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<h1 style="text-align: center;"><br>
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<h1 style="text-align: center;">Dar/Libdar Internals - Notes<br>
</h1>
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<div style="text-align: justify;">
<h2>Introduction</h2>
<div style="text-align: justify; margin-left: 40px;">Here take
place a collection of notes. These have been created after
implementation of a given feature, mainly for further reference but
also for user information. The ideas behind these notes are to remind
some choices of implementation, the arguments that lead to this choices
in on side, and in the other side let the user have a room to be
informed on the choices done and be able to bring his remarks without
having to deeply look in the code to learn dar's internals.<br>
</div>
</div>
<h2>Contents</h2>
<div style="margin-left: 40px;"><a href="#EA_and_diff">EA
& differential backup</a><span style="font-weight: bold;"></span><span style="font-weight: bold;"></span><span style="font-weight: bold;"></span><br>
<span style="font-weight: bold;"></span><a href="#archive_structure">Archive
structure in brief</a><br>
<span style="font-weight: bold;"></span><a href="#scrambling">Scrambling</a><br>
<span style="font-weight: bold;"></span><a href="#overflow">Overflow
in arithmetic integer operations</a><span style="font-weight: bold;"></span><br>
<span style="font-weight: bold;"></span><span style="font-weight: bold;"></span><span style="font-weight: bold;"></span><a href="#strong_encryption">Strong
encryption</a><br>
<a href="#thread_safe">libdar
and thread-safe requirement</a><span style="font-weight: bold;"></span><br>
<span style="font-weight: bold;"></span><a href="#dar_manager_deleted">Dar_manager
and delete files</a><span style="font-weight: bold;"></span><br>
<span style="font-weight: bold;"></span><a href="#NLS">Native
Language Support / gettext / libintl</a><br>
<a href="#Dar_relase_Process_in_brief">Dar Release Process</a><br>
<a href="#Dar_version_naming">Dar's
Versions</a><br>
<br>
<br>
<br>
<br>
</div>
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<hr style="width: 100%; height: 2px;">
<h3><a name="EA_and_diff"></a></h3>
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<h3>EA & differential backup</h3>
<h4>Brief presentation of EA:</h4>
<div style="margin-left: 40px;">
<div style="text-align: justify;">EA stands for Extended
Attributes. In
Unix filesystem a regular file is composed of a set of byte (the data)
and an inode. The inode add properties to the file, such as owner,
group, permission, dates (last modification date of the data [mtime],
last access date to data [atime], and last inode change date [ctime]),
etc). Last, the name of the file is not contained in the inode, but in
the directory(ies) it is linked to. When a file is linked more than
once in the directory tree, we speak about "hard links". This way the
same data and associated inode appears several time in the same or
different directories. This is not the same as a symbolic links, which
is a file that contains the path to another file (which may or may not
exist). A symbolic link has its own inode. OK, now let's talk about EA:
<br>
</div>
<br>
</div>
<div style="text-align: justify; margin-left: 40px;">Extended
attributes is a recent feature of Unix file system (at the time of the writing, year 2002). They extend
attributes provided by the inode and associated to a data. They are not
part of the inode, nor part of the data, nor part of a given directory.
They are stored beside the inode and are a set of pair of key and
value. The owner of the file can add or define any key and eventually
associate data to it. It can also list and remove a particular key.
What they are used for ? A way to associate information to a file. <br>
<br>
One particular interesting use of EA, is ACL: Access Control List. ACL
can be implemented using EA and add a more fine grain in assigning
access permission to file. For more information one EA and ACL, see the
site of Andreas Grunbacher: <br>
<br>
<div style="margin-left: 40px;"><a href="http://acl.bestbits.at/">http://acl.bestbits.at/</a><br>
</div>
</div>
<h4>EA & Differential Backup</h4>
<div style="text-align: justify; margin-left: 40px;">to determine
that
an EA has changed dar looks at the ctime value. if ctime has changed,
(due to EA change, but also to permission or owner change) dar saves
the EA. ctime also changes, if atime or mtime changes. So if you access
a file or modify it, dar will consider that the EA have changed also.
This is not really fair, I admit.<br>
<br>
Something better would be to compare EA one by one, and record those
that have changed or have been deleted. But to be able to compare all
EA and their value reference EA must reside in memory. As EA can grow
up to 64 KB by file, this can lead to a quick saturation of the virtual
memory, which is already enough solicited by the catalogue. <br>
<br>
These two schemes implies a different pattern for saving EA in
archive. In the first case (no EA in memory except at time of operation
on it), to avoid skipping in the archive (and ask the user to change of
disks too often), EA must be stored beside the data of the file (if
present). Thus they must be distributed all along the archive (except
at the end that only contains the catalogue).<br>
<br>
In the second case (EA are loaded in memory for comparison), EA must
reside beside or within the catalogue, in any case at the end of the
archive, not to have to user to need all disks to just take an archive
as reference.<br>
<br>
As the catalogue, grows already fast with the number of file to save
(from a few bytes for hard_link to 400 bytes around per directory
inode), the memory saving option has been adopted.<br>
<br>
Thus, EA changes are based on the ctime change. Unfortunately, no
system call permits to restore ctime. Thus, restoring a differential
backup after its reference has been restored, will present restored
inode as more recent than those in the differential archive, thus the
-r option would prevent any EA restoration. In consequence, -r has been
disabled for EA, it does only concern data contents. If you don't want
to restore any EA but just more recent data, you can use the following
: -r -u "*"</div>
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<br>
<hr style="width: 100%; height: 2px;"><a name="archive_structure"></a><br>
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<h3>Archive structure in brief</h3>
<br>
<h4>The Slice Level</h4>
<div style="margin-left: 40px;">A slice is composed of a header, data and trailer (the trailer appeared with archive format version 8)<br>
</div>
<br>
<div style="text-align: justify; margin-left: 80px;"><code>+--------+-------------------------------------------+-------+</code><br>
<code>|
header |
Data
|Trailer|</code><br>
<code>|
|
| |</code><br>
<code>+--------+-------------------------------------------+-------+</code><br>
</div>
<div style="text-align: justify; margin-left: 40px;"><br>
the<span style="font-weight: bold;"> </span><span style="text-decoration: underline; font-weight: bold;">slice header</span><span style="font-weight: bold;"> </span>is composed of<br>
</div>
<ul style="text-align: justify; margin-left: 40px;">
<li>a magic number that tells this is a dar slice</li>
<li>a internal_name which is unique to a given archive and shared by all slices<br>
</li>
<li>a flag that tells whether the slice is the last of the archive or whether a trailer is present that contains this info.<br>
</li>
<li>a extension flag, that was used in older archive but which now always set to 'T' telling that a TLV list follows</li>
<li>A
TLV (Type Length Value) list of item, it contains the slice size, first
slice size. The TLV list will receive any future new field related to
slice header.<br>
</li>
</ul>
<div style="text-align: justify; margin-left: 80px;"><code>+-------+----------+------+-----------+-------+</code><br>
<code>| Magic | internal | flag | extension | TLV |<br>
</code>
<code>| Num. | name | byte |
byte | list |</code><br>
<code>+-------+----------+------+-----------+-------+</code><br>
</div>
<div style="text-align: justify; margin-left: 40px;"><br>
<div style="text-align: justify;">The
header is the first thing
to be written, and if the current slice is not the last
slice (all data to write could not fit in it), the flag field is
changed indicating that another slice follows. The header is also the
first part
to be read. Since archive format 8, the flag is set to a specific value
indicating that the information telling whether the slice is the last
is placed in a slice trailer.<br>
</div>
<br>
The TLV list may contain several fields:<br>
<ul>
<li>First slice size [type 1]<br>
</li>
<li>Other slice size / all slice size if no first slice size is present [type 2]<br>
</li>
<li>data_name [type 3] . This field is detailed below.<br>
</li>
</ul>
A TLV list is of course a list of TLV:<br>
<br>
<div style="margin-left: 40px;"><code>+-------+----------+------+-----------+- ...-----+-------+</code><br>
<code>| Number| TLV 1 | TLV 2| TLV 3 | | TLV n |</code><br>
<code>
</code><code>| of TLV|
| |
|
| |</code><br>
<code>+-------+----------+------+-----------+--...-----+-------+<br>
<br>
</code></div>
</div>
<div style="text-align: justify;">
<div style="margin-left: 40px;">Each TLV item is, as commonly, defined as set of three fields:<br>
<br>
<div style="margin-left: 40px;"><code>+---------+-------------------------+-------------------------+</code><br>
<code>| Type |
Length
|
Value
|<br>
|(2 bytes)| (arbitrary large value) | (arbitrary large data) |</code><br>
<code>+---------+-------------------------+-------------------------+</code></div>
</div>
</div>
<div style="text-align: justify; margin-left: 40px;">
<br>
<div style="text-align: justify;">The 2 bytes type is large
enough for today's need (65535 different types while only three used),
however TLV 65535 is reserved for future use and will signal a new
format for the type field.<br>
</div>
<br>
</div>
<div style="margin-left: 40px; text-align: justify;">To know in
which slice and at which position to find a particular data, dar needs
to know each file's size. This is the reason why each slice contains
the slice size information, in particular the last slice. In older
version, dar had to read the first slice first to get this slicing
information. Then it could read the archive contents at the end of the
last slice. Today, reading the last slice, dar can fetch the slicing
scheme from the slice header (what we just detailed) and fetch the
archive contents at the end of this same last slice.<br>
</div>
<div style="text-align: justify; margin-left: 40px;"><br>
<span style="font-weight: bold; text-decoration: underline;">The trailer</span>
(which is one byte length) is new since archive format version 8
