/CTM/ won't actually touch your tree; it will
	merely verify the integrity of the delta and see if it would apply
        cleanly to your current tree.

        There are other options to <tt/CTM/ as well, look in the sources
        for more details.

        I would also be very happy if somebody could help with the ``user
        interface'' portions, as I have realized that I can't make up my
        mind on what options should do what, how and when...

        That's really all there is to it.  Every time you get a new delta,
        just run it through <tt/CTM/ to keep your sources up to date.

        Don't remove the deltas if they are hard to download again.  You
        just might want to keep them around in case something bad happens.
        Even if you only have floppy disks, consider using <tt/fdwrite/ to
        make a copy.


    <sect1><heading>Future plans for <tt/CTM/</heading>
      <p>
        Tons of them:
        <itemize>
          <item>
            Make local modifications to the tree possible.  One way to do
            it could be this:<p> When <tt/CTM/ wants to edit the file
            ``<tt>foo/bar.c</tt>'', it would first check for the existence
            of <tt>foo/bar.c&num;CTM</tt> If this file exists, the delta is
            applied to it instead.  This way the <tt>foo/bar.c</tt> file
            can be edited to suit local needs.
          <item>
            Make a ``restore file(s)'' option to <tt/CTM/, something like:
            <verb>
      ctm -r src/sys/i386/wd.c /here/are/my/deltas/src-cur.*
            </verb>
            would restore <tt/wd.c/ to the current status from the files.
          <item>
            Clean up the options to <tt/CTM/, they became confusing and
            counter intuitive.
        </itemize>

        The bad news is that I am very busy, so any help in doing this will
        be most welcome.  And don't forget to tell me what you want also...

    <sect1><heading>Miscellaneous stuff</heading>
      <p>
        All the ``DES infected'' (e.g. export controlled) source is not
        included.  You will get the ``international'' version only.  If
        sufficient interest appears, we will set up a ``<tt/sec-cur/''
        sequence too.

        If you are a frequent or valuable contributor to FreeBSD, I will be
        willing to arrange special services, one option is delivery via
        <tt/ftp/ or <tt/rcp/ to a machine closer to you.  You need to have
        earned this, since it takes time to do, but I'll be all the more
        happy to do it for you then.

        There is a sequence of deltas for the <tt/ports/ collection too,
        but interest has not been all that high yet.  Tell me if you want
        an email list for that too and we'll consider setting it up.

        If you have commit privileges or are similarly authorized by the
        FreeBSD core team, you can also get access to the CVS repository
        tree by the same means.  Contact &a.phk;
        for details.


    <sect1><heading>Thanks!</heading>
      <p>
        <descrip>
          <tag/Bruce Evans/
            for his pointed pen and invaluable comments.
          <tag/S&oslash;ren Schmidt/
            for patience.
          <tag/Stephen McKay/
            wrote <tt/ctm_&lsqb;rs&rsqb;mail/, much appreciated.
          <tag/Jordan Hubbard/
            for being so stubborn that I had to make it better.
          <tag/All the users/
            I hope you like it...
        </descrip>

