Browse Prior Art Database

Twinax Line Monitor for Express Data Stream

IP.com Disclosure Number: IPCOM000123376D
Original Publication Date: 1998-Oct-01
Included in the Prior Art Database: 2005-Apr-04
Document File: 3 page(s) / 121K

Publishing Venue

IBM

Related People

Dancker, GA: AUTHOR

Abstract

This disclosure describes an enhanced twinax line monitor (TLM), that will work with the existing 5250* protocol and the new Express Data Stream enhancement for the 5250 protocol.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 48% of the total text.

Twinax Line Monitor for Express Data Stream

   This disclosure describes an enhanced twinax line monitor
(TLM), that will work with the existing 5250* protocol and the new
Express Data Stream enhancement for the 5250 protocol.

   The 5250 (twinax) protocol has been enhanced to provide
up to a 4X improvement in thruput.  These changes to the 5250
protocol are significant enough that existing twinax line monitor
trace tools are not able to work properly.  This tool is used for
debugging customer problems.  Without this tool, it will be much
more difficult to help our customers if they have problems with the
new twinax enhancements.

   A twinax line monitor is not a new idea, but including
trace capabilities for the enhanced twinax functions is new.  These
enhanced functions, called the Express Data Stream, include two new
changes to the twinax protocol:
  o  2 MHz operation: This involves switching the port from
     1 MHz (standard speed) to 2 MHz.  The capability also
     exists to switch the port back to 1 MHz.  There are two
     reasons the port would be switched back to 1 MHz.  The
     first is if errors occur at 2 MHz.  The second is because
     of how the Work Station Controller (WSC) auto-config
     program works.  The WSC auto-config program runs
     continuously, and polls each unused station address every
     7 to 8 seconds.  Auto-config always runs at 1 MHz, so every
     7 to 8 seconds, the 2 MHz port will be temporarily switched
     to 1 MHz (if there are any unused addresses on this port).
  o  Optimized Mode: This involves removing the standard twinax
     overhead from most frames (for block transfers of data).
     This almost doubles the amount of data that can be
     transferred during a given time.

   Enhanced triggering capabilities have also been added to
the new TLM.

   This particular implementation of a TLM uses a peripheral
component interconnect (PCI) adapter card, a PC that supports the PCI
bus, and a program (written in C) to provide the user interface.  The
PCI TLM adapter is based upon an existing twinax adapter card, that
has been reprogrammed to act as a TLM.  A small program (1500 lines
of assembly level code) is downloaded to the adapter in the PC.  This
causes the adapter to function as a TLM instead of a twinax adapter.

   The C program provides menus for selecting what to trace,
what to trigger on, and providing a way to view, save, or print the
trace.

   The following sections describe the new features of this
TLM.

   1MHz/2MHz Detect at Startup

   Once the TLM is attached to the twinax line to be
monitored, it has to determine if the line is running at 1 MHz or 2
MHz.  This is done by detecting transitions on the line.  The TLM
will initially start up at 1 MHz.  If a transition is detected, the
TLM waits a set amount of time for a valid frame to be received.  If
no frame is received at 1 MHz, the TLM will...