FPGA VAX update (CDC song)

[Paul Koning]

>>>>> "J" == J C Wren <J.C.> writes:

 J> Do you remember the CDC song?  "I/O, I/O, it's off to disk we go!
 J> Put CIO in RA+1, I/O, I/O..."

Eek.

It's amazing to me that still to this day lots of people do not know
that circular buffers are the way to do inter-processor communication
without interlocking.  For example, RTLinux did (perhaps still does)
have to disable interrupts for its IPC, because it uses queue
structures that aren't interrupt-safe, rather than CIO style buffers
that are.  In systems like that, the penalty for not knowing the right
technology is pretty steep.

     paul