61 lines
2.5 KiB
HTML
61 lines
2.5 KiB
HTML
<html>
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<head>
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<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
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<link rel="stylesheet" href="style.css">
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<title>Design recovery files</title>
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</head>
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<body>
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<font size=5>How to design the recovery files</font><br><font size=1><br></font> 
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After selecting source files, you design how the recovery files will become.
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<hr>
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<h3>How much redundancy you need</h3>
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<p> 
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The most important setting in creating recovery files is "<b>Redundancy</b>".
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As you set more redundancy, it will be possible to repair,
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but more time and space are required.
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The required quantity depends on your circumstance;
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like error rate of the saving drive or reliability of the network.
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If you create as an insurance against rare incident, 5% or 10% may be enough.
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If you get error often, you may require more, such as 30% or 50%.
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If you want to protect seriously, backup source files and create recovery files.
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</p>
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<p> 
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A whole file is lost by a human mistake like careless deletion or forgotten transport.
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In this case, the problem is whether you have enough redundancy to reconstruct the whole file.
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The measure is "<b>Number of files that can be fully reconstructed if missing</b>" on the bottom of Create window.
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The "<b>Min - Max</b>" means that, how many files you can repair at least min and under than max.
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The min should be 1 or more for safety.
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</p>
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<h3>How is the efficiency</h3>
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<p> 
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There is a measure of recovering capability,
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that is "<b>Efficiency</b>" on the bottom of Create window.
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Unless you have a trouble to keep saving space,
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you don't need to take care usually.
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When there is a big difference between settings,
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you would better to select a efficient way,
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but you can ignore small difference like several percent.
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Because the possibility of repair is largely varied by distribution of damage,
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it is worthless to aim for the best efficiency.
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</p>
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<hr>
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<h3>If you post the recovery files on UseNet</h3>
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<p> 
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On Option window,
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it is important to set <a href="option2.htm#unit_size">the unit of blocks</a> for UseNet.
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Though it depends on the server, mostly it is "For yEnc: 3,000 lines" or "For yEnc: 5,000 lines".
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No need to change other settings.
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If you want smaller recovery files,
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you may limit <a href="option3.htm#packet_repetition">repetition of packets</a> by selecting "<b>Upto 4 times</b>".
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On Create window, you should select "<b>Powers of 2 sizing scheme</b>" at "Sizing scheme".
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</p>
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</body>
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</html>
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