(released 2.4.0). It contains the value that was located in the header flag field in older archive format, telling
whether the slice is the last of the archive or not. When writting down
a single sliced archive (no -s option provided), both the header and
the trailer tell that the slice is the last of the archive (duplicated
information). However, when doing multi-sliced archive, it is not
possible to known whether a slice is the last before reaching the
requested amount of data per slice (which depends on the amount of byte
to save, compression ratio, encryption overhead, etc.). Thus the header
flag contains a value telling that to know whether the slice is the
last or not, one must read the trailer.<br>
<br>In
older format, it was necessary to seek back to update the header
with the correct information when a new slice had to be created. But,
keeping this behavior, it would not have been possible to make a digest
"on the fly" (see --hash
option). The addition of the trailer was required for that feature: to
compute a md5 or sha1 hash of each slice. But, this costs one byte per
slice, yes.<br>
</div>
<h4>Data Name</h4>
<div style="margin-left: 40px;">As seen above in the header fields, we have among others the three following identifiers:<br>
<ul>
<li>magic number</li>
<li>internal name</li>
<li>data name<br>
</li>
</ul>
</div>
<div style="margin-left: 40px;">
<div style="text-align: justify;">as already said, magic number
is constant and let dar be (almost) sure a given file is a dar slice
file. Also briefly explained, the internal_name is a identifier that
let dar be almost sure that several slices are from the same archive
(problem car arise if two archives of same basename have their slices
mixed together: dar will see that and report it to the user).<br>
<br>
The new and not yet described field is the "data_name". A new feature
with release 2.4.0 is the ability to use an extracted catalogue to
backup a internal catalogue of a given archive. However dar must be
(almost) sure that the extracted catalogue is not extracted from an
other archive than the one the user is trying to use it with. For this
reason, the data_name identifier is kept identical between an archive
and any of its extracted catalogue. Dar_xform also does not modify
data_name, thus one can reslice an extracted catalog or a given archive
and still be able to use these new archive or extracted catalogue with
older archive or extracted catalogues. Instead the merging operation
creates a new archive with a different data_name, to avoid one to use a
isolated catalogue of the original archive to backup the internal
catalogue of a merged archive.<br>
</div>
</div>
<br>
<h4>Archive Level</h4>
<div style="margin-left: 40px;">
<div style="text-align: justify;">The
archive level describes the
structure of the slice's data field (removing header and trailer of
each slice), when they are all sticked together from slice to slice:<br>
</div>
<br>
</div>
<div style="margin-left: 80px;"><code>+---------+----------------------------+-----------+--------+---------+--------+</code><br><code>|
version | Data
| catalogue | term 1 | version | term 2 |<br>| header </code><code>|
|
| | trailer
| |</code><br>
<code>+---------+----------------------------+-----------+--------+---------+--------+</code><br>
</div>
<div style="margin-left: 80px;"><code></code></div>
<div style="margin-left: 40px;"><br>The <span style="text-decoration: underline; font-weight: bold;">version header</span>
is a short version of the trailer version. It is used when reading an
archive in sequential mode, to be able to prepare the proper
compression layer, and known whether escape sequence mark are present
in the archive.<br>
<br>
the <span style="font-weight: bold; text-decoration: underline;">version trailer</span> (which may still be called "version header" in some
part of the documentation because it was only located at the
beginning of the archive in previous archive format) is composed of:<br>
</div>
<ul style="margin-left: 40px;">
<li>edition version of the archive</li>
<li>compression algorithm used</li>
<li>command line used for creating the archive, now known as "user comment"<br>
</li>
<li>flag (telling whether the archive is encrypted, whether it has escape sequence marks, etc.)</li>
<li>initial offset (telling where starts the data in the archive, is only present in the trailer)<br>
</li>
<li>CRC (Cyclic Redundancy Check) computed on the whole version header or trailer<br>
</li>
</ul>
<div style="margin-left: 80px;"><code>+---------+------+---------------+------+--------+--------+</code><br>
<code>| edition | algo | command line | flag | initial| CRC |<br>
</code><code>|
|
|
| | offset | |</code><br>
<code>+---------+------+---------------+------+--------+--------+<br>
</code></div>
<div style="margin-left: 80px;">
</div>
<div style="margin-left: 40px;"><br>
<div style="text-align: justify;">
The trailer is used when reading an archive in direct access mode, to build
the proper compression layer, escape layer (it is needed if mark have
been inserted in the archive to un-escape data that could else be taken as an escape sequence mark).<br>
</div>
<br>
<span style="text-decoration: underline; font-weight: bold;">The data</span> is a suite of file contents, with EA if present<br>
<br>
</div>
<div style="margin-left: 80px;"><code> ....</code><code>--+---------------------+----+------------+-----------+----+---....</code><br>
<code> | file
data | EA | file
data | file data | EA |</code><br>
<code> | (may be
compressed) | | (no EA)
|
| |</code><br>
<code>
....--+---------------------+----+------------+-----------+----+---....</code><br>
<code></code></div>
<div style="margin-left: 40px;"><br>
</div>
<div style="text-align: justify; margin-left: 40px;"><span style="text-decoration: underline; font-weight: bold;">the
catalogue</span>,
contains all inode, directory structure and hard_links information. The
directory structure is stored in a simple way: the inode of a directory
comes, then the inode of the files it contains, then a special entry
named "EOD" for End of Directory. Considering the following tree:<br>
</div>
<div style="margin-left: 40px; text-align: justify;"><br>
</div>
<div style="margin-left: 80px; text-align: justify;"><code> -
toto</code><br>
<code> | titi</code><br>
<code> | tutu</code><br>
<code> | tata</code><br>
<code> | | blup</code><br>
<code> | +--</code><br>
<code> | boum</code><br>
<code> | coucou</code><br>
<code> +---</code><br>
</div>
<div style="margin-left: 40px; text-align: justify;"><br>
it would generate the following sequence for catalogue storage:<br>
<br>
</div>
<div style="margin-left: 80px; text-align: justify;"><code>+-------+------+------+------+------+-----+------+--------+-----+</code><br>
<code>| toto | titi | tutu | tata | blup | EOD | boum |
coucou | EOD |</code><br>
<code>|
| |
| |
| |
| | |</code><br>
<code>+-------+------+------+------+------+-----+------+--------+-----+</code><br>
</div>
<div style="margin-left: 40px; text-align: justify;"><br>
EOD takes on byte, and this way no need to store the full path of each
file, just the filename is recorded.<br>
<br><span style="text-decoration: underline; font-weight: bold;">
the terminator</span>
stores the position of the beginning of the catalogue,
it is the last thing to be written. Thus dar first reads the
terminator, then the catalogue. Well there is now two terminators, both
are meant to be read backward. The second terminator points to the
beginning of the "trailer version" which is read first in direct access
mode. The first terminator points to the start of the catalogue, which
is read once the adhoc compression layer has been built based on the
information found on the "trailer version"<br>
</div>
<br>
<h4>All Together</h4>
<div style="text-align: justify; margin-left: 40px;">Here is an
example of how data can be structured in a four slice archive:<br>
<br>
</div>
<div style="text-align: justify; margin-left: 80px;"><code>+--------+--------+------------------------+--+</code><br>
<code>| slice | version| file data +
EA |Tr|</code><br>
<code>|
header | header
|
| |</code><br>
<code>+--------+--------+------------------------+--+</code><br>
</div>
<div style="text-align: justify; margin-left: 40px;"><br>
the first slice (just above) has been defined smaller using the -S option<br>
<br>
</div>
<div style="text-align: justify; margin-left: 80px;"><code>+--------+-----------------------------------------------------------------+--+</code><br>
<code>|
slice
| file data
+
EA
|Tr|</code><br>
<code>|
header
|
| |</code><br>
<code>+--------+-----------------------------------------------------------------+--+</code><br>
</div>
<div style="text-align: justify; margin-left: 40px;"><code></code><br>
<code></code></div>
<div style="text-align: justify; margin-left: 80px;"><code>+--------+-----------------------------------------------------------------+--+</code><br>
<code>|
slice
| file data
+
EA
|Tr|</code><br>
<code>|
header
|
| |</code><br>
<code>+--------+-----------------------------------------------------------------+--+</code><br>
<code></code><br>
<code>+--------+---------------------+-----------+------ +---------+--------+--+</code><br>
<code>| slice | file data +
EA | catalogue | term 1| version | term 2 |Tr|</code><br>
<code>| header
|
|
| | trailer | | |</code><br>
<code>+--------+---------------------+-----------+-------+---------+--------+--+<br>
<br>
</code></div>
<div style="text-align: justify; margin-left: 40px;">the last
slice is smaller because there was not enough data to make it full.<br>
<br>
The archive is written sequentially this way.<br>
<br></div>
<br>
<h4>Other Levels</h4>
<div style="text-align: justify; margin-left: 40px;">Things get a
bit
more complicated if we consider compression and encryption. The way the
problem is addressed in dar's code is a bit like networks are designed
in computer science, using the notion of <span style="text-decoration: underline;">layers</span>.
Here, there is a
additional constraint, a given layer may or may not be present
(encryption, compression, slicing for example). So all layer must have
the same interface for serving the layer above them. This interface is
defined by the pure virtual class "generic_file", which provides
generic methods for reading, writing, skipping, getting the current
offset when writing or reading data to a "generic_file". This way the
compressor class
acts like a file which compresses data wrote to it and writes
compressed data to another "generic_file" below it. The strong
encryption and scramble
classes act the same but in place of compressing/uncompressing they
encrypt/decrypt the data to/from another generic_file object. The
slicing we have seen above follows the same principle, this is a "sar"
object that transfers data wrote to it to several fichier [=file]
objects.
