XD Ada MIL-STD-1750A Semaphore
and Message Passing for OpenVMS Systems Version 4.0
The Semaphores and Message Passing (SMP) Option is a separately licensed
option that is available with the XD Ada™ MIL-STD-1750A Version 4.0 product on
OpenVMS™ Systems. It provides support for two types of inter-task
communication: semaphores and message passing.
XD Ada MIL-STD-1750A Semaphore Package Features
The XD Ada semaphore package provides support for semaphore operations
between tasks. Semaphores are commonly used in conjunction with tasking to
control the interactions among and between multiple tasks and shared resources.
Three types of semaphore are provided to support a wide range of user
applications, including the classic producer/consumer problems using bounded
buffers, as follows:
·
General Semaphore
·
Counting Semaphore
·
Binary Semaphore
The following semaphore operations are supported:
·
WAIT — if the semaphore is raised, decrement the value
of the semaphore, else suspend the task. Conditional and timed wait operations
are also supported.
·
SIGNAL — if a task is suspended at the semaphore then
resume the task, else increment the semaphore. The signal operation from within
an interrupt handler is also supported.
XD Ada MIL-STD-1750A Message Passing Features
The XD Ada message passing package allows application program tasks to
synchronize and communicate with each other by sending and receiving messages
to and from mailboxes. Messages may be passed both between tasks within the
same simple
The following gives a summary of the message passing
operations supported:
·
CREATE — creates a new mailbox for intraprogram or
interprogram messages.
·
SEND — sends a message to a specified mailbox; if the
mailbox is full then the calling task is suspended until a message slot becomes
available in that mailbox. Conditional and timed send operations are also supported.
·
RECEIVE — receives a message from a specified mailbox;
if the mailbox is empty then the calling task is suspended until a message
becomes available in that mailbox. Conditional and timed receive operations are
also supported.
·
EXPORT — makes a mailbox accessible to all
·
IMPORT — makes an exported mailbox visible in the calling
program.
Software Components
The software for XD Ada MIL-STD-1750A Semaphores and Message Passing
Version 4.0 for OpenVMS Systems consists of the following:
·
Additional
The software is supplied in source form so that the message passing
package can be reconfigured for other target configurations based on the
MIL-STD-1750A processor.
Documentation
Details of the Semaphores and Message Passing Option are documented in
the manuals supplied with the XD Ada MIL-STD-1750A Version 4.0 product.
Instructions for installing the XD
Ada MIL-STD-1750A Semaphores and Message Passing Option are detailed in
the XD Ada MIL-STD-1750A, Installation Guide for OpenVMS Systems.
HOST SOFTWARE REQUIREMENTS
The host software requirements are listed in the XD Ada MIL-STD-1750A for OpenVMS
Integrity ServersTM Version
4.0 Software Product Description and XD Ada MIL-STD-1750A for OpenVMS AXP Systems
Version 4.0 Software Product Description. In addition the following is required:
·
Optionally for use with a Hewlett-Packard emulator the
HP64888 File Format Conversion Utilities at Edition 3.
For information on how to order the product see the contact information below.
This software is furnished under the provisions
of a software license.
Licenses for educational institutions are
available.
For more information on licensing terms and conditions, see the contact information below.
Warranty for this product is provided in
accordance with the terms and conditions of the license.
The above information is valid at time of release.
TM AXP, DEC, DEC Ada, DECset,
DEC Test Manager, Digital, Integrity server, OpenVMS, TK, VAX, VAX DOCUMENT,
VMS and XD Ada are trademarks of Hewlett-Packard Development Company, L.P.
swep.sales@hp.com; www.swep-eds.com