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Date: Fri, 16 Apr 93 13:37:12 -0400
From: munck@STARS.Reston.Paramax.COM
Subject: Re: Ada Law -- the EMSP Exemption
Message-ID: <18975.734981832@blackbird>
List-Id: <comp.lang.ada>

In V93 #221, Mike Feldman quotes a DoD Appropriation Conf. Report
paragraph on the use of Ada.  One sentence caught my eye:

"The Committee directs that applications using or currently planning to
use the Enhanced Modular Signal Processor (EMSP) be exempted from
mandatory use of Ada as a matter of policy."

I've had to do with the EMSP program at various times in the last decade
while working for SofTech, NRL, and MITRE.  At SofTech, we did a project
for the AN/UYS-1 called ACOS that evolved into ECOS for the EMSP, which
I believe is also called AN/UYS-2.  The last I heard, Bell Labs was
moving into production of the hardware, but another large DoD contractor
was fighting the project tooth and nail.

EMSP has the interesting property of being programmed in data flow
diagrams, which are compiled (assembled?) into an internal form and then
actually executed.  The hardware consists of a number of fairly powerful
general-purpose processors (68K's), a number of specialized I/O
processors, memory modules (up to a gigabye of RAM, with a little
processor to move data around), and specialized signal processors that
are each a 4-CPU SIMD microprogrammed to execute various signal
processing primitive operations such as FFT.  All of these devices are
interconnected by a NxN crosspoint switch with large buffers.  One of
the GP processors executes the DFD by sending commands to the other
processors and the crosspoint to move data around and execute operations
on it as appropriate.  The operations in the DFD would mostly be the
microprogrammed operations on the SIMD machines, but could also be
programs on the GP and I/O processors.  User interaction and displays
are handled by GPs.

So what does this have to do with Ada, or an exemption from Ada?  Well,
the DFD's definitely aren't Ada, and that's really how it is programmed.
(In previous generations, the acoustical engineers produced DFDs and
gave them to a building-full of programmers to implement.  Eliminating
that step angered the contractor that employed the programmers.)  The SP
primitives likewise aren't Ada, but rather an esoteric register-transfer
language, but there aren't very many primitives.  The GP processors are
meant to be programmed in Ada; that decision was made around 1981.

The Ada exemption sentence was probably included by Congress because of
the DFD programming, but it's really an indication of the level to which
the Large Contractor has taken the fight against this architecture.  I
would hope that the Ada requirement would not have a chilling effect on
R&D in this and other exotic hw/sw arrangements.

BTW, I recently saw a short article about how Bell Labs ASW technology
is being used in traffic control; it was titled "The Hunt for Red
Toyota."  I'd hate to be caught speeding as a result of my deep-seated
dislike of submarines.

Bob Munck