Browse Prior Art Database

Enhanced Reliability Mode for Work Station Controllers

IP.com Disclosure Number: IPCOM000102229D
Original Publication Date: 1990-Nov-01
Included in the Prior Art Database: 2005-Mar-17
Document File: 3 page(s) / 115K

Publishing Venue

IBM

Related People

Dancker, GA: AUTHOR

Abstract

Some newer twinaxial (IBM 5250 protocol) work station controllers (WSCs) can contain multiple serializers/deserializers (SERDES) for transmitting and receiving data on multiple ports at the same time. This is to improve overall WSC performance. However, if the external cabling to work stations (WS) is bundled (e.g., 25 twisted pairs), or a multiplexer is used (e.g., 8 ports to a fiber-optic converter), an unacceptably high error rate can occur. Described is a WSC hardware design which runs multiple ports simultaneously or, if necessary, one at a time to reduce the errors that occur.

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Enhanced Reliability Mode for Work Station Controllers

       Some newer twinaxial (IBM 5250 protocol) work station
controllers (WSCs) can contain multiple serializers/deserializers
(SERDES) for transmitting and receiving data on multiple ports at the
same time.  This is to improve overall WSC performance.  However, if
the external cabling to work stations (WS) is bundled (e.g., 25
twisted pairs), or a multiplexer is used (e.g., 8 ports to a
fiber-optic converter), an unacceptably high error rate can occur.
Described is a WSC hardware design which runs multiple ports
simultaneously or, if necessary, one at a time to reduce the errors
that occur.

      A typical WSC would control many ports (e.g., 8), but only one
would be active at any time.  The WSC would communicate on one port,
then the next, and so on, but never two at the same time.  A
customer's cabling network for attaching the WSs may work fine in
this configuration. However, if a new WSC, that communicates on
multiple ports simultaneously, is installed with the existing cabling
network, the error rate could be so great that the WSC might not
function at all.  This hardware design allows ports to run one at a
time or simultaneously.
      Features of this design:
      1.   Reduced error rate.
      2.   Improved customer satisfaction. (The new WSC will
          function with the same attached equipment and
          cabling that the old WSC used.)

      When two or more ports are driven simultaneously, separate port
control logic (PCL) would be provided for each port (or set of
ports).  For example, if a WSC controlled 8 ports, these might be
divided into two sets of 4 ports.  One port from each set could be
active at the same time.  The PCL could be designed with an enable
condition, as shown in Fig. 1.  This logic would be repeated for each
group of ports that are to be operated simultaneously.  The enable
would only be checked in the idle state.  If the enable were shut off
while an oper ation was running (e.g., not in idle state), the
disable would not take affect until the PCL state machine returned to
the idle state.

      A "master" state machine would be designed that would contain a
1-bit register, called enhanced reliability mode (ERM).  This bit
could be set or reset by the licensed intern...