GDSX (Extended General Device Support) Manual

Overview of GDSX

Extended General Device Support (GDSX) Manual—529931-001

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GDSX and Pathway/iTS

The Pathway/iTS transaction processing software, together with its parent product,

TS/MP, provides an easy-to-use, powerful, and effective means of implementing online

transaction processing (OLTP) applications.

Pathway/iTS was designed to support the following terminals:

•

6510, 6520, 6530, 6540, and IBM 3270 terminals operating in block mode.

•

6510, 6520, 6530, 6540, and IBM 3270 terminals, or any other devices that the

Guardian file system recognizes as operating in conversational mode.

•

Intelligent devices such as personal computers, point-of-sale devices, ATMs,

communication lines, or Guardian processes, and the 6540 terminal operating as a

personal computer.

There is a wide variety of other general-purpose and special-purpose terminals in the

marketplace, and many of these terminals differ significantly from those that

Pathway/iTS supports. Despite not being able to interface Pathway/iTS to these

nonsupported terminals directly, many applications stand to benefit greatly from TS/MP

server class resource management and other features.

To widen the applicability of Pathway/iTS, the GDSX product was developed to serve

as an intermediate process between Pathway/iTS and an I/O process, handling the

terminal protocol on the I/O process side, and sometimes simulating a terminal

supported by Pathway/iTS on the TCP side. (The Pathway/iTS requester is usually

configured for Intelligent Device Support [IDS] mode, so that the program does not

control how data appears to the intelligent device, nor does it perform any other

device-dependent functions.)

Direct Terminal Access

In an application using Pathway/iTS and GDSX, the Pathway/iTS TCP simultaneously

supports multiple threads. Each thread is a continuing session with an I/O device,

typically a terminal. A SCREEN COBOL program controls data transmission with the

terminals. The terminals typically act as input devices for requests that are sent to

server classes for processing.

When an application using Pathway/iTS and GDSX is started, the GDSX process is

started first. For example, the following TACL RUN command can be issued to run a

GDSX object named $GDS:

> RUN GDSE /NAME $GDS, NOWAIT/

Then, depending on the application design, SCF might or might not be used to

configure subdevices (SUs) and lines (LINEs) before Pathway/iTS is started. For