<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<title>with error correction files</title>
<link rel="stylesheet" type="text/css" href="../include/dvdisaster.css">
</head>
<body>
<!-- Title header -->
<table width="100%" cellpadding="0" border="0">
<tr>
<td align="left">
<span class="fxxl"><b>dvdisaster</b></span>
<i>Version 0.72.4 / 0.72 (pl4)</i>
</td>
<td align="right">
<span class="fxxl"> </span><a href="http://dvdisaster.net/en/">To the Internet version</a>
<a href="../cs/howtos91.html"></a>
<a href="../de/howtos91.html"></a>
<a href="../ru/howtos91.html"></a>
</td>
</tr>
</table>
<!-- Language chooser or separator -->
<table width="100%" cellpadding="0" border="0">
<tr>
<td colspan="2" class="hsep"></td>
</tr>
<tr><td colspan="2" style="height: 10px">
</td></tr>
</table>
<!-- Main body (Navigation, actual page content, optional news column) -->
<table width="100%" cellspacing=0>
<tr>
<!-- Navigation -->
<td style="background-color:#f0f0f0; vertical-align:top; width:20%;">
<table width="100%" cellpadding="10">
<tr>
<td>
<span class="fs"><b>Contents</b></span>
<table width="100%" cellpadding="0" cellspacing="0">
<tr>
<td class="hsep"></td>
</tr>
</table><p>
<table width="100%">
<tr><td colspan=3><span class="fs"><a href="news.html">News</a></span></td></tr>
<tr><td></td><td></td><td style="height:10px;"></td></tr>
<tr><td colspan=3><span class="fs"><a href="index.html">Overview</a></span></td></tr>
<tr><td></td><td></td><td style="height:10px;"></td></tr>
<tr><td colspan=3><span class="fs"><a href="howtos.html">Howtos</a></span></td></tr>
<tr><td style="width:1%; vertical-align:top;">·</td><td colspan=2><span class="fs"><a href="howtos60.html">The big picture</a></span></td></tr>
<tr><td style="width:1%; vertical-align:top;">·</td><td colspan=2><span class="fs"><a href="howtos10.html">Scanning media for errors</a></span></td></tr>
<tr><td style="width:1%; vertical-align:top;">·</td><td colspan=2><span class="fs"><a href="howtos20.html">Putting error correction data on a separate file</a></span></td></tr>
<tr><td style="width:1%; vertical-align:top;">·</td><td colspan=2><span class="fs"><a href="howtos30.html">Putting error correction data on the medium</a></span></td></tr>
<tr><td style="width:1%; vertical-align:top;">·</td><td colspan=2><span class="fs"><a href="howtos40.html">Recovering media images</a></span></td></tr>
<tr><td style="width:1%; vertical-align:top;">·</td><td colspan=2><span class="fs"><a href="howtos50.html">Getting information about images and error correction data</a></span></td></tr>
<tr><td style="width:1%; vertical-align:top;">·</td><td colspan=2><span class="fs"><a href="howtos90.html">Testing image compatibility</a></span></td></tr>
<tr><td></td><td style="vertical-align:top; font-size:small;">-</td><td><span class="fs">with error correction files</span></td></tr>
<tr><td></td><td style="vertical-align:top; font-size:small;">-</td><td><span class="fs"><a href="howtos92.html">when augmenting images with error correction data</a></span></td></tr>
<tr><td style="width:1%; vertical-align:top;">·</td><td colspan=2><span class="fs"><a href="howtosa0.html">Dialogs and buttons</a></span></td></tr>
<tr><td></td><td></td><td style="height:10px;"></td></tr>
<tr><td colspan=3><span class="fs"><a href="download.html">Download</a></span></td></tr>
<tr><td></td><td></td><td style="height:10px;"></td></tr>
<tr><td colspan=3><span class="fs"><a href="qa.html">Questions and Answers</a></span></td></tr>
<tr><td></td><td></td><td style="height:10px;"></td></tr>
<tr><td colspan=3><span class="fs"><a href="feedback.html">Bug reporting</a></span></td></tr>
</table>
</td>
</tr>
</table>
</td>
<td></td>
<!-- Actual page contents -->
<td style="vertical-align:top; width:77%;" rowspan="2">
<!-- Insert actual page content below -->
<h3 class="top">Testing compatibility between error correction files and ISO images</h3>
<b>Motivation:</b> You want to write data to a medium and create an
error correction file for it. In order to save time you do the following:
<ol>
<li>You create an ISO image using your CD/DVD/BD writing software.</li>
<li>You write the image to a medium.</li>
<li>You create the error correction file from the same image.</li>
</ol>
<b>Possible incompatibility:</b> The writing software creates a medium
which does not exactly match the image. This might prevent the error
correction from recovering the medium contents when it becomes defective.
