<story><title>Restoring YC&apos;s Xerox Alto: how our boot disk was trashed with random data</title><url>http://www.righto.com/2016/09/restoring-ycs-xerox-alto-how-our-boot.html</url></story><parent_chain></parent_chain><comment><author>russellsprouts</author><text>The shift-xor &amp;quot;random&amp;quot; number generator described actually has an interesting property. The algorithm looks like this:&lt;p&gt;1. If the value is 0, output the magic number.&lt;p&gt;2. If the value has only its high bit set, output 0.&lt;p&gt;3. Otherwise, shift the value to the left&lt;p&gt;4. if there was an overflow (the high bit was 1 before the shift), xor the value by a magic constant.&lt;p&gt;For certain values of the magic constant, this has the property of generating every integer in the range exactly once.</text></comment>
<story><title>Restoring YC&apos;s Xerox Alto: how our boot disk was trashed with random data</title><url>http://www.righto.com/2016/09/restoring-ycs-xerox-alto-how-our-boot.html</url></story><parent_chain></parent_chain><comment><author>vcarl</author><text>I love these posts. I don&amp;#x27;t properly understand the majority of what&amp;#x27;s being done, but a step by step of somebody solving a difficult problem in a space I know nothing about is so fascinating.</text></comment>