 






     Software
     Product
     Description

     ________________________________________________________________

     PRODUCT NAME:  VAXELN Ada, Version 2.2              SPD 27.22.05

     DESCRIPTION

     VAXELN Ada is a VMS layered product for developing Ada language
     applications which run in a standalone or embedded environment
     on VAX processors under the VAXELN real-time executive.

     Typical VAXELN Ada applications are ones in which individual
     processors have "dedicated" or otherwise predetermined functions
     and are not needed simultaneously for general computing, program
     development, or other uses for which a general-purpose operat-
     ing system (e.g., VMS) is more appropriate. Other uses are in
     "embedded" systems, where the processor is an integral part of
     a larger device and the resources of a general-purpose computer
     system, such as a disk, are not available. Examples include
     industrial automation, workstations designed for a particular
     profession, Ethernet server networks and robots.

     VAXELN Ada is especially suited to, although not limited to,
     creating "real-time" applications; that is, applications in
     which the system's response to external events is critical. Such
     applications include the typical scientific and industrial data
     processing situations in which the computer's operation has to
     be precisely synchronized with machines and special input/output
     devices.

     VAXELN Ada applications are developed using VAX Ada and the
     VAXELN Toolkit on a host VMS system. The resulting bootable,
     VAXELN-based Ada application is then moved to the VAXELN target
     system using disk or tape media, an Ethernet Local Area Network
     (LAN) link, or programmable read-only memory (PROM). The ap-
     plication program executes on the target system as a dedicated

                                  DIGITAL               February 1991

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     VAXELN Ada, Version 2.2                             SPD 27.22.05



     system. The network link to the host development system may be
     used for remote debugging.

     Users are expected to have the necessary hardware to provide
     both host development and target execution environments. Appli-
     cations may not be run in the development environment if they
     use any VAXELN-specific features.

     VAXELN Ada, in combination with VAX Ada and VAXELN, has been
     validated as fully conforming to ANSI/MIL-STD-1815A-1983 (Refer-
     ence Manual for the Ada Programming Language) by the Ada Joint
     Program Office.

     System Features and Special Extensions

     o  VAXELN Ada applications are compiled with the Ada compiler
        supplied with the VAX Ada product. The choice of target
        system can be deferred until the application is linked.

     o  VAXELN Ada supports all VAX Ada features except the follow-
        ing:

        1. Access to relative and indexed organization files. The VAX
           Ada packages RELATIVE_IO, RELATIVE_MIXED_IO, INDEXED_IO
           and INDEXED_MIXED_IO are not supported.

        2. Support of the VMS Asynchronous System Trap (AST) mecha-
           nism.

        3. Timeslicing. VAXELN Ada tasks run until blocked or pre-
           empted.

     o  Applications are linked using the program library manager
        utility supplied with the VAX Ada product. Each program
        library or sublibrary has a default target associated with
        it. This default can be changed or overridden as desired.

     o  A high-level, fully-symbolic remote debugging capability is
        provided. This feature requires that the user has the op-
        tional DECnet-VAX license and an Ethernet Local Area Network
        link between the host and target systems. It can be used to

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     VAXELN Ada, Version 2.2                             SPD 27.22.05



        debug remote applications from a programmer's terminal on a
        VMS system.

     o  Support is included for:

        1. Mixed Ada and non-Ada code

        2. Packages

        3. Tasking programs

     o  A user interface compatible with the VMS Debugger

     o  Integration with VAXELN real-time executive including:

        1. Conformance to the VAX Calling Standard, which allows
           Ada code to call and be called by code written in other
           languages, as well as to call VAXELN system services and
           utility routines.

        2. The ability to handle exceptions from non-Ada code and
           generate exceptions to be handled by non-Ada code.

        3. The ability of Ada-language applications to control custom
           devices, including the ability to write device drivers in
           Ada.

        4. The ability to link with shared images and access shared
           areas of memory between applications on the same target
           system.

        5. Tasks run as separate VAXELN processes under control of
           the VAXELN scheduler, and can be combined with non-Ada
           processes and jobs in the same system.

     HARDWARE REQUIREMENTS

     VAX, MicroVAX, VAXstation or VAXserver configuration as speci-
     fied in the System Support Addendum (SSA 27.22.05-x).

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     VAXELN Ada, Version 2.2                             SPD 27.22.05



     SOFTWARE REQUIREMENTS*

     For Systems Using Terminals: (No DECwindows Interface)

     o  VMS Operating System

     o  VAX Ada

     o  VAXELN Toolkit

     o  DECnet-VAX

     For Workstations Running VMS Workstation Software:

     o  VMS Operating System

     o  VMS Workstation Software

     o  VAX Ada

     o  VAXELN Toolkit

     o  DECnet-VAX

     *  Refer to the System Support Addendum for availability and
        required versions of Software Requirements (SSA 27.22.05-x).

     ORDERING INFORMATION

     Software Licenses: QL-A97A*-**
     Software Media: QA-A97A*-**
     Software Documentation: QA-A97AA-GZ
     Software Product Services: QT-A97A*-**

     *  Denotes variant fields. For additional information on avail-
        able licenses, services and media, refer to the appropriate
        price book.


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     VAXELN Ada, Version 2.2                             SPD 27.22.05



     SOFTWARE LICENSING

     This software is furnished under the licensing provisions of
     Digital Equipment Corporation's Standard Terms and Conditions.
     For more information about Digital's licensing terms and poli-
     cies, contact your local Digital office.

     LICENSE MANAGEMENT FACILITY SUPPORT

     This layered product supports the VMS License Management Facil-
     ity.

     License units for this product are allocated on a CPU-capacity
     basis.

     For more information on the License Management Facility, refer
     to the VMS Operating System Product Description (25.01.xx) or
     the VMS Operating System documentation set.

     For more information on Digital's licensing policies, contact
     your local Digital office.

     SOFTWARE PRODUCT SERVICES

     A variety of service options are available from Digital. For
     more information contact your local Digital office.

     SOFTWARE WARRANTY

     Warranty for this software product is provided by Digital with
     the purchase of a license for the product as defined in the
     Software Warranty Addendum of this SPD.

     [TM]  The DIGITAL Logo, VMS, DECwindows, Decnet, VAXELN, VAX,
           MicroVAX, VAXstation, VAXserver and VAXset are trademarks
           of Digital Equipment Corporation.



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