From mboxrd@z Thu Jan  1 00:00:00 1970
Message-ID: <927fb5452b4655606d7ee06a84f40811@collyer.net>
To: 9fans@cse.psu.edu
Subject: Re: [9fans] Don't know much about history
From: Geoff Collyer <geoff@collyer.net>
Date: Wed, 30 Jun 2004 20:57:50 -0700
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The Interdata was odd.  I first tried to implement my interrupt
queuing scheme for changing fixed interrupt priorities (see the
Computing Systems paper) on one running Edition VII.  The machine
maintained a queue of pending interrupts in main memory.  Even with
the processor manual and the source code to Edition VII, I couldn't
get it to do what I wanted correctly.  I suspect that there was
something very subtle and not quite documented about the machine.  (I
did get my interrupt queuing scheme to work on the AMD 29200, another
odd machine.)  Steve Johnson has commented (see A Quarter Century of
UNIX) that he and dmr tried to get Interdata to fix various bugs that
they tripped across in their Unix port, without success.