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The Communication Subsystems
These libraries provide the system which is currently used to construct
programs capable of communicating with each other using the ADAM message
protocol. Messages can control the actions of programs or convey information.
SG/4
describes the simple use of the system (which is usually all that is needed for
data analysis programs) whilst
SUN/134
describes more complicated use in instrumentation control systems.
- MSP
- This library provides an inter-program communication system based
upon a system of message `queues'.
- SOCK
- This library provides a Unix-socket-based message transport system
for the MSP system.
- AMS
- This library implements the ADAM message protocol on top of MSP.
AMS is written in C but a Fortran interface, FAMS, is provided.
SUN/241
is the programmers manul for AMS.
- DTASK
- This provides an application program structure which allows the
program to be run directly from the shell or to respond to a specified set of
control messages from other programs using the ADAM message protocol.
The application may consist of multiple `actions' which can be controlled
separately.
DTASK provides the main routine of the program and applications are written
as subroutines which are called by the DTASK layer after the communication and
parameter systems have been initialised. This is described for system
programmers in
SSN/77
The package also includes shell scripts to link such applications with PCS and
the other Starlink subroutine libraries required.
- TASK
- This library provides an interface between the application code
and the DTASK layer so that an application can find out some information
about its own status. It also enables programs to control other co-operating
programs using the ADAM message protocol and includes subroutines for encoding
and decoding data values in messages.
For more details, see
SUN/134.
- ATIMER
- This library provides a system of millisecond interval timers
used by the message system and DTASK.
Each timer has an associated handler which is invoked when the timer expires.
The library is written in C but a Fortran interface, FATIMER, is provided.
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PCS The Parameter and Communication Subsystems
Starlink System Note 29
A J Chipperfield
20 August 2001
E-mail:ussc@star.rl.ac.uk
Copyright © 2000 Council for the Central Laboratory of the Research Councils