GDSX Manual
Extended General Device Support (GDSX) Manual–134303
2-1
2
Design and Development
This section contains design prerequisites and considerations for designing GDSX
applications; information on D-series features; steps for converting applications to use
extended features of the D-series operating system; considerations for coding,
compiling, and binding GDSX procedures; a description of the basic internal control
flow; procedure call and space restrictions; and information on memory pools, fault
tolerance, semaphores, linked lists, EMS filters, file-system errors, tracing, GDSX
internals, and the USAMPLE example program.
Prerequisites for Design and Development
A programmer developing a GDSX application must:
•
Be an expert TAL programmer
•
Know the requirements for the application to be developed
•
Know Tandem architecture and NonStop Kernel programming
•
Be familiar with multithreaded processes
•
Be familiar with fault-tolerance principles, if the application is to run as a process
pair
•
Know data communications, if the application is to include protocol conversion
Before you begin designing a GDSX application, you should read the overview of
GDSX in Section 1 and do the tutorial in Sections 4 through 7, unless you are already
proficient in GDSX programming. (If your application does not involve a
LINE^HANDLER, you do not need to do Sections 6 and 7 of the tutorial.)
Finally, before designing a GDSX application, it is recommended that you consider
alternative implementations, such as Pathway/TS IDS or conversational mode. See
"When to Use GDSX" on page 1-14.
Design Considerations
The following considerations and suggestions may be helpful when designing a GDSX
application.
•
Determine the environment in which GDSX is to function. Chart the overall
interprocess data flow. Include the interprocess flow of data from external business
application to GDSX to IOP/other process. Diagram the GDSX internal data flow.
•
Determine which D-series features will be used, including whether GDSX will run
at a low PIN or a high PIN. For information on using these features, see "Using D-
Series Features" on page 2-2.
•
Complete a detailed business application design, including specifying:
°
Requester processes with which GDSX is to communicate