Class fichier [=file] also inherit from generic_file class, and is a
wrapper
for the plain file system calls. Some new classes have been added with
format 8, in particular the escape class, which inserts escape sequence
mark at requested position, and modifies data wrote to it to never look
like an escape sequence mark. To reduce the level of context switch
when reading the catalogue (which makes a ton of small read), a cache
class is also present, it gather small writes made to it into larger
writes, and pre-reads a large amount of data to answer to the many
small reads when building the catalogue in memory from the archive.<br>
</div>
<div style="margin-left: 40px;"><br>
Here are now all currently possible layers together:<br>
<br>
</div>
<div style="margin-left: 80px;"><code>
+----+--+----+-...........+---------+</code><br>
<code>archive
|file|EA|file|
|catalogue|</code><br>
<code>layout
|data|
|data|
| |</code><br>
<code>
+----+--+----+-...........+---------+</code><br>
<code> |
| |
|
|<br>
+-----+ | +-------+ |
+----------+ <br>
sparse |spars| | |sparse | | | caching |<br>
file |file | |
|file | | | layer
for|<br>
detection |detec| | |detect.| | | catalogue|<br>
layer +-----+ | +-------+ | +----------+<br>
</code>
<code>(optional) |
| |
|
|</code><br>
<code> V
V V
V
V</code><br>
<code>
+-----------------------------------+</code><br>
<code>compression
| (compressed)
data |</code><br>
<code>
+-----------------------------------+</code><br>
<code>
|
|<br>
|
|<br>
V
V<br>
</code><code> +-----------------------------------+</code><br>
<code>escape layer | escaped data / escape sequences |<br>
</code><code>(optional) +-----------------------------------+</code><br>
<code>
|
| / First Terminateur</code><br>
<code>
|
| |</code><br>
<code>
|
| V</code><br>
<code>elastic +---+
|
| +----+---+</code><br>
<code>buffers |EEE|
|
| | T1 |EEE|</code><br>
<code>
+---+
|
| +----+---+</code><br>
<code>
|
|
|
| Second </code><br>
<code>
V
V
V
V Terminator</code><br>
<code>
+--------------------------------------------------+
|</code><br>
<code>cipher
| (encrypted)
data
|
|</code><br>
<code>
+--------------------------------------------------+
V</code><br>
<code> </code><code>
|
|
</code><code>+---------+----+</code><br>
<code>+-------+
|
|
</code><code>| trailer | T2 |</code><br>
<code>|
header|
|
|
</code><code>+---------+----+<br>
+-------+
|
|
| |<br>
| |
|
| |<br>
</code>
<code>
V
V
V
V v<br>
</code><code>+-----------------------------------------------------------------------------+</code><br>
<code>|
data
|</code><br><span style="font-family: monospace;">+</span><code>-----------------------------------------------------------------------------+</code><br>
<code>
| |
| |
| |
| | | | | |</code><br>
<code>slice
| |
| |
| |
| | | | | |</code><br>
<code>headers |
| | |
| |
| | | | | |</code><br>
<code> | |
| |
| |
| |
| | | | | |</code><br>
<code> | +---|------\ |
| |
| |
| | | | | |</code><br>
<code> V
V V V
V V
V V
V V V V V V</code><br>
<code>+---------+ +---------+ +---------+
+---------+ +-------+ </code><code>+-------+ </code><code>+----+</code><br>
<code>|HH| data | |HH| data | |HH| data | |HH|
data | |HH|data| </code><code>|HH|data| </code><code>|HH| |</code><br>
<code>+---------+ +---------+ +---------+
+---------+ +-------+ </code><code>+-------+ </code><code>+----+</code><br>
<code> slice 1 slice
2 slice 3
slice 4 slice 5</code><br>
<code></code></div>
<div style="margin-left: 40px;"><br>
</div>
<br>
<div style="margin-left: 40px;">
<div style="text-align: justify;">The <span style="text-decoration: underline; font-weight: bold;">elastic buffers</span>
are here to prevent plain text attack, where one knows which data is
expected at a given place, an trying to guess the cipher comparing the
expected data and the encrypted one. As dar generates structured
archives, there would have some possibility that one use this attack to
crack an archive encryption. To overcome this problem, elastic buffers
have been added at the beginning and at the end of encrypted data. This
way it is not possible to know where is located a given archive
structure within the encrypted data. The elastic buffers are random
data that contain at a random place a pattern that tells the overall
size of the buffer (which size is randomly chosen during archive
creation). The pattern is of the form ">###<" where the hash field
(###) contains the elastic buffer size in binary. Small elastic buffer
can be "><" for two bytes or "X" for one byte, but as it is
encrypted beside archive data, it is not possible to determine its size
for one that does not hold the archive encryption key. Elastic buffer
are usually several kilobyte long. Here follows an example of elastic
buffer:<br>
</div>
<code><br>
</code>
<div style="margin-left: 40px;"><code>972037219>20<8172839</code><br>
<code><br>
<br>
</code></div>
</div>
<div style="margin-left: 40px; text-align: justify;">For clarity,
the size field between '>' and '<' has been written in decimal
instead of binary, as well as the random data inside the elastic
buffer. The location of the size field '>20<' is also randomly
chosen at creation time.<span style="text-decoration: underline; font-weight: bold;"><br>
<br>
</span>A <span style="text-decoration: underline; font-weight: bold;">Teminateur</span>
is short structure that is intended to be read backward. It gives the
absolute position of a given item within the archive: The second
terminateur let dar skip at the beginning of the archive trailer.
The first terminateur (eventually encrypted) let dar skip at the
beginning of the catalogue).<br>
</div>
<div style="margin-left: 40px;"><code></code><br>
</div>
<br>
<br>
</td>
</tr>
</tbody>
</table>
<br>
<hr style="width: 100%; height: 2px;"><a name="scrambling"></a>
<table style="width: 90%; text-align: left; margin-left: auto; margin-right: auto;" border="0" cellpadding="2" cellspacing="2">
<tbody>
<tr>
<td style="vertical-align: top;">
<h3>Scrambling</h3>
<br>
<div style="text-align: justify;">Before strong encryption was
implemented, dar had only a very simple and weak encryption mechanism.
It remains available in current release under the "scram" algorithm
name. It mains advantage is that is does not rely on any external
library, it is completely part of libdar.<br>
</div>
<br>
How does it works?<br>
<br>
<div style="text-align: justify;">Consider the pass phrase as a
string,
thus a sequence of bytes, thus a sequence of integer each one between 0
and 255 (including 0 and 255). The data to "scramble" is also a
sequence of byte, usually much longer than the pass phrase. The
principle is to add byte by byte the pass phrase to the data, modulo
256. The pass phrase is repeated all along the archive. Let's take an
example: <br>
</div>
<br>
the pass phrase is "he\220lo" (where \220 is the character which decimal value
is 220). the data is "example"<br>
<br>
taken from ASCII standard:<br>
<div style="margin-left: 40px;">h = 104<br>
l = 108<br>
o = 111<br>
e = 101<br>
x = 120<br>
a = 97<br>
m = 109<br>
p = 112<br>
</div>
<br>
<code>
e
x
a
m
p
l e<br>
101
120 97
109 112
108 101<br>
<br>
+
h
e \220
l
o
h e<br>
104
101 220
108 111
104 101<br>
<br>
---------------------------------------------------------------<br>
<br>
205
221 317
217 223
212 202<br>
<br>
---------------------------------------------------------------<br>
modulo<br>
256 : 205
221 61
217 223
212 202<br>
\205
\201 =
\217 \223 \212
\202</code><br>
<br>
thus the data "example" will be written in the archive
"\205\201=\217\223\212\202"<br>
<br>
<div style="text-align: justify;">This method allows to decode
any
portion without knowing the rest of the data. It does not consume much
resources to compute, but it is terribly weak and easy to crack. Of
course, the data is more difficult to retrieve without the key when the
key is long. Today dar can also use strong encryption (blowfish and few others) and thanks to a encryption block can still avoid
reading the whole archive to restore any single file.</div>
</td>
</tr>
</tbody>
</table>
<br>
<hr style="width: 100%; height: 2px;"><a name="overflow"></a><br>
<table style="width: 90%; text-align: left; margin-left: auto; margin-right: auto;" border="0" cellpadding="2" cellspacing="2">
<tbody>
<tr>
<td style="vertical-align: top;">
<h3>Overflow in arithmetic integer operations</h3>
<br>
<div style="text-align: justify;">Some code explanation about the
detection of integer arithmetic operation overflows. We speak about
*unsigned* integers, and we have only portable standard ways to detect
overflows when using 32 bits or 64 bits integer in place of infinint.<br>
<br>
Developed in binary, a number is a finite suite of digits (0 or 1). To
obtain the original number from the binary representation, we must
multiply each digit by a power of two. example the binary
representation "101101" designs the number N where:<br>
<br>
</div>
<div style="margin-left: 40px; text-align: justify;">N = 2^5 +
2^3 + 2^2 + 2^0<br>
</div>
<div style="text-align: justify;"><br>
in that context we will say that 5 is the maximum power of N (the power
of the higher non null binary digit).<br>
<br>
</div>
for the addition "+" operation, if an overflow occurs, the result is
less than one or both operands, so overflow is not difficult to detect.
To convince you, let's assume that the result is greater both operands
while it has overflowed. Thus the real result (without overflow) less
the first operands should gives the second argument, but here we get a
value that is greater than the all 1 bits integer (because there was an
overflow and the resulting overflowed value is greater than the first
second and the first operand), so this is absurd, and in case of
overflow the resulting value is less than one of the operands.<br>
<div style="text-align: justify;"><br>
for substraction "-" operation, if the second operand is greater than
the first there will be an overflow (result must be unsigned thus
positive) else there will not be any overflow. Thus detection is even
more simple.<br>
<br>
for division "/" and modulo "%" operations, there is never an overflow
(there is just illicit the division by zero).<br>
<br>
for multiplication "*" operation, a heuristic has been chosen to
quickly detect overflow, the drawback is that it may triggers false
overflow when number get near the maximum possible integer value. Here
is the heuristic used:<br>
<br>
given A and B two integers, which max powers are m and n respectively,
we have<br>
<br>
</div>
<div style="margin-left: 40px; text-align: justify;">A <
2^(m+1)<br>
</div>
<div style="text-align: justify;">and<br>
</div>
<div style="margin-left: 40px; text-align: justify;">B <
2^(n+1)<br>
</div>
<div style="text-align: justify;"><br>
thus we also have:<br>
<br>
</div>
<div style="margin-left: 40px; text-align: justify;">A.B <
2^(m+1).2^(n+1)<br>
</div>
<div style="text-align: justify;"><br>
which is:<br>
<br>
</div>
<div style="margin-left: 40px; text-align: justify;">A.B <
2^(m+n+2)<br>
</div>
<div style="text-align: justify;"><br>
</div>
by consequences we know that the maximum power of the product of A by B
is at most m+n+1 and while m+n+1 is less than or equal to the maximum
power of the integer field there will not be overflow else we consider
there will be an overflow even if it may not be always the case (this
is an heuristic algorithm). </td>
</tr>
</tbody>
</table>
<br>
<hr style="width: 100%; height: 2px;"><a name="strong_encryption"></a><br>
<table style="width: 90%; text-align: left; margin-left: auto; margin-right: auto;" border="0" cellpadding="2" cellspacing="2">
<tbody>
<tr>
<td style="vertical-align: top;">
<h3>Strong encryption</h3>
<br>
<div style="text-align: justify;">Several cyphers are available.
