Programming Support; Response Time - IBM 3270 Manual

Programming Support
Response Time
1-6
It is important to plan for proper programming support at the host system.
The 3274 clusters can be added to most 3270 display/printer systems with
minimal impact on the existing programs. In certain cases, however, host
system definition (SYSGEN) parameters will have to be changed to
accommodate attachment of a 3274 cluster. Information on programming
requirements is given in IBM 3270 Information Display System: 3274 Control
Unit Description and Programmer's Guide, GA23-0061.
In addition, it is recommended that for 3274 clusters you enhance your
system availability and serviceability by installing the online test executive
program (OLTEP) at the host system. Contact your IBM representative for
information about OLTEP.
For IBM 3270 Personal Computers attached to the 3274, the file transfer
program can be used to send and receive files between a personal computer
session and a host virtual machine/conversational monitor system
(VM/CMS) VM/SP 2.1 or time sharing option (TSO) session. Before either
program can be used, the IBM
host~supported
file transfer program, 5664-281
for VM/CMS or
5665~311
for TSO, must be installed at the host site.
The response time (performance/throughput) of the terminals (displays and
printers) attached to a 3274 can be significantly affected by many factors.
Some of these factors are:
• Inbound and outbound message lengths
• Frequency and content of message (tabbing, modified data tags (MDTs),
selects, and so on)
• Type of channel and size of processing unit
• Protocol (systems network architecture [SNA] or non-SNA; binary
synchronous communication [BSC] or Synchronous Data Link Control
[SDLC])
• Cluster size, network content, and line speed
• Printer speed and type (with or without intelligence, matrix or line
printing, LUl, LU2, or LU3 mode, and with or without color option)
e
Screen size and features (Programmed Symbols [PS], color, and so on)
• The associated system control and application programs.
To help you to determine response time during the early planning stages of
your 3274 display/printer subsystem, it is recommended that you contact
your IBM sales representative. He has the tools and facilities to evaluate
your 327 4 subsystem response time.
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