Pathway/iTS Web Client Programming Manual (H06.03+, J06.03+)

Introduction to Pathway/iTS 1.1
HP NonStop Pathway/iTS Web Client Programming Manual—520270-003
7-3
SCOBOL Verbs and Special Register
Pathway/iTS 1.1 contains two TCP components, PATHTCP4 and the legacy TCP
component PATHTCP3. PATHTCP4 serves the same Java clients and the SCREEN
COBOL applications but with a different architecture. It does not perform the link
management activities and therefore does not communicate with the target PATHMON
process directly. It acts as a Pathsend requester and calls SERVERCLASS_* APIs for
the LINKMON/ROUT process to forward the request to the server process.
The LINKMON/ROUT process supports context-sensitive communication by enabling
transfer of more than 32,000 bytes of data between the client process and the same
server process. Hence, PATHTCP4 component can use this feature to support data
transfer of more than 32,000 bytes between the SCREEN COBOL programs or the
converted Java clients and the same Pathway server process. In Pathway/iTS 1.0, the
PATHTCP3 component communicates with the target Pathmon process to act as a link
manager and then forwards the application message by doing WRITEREAD call on the
server process.
PATHTCP4 does not communicate with the target Pathmon process. In PATHTCP4,
the owning Pathmon process opens the PATHTCP4 process to send or receive the
configuration or operational messages.
The LINKMON/ROUT process plays the real link manager role by communicating to
the target Pathmon. While the TCP process collects the terminal statistics, the
LINKMON/ROUT process reports the server side statistics.
SCOBOL Verbs and Special Register
The data item sent to a server process from TCP of Pathway/iTS 1.0 (PATHTCP2 or
PATHTCP3) cannot exceed 32,000 bytes. Also, there is no guarantee that a second
SEND verb to the same server class will enter to the same server process as the
previous one. Pathway/iTS 1.1 address this issue by a context sensitive or dialog-
based communication model. The dialog-based communication between a SCOBOL
requester or Java client and a Pathway server involves establishing a dialog between
the requester and server process in a server class, and then sending messages within
the dialog. After a dialog is established, the same server process is used for all the
messages in the dialog and thus the server can retain the context between the SEND
operations.
For a dialog-based communication, Pathway/iTS 1.1 includes:
•
Four SCOBOL verbs, DIALOG-ABORT, DIALOG-BEGIN, DIALOG-END, and
DIALOG-SEND
•
A special register, DIALOG-INFO
A terminal starts a dialog (and optionally sends data) with a server process in a server
class by making a DIALOG-BEGIN statement. The successful execution of the
DIALOG-BEGIN statement starts a dialog for the terminal. The terminal continues to
send messages to the same server by making DIALOG-SEND statements. At any
point of time, either the terminal or the server can abort the dialog, but only the server
can end it. The server aborts the dialog by returning the file-system error 1 (FEEOF) in