Remind that "scrambling" is not a strong encryption cypher, all other
are.<br>
<br>
to be able to use a strong encrypted archive you need to know the three
parameters used at creation time:<br>
</div>
<ul style="text-align: justify;">
<li>the cypher used (blowfish, ...)</li>
<li>the key or password used</li>
<li>the encryption block size used</li>
</ul>
<div style="text-align: justify;">no information about these
parameters
is stored in the generated archive. If you make an error on just one of
them, you will not be able to use your archive. If you forgot one of
them, nobody can help you, you can just consider the data in this
archive as lost. This is the drawback of strong encryption. <br>
<br>
</div>
<h4 style="text-align: justify;">How is it implemented?</h4>
<div style="text-align: justify;">To not completely break the
possibility to directly access file, the archive is not encrypted
as a
whole (as would do an external program). The encryption is done block
of data by block of data. Each block can be decrypted, and if you want
to read some data somewhere you need to decrypt the whole block(s) it
is in.<br>
<br>
In consequence, the larger the block size is, the stronger the
encryption is. But the larger the block size is too, the longer it will
take to recover a given file, in particular when the file size to
restore is much smaller than the encryption block size used.<br>
<br>
An encryption block size can range from 10 bytes to 4 GB.<br>
<br>
If encryption is used as well as compression, compression is done
first, then encryption is done on compressed data.<br>
<br>
An "elastic buffer" is introduced at the beginning and at the end of
the archive, to protect against plain text attack. The elastic
buffer
size randomly varies and is defined at execution time. It is composed
of random (srand()) values. Two marks characters '>' and '<'
delimit the size field, which indicate the byte size of the elastic
buffer. The size field is randomly placed in the buffer. Last, the
buffer is encrypted with the rest of the data. Typical elastic buffer
size range from 1 byte to 10 kB, for both initial and terminal elastic
buffers. <br>
<br>
Elastic buffers are also used inside compression blocks. The underlying
cypher may not be able to encrypt at the requested block size boundary.
If necessary a small elastic buffer is appended to the data before
encryption, to be able, at restoration time, to know the amount of data
and the amount of noise around it.<br>
<br>
Let's take an example with blowfish. Blowfish encrypts by multiple of 8
bytes (blowfish chain block cypher). An elastic buffer is always added
to the data of a encryption block, its minimal size is 1 byte. <br>
<br>
Thus, if you request a encryption block of 3 bytes, these 3 bytes will
be padded by an elastic buffer of 5 bytes for these 8 bytes to be
encrypted. This will make a very poor compression ratio as only 3 bytes
on 8 bytes are significant.<br>
<br>
If you request a encryption block of 8 bytes, as there is no room for
the minimal elastic buffer of 1 byte, a second 8 byte block is used to
put the elastic buffer, so the real encryption block will be 16 bytes.<br>
<br>
Ideally, a encryption block of 7 bytes, will use 8 bytes with 1 byte
for
the elastic buffer.<br>
<br>
This problem tends to disappear when the encryption block size grows,
so
this should not be a problem in normal conditions. Encryption block of
3 bytes is not a good idea to have a strong encryption scheme, for
information, the default encryption block size is 10kB.<br>
</div>
</td>
</tr>
</tbody>
</table>
<br>
<hr style="width: 100%; height: 2px;"><a name="thread_safe"></a><br>
<table style="width: 90%; text-align: left; margin-left: auto; margin-right: auto;" border="0" cellpadding="2" cellspacing="2">
<tbody>
<tr>
<td style="vertical-align: top;">
<h3>libdar and thread-safe requirement</h3>
<br>
<div style="text-align: justify;">This is for those who plane to
use libdar in their own programs.<br>
<br>
If you plan to have only one thread using libdar there is no problem,
of course, you will however have to call one of the get_version()
first, as usual. Thing change if you intend to have several concurrent
threads using libdar library.<br>
<br>
libdar is thread-safe under certain conditions:<br>
<br>
Several 'configure' options have an impact on thread-safe support:<br>
<br>
--enable-test-memory is a debug option that avoid libdar to be
thread-safe, so don't use it.<br>
--enable-special-alloc (set by default), makes a thread-safe library
only if POSIX mutex are available (pthread_mutex_t type).<br>
--disable-thread-safe avoid looking for mutex, so unless
--disable-special-alloc is also used, the generated library will not be
thread safe.<br>
<br>
You can check the thread safe capability of a library thanks to the
get_compile_time_feature(...) call from the API. Or use 'dar -V'
command, to quickly have the corresponding values and check using
'ldd' to see which library has been dynamically linked to dar, if
applicable.<br>
<br style="font-weight: bold; text-decoration: underline;">
<span style="font-weight: bold; text-decoration: underline;">IMPORTANT:</span><br>
As more as before it is mandatory to call get_version() call before any
other call, when the call returns, libdar is ready for thread safe.
Note that even if the prototype does not change get_version() *may* now
throw an exception, so use get_version_noexcept() if you don't want to
manage exceptions.<br>
<br>
For more information about libdar and its API, check the <a href="api_tutorial.html">doc/api_tutorial.html</a> document
and the API reference manual under <a href="man/index.html">doc/html/index.html</a><br>
<br>
</div>
</td>
</tr>
</tbody>
</table>
<hr style="width: 100%; height: 2px;"><a name="dar_manager_deleted"></a>
<table style="width: 90%; text-align: left; margin-left: auto; margin-right: auto;" border="0" cellpadding="2" cellspacing="2">
<tbody>
<tr>
<td style="vertical-align: top;">
<h3>Dar_manager and delete files</h3>
<br>
<div style="text-align: justify;">This is for further reference
and explanations.<br>
<br>
In dar archive when a file has been deleted since the backup of
reference (in case of differential archive), an entry of a special type
(called "detruit") is put in the catalogue of the archive which only
contains the name of the missing file. <br>
<br>
In a dar_manager database, to each files that have been found in one of
the archive used to build this database corresponds a list of
association. These associations put in relation the mtime (date of
modification of the file) to the archive number where the file has been
found in that state. <br>
<br>
There is thus no way to record "detruit" entries in a dar_manager
database, as no date is associated with this type of object. Yes, in a dar archive, we
can only notice a file has been destroyed because it is not present in
the filesystem but is present in the catalogue of the archive of
reference. Thus we know the file has been destroyed between the date
the archive of reference has been done and the date the current archive
is actually done. Unfortunately, no date is recorded in dar archives
telling it has been done at which time.<br>
<br>Thus, from dar_manager, inspecting a catalogue, there is no way to give
a significant date to a "detruit" entry. In consequences, for a given
file which has been removed, then recreated, then removed again along a
series of differential backups, it is not possible to order the times
when this file has been removed in the series of date when it has
existed. <br>
<br>
The ultimate consequence is that if the user asks dar_manager to
restore a directory in the state just before a given date (-w option),
it will not be possible to know if that file existed at that time. We
can effectively see that it was not present in a given archive but as
we don't know the date of that archive we cannot determine if it is
before of after the date requested by the user, and dar_manager is not
able to restore the non existence of a file for a given time, we must
use dar directly with the archive that has been done at the date we
wish. <br>
<br>
Note that having a date stored in each dar archive would not solve the
problem without some more informations. First, we should assume that
the date is consistent from host to host and from time to time (What if
the user change of time due to daylight saving or move around the
Earth, or if two users in two different places share a filesystem ---
with rsync, nfs, or other mean --- and do backups alternatively...).
Let's assume the system time is significant and thus let's imagine
what would be the matter if in each archive this date of archive
construction was stored. <br>
<br>
Then when a detruit object is met in an archive it can be given the
date the archive has been built and thus ordered in the series of dates
when the corresponding file was found in other archives. So when the
user asks for restoration of a directory a given file's state is
possible to know, and thus the restoration of the corresponding archive
will do what we expect : either remove the file (if the selected backup
contains an "detruit" object, or restore the file in the
state it
had).<br>
<br>
Suppose now, a dar_manager database built with a series of full backup.
There will thus no be any "detruit" objects, but a file may be present
or may be missing in a given archive. The solution is thus that once an
archive has been integrated in the database, the last step is to scan
the whole database for files that have no date associated with this
last archive, thus we can assume these files were not present and add
the date of the archive creation with the information that this file
was removed at that time. Moreover, if the last archive add a file
which was not know in archives already present in the database, we must
consider this file was deleted in each of these previous archives, but
then we must record the dates of creation for all these previous
archive to be able to put this information properly in the database.
But, in that case we would not be able to make dar removing a file, as no
"detruit" object exist (all archive are full backups), and dar_manager
should remove itself the entry from the filesystem. Beside the fact
that it is not the role to dar_manager to directly interact with the
filesystem, dar_manager should record an additional information to know
if a file is deleted because it has been found a "detruit" object in an
archive, or if it is deleted because it has not been found any entry in
an given archive. This is necessary to known whether to rely on dar to
remove the file or to make dar_manager do it itself, or maybe better is
to never rely on dar to remove a file but always let dar_manager do it
itself. <br>
<br>
Assuming we accept to make dar_manager able to rm entries from
filesystem without relying on dar, we must store the date of the
archive creation in each archive, and store these dates for each
archive in dar_manager databases. Then instead of using the mtime of
each file, we could do something much more simple in database: for each
file, record if it was present or not in each archive used to built the
database, and beside this, store only the archive creation date of each
archive. This way, dar_manager would only have for each file to take
the last state of the file (deleted or present) before the given date
(or the last known state if no date is given) and either restore the
file from the corresponding archive or remove it.<br>
<br>
But if a user has removed a file by accident and only notice this
mistake after several backups, it would become painful to restore this
file, as the user should find manually at which date it was present to
be able to feed dar_manager with the proper -w option, this worse than
looking for the last archive that has the file we look for.<br>
<br>
Here we are back to the restoration of a file and the restoration of a
state. By state, I mean the state a directory tree had at a given time,
like a photo. In its original version dar_manager was aimed to restore
files, whatever they exist or not in the last archive added to a
database. It only finds the last archive where the file is present.
