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Testing a Channel by Wrapping at the Input/Output Interface

IP.com Disclosure Number: IPCOM000116933D
Original Publication Date: 1995-Nov-01
Included in the Prior Art Database: 2005-Mar-31
Document File: 2 page(s) / 73K

Publishing Venue

IBM

Related People

Gregg, TA: AUTHOR

Abstract

Disclosed is a method for testing channel hardware by connecting the output conductors to the input conductors at the I/O interface. A peer mode is established in the channel so that messages sent from a sending entity in the channel are transmitted over the wrap connection to a receiving entity in the same channel. The receiving entity generates a response and sends it back to the sending entity over the same wrap connection, and the test is complete. Special diagnostic programs and not required, and normal programs executed by the system are used to perform the tests.

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Testing a Channel by Wrapping at the Input/Output Interface

      Disclosed is a method for testing channel hardware by
connecting the output conductors to the input conductors at the I/O
interface.  A peer mode is established in the channel so that
messages sent from a sending entity in the channel are transmitted
over the wrap connection to a receiving entity in the same channel.
The receiving entity generates a response and sends it back to the
sending entity over the same wrap connection, and the test is
complete.  Special diagnostic programs and not required, and normal
programs executed by the system are used to perform the tests.

      Computer systems have external I/O interfaces that require a
method of testing without connecting external test equipment.
Typically, wrap connectors are installed at these connectors and
special diagnostic exercisers send information over the I/O interface
through the wrap connection.

      In particular, this disclosure relates to the message channel
described in (*).  This channel is tested by placing it in wrap mode
and executing normal programs; special diagnostic code is not
required.

      The Figure shows the present implementation of the docket where
the channel is operated as either a sender or receiver.  As messages
or responses are received, bits in the Link Control Word (LCW) are
examined to determine which buffer set receives the information.  In
sender mode the two buffer sets in the channel (called ORIGINATE 0
and ORIGINATE 1) are configured to receive the responses from the
messages (u...