SNAP-IX TN3270 Administrator's Guide - 5.3 Trace File Formats

5.3 Trace File Formats

This section provides examples and information about how to interpret the trace output for the different trace types.

5.3.1 Common File Information

The trace data for a single message can occupy more than one line in the trace file. Each individual message is preceded by a horizontal line indicating the time at which the trace entry was made. The following information is common to both TN3270 emulation program tracing and HLLAPI tracing:

The 5-digit process ID of the component being traced appears at the start of each line. The process ID is followed by an indicator of the type of component being traced (EHLL for a HLLAPI application, or 3270 for the 3270 emulation program).
Message data is shown in the following formats in separate columns to ensure that a character string in the message data appears as readable text in either the EBCDIC or the ASCII column according to its character set:
- Hexadecimal
- Interpreted as EBCDIC
- Interpreted as ASCII

5.3.2 File Information for TN3270 Message Tracing

SNAP-IX TN3270 provides the following types of message tracing for the TN3270 program:

Internal: Traces messages internal to SNAP-IX TN3270. These messages are used primarily by SNAP-IX TN3270 support personnel, who may ask you to provide trace files to assist them in diagnosing problems with SNAP-IX TN3270.
TCP/IP data: Traces the messages sent over TCP/IP to the host in the format in which they flow over the network. These messages are useful for investigating network problems.
FMI data: Traces data transferred between SNAP-IX TN3270 and the host in the format in which they are represented inside SNAP-IX TN3270. These messages can be useful for investigating local problems and problems with remote systems.

The start of each trace entry shows the type of message being traced and a decoded version of some of the header information. The header information and message data is then traced.

The header information in trace messages uses the following abbreviations:

Abbreviations Used in Trace Message Headers

+RSP	Positive response
-RSP	Negative response
BBI	Begin bracket indicator
BCI	Begin chain indicator
CEB	Conditional end bracket
DAF	Destination address field
DR1,DR2	Definite response 1 and 2 indicators
EBI	End bracket indicator
ECI	End chain indicator
ERI	Exception response indicator
OAF	Origin address field
ODAI	OAF/DAF indicator
RH	Request header or response header
RU	Request unit or response unit
SC	Session control
TH	Transmission header

5.3.3 File Information for HLLAPI Tracing

The following parameters for each HLLAPI function are traced when the function is issued and again when it returns.

func_number: This parameter is shown in parentheses after the name of the function.
data_length and ps_position/return code: These parameters are always shown following func_number.
data_string: This parameter is traced only if it is used by this function.