PDP-11/45 RSTS/E boot problem

Peter Coghlan cctalk at beyondthepale.ie
Fri Feb 15 18:00:44 CST 2019

Liam Proven wrote:
> And some of my younger colleagues thought it was strange that I could
> predict hard disk failures from the running noises they made, and
> later than that, whether WinNT's bus-mastering DMA-mode disk
> controller device driver was installed from the sound of the disk
> accesses while the machine booted.

The little 8GB SCA system disk in my Alphaserver 800 started making
awful bloodcurdling clattering noises a few years ago.  The first time
I heard it, I was convinced that the works were splattered all over the
inside of the HDA casing and the machine was only continuing to run
because of what was left in the disk cache or something like that.  I
started running a backup in case I might be able to salvage some part of
the contents.  Despite several more heartstopping clunks and clatters
while the backup was running, it ran to completion, with no errors logged
to my complete surprise.  I ran an ANALYZE /DISK /READ which attempts to
read all blocks on the disk that are allocated to files.  Again, several
more awful clanks and clatters but it completed with no errors.  I lined
up a replacement disk for it but I was curious to see how exactly it
was going to fail so I decided to keep on using it for a while to see
what happens.  Days turned into weeks, weeks into months and months into
years.  It continued to occasionally make the same ghastly noises that
never should be heard coming from a hard disk but with absolutely no sign
of any errors being logged or damage to data whatsoever.  The noises seem
to be associated with seek activity because I have never heard them when
the disk is just spinning but otherwise idle.  I eventually retired it
and replaced it with a much larger one, purely because I ran out of
space on it.  Any thoughts on what might be happening with it?

Peter Coghlan.

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