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Browse Prior Art Database

Intersystem Channel Wrap Testing

IP.com Disclosure Number: IPCOM000115316D
Original Publication Date: 1995-Apr-01
Included in the Prior Art Database: 2005-Mar-30
Document File: 2 page(s) / 70K

Publishing Venue

IBM

Related People

Burrow, SR: AUTHOR [+4]

Abstract

Disclosed is a method for testing the intersystem channel hardware by connecting the output conductors to the input conductors at the I/O interface. The channel and I/O processor use a wrap mode that allows a test program to send and receive all of the frame types required to test the channel hardware message buffers. Shadow buffers in main store are used as the source and destination for the information fields of the frames, and these buffers can be compared to the normal buffers by the test program to verify the operation of the hardware.

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

Intersystem Channel Wrap Testing

      Disclosed is a method for testing the intersystem channel
hardware by connecting the output conductors to the input conductors
at the I/O interface.  The channel and I/O processor use a wrap mode
that allows a test program to send and receive all of the frame types
required to test the channel hardware message buffers.  Shadow
buffers in main store are used as the source and destination for the
information fields of the frames, and these buffers can be compared
to the normal buffers by the test program to verify the operation of
the hardware.

      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.

      Fig. 1 shows the organization of the control blocks and buffers
in main store for one of the buffer sets.  Each buffer set (there are
a total of two buffer sets) has a group of normal buffers in main
store that is used to send the Message Command Block (MCB), send the
DATA area, and receive the Message Response Block (MRB).  The Message
Operation Block (MOB) has a pointer to the MCB and MRB, and to the
Message Buffer Address List (MBAL) which in turn points to the DATA
buffers.  The SHADOW buffers are concatenated to the normal buffers
and are used to perform the complementary function, namely receive
the MCB, receive the D...