title: Why use hashing to create pathnames for large collections of files?
body: <p>I noticed a number of cases where an application or database stored collections of files/blobs using a has to determine the path and filename. I believe the intended outcome is a situation where the path never gets too deep, or the folders ever get too full - too many files (or folders) in a folder making for slower access. </p>
  
  <p>EDIT: Examples are often Digital libraries or repositories, though the simplest example I can think of (that can be installed in about 30s) is the <a href="http://zotero.org" rel="nofollow noreferrer">Zotero document/citation database.</a> </p>
  
  <p>Why do this? </p>
  
  <p>EDIT: thanks Mat for the answer - does this technique of using a hash to create a file path have a name? Is it a <em>pattern</em>? I'd like to read more, but have failed to find anything in the <a href="http://portal.acm.org/portal.cfm" rel="nofollow noreferrer">ACM Digital Library</a></p>