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Computer revision port

  • US 4,649,514 A
  • Filed: 11/30/1983
  • Issued: 03/10/1987
  • Est. Priority Date: 11/30/1983
  • Status: Expired due to Term
First Claim
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1. A computer system comprising,a central processing unit having a control bus for transferring control signals between said central processing unit and various peripheral units and a data bus for transferring data between said central processing unit and the remainder of the computer system, said central processing unit being comprised of a plurality of circuit modules subject to circuit revisions and means for assembling operating systems software;

  • a programmable interface unit, said interface unit having a plurality of ports and being controlled by control signals on said control bus for transferring information between one of said ports and said data bus and for generating interface control signals at another of said ports when said central processing unit is assembling the operating system software;

    a control decoder responsive to said interface control signals for generating an enable control signal,a buffer circuit having a plurality of inputs and a plurality of outputs, said outputs being connected via said one of said ports of said programmable interface unit to said data bus in response to said enable control signal; and

    means for generating at said inputs of said buffer circuit a code number corresponding to the revision level of said circuit modules;

    said central processing unit including means for reading, during assembling of the operating system software, said code number from said data bus and for using said revision level information in said code number to load and link software routines which will operate properly with the revised circuit modules.

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