RD53s are always good for a discus throw.  Other than that, worthless.
RD54s are much more reliable.
  -----Original Message-----
 From: cctalk-bounces at 
classiccmp.org
 [mailto:cctalk-bounces at 
classiccmp.org] On Behalf Of Tobias Russell
 Sent: Tuesday, October 10, 2006 3:00 PM
 To: cctalk at 
classiccmp.org
 Subject: RD53s and RD54s
 Hi,
 I've decided after many years of accumulating PDP-11s that
 the time has come to restore a few of them to operational
 condition. I've decided to start with some QBUS machines as
 they give me the best chance of a warm fuzzy feeling of success.
 The first thing I've decided to do was to retrieve all of my
 RD series harddisks and establish which ones are still
 operational. I've initially started with 4 RD53s and 4 RD54s
 which I've connected upto an 11/73 and used XXDP to format.
 All RD54s have formatted perfectly, confirming their
 reputation for reliability. However none of the RD53s would
 format, which I guess also backs up their reputation. I had
 hoped at least a few of the RD53s would have still been
 usable (I have about 6 more I've not tested yet).
 Does anyone have a RD53 still in working condition? Is there
 any point in keeping the duff drives or should I consign them
 to the skip?
 Toby
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