LISTSERV mailing list manager LISTSERV 16.0

Help for TEAM-ADA Archives


TEAM-ADA Archives

TEAM-ADA Archives


TEAM-ADA@LISTSERV.ACM.ORG


View:

Message:

[

First

|

Previous

|

Next

|

Last

]

By Topic:

[

First

|

Previous

|

Next

|

Last

]

By Author:

[

First

|

Previous

|

Next

|

Last

]

Font:

Proportional Font

LISTSERV Archives

LISTSERV Archives

TEAM-ADA Home

TEAM-ADA Home

TEAM-ADA  November 2004

TEAM-ADA November 2004

Subject:

Re: If You Can't Beat Them, Join Them

From:

Roger Racine <[log in to unmask]>

Reply-To:

[log in to unmask]

Date:

Fri, 19 Nov 2004 10:45:50 -0500

Content-Type:

text/plain

Parts/Attachments:

Parts/Attachments

text/plain (104 lines)

On Fri, 2004-11-19 at 03:56, Paul Colin Gloster wrote:
> On Thu, Nov 18, 2004 at 08:12:42AM -0500, Roger Racine wrote:
> "[..]
>
> What does Java have that Ada doesn't?  [..]"
>
> Inheritance anomalies. Nondeterminism. Incompatible attempts at JVMs
> implemented by Sun as reported in an attempt at a VHDL grammar with
> JavaCC.
>
And who cares?  It is still -thought to be- easier to create an
application when there are all those libraries of classes out there.
>
> 1) Graphical approaches for flight control applications.  Controls
> engineers have written their algorithms in diagrams since the 60s.  If
> those diagrams can be automatically made into code, it saves a fair amount
> of effort.  Thus, Simulink, Matlab, etc."
>
> Hardware design matured from unwieldly CAD schematics to text-like VHDL
> and Verilog.
>

I won't argue with you, except to say that the controls engineers I work
with love their diagrams.

> "2) Libraries.  For guidance, navigation, and other applications that work
> in floating point (science applications in general), Matlab is an excellent
> example of an excellent design environment.  Why?  Because it has a large
> number of tools available to analyze the data coming out of the
> program.  It is essentially a great code completion editor, compiler, and
> debugger in one integrated tool.  It completes code by adding data
> declarations (I have never met a GN&C engineer who liked to declare their
> variables. "They are all double precision floating point anyway; why can't
> the system create them for me").  It takes the code ("M" files, in a
> proprietary programming language) and compiles it.  And then the debugger
> allows the code to be executed using all sorts of data analysis routines.
>
> [..]"
>
> MATLAB is extremely weakly typed: I have seen someone with a doctorate who
> annually lectures the same material in digital signal processing
> accidentally let MATLAB (which provides no help in resolving the matter)
> perform a one dimensional Fast Fourier Transform on a two dimensional
> array which needed a 2D

Again, no argument except to say it is not keeping anyone from using
it.  What I proposed (an open-source alternative, based on Ada) could
easily be made to be strongly typed, at least with respect to cases
where the user defines the type (as in arrays).  Of course, when there
are overloaded functions, Ada will have the same problem as Matlab in
your example (if there are two FFT functions with the same name, one of
which can be given a one dimensional array and the other given a two
dimensional array, a mistake could be made).  But for non-overloaded
cases, the underlying Ada compiler would catch the problems.

Instead of finding fault with current practice, and attempting to talk
engineers into using Ada, I thought it might be better to work on giving
them what they want -and- what we want.  First, everyone must understand
that I consider GN&C engineers to be types of software engineers.  They
are not different (some people think they are systems engineers).  They
work, generally, at the highest levels of development of software
(requirements and design), and rarely get into the development of flight
code development (at least they typically don't like to worry about
things that matter at that level, like data protection, declarations of
variables, program structure, etc).  From other application areas, say
compilers, they would be like the person responsible for coming up with
optimization algorithms.  They might write code, but that is not their
primary job.  However, since they are likely to write code to test their
algorithms, it is quite reasonable to have them write the code in a way
that can simply be grabbed and incorporated into the compiler.

The reason Lisp, Prolog, etc. did not end up to be viable tools for
software development in their application areas was because it was not
easy to go from the algorithm development environment (Lisp, Prolog) to
the final product (Ada, C, . . .).  The cost of re-writing the
algorithms was too great, so those designers in those application areas
are using more common development tools.

