TS/MP Pathsend and Server Programming Manual (G06.24+, H06.03+)

Designing Your Application
NonStop TS/MP Pathsend and Server Programming Manual–132500
2-16
Requesters Using GDSX
classes by using either the Pathsend API and the LINKMON process or the terminal
control process (TCP) provided in the Pathway/TS product. If the TCP is used, it can
route a request message to a Pathway server by using either the intelligent device
support (IDS) requester supplied as part of RSC or an IDS requester that you develop
yourself. The TDP can also send request messages from a workstation to a Guardian
process.
The Pathway Open Environment Toolkit (POET) provides tools for developing RSC
clients for the Microsoft Windows environment. These tools include a simplified
programmatic interface, name mapping, and data conversion mapping.
For information about designing and coding requesters with the RSC product, refer to
the Remote Server Call (RSC) Programming Manual. For information about using the
POET product, refer to the Pathway Open Environment Toolkit (POET) Programming
Manual.
Requesters Using GDSX
The Extended General Device Support (GDSX) communications subsystem product
simplifies the development of front-end processes and back-end processes for
communication with I/O devices. These devices can be of any type, including
workstations, terminals, ATMs, point-of-sale (POS) devices, and industrial robots.
GDSX supplies code that provides multitasking and other features useful for developing
these front-end and back-end processes.
A GDSX process can act as a front-end process for LINKMON processes or a
Pathway/TS terminal control process (TCP).
A GDSX process contains two primary parts:
•
TSCODE, supplied by Tandem
•
USCODE, supplied by the application programmer
TSCODE provides generic routines and management services that help you build a
multithreaded, fault-tolerant process. TSCODE provides the following functions:
•
Creates new tasks and stops tasks
•
Receives all system messages and I/O requests
•
Dispatches (wakes up and executes) the appropriate active task to process messages
and requests
•
Handles errors
USCODE consists of user exits that are called by TSCODE to handle the application-
specific, data communications-related functions, such as data manipulation, protocol
conversion, and message routing for the I/O process. USCODE is typically written in the
Transaction Application Language (TAL) or the Portable Transaction Application
Language (pTAL) and bound with TSCODE to produce a functional GDSX process.
GDSX provides its own interface to Guardian procedures, NonStop TM/MP procedures,
and Pathsend procedures. The names of the GDSX procedures typically look like their
Guardian, NonStop TM/MP, or Pathsend equivalents, but they have a circumflex (^)