Attachment filesystem
 

In the root of my /attachments directory* I have a few files that are named as nothing more than a hash* a few thousand named as a hash with a .file extension* and many thousands more that are named numerically in a series of subfolders like this: /attachments/1/5/4/9/3293.attach

Could anyone explain to me how the information in the attachment table is used to locate the associated physical file? I don't see an obvious pattern and am trying to avoid tracing the whole thing back through the attachment.php file. Thanks :)