<p>
<b>How to test compatibility:</b><p>
Please note that some steps are only sketched out here;
follow the links to the respective sections to find detailed instructions
and examples.<p>
<table>
<tr>
<td class="w200x" align="center"><img src="../images/good-image.png" alt="Icon: Complete image">
<p><img src="../images/down-fork-arrow.png" alt="Icon: Forked arrow"></td>
<td> </td>
<td class="valignt"><b>Create an ISO image of the data</b> you want
to write on the medium. If you need help on creating ISO images
please refer to the
<a href="howtos33_way=1.html">example of creating ISO images</a>.
</td>
</tr>
</table>
<table>
<tr>
<td class="w100x" align="center">
<img src="../images/good-cd.png" alt="Icon: Good medium (without read errors)" class="nobordervalignm"><p>
<img src="../images/down-arrow.png" alt="Icon: Arrow down" class="noborder">
</td>
<td class="w100x" align="center" valign="top">
<img src="../images/ecc.png" alt="Icon: Separate file with error correction data" class="nobordervalignm">
</td>
<td> </td>
<td class="valignt"><b>Write the medium and create the error correction file.</b>
Use the just created image to
<a href="howtos33_way=3.html#c">write the medium</a>.
Then perform these <a href="howtos22.html#ecc">basic settings</a> and
<a href="howtos23_way=2.html">create an error correction file</a>
from the image.
</td>
</tr>
</table>
<table>
<tr>
<td class="w100x" align="center">
<img src="../images/good-image2.png" alt="Icon: Complete image from the previously written medium" class="noborder"><p>
<img src="../images/down-arrow.png" alt="Icon: Arrow down" class="noborder">
</td>
<td class="w100x" align="center"> </td>
<td> </td>
<td class="valignt"><b>Create a <i>second</i> image from the <i>written</i>
medium.
</b> Use these <a href="howtos22.html#read">settings</a>
and read the medium as described
in <a href="howtos23_way=1.html">creating an image</a>
for making an error correction file. However you can stop the walk-through
when the reading is finished as we do not need to create the error
correction file again.
</td>
</tr>
</table>
<table>
<tr>
<td class="w200x" align="center">
<a href="howtosa2.html">
<img src="../images/select-image.png" alt="dvdisaster UI: Image file selection (input field and button)" class="noborder">
<br><img src="../images/down-arrow.png" alt="Icon: Arrow down" class="noborder"></a></td>
<td> </td>
<td class="valignt"><b>Enter the name of the <i>second</i> ISO image</b>
which you have just read from the medium. Please note that the following
test is useless when working with the image which was initially created
using the CD/DVD/BD authoring software.
</td>
</tr>
</table>
<table>
<tr>
<td class="w200x" align="center">
<a href="howtosa3.html">
<img src="../images/select-ecc.png" alt="dvdisaster UI: Error correction file selection (input field and button)" class="noborder">
<br><img src="../images/down-arrow.png" alt="Icon: Arrow down" class="noborder"></a></td>
<td> </td>
<td class="valignt">
<b>Enter the name of the error correction file</b>
in case it is not already present from the previous actions.
</td>
</tr>
</table>
<table>
<tr>
<td class="w200x" align="center">
<a href="howtosa4.html">
<img src="images/compare-icon.png" alt="dvdisaster UI: Verify (button)" class="noborder">
<br><img src="../images/down-arrow.png" alt="Icon: Arrow down" class="noborder"></a></td>
<td> </td>
<td class="valignt"><b>Start the evaluation</b> by clicking
on the "Verify" button.</td>
</tr>
</table>
<!-- begin of screen shot -->
<table>
<tr>
<td class="w200x" align="center">
<a name="snap1"></a>
<a href="howtos91_expand=1.html#snap1"> <img src="thumbnails/compat-okay-rs01.png" alt="" class="noborder">
</a>
</td><td> </td>
<td class="valignt">
<b>Look at the verification results.</b>
If you get the green messages "Good image." and "Good error correction file."
your authoring software and dvdisaster are compatible. You can continue
creating the error correction files directly from the ISO images produced
by the authoring software.
