×

Providing indirect data addressing for a control block at a channel subsystem of an I/O processing system

  • US 8,516,161 B2
  • Filed: 01/16/2012
  • Issued: 08/20/2013
  • Est. Priority Date: 02/14/2008
  • Status: Active Grant
First Claim
Patent Images

1. A computer program product for facilitating input/output (I/O) processing for an I/O operation at a host computer system configured for communication with a control unit, the computer program product comprising:

  • a tangible storage medium readable by a processing circuit and storing instructions for execution by the processing circuit for performing a method comprising;

    obtaining a transport command word (TCW) for an I/O operation, the TCW specifying a location address and a flag, the flag indicating whether the TCW directly or indirectly addresses a message for transmitting one or more commands to the control unit;

    extracting the specified location address and the flag from the TCW;

    obtaining the message from the specified location address based on the flag having a first value indicating direct addressing, the message comprising one or more I/O commands;

    gathering one or more I/O commands from command locations specified by a list of addresses identified by the specified location address to form the message based on the flag having a second value indicating indirect addressing, the message comprising the gathered one or more I/O commands; and

    forwarding the message to the control unit for execution.

View all claims
  • 0 Assignments
Timeline View
Assignment View
    ×
    ×