Making dar_manager restore a state, and thus considering files that
have been removed at a given date, is no more no less than restoring
from a given archive, directly with dar. So all this discussion about
the fact that dar_manager is not able to handle files that have been
removed, to arrive to the fact that adding this feature to dar_manager
will make it become quite useless... sight. But, that was necessary. </div>
</td>
</tr>
</tbody>
</table>
<br>
<hr style="width: 100%; height: 2px;"><a name="NLS"></a><br>
<table style="width: 90%; text-align: left; margin-left: auto; margin-right: auto;" border="0" cellpadding="2" cellspacing="2">
<tbody>
<tr>
<td style="vertical-align: top;">
<h3>Native Language Support / gettext / libintl</h3>
<br>
<div style="text-align: justify;">Native Language Support (NLS)
is the fact a given program can display
its messages in different languages. For dar, this is implemented using
the gettext tools. This tool must be installed on the system for dar
can be able to display messages in another language than English.
<br>
<br>
Things are the following:<br>
- On a system without gettext dar will not use gettext at all. All
messages will be in English (OK maybe better saying Frenglish) ;-)<br>
- On a system with gettext dar will use the system's gettext, unless
you use --disable-nls option with the configure script.<br>
<br>
If NLS is available you just have to set the LANG environment variable
to your locale settings to change the language in which dar displays
its messages (see ABOUT-NLS for more about the LANG variable).<br>
<br>
just for information, gettext() is the name of the call that makes
translations of string in the program. This call is implemented in the
library called 'libintl' (intl for Internationalization). Last point,
gettext by translating strings, makes the Native Language Support (NLS)
possible, in other words, it let you have the messages of your
preferred programs being displayed in you native language for
those
not having the English as mother tong. <br>
<br>
This was necessary to say, because you may miss the links between
"gettext" , "libintl" and "NLS".<br>
<br>
READ the ABOUT-NLS file at the root of the source package to learn more
about
the way to display dar's messages in your own language. Note that not
all languages are yet supported, this is up to you to send me a
translation in your language and/or contact a translating team as
explained in ABOUT-NLS.<br>
<br>
To know which languages are supported by dar, read the po/LINGUAS file
and check out for the presence of the corresponding *.po files in this
directory. </div>
</td>
</tr>
</tbody>
</table>
<br>
<hr style="width: 100%; height: 2px;"><br>
</center>
<table style="width: 90%; margin-right: auto; margin-left: auto; text-align: left;" border="0" cellpadding="2" cellspacing="2">
<tbody>
<tr>
<td style="vertical-align: top;">
<h3><span style="font-weight: bold;"><a name="Dar_relase_Process_in_brief"></a>Dar Release Process<br>
</span></h3>
<div style="text-align: justify;"><span style="font-weight: bold;"></span><span style="text-decoration: underline;">Development Phase:</span><br>
Dar receive new features during the development phase, at this stage
sources are modified and tested after each feature addition. The
development sources are stored in a <a href="http://sourceforge.net/cvs/?group_id=65612">CVS repository</a>
at sourceforge,
repository you can access in read-only. <br>
<br>
<span style="text-decoration: underline;">Frozen API Phase:</span><br>
No new feature that would change the API are added. The API shall be
documented enough to let API users give their feedback about the design
and its implementation. During this time, development continues,
whatever is necessary while it does not changes the API, like
documentation of the whole project, problem fix in libdar, new features
in command-line part of the source, and so on.<br>
<br>
<span style="text-decoration: underline;">Pre-release Phase:</span><br>
Once the documentation and API is stable, comes the pre-release phase,
this phase starts and ends by a email to the dar-news mailing-list. At
this period intensive test is done on the pre-release source, feedback
and information about <a href="http://dar.linux.free.fr/pre-release">new
pre-release packages</a> are exchanged
through the <a href="http://lists.sourceforge.net/lists/listinfo/dar-pre-release">pre-release
mailing-list</a>, this mailing-list lives only
during the pre-release phases and is not archived, nor visible through
a mail to news gateway. Of course, you are welcome to participate
in the testing process and report to the pre-release mailing list any
problem you could meet with a given pre-release package.<br>
<br>
<span style="text-decoration: underline;">Release Phase:</span><br>
Some little time after pre-release has ended, a first package is
released (last number version is zero) and <a href="http://sourceforge.net/project/showfiles.php?group_id=65612">available
at sourceforge</a> for
download. This phase also begins by an email to dar-news mailing-list.
During that phase, users may report bugs/problem about the released
software, depending on the amount of bugs found and of their
importance a new release will take place to only fixe these found bugs
(no features is added), the last number of the version is incremented
by one and a new mail to dar-news is sent with the list of problem
fixed by the new release. The release phase ends when a new release
phase begins, thus during a release phase a concurrent development
phase takes place, then a frozen API, then a pre-release phase but for
a new major version (the first or the second number of the version
changes).<br>
</div>
<span style="font-weight: bold;"><br>
</span>
<h3><span style="font-weight: bold;"><a name="Dar_version_naming"></a>Dar's
Versions<br>
</span></h3>
<span style="font-weight: bold;"></span>
<h4>package release version</h4>
<div style="text-align: justify;">Dar packages are release during
the pre-release phase (<a href="#Dar_relase_Process_in_brief">see above</a>).
Each version is identified by three number separated by dot like for
example, version 2.3.0 . The last number is incremented between
releases that take place in the same release phase (just bug have been
fixed), the middle number increments at each pre-release phase. Last
the first number is incremented when a major change in the software
structure took place [version 2.0.0 has seen the split of dar's code in
one part related to command-line and the rest put in a library called
libdar, that can be accessed by a well defined API even by external
softwares (like <a href="http://kdar.sourceforge.net/">kdar</a> for
example). Version 2.0.0 has also seen the apparition of the configure
script and the use of the gnu tools autoconf, autmake, libtool and
gettext, thus in particular the possibility to have
internationalization]. <br>
<br>
Note that release versionning is completely different from what is done
for the Linux kernel, here for dar all versionnized packages are stable
released software and thus stability increases with the last number of
the version.<br>
<br>
</div>
<h4>Libdar version</h4>
<div style="text-align: justify;">Unfortunately, the release
version does not give much information about the compatibility of
different libdar version, from the point of view of an external
application, that thus has not been released with libdar and may be
faced to different libdar versions. So, libdar has its own version. It
is also a three number version, (for example, current libdar version is
version 3.1.2), but each number has a different meaning. The last
number increases with a new version that only fixes bugs, the middle
number increases with when new features has been added but stay
compatible with older libdar version in the way to use older features.
Last the first number changes when the API has been changed in a way
that no ascendant compatibility is no more possible for some features.<br>
<br>
</div>
<h4>Other versions</h4>
<div style="text-align: justify;"><br>
beside the libdar library, you can find five command-line applications:
dar, dar_xform, dar_slave, dar_manager and dar_cp. These except dar
have their own version which is here too made of three numbers. Their
meaning is the same as the meaning for the package release version: The
last number increases upon bug fix, the middle upon new feature, the
first upon major architecture changes.<br>
<br>
<h4>Archive format version</h4>
When new features come, it is sometime necessary to change the
structure of the archive. To be able to know the format used in the
archive, a field is present in each archive that defines this format.
