A computer program product, apparatus and method for processing a variable length device command word (DCW) at a control unit configured for communication with an input/output (I/O) subsystem in an I/O processing system. The computer program product includes a tangible storage medium readable by a processing circuit and storing instructions for execution by the processing circuit for performing a method. The method includes receiving a DCW at the control unit from the I/O subsystem. The DCW specifies one or more I/O operations and includes a command, a control data count, and control data having a varying length specified by the control data count. The control data is extracted in response to the control data count. The command is then executed in response to the extracted control data to perform the specified one or more I/O operations.

Title
Processing a variable length device command word at a control unit in an i/o processing system
Application Number
12/030939
Publication Number
20090210559
Application Date
February 14, 2008
Publication Date
August 20, 2009
Inventor
Catherine C Huang
Poughkeepsie
NY, US
Ugochukwu C Njoku
Yonkers
NY, US
Gustav E Sittmann
Webster Groves
MO, US
Dale F Riedy
Poughkeepsie
NY, US
Matthew J Kalos
Tucson
AZ, US
Daniel F Casper
Poughkeepsie
NY, US
John R Flanagan
Poughkeepsie
NY, US
Agent
Cantor Colburn IBM Poughkeepsie
CT, US
Assignee
International Business Machines Corporation
NY, US
IPC
G06F 03/00
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