</td>
</tr>
</table><p>
<!-- end of screen shot -->
<hr>
<a name="err"> </a>
<b>Possible error causes and remedy:</b><p>
<!-- begin of screen shot -->
<table>
<tr>
<td class="w200x" align="center">
<a name="snap2"></a>
<a href="howtos91_expand=2.html#snap2"> <img src="thumbnails/compat-150-rs01.png" alt="" class="noborder">
<br><img src="../images/down-arrow.png" alt="" class="noborder">
</a>
</td><td> </td>
<td class="valignt">
<b>Typical problem: wrong image size.</b>
The verification may find out that the image is larger as expected.
Typically the difference is 150 or 300 sectors for CD media and
1-15 sectors for DVD/BD media. These might simply be zero padding sectors
appended by the writing software. To find out if this really is the case
do the following:
</td>
</tr>
</table><p>
<!-- end of screen shot -->
<table>
<tr>
<td class="w200x" align="center">
<img src="images/fix-icon.png" alt="dvdisaster UI: Fix (button)" class="noborder">
<p><img src="../images/down-arrow.png" alt="Icon: Arrow down" class="noborder"></td>
<td> </td>
<td class="valignt"><b>Start a recovery process.</b>
</td>
</tr>
</table>
<!-- begin of screen shot -->
<table>
<tr>
<td class="w200x" align="center">
<a name="snap3"></a>
<a href="howtos91_expand=3.html#snap3"> <img src="thumbnails/compat-dialog-rs01.png" alt="" class="noborder">
<br><img src="../images/down-arrow.png" alt="" class="noborder">
</a>
</td><td> </td>
<td class="valignt">
<b>Confirm the dialog.</b>
A dialog will appear asking you if it is okay to remove the superflous
sectors from the image. Answer "OK".
</td>
</tr>
</table><p>
<!-- end of screen shot -->
<table>
<tr>
<td class="w200x" align="center">
<img src="images/stop-icon.png" alt="dvdisaster UI: Stop (button)" class="noborder">
<p><img src="../images/down-arrow.png" alt="Icon: Arrow down" class="noborder"></td>
<td> </td>
<td class="valignt"><b>Stop the recovery process,</b>
as after truncating the image there is nothing more to do.
</td>
</tr>
</table>
<table>
<tr>
<td class="w200x" align="center">
<a href="howtosa4.html">
<img src="images/compare-icon.png" alt="dvdisaster UI: Verify (button)" class="noborder">
<br><img src="../images/down-arrow.png" alt="Icon: Arrow down" class="noborder"></a></td>
<td> </td>
<td class="valignt"><b>Start the verification again</b>
by clicking on the "Verify" button.</td>
</tr>
</table>
<!-- begin of screen shot -->
<table>
<tr>
<td class="w200x" align="center">
<a name="snap4"></a>
<a href="howtos91_expand=4.html#snap4"> <img src="thumbnails/compat-okay-rs01.png" alt="" class="noborder">
</a>
</td><td> </td>
<td class="valignt">
<b>Consider the new results.</b>
If you now get the green messages "Good image." and "Good error correction
file." your problem is purely cosmetic: The writing software has indeed
added zero padding sectors while writing the medium.
</td>
</tr>
</table><p>
<!-- end of screen shot -->
<span class="red">If the problem persists after carrying out the above
steps do <i>not</i> assume that dvdisaster and the writing software
are compatible. The created error correction files will probably be
unusable.</span> <p>
Use the following method for creating the error correction files instead:
<hr>
<pre> </pre>
<b>Alternative method avoiding incompatibilities:</b>
<ol>
<li>First write the data to the medium.</li>
<li>Use dvdisaster to create an ISO image from the written medium.</li>
<li>Use this image to create the error correction file.</li>
</ol>
This method takes more time due to the additional reading process,
but it also has the advantage of testing the newly created
medium for readability.
<!-- do not change below -->
</td> <!-- end of page contents -->
</tr>
<!--
<tr valign="bottom">
<td style="background-color:#f0f0f0;">
<table cellpadding="10"><tr><td><a href="http://dvdisaster.net/legacy/en/index.html"><span class="fs"></span></a></td></tr></table>
</td>
<td></td>
<td></td>
</tr>
-->
</table> <!-- end of main body table -->
<!-- Page footer -->
<table width="100%" cellpadding="0" border="0">
<tr><td colspan="2" style="width:100%; height:10px;"></td>
</tr>
<tr><td colspan="2" class="hsep"></td>
</tr>
<tr>
<td align="center">
<span class="fs">
<i> Copyright 2004-2012 Carsten Gnörlich.<br>
Verbatim copying and distribution of this entire article is permitted in any medium, provided this notice is preserved.
</i>
</span>
</td>
</tr>
<tr><td colspan="2" class="hsep"></td>
</tr>
</table>
</body>
</html>