Each dar binary can thus read all archive format, well of course a
particular version cannot guess the format of archive that have been
defined *after* that dar binary version has been released. If you try to open
a recent archive with an old dar binary, you will have a warning about
the fact that dar is probably not able to read the archive, dar will
then ask you if you want to proceed anyway. Of course, you can try to
read it, but this is at your own risk. In particular, depending on the
feature used (See the Changelog to know which feature required to
upgrade the archive format), you may succeed reading a recent archive
with an old dar binary and get neither error nor warning, but this
does not mean that dar did all that was necessary to restore the files
properly, so it is advised to avoid using an archive with a version of
dar that is tool old to handle the archive format properly (and rather reserve this
possibility only in case of necessity).<br>
</div>
<h4>Cross reference matrix</h4>
<div style="text-align: justify;">OK, you may now find that this
is a bit complex so a list of version is give below. Just remember that
there are two points of view: The command-line user and the external
application developer.<br>
</div>
<span style="font-weight: bold;"></span></td>
</tr>
</tbody>
</table>
<br>
<table style="width: 90%; text-align: left; margin-left: auto; margin-right: auto;" border="1" cellpadding="2" cellspacing="2">
<tbody>
<tr>
<td style="vertical-align: top; width: 20%; font-weight: bold;">Date<br>
</td>
<td style="vertical-align: top; width: 20%; text-align: center; font-weight: bold;">released
package and dar version<br>
</td>
<td style="vertical-align: top; text-align: center;"><span style="font-weight: bold;">Archive format</span><br>
</td>
<td style="vertical-align: top; width: 10%; font-weight: bold; text-align: center;">libdar
version<br>
</td>
<td style="vertical-align: top; width: 10%; font-weight: bold; text-align: center;">dar_xform<br>
</td>
<td style="vertical-align: top; width: 10%; font-weight: bold; text-align: center;">dar_slave<br>
</td>
<td style="vertical-align: top; width: 10%; font-weight: bold; text-align: center;">dar_manager<br>
</td>
<td style="vertical-align: top; width: 10%; font-weight: bold; text-align: center;">dar_cp<br>
</td>
</tr>
<tr>
<td style="vertical-align: top; text-align: right;">April 2nd,
2002<br>
</td>
<td style="vertical-align: top; text-align: center;">1.0.0<br>
</td>
<td style="vertical-align: top; text-align: center;">01<br>
</td>
<td style="vertical-align: top; text-align: center;">-----</td>
<td style="vertical-align: top; text-align: center;">-----</td>
<td style="vertical-align: top; text-align: center;">-----</td>
<td style="vertical-align: top; text-align: center;">-----</td>
<td style="vertical-align: top; text-align: center;">-----</td>
</tr>
<tr>
<td style="vertical-align: top; text-align: right;">April 24th,
2002<br>
</td>
<td style="vertical-align: top; text-align: center;">1.0.1<br>
</td>
<td style="vertical-align: top; text-align: center;">01<br>
</td>
<td style="vertical-align: top; text-align: center;">-----</td>
<td style="vertical-align: top; text-align: center;">-----</td>
<td style="vertical-align: top; text-align: center;">-----</td>
<td style="vertical-align: top; text-align: center;">-----</td>
<td style="vertical-align: top; text-align: center;">-----</td>
</tr>
<tr>
<td style="vertical-align: top; text-align: right;">May 8th, 2002<br>
</td>
<td style="vertical-align: top; text-align: center;">1.0.2<br>
</td>
<td style="vertical-align: top; text-align: center;">01<br>
</td>
<td style="vertical-align: top; text-align: center;">-----</td>
<td style="vertical-align: top; text-align: center;">-----</td>
<td style="vertical-align: top; text-align: center;">-----</td>
<td style="vertical-align: top; text-align: center;">-----</td>
<td style="vertical-align: top; text-align: center;">-----</td>
</tr>
<tr>
<td style="vertical-align: top; text-align: right;">May 27th, 2002<br>
</td>
<td style="vertical-align: top; text-align: center;">1.0.3<br>
</td>
<td style="vertical-align: top; text-align: center;">01<br>
</td>
<td style="vertical-align: top; text-align: center;">-----</td>
<td style="vertical-align: top; text-align: center;">-----</td>
<td style="vertical-align: top; text-align: center;">-----</td>
<td style="vertical-align: top; text-align: center;">-----</td>
<td style="vertical-align: top; text-align: center;">-----</td>
</tr>
<tr>
<td style="vertical-align: top; text-align: right;">June 26th,
2002<br>
</td>
<td style="vertical-align: top; text-align: center;">1.1.0<br>
</td>
<td style="vertical-align: top; text-align: center;">02<br>
</td>
<td style="vertical-align: top; text-align: center;">-----</td>
<td style="vertical-align: top; text-align: center;">1.0.0<br>
</td>
<td style="vertical-align: top; text-align: center;">1.0.0<br>
</td>
<td style="vertical-align: top; text-align: center;">-----</td>
<td style="vertical-align: top; text-align: center;">-----</td>
</tr>
<tr>
<td style="vertical-align: top; text-align: right;">Nov. 4th, 2002<br>
</td>
<td style="vertical-align: top; text-align: center;">1.2.0<br>
</td>
<td style="vertical-align: top; text-align: center;">03<br>
</td>
<td style="vertical-align: top; text-align: center;">-----</td>
<td style="vertical-align: top; text-align: center;">1.1.0<br>
</td>
<td style="vertical-align: top; text-align: center;">1.1.0<br>
</td>
<td style="vertical-align: top; text-align: center;">1.0.0<br>
</td>
<td style="vertical-align: top; text-align: center;">-----</td>
</tr>
<tr>
<td style="vertical-align: top; text-align: right;">Jan. 10th,
2003<br>
</td>
<td style="vertical-align: top; text-align: center;">1.2.1<br>
</td>
<td style="vertical-align: top; text-align: center;">03<br>
</td>
<td style="vertical-align: top; text-align: center;">-----</td>
<td style="vertical-align: top; text-align: center;">1.1.0</td>
<td style="vertical-align: top; text-align: center;">1.1.0</td>
<td style="vertical-align: top; text-align: center;">1.0.0<br>
</td>
<td style="vertical-align: top; text-align: center;">-----</td>
</tr>
<tr>
<td style="vertical-align: top; text-align: right;">May 19th, 2003<br>
</td>
<td style="vertical-align: top; text-align: center;">1.3.0<br>
</td>
<td style="vertical-align: top; text-align: center;">03<br>
</td>
<td style="vertical-align: top; text-align: center;">-----</td>
<td style="vertical-align: top; text-align: center;">1.1.0<br>
</td>
<td style="vertical-align: top; text-align: center;">1.1.0<br>
</td>
<td style="vertical-align: top; text-align: center;">1.1.0<br>
</td>
<td style="vertical-align: top; text-align: center;">-----</td>
</tr>
<tr>
<td style="vertical-align: top; text-align: right;">Nov. 2nd, 2003<br>
</td>
<td style="vertical-align: top; text-align: center;">2.0.0<br>
</td>
<td style="vertical-align: top; text-align: center;">03<br>
</td>
<td style="vertical-align: top; text-align: center;">1.0.0<br>
</td>
<td style="vertical-align: top; text-align: center;">1.1.0<br>
</td>
<td style="vertical-align: top; text-align: center;">1.1.0<br>
</td>
<td style="vertical-align: top; text-align: center;">1.2.0<br>
</td>
<td style="vertical-align: top; text-align: center;">1.0.0<br>
</td>
</tr>
<tr>
<td style="vertical-align: top; text-align: right;">Nov. 21th,
2003<br>
</td>
<td style="vertical-align: top; text-align: center;">2.0.1<br>
</td>
<td style="vertical-align: top; text-align: center;">03<br>
</td>
<td style="vertical-align: top; text-align: center;">1.0.1<br>
</td>
<td style="vertical-align: top; text-align: center;">1.1.0<br>
</td>
<td style="vertical-align: top; text-align: center;">1.1.0<br>
</td>
<td style="vertical-align: top; text-align: center;">1.2.0<br>
</td>
<td style="vertical-align: top; text-align: center;">1.0.0<br>
</td>
</tr>
<tr>
<td style="vertical-align: top; text-align: right;">Dec. 7th, 2003<br>
</td>
<td style="vertical-align: top; text-align: center;">2.0.2<br>
</td>
<td style="vertical-align: top; text-align: center;">03<br>
</td>
<td style="vertical-align: top; text-align: center;">1.0.2<br>
</td>
<td style="vertical-align: top; text-align: center;">1.1.0<br>
</td>
<td style="vertical-align: top; text-align: center;">1.1.0<br>
</td>
<td style="vertical-align: top; text-align: center;">1.2.0<br>
</td>
<td style="vertical-align: top; text-align: center;">1.0.0<br>
</td>
</tr>
<tr>
<td style="vertical-align: top; text-align: right;">Dec. 14th,
2003<br>
</td>
<td style="vertical-align: top; text-align: center;">2.0.3<br>
</td>
<td style="vertical-align: top; text-align: center;">03<br>
</td>
<td style="vertical-align: top; text-align: center;">1.0.2<br>
</td>
<td style="vertical-align: top; text-align: center;">1.1.0<br>
</td>
<td style="vertical-align: top; text-align: center;">1.1.0<br>
</td>
<td style="vertical-align: top; text-align: center;">1.2.1<br>
</td>
<td style="vertical-align: top; text-align: center;">1.0.0<br>
</td>
</tr>
<tr>
<td style="vertical-align: top; text-align: right;">Jan. 3rd, 2004<br>
</td>
<td style="vertical-align: top; text-align: center;">2.0.4<br>
</td>
<td style="vertical-align: top; text-align: center;">03<br>
</td>
<td style="vertical-align: top; text-align: center;">1.0.2<br>
</td>
<td style="vertical-align: top; text-align: center;">1.1.0<br>
</td>
<td style="vertical-align: top; text-align: center;">1.1.0<br>
</td>
<td style="vertical-align: top; text-align: center;">1.2.1<br>
</td>
<td style="vertical-align: top; text-align: center;">1.0.0<br>
</td>
</tr>
<tr>
<td style="vertical-align: top; text-align: right;">Feb. 8th, 2004<br>
</td>
