Ada 9X(ID:1380/ada025)

Review and update of Ada 83 

Revision and extension of Ada begun in 1988. Additions include object-orientation (tagged types, abstract types and class-wide types), hierarchical libraries, and synchronization with shared data (protected types) similar to Orca. Lacks multiple inheritance.

Eventually called Ada95

Structures:
Related languages
Ada 83 => Ada 9X   Evolution of
Orca => Ada 9X   Influence
Ada 9X => Ada 95   Evolution of
References:
  • "Ada 9X Rationale: The Language, The Standard Libraries", Ada9X Mapping/Revision Team, Intermetrics, Inc., Cambridge, MA, September 1993. view details
  • "Ada 9X Reference Manual: The Language, The Standard Libraries" Ada 9X Mapping/Revision Team, Intermetrics, Inc., Cambridge, MA, eptember 1993. view details
  • Barnes, J.G.P. "Introducing Ada 9X", Feb 1993 view details
  • S. Tucker Taft, "Ada 9X: From abstraction-oriented to object-oriented" view details
          in [ACM SIGPLAN] SIGPLAN Notices 28(10) October 1993 Proceedings of the Conference on Object Oriented Programming Systems, Languages and Applications, Sept-Oct 1993. (OOPSLA '93) view details
  • Duncan, Arthur G. "Implementing internal program representations with Ada and Ada 9X" view details Abstract: In an earlier paper, the author discussed the use of Ada to implement the internal program representation for an Ada software re-engineering system. While many of Ada's features were used to advantage in the implementation, the lack of an inheritance mechanism and an expressive subtyping system make the implementation unnecessarily cumbersome and insecure.Had Ada 9X been available at the time, we could have achieved a simpler, more readable, and more secure design; furthermore, the implementation (most likely) would have been more efficient.Contrasting the Ada and Ada 9X implementations leads naturally to some observations on how one could build tools to convert Ada legacy code to Ada 9X. DOI
          in Proceedings of the conference on TRI-Ada '94 November 1994 view details
  • H.E. Bal: " Comparing data synchronization in Ada 9X and Orca", ACM Ada Letters, Vol. 15, No. 1, pp. 50-63 (Jan/Feb 1995). view details ps
          in Proceedings of the conference on TRI-Ada '94 November 1994 view details
  • Singhal, Amit "Real Time Systems: A Survey" Computer Science Department University of Rochester December 4, 1996 view details External link: Online at Citeseer Abstract: What are real­time systems? Instead of trying to define them, we can think of real time systems as those that react to external stimuli in a timely and  reliable fashion. Real time systems are often used to solve real world problems.  Some examples of real time systems include air traffic control, automatic pilots,  unmanned robots etc.

    Current research in real time systems lags far behind that in other areas. This is due to a largely false notion of what real time systems are and what  they involve. I begin this survey by describing some of the characteristics of  real time systems. Then I will dispel some of the misconceptions and make an  argument for the importance of further research in the area. Next I will present  some formal methods for specifying and verifying real time systems.

    Most of the current real time systems have been written in conventional programming languages which are not very suitable for the task and do not  provide control over timing constraints. Most of the real time languages that  have been developed have found limited use (mostly in the labs where they  were designed) and have not been embraced widely by the real time developers  community. I will deal with this issue at length and present an overview of  what real time languages are and where the current research stands.

    Next I will present some design methodologies and techniques used in designing and developing real time systems. Some of these have good formal and mathematical backgrounds while others originate from rules of thumb.  One of the most active areas of research in real time systems has been  scheduling algorithms. I will present some models of scheduling algorithms and  compare them with respect to their adherence to real time principles. In the  last part of this survey, I will present some of the hardware and architectural  issues facing real time system developers and also provide some information on  how operating systems need to be geared to support real time tasks.  Finally, I will present some of the future directions for research in real time  systems and some of the challenges faced by the researchers today.
    Extract: PEARL and ADA 9X
    PEARL and ADA 9X are the most commonly used real time languages and are being continually enhanced and standardized. PEARL was developed in West Germany and has become one of the most popular languages for  real time systems all across Europe. ADA was commissioned by the Department of  Defense in the United States and has become the long standing standard for real  time programming here. Both of them are quite similar. Their advantages include  strong typing, well structured, direct hardware access, modular, separate compilation  and process synchronization. However, they are both very large and complex, lack  efficient implementations, and do not allow for much schedulability analysis.

          in Proceedings of the conference on TRI-Ada '94 November 1994 view details