Browse Prior Art Database

Microprocessor Y Cable

IP.com Disclosure Number: IPCOM000122589D
Original Publication Date: 1991-Dec-01
Included in the Prior Art Database: 2005-Apr-04
Document File: 3 page(s) / 90K

Publishing Venue

IBM

Related People

Snidow, RE: AUTHOR

Abstract

This article describes a microprocessor cable which is used to allow identical processors to execute identical instructions synchronously.

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

Microprocessor Y Cable

      This article describes a microprocessor cable which is
used to allow identical processors to execute identical instructions
synchronously.

      Development of fault tolerant hardware which utilizes two
microprocessors executing identical instructions synchronously while
their address bus, data bus, and control bus are being compared for
identity presents an environment in which a single microprocessor
emulator is of limited value.  When the emulator is installed, the
two "sides" (a side being the microprocessor and its associated
storage and logic) will not execute identically when emulation
functions are used such as examine memory, modify registers, etc.
Further, the hardware timings presented by the emulator as compared
to the actual microprocessor may not permit synchronous operation
though no special emulation features are used.

      The microprocessor Y cable disclosed herein provides two
identical microprocessor appearances for either the microprocessor
emulator or the actual microprocessor.  The timing and instruction
execution are identical for both sides permitting the system to be
debugged while providing the resources of emulation.  Also, with a
knowledge of the interaction of two shorted outputs in a particular
technology, differences in the execution of the two sides can be
detected.

      The drawing is a functional block diagram showing the
interconnection scheme of this disclosure which permits a single
processing element to act as multiple synchronous processing
elements.

      The microprocessor Y cable consists of the following elements:
1.   Microprocessor or Emulator - a socket into which either the
microprocessor emulator or an actual microprocessor is inserted.
2.   Microprocessor Plug - two pin headers which are physically
identical in connection arrangement to the microprocessor for which
they are substituted.
3.   Address Bus - physical connections from the micropro...