Dismiss
InnovationQ will be updated on Sunday, Oct. 22, from 10am ET - noon. You may experience brief service interruptions during that time.
Browse Prior Art Database

Determination of a Non-SNA Local Channel Chained Command in a TN3270 Client

IP.com Disclosure Number: IPCOM000015910D
Original Publication Date: 2002-Apr-06
Included in the Prior Art Database: 2003-Jun-21
Document File: 2 page(s) / 43K

Publishing Venue

IBM

Abstract

The current level of support in TN3270 and/or TN3270E for Non-SNA Local Channel Chaining support is lacking. A Non-SNA local channel chained command's starting location is different from a non-chained command. Hence applications that make use of this function may not work correctly in a TN environment. This is gaining attention mainly due to the fact that CONSOLEs are still a required 3270 application and with the advent of IBM no longer manufacturing a channel attached 3174 which was the channel attached box of choice for many a year other ways had to be used to still supply the CONSOLE facility. Current known solutions:

This text was extracted from a PDF file.
This is the abbreviated version, containing approximately 52% of the total text.

Page 1 of 2

Determination of a Non-SNA Local Channel Chained Command in a TN3270 Client

    The current level of support in TN3270 and/or TN3270E for Non-SNA Local Channel Chaining support is lacking.

A Non-SNA local channel chained command's starting location is different from a non-chained command. Hence applications that make use of this function may not work correctly in a TN environment.

This is gaining attention mainly due to the fact that CONSOLEs are still a required 3270 application and with the advent of IBM no longer manufacturing a channel attached 3174 which was the channel attached box of choice for many a year other ways had to be used to still supply the CONSOLE facility.

Current known solutions:

1: A Server side only solution is possible but that would require a 3270 data stream parser on the server and hence would have a performance impact. It is known that 2074 attempts to implement this solution but does not have a full 3270 parser and hence has known limitations.

2: Some Clients after examining particular data stream sequences have noted that most chained operations follow a particular sequence and will GUESS that a chained operation has occurred when the sequence is detected. This has obvious flaws in that guessing could be wrong in either direction, it isn't chained when chaining is guessed or it is chained when chaining isn't guessed. Additionally the clients of which the author is aware only support chained read operations and NOT chained writes.

3: Visara Console controller has a propriately solution that uses TN3270E as a base and adds bit definitions to the headers and uses New Environment telnet negotiations.

4: IETF has NO published/architected/approved architecture.

Background: TN3270 architecture defined both columns below as valid TN3270 commands.

Command Local Non-SNA SNA Write 01 F1 Erase/Write 05 F5 Erase/Write Alternate 0D 7E Write Structured Field 11 F3 Read Buffer 02 F2 Read Modified 06 F6 Erase All Unprotected 0F 6F

Both the 3270 SNA Write Command (x'F1') as well as the Local...