Date   : Fri, 26 Jul 1985 17:40:45 EDT (Friday)
From   : Jim Reno <Reno.wbst@XEROX.ARPA>
Subject: Re: using both side of disks

 Back in 1975 or 76 when true double sided disks were just new I ordered
some "two" sided disks and received what I didn't want. I got a disk
with two cutouts for both index and write protect holes presumably
certified for both sides.
  The one disturbing thing about a disk like this in my mind has to do
with the purpose of the disk cover itself. If I am not mistaken
considerable effort goes into the design of the cover to promote its
ability to clean particles off the disk media. I believe this function
is unidirectional and note that when flipped the disk will be spinning
in the opposite direction with respect to the cover.

Reno