NAME

 
   rtdServer - image event dispatcher for RTD

SYNOPSIS

 
   rtdServer [-v] [-p <port number>]

DESCRIPTION

 
rtdServer is the process that manages the image event mechanism.
Clients register to the rtdServer via the rtdInitImageEvt call.
When a client attaches to a camera source an incomming image event
will be forwarded to this client. Several clients can attach to the
same camera source as the multicasting of event notification is
supported by the rtdServer.
Image events received from image sources where no clients are attached
are simply discarded. Clients can also attach to image sources
that not have registered yet as the rtdServer supports a independence
between image event producer and image event consumer.

Furthermore rtdServer contains a simulator part that can be used
to simulate the generation of image events. This feature is reserved
for testing purposes only. Similarly, it also contains a performance
test facility, in which several areas of shared memory are sent to
a client Rtd in quick succession, and measurements are taken on
certain performance parameters (see RtdPerformanceTool(3/n).

The rtdServer also implements semaphore locking of shared memory, to
avoid the possibility of the RTD client reading the shared memory
at the same time as the CCD writes (this is known as "image jitter").
The server program expects the CCD software to set a semaphore against
any shared memory that has been written to (effectively to lock it).
The server will then increment this semaphore by the number of RTD
clients less one. If semaphores are not implemented in the incoming
image event, no action is taken. The overall locking scheme is discussed
in more detail in rtdSem(1). Semaphore locking is implemented in the
simulator facility.

ENVIRONMENTS

 
The rtdServer (and RTD) uses 5555 as the default port number. If another
copy of the rtdServer is needed e.g. for debugging purposes or if another
port number shall be used then set the environment variable RTD_SERVER_PORT
to the port number before starting the rtdServer (and RTD).

SEE ALSO

 
 rtdCubeDisplay(1), rtdInitImageEvt(3), rtdSendImageInfo(3), rtdSem(1)

 


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Last change: 07 May 99