Form G30-0593
9XNEWS.HLP

                          Ada 9X Report to the Public
                                   May 1993

                                 The Schedule

I hope 1993 has been progressing well for you.  This year, we begin canvassing 
on Ada 9X for the American National Standards Institute (ANSI) and the 
International Standardization Organization (ISO).

All Ada 9X Teams are working very hard to produce the draft Standard by August 
1993 and to begin balloting by September.  Many vendors are gearing up for Ada 
9X, and I fully expect 9X beta-compilers to appear within the next 12 months.

                         ISO Approves Ada 9X Baseline

The ISO Working Group on Ada approved the entire Ada 9X baseline in November.  
This followed last April's ISO approval of the language core minus the 
Annexes.

With November's approval, essentially all of the baseline is defined and 
attention is now focused on translating the base into precise Language 
Reference Manual wording.  While it is often the case with standards that not 
everyone is happy, I am extremely pleased with the level of consensus we've 
achieved and appreciate all the help given us by the ISO delegations, the ANSI 
Technical Advisory Group, the ANSI Canvassees, and the Ada 9X Volunteer 
Reviewers.

                             Upward Compatibility

I read an account of a recent conference panel in which the members stressed 
the necessity for 100% upward compatibility between Ada 83 and Ada 9X.  As is 
often the case, certain rules and metrics seen to be applied to Ada that are 
not applied to other languages.  Achieving 100% upward compatibility is 
virtually impossible in language revisions and has not been achieved in 
recent/on-going revisions of COBOL, C/C++, or FORTRAN.  It is inevitable that 
by enhancing a language, certain incompatibilities are, by necessity, 
introduced.  The trick, of course is to minimize the impact of these on 
mainstream programs.

A major design goal of Ada 9X has always been to minimize the need for 
modifying the existing base of Ada 83 software to make it compatible with Ada 
9X.  This involves not only pursuing upward compatibility but also pursuing 
implementation-dependent behaviors that are currently being relied upon.

In common with the experience of revising other language standards, it is 
infeasible to guarantee 100% compatibility.  For example, in COBOL 83 there 
were some minor incompatibilities introduced which affect existing programs.  
One example in COBOL is IS_ALPHABETIC, which now accepts upper- and lowercase 
letters in the new standard.  The transition from C to ANSI-C and from there 
to C++ has not achieved 100% upward compatibility either.  For example, C++ 
requires all procedure definitions in old style C to be modified.

In the Ada 9X design, we have succeeded in adopting a very conservative 
approach.  The few incompatibilities that exist can for the most part be dealt 
with in a simple mechanical way.  For example, the few new Ada 9X reserved 
words require replacement in any Ada 83 program that uses them as identifiers.  
A few other incompatibilities involve obscure or pathological programming 
styles that we expect to appear very infrequently in existing code.  The great 
majority of programs will be unaffected by these changes and public-domain 
tools are being developed to aid in their reliable detection.

In summary, few, if any, standard programming language revisions have ever 
achieved 100% upward compatibility.  We expect the few incompatibilities in 
Ada 9X to cause very minor impact to existing code -- and for the overwhelming 
majority of users, straightforward mechanical changes will correct the 
inconsistencies.

(For more on this subject, see the papers "How to Program in Ada 9X, Using Ada 
83" by Erhard Ploedereder and "Ada 9X Compatibility Guide" by Bill Taylor.  
They're available on the AJPO host -- ajpo.sei.cmu.edu -- on the Internet; 
look under the ada9x directory for files 9x-guide.txt or 9x-guide.ps, and 
compat-guide.txt or compat-guide-10b-a4.rtf and compat-guide-10b-lt.rtf.)

                            Upcoming Presentations

We have many opportunities to present the latest status of Ada 9X in the 
coming months including the Fifth Annual Software Technology Conference, 18-23 
April in Salt Lake City, Utah; the National Conference, on Ada Technology, 
15-18 March in Williamsburg, Va.; Object Expo, 20 April in New York City, 
N.Y.; and Ada Europe 14-17 June in Paris, France.

                                  Ada Lives!

I'm constantly amazed that many people still regard Ada as "that DoD 
language."  Ada is a widely accepted ANSI and ISO standard with over 22 
countries using it for commercial as well as defense purposes.  Applications 
include the signaling on the Chunnel between the UK and France, the National 
Census System in Singapore, the Reuters Money Management System, Boeing 777 
avionics, the FAA Air Traffic Control System (under development), and the 
Space Station Freedom.  Also witness the interest and very active 
participation of 12 countries in the Ada revision process.

So, the next time you sit though a panel discussing Ada's demise, please keep 
in mind the very important reason why Ada lives -- complex software systems 
need to be engineered.  In these times of dwindling resources, this has never 
been more true.

                             Ada Goes to College!

I've always maintained, if Ada is to continue to grow and prosper it must 
become integrated into academia's curriculum.  There is growing evidence of 
this occurrence.  Again, it's because academia is beginning to regard software 
from a disciplined engineering perspective versus from a more theoretical 
science perspective.

As of Dec. 92, over 373 universities/colleges are using/teaching Ada; with the 
impending award of additional AJPO/DARPA grants, this figure will be boosted 
even higher.

                           Ada 9X Reports Available

The Ada 9X Project Office maintains a mailing list for periodic distribution 
of interim Ada 9X reports.  The next report, "Introducing Ada 9X", will be out 
by the time you read this.  Contact my assistant, Robin Keeney, at the Ada 9X 
Project Office to get on our mailing list if you are not already on it.  You 
can also send your address via e-mail to Ms.  Keeney at keeneyr@plk.af.mil.

Many reports are also available electronically via our Ada 9X bulletin board 
1-800-Ada9X-25 or on the AJPO host machine.  In addition, if you want 
day-by-day updates you can sign up to be an Ada 9X Volunteer Reviewer by 
sending a message to ada9X-vr@ajpo.sei.cmu.edu.

Christine M. Anderson, Ada 9X Project Manager
Air Force Philips Laboratory/VTES
3550 Aberdeen Avenue, S.E.
Kirtland AFB, NM 87117-5776
505/846-0817, -0461; fax: 505/856-2290
e-mail: anderson@plk.af.mil

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