<html> <head> <meta http-equiv="content-type" content="text/html; charset=UTF-8"> <title>dvdisaster</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"> <font size="+3"><b>dvdisaster</b></font> <i>Version 0.72 (pl1)</i> </td> <td align="right"> <font size="+3"> </font><a href="http://dvdisaster.net/en/">To the Internet version</a> <a href="../de/index20.html"></a> <a href="../ru/index20.html"></a> </td> </tr> </table> <!--- Language chooser or separator ---> <table width="100%" cellpadding="0" border="0"> <tr bgcolor="#000000"> <td colspan="2" width="100%"><img width=1 height=1 alt=""></td> </tr> <tr><td colspan="2" width="100%" height="10"> <img width=1 height=1 alt=""> </td></tr> </table> <!--- Main body (Navigation, actual page content, optional news column) ---> <table width="100%" cellspacing=0> <tr> <!--- Navigation ---> <td bgcolor="#f0f0f0" valign="top" width="20%"> <table width="100%" cellpadding="10"> <tr> <td> <font size="-1"><b>Contents</b></font> <table width="100%" cellpadding="0" cellspacing="0"> <tr bgcolor="#000000"> <td width="100%"><img width=1 height=1 alt=""></td> </tr> </table><p> <table width="100%"> <tr><td colspan=3><font size="-1"><a href="news.html">News</a></font></td></tr> <tr><td></td><td></td><td height="10"></td></tr> <tr><td colspan=3><font size="-1"><a href="index.html">Overview</a></font></td></tr> <tr><td valign="top" width="1%">·</td><td colspan=2><font size="-1"><a href="index10.html">Examples of the error correction</a></font></td></tr> <tr><td valign="top" width="1%">·</td><td colspan=2><font size="-1">dvdisaster complements quality scans</font></td></tr> <tr><td valign="top" width="1%">·</td><td colspan=2><font size="-1"><a href="index30.html">Pro and con of dvdisaster</a></font></td></tr> <tr><td></td><td></td><td height="10"></td></tr> <tr><td colspan=3><font size="-1"><a href="howtos.html">Howtos</a></font></td></tr> <tr><td></td><td></td><td height="10"></td></tr> <tr><td colspan=3><font size="-1"><a href="download.html">Download</a></font></td></tr> <tr><td></td><td></td><td height="10"></td></tr> <tr><td colspan=3><font size="-1"><a href="qa.html">Questions and Answers</a></font></td></tr> <tr><td></td><td></td><td height="10"></td></tr> <tr><td colspan=3><font size="-1"><a href="feedback.html">Bug reporting</a></font></td></tr> </table> </td> </tr> </table> </td> <td></td> <!--- Actual page contents ---> <td valign="top" width="77%" rowspan="2"> <!--- Insert actual page content below ---> <h3>dvdisaster as a complement to quality scans</h3> <a href="qa.html#pipo">Quality scans</a>, e.g. C2 error or PI/PO scans are a valuable tool for testing the results of the media writing process.<p> But quality scans are <b>not</b> a reliable means of <b>predicting the lifetime</b> of optical media. <br> Consider we are looking for the right time to copy a worn-out medium onto a new one: <ul> <li>Too early: Copying media because of a bad quality scan is cost-ineffective. Sometimes such media remain readable much longer than expected.<p></li> <li>Too late: When the quality scan reveals unreadable sectors some data has already been lost.<p></li> <li>Right before the medium fails: The ideal case, but how to tell? </ul> However, we could do it the dvdisaster way: <ul> <li><a href="howtos20.html">Create error correction data</a> for the medium.<p></li> <li><a href="howtos10.html">Scan the medium</a> regularly. Use it until the first read errors occur.<p></li> <li><a href="howtos40.html">Recover</a> the read errors <a href="howtos40.html">using the error correction data</a>. Write the recovered image to a new medium.</li> </ul> <p> <a href="index30.html">Pro and con of dvdisaster at a glance...</a> <!--- do not change below ---> </td> <!--- end of page contents ---> </tr> <tr valign="bottom"> <td bgcolor="#f0f0f0"> <table cellpadding="10"><tr><td><a href="http://dvdisaster.net/legacy/en/index.html"><font size="-1">Old documentation (V0.70)</font></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" width="100%" height="10"><img width=1 height=1 alt=""></td> </tr> <tr bgcolor="#000000"><td colspan="2" width="100%"><img width=1 height=1 alt=""></td> </tr> <tr> <td align="center"> <font size="-1"> <i> Copyright 2004-2009 Carsten Gnörlich.<br> Verbatim copying and distribution of this entire article is permitted in any medium, provided this notice is preserved. </i> </font> </td> </tr> <tr bgcolor="#000000"><td colspan="2" width="100%"><img width=1 height=1 alt=""></td> </tr> </table> </body> </html>