[evla-sw-discuss] [Fwd: CMIB solution?]

[Bill Sahr]

-------- Original Message --------
Subject: CMIB solution?
Date: Thu, 13 Dec 2001 10:27:04 -0800
From: B Carlson <Brent.Carlson at hia.nrc.ca>
Organization: National Research Council of Canada
To: bsahr <bsahr at cv3.cv.nrao.edu>

Hi Bill:

I've been looking at possible solutions to the CMIB (Correlator MIB),
and I've
been pointed to this little CPU module.  This module can be used as a
standalone
mezzanine card, or plugs into a PC/104+ carrier module so it is PC/104+
compliant.  I'm starting to become really attracted to the PC/104+
standard
since it is cheap, high-performance, can run Linux or VxWorks (and
apparently
the VxWorks target licenses for these modules are really inexpensive)
and lots
of manufacturers make them so you are never locked into one.  I'm
leaning toward
Linux since the module then just looks like a Linux box with a file
system on
its "disk on a chip", rlogin etc.  Code can be developed on your desktop
(in
fact, one could almost start writing code right now!), and then the
binaries are
just copied to the embedded module's disk on a chip, and invoked using
standard
Unix-style multiprocessing calls.  The only thing is that on the Station
Board,
we would need an ISR.  The module has multiple IRQ lines and we would
have to
make sure Linux doesn't do anything goofy to turn off the IRQ.  I
believe there
are real-time extensions of Linux that handle these sorts of things.

In a way, a PC/104+ module is the embedded "analog" of what we want to
do with
other computer systems.  Namely that we use throw-away COTS equipment
that can
be easily replaced with the latest thing since the software is always
loosely
coupled to the hardware.

I was thinking that at least the 586 core module may be attractive for
the
antenna MIB (I think its about $110 each in 1000 quantity), and then on
each
carrier card you put the needed A/D converters etc. etc.  Of course, you
could
do the PC/104+ thing and then any manufacturer's module could be used. 
If you
ran Linux, then its really generic.  All of the binaries for various
flavours of
antenna boards that this thing plugs into reside on the module's disk on
a chip,
and then the antenna control computer just starts up the one it wants. 
This
gets around the problem of having to have many flavours of the MIB, if
it is
desired to put more intelligence into the antenna MIB than you are
currently
thinking.

Just some thoughts,
Brent.

>
> Please visit this web link for more details on this board,
> http://www.compulab-systems.com/586core.htm
>
>