SIS - Application Programmatic Interface, Reference Manual - ICS ...

SIS- Application Programmatic Interface, Reference Manual
Figure 1: The query model
SIS server is a process running independently and serving a client application. The
client-server communication is achieved through sockets. The client application is
linked only with the client part of API which simply sends the query /update request
to the server where the query /update processing is done.
2.1 Client-server model to access the SIS base
With the first implementation of the API the application is the client of a client-server
model of querying and/or modifying the SIS base. This means that a second process
(the SIS server) has to run in parallel to the application and this process gives the
answers to any question from the application, and modifies the data in the SIS base.
The server is responsible for reading and writing the SIS base files.
The main advantage of this model is that the client (or clients) need not run on the
same machine the SIS server is running. The communication between the client
process and the server process is achieved through Windows sockets.
2.2 Immediate access the SIS base
With the other implementation of the API the application does not communicate with
some other process to retrieve the information but the query and update functions
themselves access the data from the SIS base. This implementation eliminates the
delay on the socket communication but creates a bigger process both in disk demands
(executable file) and in run-time memory requirements since the process itself reads
the whole SIS base.
August 2002/v2.2.2 -6- ICS-FORTH