On to GN&C designers.  They have tools that help them create their
algorithms.  In the case of Matlab, the M-file language is similar
enough to the final language that it is very easy to translate, so the
cost, while not trivial, is still thought to be less than having the
analyst use inadequate tools using the final language, even a language
with the benefits of Ada.

In the case of Simulink, the tool will automatically create source code
that implements the design.  The avionics developers have found that
this does save money over the manual translation method used in the
past.  One might make the case that initial development in Ada by the
algorithm engineer might save even more money, but that will not be
accepted by the engineers until the tools give them the capabilities
they currently have.

In the case of Matlab, on the other hand, the case can be made much
easier that M-file notation in Ada would be much easier to translate
(i.e. automatic), and be portable to other environments than the
proprietary (and expensive) development tool.  It would also have many
of the benefits of Ada (array protection, strong typing, . . .).

Unless this changes peoples' opinions, it appears that the status quo is
acceptable to everyone.  That is sad.

Roger Racine

Top of Message | Previous Page | Permalink

Advanced Options


Options

Log In

Log In

Get Password

Get Password


Search Archives

Search Archives


Subscribe or Unsubscribe

Subscribe or Unsubscribe


Archives

December 2017
November 2017
October 2017
September 2017
June 2017
May 2017
April 2017
January 2017
December 2016
November 2016
October 2016
August 2016
July 2016
June 2016
May 2016
April 2016
March 2016
February 2016
January 2016
December 2015
November 2015
October 2015
September 2015
August 2015
June 2015
May 2015
April 2015
March 2015
February 2015
January 2015
December 2014
November 2014
September 2014
August 2014
July 2014
June 2014
May 2014
April 2014
March 2014
February 2014
January 2014
December 2013
November 2013
October 2013
September 2013
June 2013
May 2013
April 2013
March 2013
February 2013
January 2013
December 2012
November 2012
October 2012
September 2012
August 2012
July 2012
June 2012
May 2012
April 2012
February 2012
January 2012
December 2011
November 2011
October 2011
September 2011
August 2011
July 2011
June 2011
May 2011
April 2011
December 2010
November 2010
October 2010
September 2010
June 2010
May 2010
April 2010
March 2010
February 2010
January 2010
December 2009
November 2009
October 2009
September 2009
August 2009
July 2009
June 2009
May 2009
April 2009
February 2009
January 2009
December 2008
November 2008
October 2008
September 2008
August 2008
June 2008
May 2008
April 2008
March 2008
February 2008
January 2008
December 2007
November 2007
October 2007
September 2007
June 2007
May 2007
March 2007
February 2007
December 2006
November 2006
October 2006
September 2006
August 2006
July 2006
June 2006
May 2006
April 2006
March 2006
February 2006
January 2006
December 2005
November 2005
October 2005
August 2005
July 2005
June 2005
May 2005
April 2005
March 2005
February 2005
January 2005
December 2004
November 2004
October 2004
September 2004
August 2004
July 2004
June 2004
May 2004
March 2004
February 2004
January 2004
December 2003
November 2003
October 2003
September 2003
August 2003
July 2003
June 2003
May 2003
April 2003
March 2003
February 2003
January 2003
December 2002
November 2002
October 2002
September 2002
August 2002
July 2002
June 2002
May 2002
April 2002
March 2002
February 2002
December 2001
November 2001
October 2001
September 2001
August 2001
July 2001
June 2001
May 2001
April 2001
March 2001
February 2001
January 2001
December 2000
November 2000
October 2000
September 2000
August 2000
July 2000
June 2000
May 2000
April 2000
March 2000
February 2000
January 2000
December 1999
November 1999
October 1999
September 1999
August 1999
July 1999
June 1999
May 1999
April 1999
March 1999
February 1999
January 1999
December 1998
November 1998
October 1998
September 1998
August 1998
July 1998
June 1998
May 1998
April 1998
March 1998
February 1998
January 1998
December 1997
November 1997
October 1997
September 1997
August 1997
July 1997
June 1997
May 1997
April 1997
March 1997
February 1997
January 1997
December 1996
November 1996
October 1996

ATOM RSS1 RSS2



LISTSERV.ACM.ORG

Secured by F-Secure Anti-Virus CataList Email List Search Powered by the LISTSERV Email List Manager