<td style="vertical-align: top; text-align: center;">2.1.0<br>
</td>
<td style="vertical-align: top; text-align: center;">03<br>
</td>
<td style="vertical-align: top; text-align: center;">2.0.0<br>
</td>
<td style="vertical-align: top; text-align: center;">1.2.0<br>
</td>
<td style="vertical-align: top; text-align: center;">1.2.0<br>
</td>
<td style="vertical-align: top; text-align: center;">1.2.1<br>
</td>
<td style="vertical-align: top; text-align: center;">1.0.0<br>
</td>
</tr>
<tr>
<td style="vertical-align: top; text-align: right;">March 5th,
2004<br>
</td>
<td style="vertical-align: top; text-align: center;">2.1.1<br>
</td>
<td style="vertical-align: top; text-align: center;">03<br>
</td>
<td style="vertical-align: top; text-align: center;">2.0.1<br>
</td>
<td style="vertical-align: top; text-align: center;">1.2.1<br>
</td>
<td style="vertical-align: top; text-align: center;">1.2.1<br>
</td>
<td style="vertical-align: top; text-align: center;">1.2.2<br>
</td>
<td style="vertical-align: top; text-align: center;">1.0.0<br>
</td>
</tr>
<tr>
<td style="vertical-align: top; text-align: right;">March 12th,
2004<br>
</td>
<td style="vertical-align: top; text-align: center;">2.1.2<br>
</td>
<td style="vertical-align: top; text-align: center;">03<br>
</td>
<td style="vertical-align: top; text-align: center;">2.0.2<br>
</td>
<td style="vertical-align: top; text-align: center;">1.2.1<br>
</td>
<td style="vertical-align: top; text-align: center;">1.2.1<br>
</td>
<td style="vertical-align: top; text-align: center;">1.2.2<br>
</td>
<td style="vertical-align: top; text-align: center;">1.0.0<br>
</td>
</tr>
<tr>
<td style="vertical-align: top; text-align: right;">May 6th, 2004<br>
</td>
<td style="vertical-align: top; text-align: center;">2.1.3<br>
</td>
<td style="vertical-align: top; text-align: center;">03<br>
</td>
<td style="vertical-align: top; text-align: center;">2.0.3<br>
</td>
<td style="vertical-align: top; text-align: center;">1.2.1<br>
</td>
<td style="vertical-align: top; text-align: center;">1.2.1<br>
</td>
<td style="vertical-align: top; text-align: center;">1.2.2<br>
</td>
<td style="vertical-align: top; text-align: center;">1.0.1<br>
</td>
</tr>
<tr>
<td style="vertical-align: top; text-align: right;">July 13th,
2004<br>
</td>
<td style="vertical-align: top; text-align: center;">2.1.4<br>
</td>
<td style="vertical-align: top; text-align: center;">03<br>
</td>
<td style="vertical-align: top; text-align: center;">2.0.4<br>
</td>
<td style="vertical-align: top; text-align: center;">1.2.1<br>
</td>
<td style="vertical-align: top; text-align: center;">1.2.1<br>
</td>
<td style="vertical-align: top; text-align: center;">1.2.2<br>
</td>
<td style="vertical-align: top; text-align: center;">1.0.1<br>
</td>
</tr>
<tr>
<td style="vertical-align: top; text-align: right;">Sept. 12th,
2004<br>
</td>
<td style="vertical-align: top; text-align: center;">2.1.5<br>
</td>
<td style="vertical-align: top; text-align: center;">03<br>
</td>
<td style="vertical-align: top; text-align: center;">2.0.5<br>
</td>
<td style="vertical-align: top; text-align: center;">1.2.1<br>
</td>
<td style="vertical-align: top; text-align: center;">1.2.1<br>
</td>
<td style="vertical-align: top; text-align: center;">1.2.2<br>
</td>
<td style="vertical-align: top; text-align: center;">1.0.1<br>
</td>
</tr>
<tr>
<td style="vertical-align: top; text-align: right;">Jan. 29th, 2005<br>
</td>
<td style="vertical-align: top; text-align: center;">2.1.6<br>
</td>
<td style="vertical-align: top; text-align: center;">03<br>
</td>
<td style="vertical-align: top; text-align: center;">2.0.5<br>
</td>
<td style="vertical-align: top; text-align: center;">1.2.1<br>
</td>
<td style="vertical-align: top; text-align: center;">1.2.1<br>
</td>
<td style="vertical-align: top; text-align: center;">1.2.2<br>
</td>
<td style="vertical-align: top; text-align: center;">1.0.1<br>
</td>
</tr>
<tr>
<td style="vertical-align: top; text-align: right;">Jan. 30th, 2005<br>
</td>
<td style="vertical-align: top; text-align: center;">2.2.0<br>
</td>
<td style="vertical-align: top; text-align: center;">04<br>
</td>
<td style="vertical-align: top; text-align: center;">3.0.0<br>
</td>
<td style="vertical-align: top; text-align: center;">1.3.0<br>
</td>
<td style="vertical-align: top; text-align: center;">1.3.0<br>
</td>
<td style="vertical-align: top; text-align: center;">1.3.0<br>
</td>
<td style="vertical-align: top; text-align: center;">1.0.1<br>
</td>
</tr>
<tr>
<td style="vertical-align: top; text-align: right;">Feb. 20th,
2005<br>
</td>
<td style="vertical-align: top; text-align: center;">2.2.1<br>
</td>
<td style="vertical-align: top; text-align: center;">04<br>
</td>
<td style="vertical-align: top; text-align: center;">3.0.1<br>
</td>
<td style="vertical-align: top; text-align: center;">1.3.1<br>
</td>
<td style="vertical-align: top; text-align: center;">1.3.1<br>
</td>
<td style="vertical-align: top; text-align: center;">1.3.1<br>
</td>
<td style="vertical-align: top; text-align: center;">1.0.1<br>
</td>
</tr>
<tr>
<td style="vertical-align: top; text-align: right;">May 12th, 2005<br>
</td>
<td style="vertical-align: top; text-align: center;">2.2.2<br>
</td>
<td style="vertical-align: top; text-align: center;">04<br>
</td>
<td style="vertical-align: top; text-align: center;">3.0.2<br>
</td>
<td style="vertical-align: top; text-align: center;">1.3.1<br>
</td>
<td style="vertical-align: top; text-align: center;">1.3.1<br>
</td>
<td style="vertical-align: top; text-align: center;">1.3.1<br>
</td>
<td style="vertical-align: top; text-align: center;">1.0.2<br>
</td>
</tr>
<tr>
<td style="vertical-align: top; text-align: right;">Sept. 13th,
2005<br>
</td>
<td style="vertical-align: top; text-align: center;">2.2.3<br>
</td>
<td style="vertical-align: top; text-align: center;">04<br>
</td>
<td style="vertical-align: top; text-align: center;">3.1.0<br>
</td>
<td style="vertical-align: top; text-align: center;">1.3.1<br>
</td>
<td style="vertical-align: top; text-align: center;">1.3.1<br>
</td>
<td style="vertical-align: top; text-align: center;">1.3.1<br>
</td>
<td style="vertical-align: top; text-align: center;">1.0.2<br>
</td>
</tr>
<tr>
<td style="vertical-align: top; text-align: right;">Nov. 5th, 2005<br>
</td>
<td style="vertical-align: top; text-align: center;">2.2.4<br>
</td>
<td style="vertical-align: top; text-align: center;">04<br>
</td>
<td style="vertical-align: top; text-align: center;">3.1.1<br>
</td>
<td style="vertical-align: top; text-align: center;">1.3.1<br>
</td>
<td style="vertical-align: top; text-align: center;">1.3.1<br>
</td>
<td style="vertical-align: top; text-align: center;">1.3.1<br>
</td>
<td style="vertical-align: top; text-align: center;">1.0.2<br>
</td>
</tr>
<tr>
<td style="vertical-align: top; text-align: right;">Dec. 6th, 2005<br>
</td>
<td style="vertical-align: top; text-align: center;">2.2.5<br>
</td>
<td style="vertical-align: top; text-align: center;">04<br>
</td>
<td style="vertical-align: top; text-align: center;">3.1.2<br>
</td>
<td style="vertical-align: top; text-align: center;">1.3.1<br>
</td>
<td style="vertical-align: top; text-align: center;">1.3.1<br>
</td>
<td style="vertical-align: top; text-align: center;">1.3.1<br>
</td>
<td style="vertical-align: top; text-align: center;">1.0.2<br>
</td>
</tr>
<tr>
<td style="vertical-align: top; text-align: right;">Jan.
19th, 2006<br>
</td>
<td style="vertical-align: top; text-align: center;">2.2.6<br>
</td>
<td style="vertical-align: top; text-align: center;">04<br>
</td>
<td style="vertical-align: top; text-align: center;">3.1.3<br>
</td>
<td style="vertical-align: top; text-align: center;">1.3.1<br>
</td>
<td style="vertical-align: top; text-align: center;">1.3.1<br>
</td>
<td style="vertical-align: top; text-align: center;">1.3.1<br>
</td>
<td style="vertical-align: top; text-align: center;">1.0.3<br>
</td>
</tr>
<tr>
<td style="vertical-align: top; text-align: right;">Feb. 24th, 2006<br>
</td>
<td style="vertical-align: top; text-align: center;">2.2.7<br>
</td>
<td style="vertical-align: top; text-align: center;">04<br>
</td>
<td style="vertical-align: top; text-align: center;">3.1.4<br>
</td>
<td style="vertical-align: top; text-align: center;">1.3.1<br>
</td>
<td style="vertical-align: top; text-align: center;">1.3.1<br>
</td>
<td style="vertical-align: top; text-align: center;">1.3.1<br>
</td>
<td style="vertical-align: top; text-align: center;">1.0.3<br>
</td>
</tr>
<tr>
<td style="vertical-align: top; text-align: right;">Feb. 24th, 2006<br>
</td>
<td style="vertical-align: top; text-align: center;">2.3.0<br>
</td>
<td style="vertical-align: top; text-align: center;">05<br>
</td>
<td style="vertical-align: top; text-align: center;">4.0.0<br>
</td>
<td style="vertical-align: top; text-align: center;">1.4.0<br>
</td>
<td style="vertical-align: top; text-align: center;">1.3.2<br>
</td>
<td style="vertical-align: top; text-align: center;">1.4.0<br>
</td>
<td style="vertical-align: top; text-align: center;">1.1.0<br>
</td>
</tr>
<tr>
<td style="vertical-align: top; text-align: right;">June 26th, 2006<br>
</td>
<td style="vertical-align: top; text-align: center;">2.3.1<br>
</td>
<td style="vertical-align: top; text-align: center;">05<br>
</td>
<td style="vertical-align: top; text-align: center;">4.0.1<br>
</td>
<td style="vertical-align: top; text-align: center;">1.4.0<br>
</td>
<td style="vertical-align: top; text-align: center;">1.3.2<br>
</td>
<td style="vertical-align: top; text-align: center;">1.4.0<br>
</td>
<td style="vertical-align: top; text-align: center;">1.1.0<br>
</td>
</tr>
<tr>
<td style="vertical-align: top; text-align: right;">Oct. 30th, 2006<br>
</td>
