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Programming Support
Response Time
Configuration Support
1-4
The 3274 Models IS and 10 also require an address range. Calculate the number of
contiguous addresses as follows:
8 X Number of Type A Terminal Adapters
+
4 X Number of Type B Terminal
Adapters
For example, a control unit address of hex 20 with 2 Type A Terminal Adapters and 3
Type B Terminal Adapters Would be 16
+
12::: 28. Therefore, 28 is the number of
contiguous addresses. The 3274 Models IB and 10 will then respond to addresses hex 20
through hex 3B.
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.
Infonnation on programming requirements is given in
An Introduction to the IBM 3270
Information Display System, GA27-2739, Introduction to Programming the IBM 3270,
GC27-6999, and
IBM 3270 Information Display System: Component Description,
GA27·2749.
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.
The response time (performance/throughput) of the devices (displays and printers)
attached to a 3274 can be significantly affected by many factors. Some of these factors
are:
1. Inbound and outbound message lengths.
2. Frequency and content of message. (tabbing, R/MOTs, selects, etc.)
3. Type of channel and size of CPU.
4. Protocol (SNA or non-SNA; BSC or SOLC).
5. Cluster size, network content, and line speed.
6. Printer speed and type (with or without intelligence, matrix or line printing, LUI,
LU2, or LU3 mode, and with or without color option).
7. Screen size and features (PS, color, etc).
8. The associated system control and application programs.
To assist 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 representa-
tive. He has the tools and facilities to evaluate your 3274 subsystem response time.
There are multiple levels of diskettes (Configuration Support levels) available for the
3274 Control Unit. These levels allow selection of the diskettes (feature and system) that
will satisfy your requirements.
If
you update your 3270 system with additional functions you may also have to change
your Configuration Support level. Consult your IBM representative for specific functions
included in each Configuration Support level.
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