Differences From:

File www/pop.html part of check-in [dbda8d6ce9] - Initial check-in of m1 sources. by drh on 2007-07-21 14:10:57. [view]

To:

File www/pop.html part of check-in [b807acf62e] - Documentation updates by drh on 2007-07-24 12:52:32. [view]

@@ -28,16 +28,16 @@
 The global state represents the content of the project.
 The local state identifies the authorized users and
 access policies for a particular repository.</p></li>
 
-<li><p>The global state of a repository is an mostly unordered
+<li><p>The global state of a repository is an unordered
 collection of files.  Each file is named by
-its SHA256 hash.  The name is encoded as a 52-digit
-base-32 number.  In many contexts, the name can be
+its SHA1 hash encoded in hexadecimal.
+In many contexts, the name can be
 abbreviated to a unique prefix.  A five- or six-character
 prefix usually suffices to uniquely identify a file.</p></li>
 
-<li><p>Because files are named by their SHA256 hash, all files
+<li><p>Because files are named by their SHA1 hash, all files
 are immutable.  Any change to the content of a file also
 changes the hash that forms the files name, thus
 creating a new file.  Both the old original version of the
 file and the new change are preserved under different names.</p></li>
@@ -46,51 +46,36 @@
 content to share the same hash.  But finding two such
 files is so incredibly difficult and unlikely that we
 consider it to be an impossibility.</p></li>
 
-<li><p>The files that comprise the global state of a repository
-consist of a header followed by optional content.  Every
-file contains an RSA signature in the header.  And every
-file contains a "file type" designator in the header.
-Additional information is also found in the header depending
-on the file type.</p></li>
+<li><p>The signature of a file is the SHA1 hash of the
+file itself, exactly as it appears on disk.  No prefix
+or meta-information about the file is added before computing
+the hash.  So you can
+always find the SHA1 signature of a file by using the
+"sha1sum" command-line utility.</p></li>
 
-<li><p>The file that comprise the global state of a repository
+<li><p>The files that comprise the global state of a repository
 are the complete global state of that repository.  The SQLite
 database that holds the repository contains additional information
 about linkages between files, but all of that added information
-can be discarded and reconstructed by scanning the content
+can be discarded and reconstructed by rescanning the content
 files.</p></li>
 
 <li><p>Two repositories for the same project can synchronize
 their global states simply by sharing files.  The local
 state of repositories is not normally synchronized or
 shared.</p></li>
 
-<li><p>The name of a file is its SHA256 hash in a base-32
-encoding.  The digits of the base-32 encode are as
-follows:
-
-<blockquote><b>
-    0123456789abcdefghjkmnpqrstuvwxy
-</b></blockquote>
+<li><p>Every repository has a special file at the top-level
+named "manifest" which is an index of all other files in
+the system.  The manifest is automatically created and
+maintained by the system.</p></li>
 
-<p>The letters "o", "i", and "l" are omitted from the
-encoding character set to avoid confusion with the
-digits "0" and "1".  On input, upper and lower case
-letters are treated the same, the letter "o" is
-interpreted as a zero ("0") and the letters "i" and
-"l" are interpreted as a one ("1").  The full name of
-a file is 52 characters long.  The first 4 bits of the
-SHA256 has are repeated onto the end of the hash so that
-the last digit in the base-32 encoding will contain a
-full 5 bits.
-For convenience, files
-may often be abbreviated to a unique prefix and the
-repository will automatically expand the name to
-its full 52 characters.  In practice, 5 or 6
-characters are usually sufficient to give a unique
-name prefix to files even in the largest of projects.</p></li>
-</ul>
+<li><p>The <a href="fileformat.html">file format</a>
+is very simple so that with access
+to the original content files, one can easily reconstruct
+the content of a baseline without the need for any
+special tools or software.</p></li>
 
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 </html>