<td style="vertical-align: top; text-align: center;">2.3.2<br>
</td>
<td style="vertical-align: top; text-align: center;">05<br>
</td>
<td style="vertical-align: top; text-align: center;">4.0.2<br>
</td>
<td style="vertical-align: top; text-align: center;">1.4.0</td>
<td style="vertical-align: top; text-align: center;">1.3.2</td>
<td style="vertical-align: top; text-align: center;">1.4.0</td>
<td style="vertical-align: top; text-align: center;">1.1.0</td>
</tr>
<tr>
<td style="vertical-align: top; text-align: right;">Feb. 24th, 2007<br>
</td>
<td style="vertical-align: top; text-align: center;">2.3.3<br>
</td>
<td style="vertical-align: top; text-align: center;">05<br>
</td>
<td style="vertical-align: top; text-align: center;">4.1.0<br>
</td>
<td style="vertical-align: top; text-align: center;">1.4.0<br>
</td>
<td style="vertical-align: top; text-align: center;">1.3.2<br>
</td>
<td style="vertical-align: top; text-align: center;">1.4.1<br>
</td>
<td style="vertical-align: top; text-align: center;">1.2.0<br>
</td>
</tr><tr>
<td style="vertical-align: top; text-align: right;">June 30th, 2007<br>
</td>
<td style="vertical-align: top; text-align: center;">2.3.4<br>
</td>
<td style="vertical-align: top; text-align: center;">06<br>
</td>
<td style="vertical-align: top; text-align: center;">4.3.0<br>
</td>
<td style="vertical-align: top; text-align: center;">1.4.0<br>
</td>
<td style="vertical-align: top; text-align: center;">1.3.2<br>
</td>
<td style="vertical-align: top; text-align: center;">1.4.1<br>
</td>
<td style="vertical-align: top; text-align: center;">1.2.0<br>
</td>
</tr><tr>
<td style="vertical-align: top; text-align: right;">Aug. 28th, 2007<br>
</td>
<td style="vertical-align: top; text-align: center;">2.3.5<br>
</td>
<td style="vertical-align: top; text-align: center;">06<br>
</td>
<td style="vertical-align: top; text-align: center;">4.4.0<br>
</td>
<td style="vertical-align: top; text-align: center;">1.4.1<br>
</td>
<td style="vertical-align: top; text-align: center;">1.3.3<br>
</td>
<td style="vertical-align: top; text-align: center;">1.4.2<br>
</td>
<td style="vertical-align: top; text-align: center;">1.2.1<br>
</td>
</tr><tr>
<td style="vertical-align: top; text-align: right;">Sept. 29th, 2007<br>
</td>
<td style="vertical-align: top; text-align: center;">2.3.6<br>
</td>
<td style="vertical-align: top; text-align: center;">06<br>
</td>
<td style="vertical-align: top; text-align: center;">4.4.1<br>
</td>
<td style="vertical-align: top; text-align: center;">1.4.1<br>
</td>
<td style="vertical-align: top; text-align: center;">1.3.3<br>
</td>
<td style="vertical-align: top; text-align: center;">1.4.2<br>
</td>
<td style="vertical-align: top; text-align: center;">1.2.1<br>
</td>
</tr><tr>
<td style="vertical-align: top; text-align: right;">Feb. 10th, 2008<br>
</td>
<td style="vertical-align: top; text-align: center;">2.3.7<br>
</td>
<td style="vertical-align: top; text-align: center;">06<br>
</td>
<td style="vertical-align: top; text-align: center;">4.4.2<br>
</td>
<td style="vertical-align: top; text-align: center;">1.4.2<br>
</td>
<td style="vertical-align: top; text-align: center;">1.3.4<br>
</td>
<td style="vertical-align: top; text-align: center;">1.4.3<br>
</td>
<td style="vertical-align: top; text-align: center;">1.2.2<br>
</td>
</tr><tr>
<td style="vertical-align: top;">
<div style="text-align: right;">June 20th, 2008<br>
</div>
</td>
<td style="vertical-align: top; text-align: center;">2.3.8<br>
</td>
<td style="vertical-align: top; text-align: center;">07<br>
</td>
<td style="vertical-align: top; text-align: center;">4.4.3<br>
</td>
<td style="vertical-align: top; text-align: center;">1.4.2<br>
</td>
<td style="vertical-align: top; text-align: center;">1.3.4<br>
</td>
<td style="vertical-align: top; text-align: center;">1.4.3<br>
</td>
<td style="vertical-align: top; text-align: center;">1.2.2<br>
</td>
</tr><tr>
<td style="vertical-align: top; text-align: right;">May 22nd, 2009<br>
</td>
<td style="vertical-align: top; text-align: center;">2.3.9<br>
</td>
<td style="vertical-align: top; text-align: center;">07<br>
</td>
<td style="vertical-align: top; text-align: center;">4.4.4<br>
</td>
<td style="vertical-align: top; text-align: center;">1.4.2<br>
</td>
<td style="vertical-align: top; text-align: center;">1.3.4<br>
</td>
<td style="vertical-align: top; text-align: center;">1.4.3<br>
</td>
<td style="vertical-align: top; text-align: center;">1.2.2<br>
</td>
</tr><tr>
<td style="vertical-align: top; text-align: right;">April 9th, 2010<br>
</td>
<td style="vertical-align: top; text-align: center;">2.3.10<br>
</td>
<td style="vertical-align: top; text-align: center;">07<br>
</td>
<td style="vertical-align: top; text-align: center;">4.4.5<br>
</td>
<td style="vertical-align: top; text-align: center;">1.4.2<br>
</td>
<td style="vertical-align: top; text-align: center;">1.3.4<br>
</td>
<td style="vertical-align: top; text-align: center;">1.4.3<br>
</td>
<td style="vertical-align: top; text-align: center;">1.2.2<br>
</td>
</tr><tr>
<td style="vertical-align: top;">
<div style="margin-left: 40px; text-align: right;">March 13th, 2011<br>
</div>
</td>
<td style="vertical-align: top; text-align: center;">2.3.11
</td>
<td style="vertical-align: top; text-align: center;">07
</td>
<td style="vertical-align: top; text-align: center;">4.5.0
</td>
<td style="vertical-align: top; text-align: center;">1.4.3
</td>
<td style="vertical-align: top; text-align: center;">1.3.4
</td>
<td style="vertical-align: top; text-align: center;">1.4.3
</td>
<td style="vertical-align: top; text-align: center;">1.2.2
</td>
</tr><tr>
<td style="vertical-align: top; text-align: right;">February 25th, 2012</td>
<td style="vertical-align: top; text-align: center;">2.3.12</td>
<td style="vertical-align: top; text-align: center;">07</td>
<td style="vertical-align: top; text-align: center;">4.5.1</td>
<td style="vertical-align: top; text-align: center;">1.4.3</td>
<td style="vertical-align: top; text-align: center;">1.3.4</td>
<td style="vertical-align: top; text-align: center;">1.4.3</td>
<td style="vertical-align: top; text-align: center;">1.2.2</td>
</tr>
<tr>
<td style="vertical-align: top; text-align: right;">June 2nd, 2011<br>
</td>
<td style="vertical-align: top; text-align: center;">2.4.0</td>
<td style="vertical-align: top; text-align: center;">08</td>
<td style="vertical-align: top; text-align: center;">5.0.0</td>
<td style="vertical-align: top; text-align: center;">1.5.0<br>
</td>
<td style="vertical-align: top; text-align: center;">1.4.0<br>
</td>
<td style="vertical-align: top; text-align: center;">1.5.0<br>
</td>
<td style="vertical-align: top; text-align: center;">1.2.3<br>
</td>
</tr><tr>
<td style="vertical-align: top; text-align: right;">July 21st, 2011<br>
</td>
<td style="vertical-align: top; text-align: center;">2.4.1<br>
</td>
<td style="vertical-align: top; text-align: center;">08<br>
</td>
<td style="vertical-align: top; text-align: center;">5.1.0<br>
</td>
<td style="vertical-align: top; text-align: center;">1.5.0<br>
</td>
<td style="vertical-align: top; text-align: center;">1.4.0<br>
</td>
<td style="vertical-align: top; text-align: center;">1.6.0<br>
</td>
<td style="vertical-align: top; text-align: center;">1.2.3<br>
</td>
</tr><tr>
<td style="vertical-align: top; text-align: right;">Sept. 5th, 2011<br>
</td>
<td style="vertical-align: top; text-align: center;">2.4.2<br>
</td>
<td style="vertical-align: top; text-align: center;">08<br>
</td>
<td style="vertical-align: top; text-align: center;">5.1.1<br>
</td>
<td style="vertical-align: top; text-align: center;">1.5.0<br>
</td>
<td style="vertical-align: top; text-align: center;">1.4.0<br>
</td>
<td style="vertical-align: top; text-align: center;">1.6.0<br>
</td>
<td style="vertical-align: top; text-align: center;">1.2.3<br>
</td>
</tr><tr>
<td style="vertical-align: top; text-align: right;">February 25th, 2012<br>
</td>
<td style="vertical-align: top; text-align: center;">2.4.3<br>
</td>
<td style="vertical-align: top; text-align: center;">08<br>
</td>
<td style="vertical-align: top; text-align: center;">5.2.0<br>
</td>
<td style="vertical-align: top; text-align: center;">1.5.0</td>
<td style="vertical-align: top; text-align: center;">1.4.0</td>
<td style="vertical-align: top; text-align: center;">1.7.0<br>
</td>
<td style="vertical-align: top; text-align: center;">1.2.3<br>
</td>
</tr><tr>
<td style="vertical-align: top; text-align: right;">March 17th, 2012<br>
</td>
<td style="vertical-align: top; text-align: center;">2.4.4<br>
</td>
<td style="vertical-align: top; text-align: center;">08<br>
</td>
<td style="vertical-align: top; text-align: center;">5.2.1<br>
</td>
<td style="vertical-align: top; text-align: center;">1.5.0<br>
</td>
<td style="vertical-align: top; text-align: center;">1.4.0<br>
</td>
<td style="vertical-align: top; text-align: center;">1.7.1<br>
</td>
<td style="vertical-align: top; text-align: center;">1.2.3<br>
</td>
</tr><tr>
<td style="vertical-align: top; text-align: right;">April 15th, 2012<br>
</td>
<td style="vertical-align: top; text-align: center;">2.4.5<br>
</td>
<td style="vertical-align: top; text-align: center;">08<br>
</td>
<td style="vertical-align: top; text-align: center;">5.2.2<br>
</td>
<td style="vertical-align: top; text-align: center;">1.5.1<br>
</td>
<td style="vertical-align: top; text-align: center;">1.4.1<br>
</td>
<td style="vertical-align: top; text-align: center;">1.7.2<br>
</td>
<td style="vertical-align: top; text-align: center;">1.2.4<br>
</td>
</tr>
</tbody>
</table>
<br>
<hr style="width: 100%; height: 2px;"><br>
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