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Form G95-0792a
ADA9X.HLP
Ada Information Clearinghouse 1-800-AdaIC-11, 703-685-1477
Ada 9X
Ada has become a billion dollar industry since its development in the late
1970s. Ada's strong support for sound software engineering practice is widely
recognized internationally in the defense and commercial sectors for both
real-time embedded and information systems.
Ada 83 is an ISO, ANSI, NATO and Federal Information Processing Standard
(FIPS) standard with strict Ada compiler conformance testing available in five
locations world-wide. This makes Ada the most widely standardized programming
language today. The strict conformance testing of every validated Ada
compiler ensures a high degree of code portability and software reuse. Ada 83
boasts more validated compilers than any other high order language and the
quality of Ada compilers is now on a par with other popular compilers.
In 1988, a revision of Ada 83 was initiated to reflect experience with the
language and to enhance its use for software development in the 1990s. The
project, called Ada 9X, is sponsored by the US Department of Defense with wide
participation by the international community to ensure continued
multi-standard status and broad acceptance.
Based on user needs communicated to the Ada 9X Project Office via a one-year
open call for revision requests, support for the three new major features is
planned: Object-Oriented Programming (OOP), Protected Records, and
Hierarchical Library Units.
For improved support of the OOP paradigm, changes include a more robust
inheritance feature and runtime polymorphism, based on enhancements to the
derived type mechanisms of Ada 83. The polymorphism allows a call to a
subprogram to perform a runtime dispatch based on a type tag contained within
one or more actual parameters. In a recent Ada 9X prototyping exercise, some
of the well-known Booch software components originally written in Ada 83 and
more recently in C++, were rewritten in Ada 9X. The resulting Ada 9X source
code was more compact by a factor of 5 to 1 than the Ada 83 version. This
leads to a potentially higher degree of software reuse and extensibility.
Furthermore, the Ada 9X code -- when compared to the C++ code -- was
comparable in size and efficiency, considerably more readable, and presumably,
more maintainable.
For the real-time community, the protected record feature offers a lightweight
language construct for task synchronization through exclusive access to data
objects. Protected records function much like the telephone answering
machine, allowing a sender to leave a message without the receiver's presence
and a receiver to retrieve a message later without the sender's presence.
Recent Ada 9X prototyping exercises have shown that use of protected records,
where appropriate speeds execution by a factor of three compared to the use of
the Ada 83 task rendezvous.
To facilitate software reuse, the Ada 9X hierarchical library feature offers a
very flexible library structure that allows the organization of what would
otherwise be a large monolithic library unit in Ada 83 into smaller more
manageable compilation units. This capability can significantly reduce
recompilation time during software development and maintenance, provide the
means to reduce the amount of code imported when accessing only portions of a
software product, and facilitate the adaptation or extension of existing
software. Recent Ada 9X exercises involving modification of an X-Windows
Library interface code in Ada 83 and in Ada 9X demonstrate a 75% decrease in
compilation time during the modification process in Ada 9X version over the
Ada 83 version.
Current plans for multiple annexes to the standard in which semantics denoted
as "implementation-defined" in Ada 83 are now more specifically defined in the
Ada 9X standard to match the unique demands or certain application areas:
real-time systems, information systems, systems programming, distributed
systems, etc. Such annexes may also include standardized packages of special
importance to the respective area. Support for a particular annex is optional
to allow Ada implementations to be finely tuned to selected domains.
The Ada 9X Project Office is working on mechanisms for smoothing the
transition from Ada 83 to Ada 9X including, but not limited to, programmers
and managers guidebooks, training programs, vendor incentives, and enhanced
compilation systems. Ada compiler vendors are being kept informed of Ada 9X
progress through workshops and special reports to hasten the time-to-market.
Ada may not be for everyone but if your shop is developing complex, highly
reliable, software-intensive applications that must be maintained for three or
more years, look no further. Ada is the language for you and you can start
now with Ada 83 and easily transition to Ada 9X when its compilers are
available. Ada may be the best investment you ever make for your software
products.
For More Information ...
For more information on the Ada 9X project, contact the Ada 9X Project Office:
Christine M. Anderson
Ada 9X Project Office
PL/VTET
Kirtland AFB NM 87117-6008
Tel: 505/846-0817
Fax: 505/846-2290
E-mail: ada9x@plk.af.mil
The reports that have been produced under the project are available for
downloading from the Ada 9X electronic bulletin board and the ada9x public
directory on the AJPO host computer on the Internet. The bulletin board can
be reached by dialing 1/800-Ada-9X25 or 301/459-8939. Users should set their
telecommunications package with the following parameters:
Baud rate = 300 through 9600 Data Bits = 8
Parity = none Stop Bits = 1
Ada 9X project reports are also available in the ada9x directory on the AJPO
host computer. This directory can be accessed via the file transfer program,
which allows a user to transfer files to and from a remote network host site.
An example ftp connection to the ada9x directory follows.
[your-prompt] ftp ajpo.sei.cmu.edu execute ftp from your remote site.
name: anonymous login using "anonymous".
password: guest enter password of "guest".
ftp> cd public change to the "public"
sub-directory.
ftp> dir get a list of accessible
sub-directories.
ftp> cd ada9x change to the ada9x subdirectory.
ftp> get README [newname.hlp] get README from ftp and copy it to
"newname.hlp" on your machine.
ftp> mget file1...fileN get multiple files from ftp and load
them onto your machine with the same
names.
ftp> bye logout when finished.
The directory structure for the ada9x directory is as follows:
ada9x/ada9x.reports
This directory contains the Ada 9X Project Reports. See
/ada9x/ada9x.reports/README for a complete list of documents.
ada9x/news
Ada 9X Project Reports to the Public and Special Project Announcements.
See /ada9x/news/README for a complete list of announcements.
ada9x/past
Outdated Announcements.
**********************
Copyright 1993. IIT Research Institute. All rights assigned to the U.S.
Government (Ada Joint Program Office). Permission to reprint this flyer, in
whole or in part, is granted, provided the AdaIC is acknowledged as the
source. If this flyer is reprinted as a part of a published document, please
send the AdaIC a courtesy copy of the publication.
Ada Information Clearinghouse (AdaIC)
P.O. Box 46593
Washington, DC 20050-6593
703/685-1477, 800/AdaIC-11, FAX 703/685-7019
adainfo@ajpo.sei.cmu.edu; CompuServe 70312,3303
The AdaIC is sponsored by the Ada Joint Program Office and operated by IIT
Research Institute.