Deconfigure storage class memory command

Abstract

An abstraction for storage class memory is provided that hides the details of the implementation of storage class memory from a program, and provides a standard channel programming interface for performing certain actions, such as controlling movement of data between main storage and storage class memory or managing storage class memory.

What is claimed is: 
     
         1 . A method of executing an instruction to execute a Deconfigure Storage Class Memory command in a computing environment comprising main storage and storage class memory, said method comprising:
 obtaining by an input/output (I/O) subsystem a request block, the request block comprising a command code indicating the Deconfigure Storage Class Memory command and a storage class memory (SCM) increment request list including one or more entries, each entry configured to include a total size field to specify a number of increments of storage class memory to be deconfigured and a starting SCM address indicating a starting location from which to deconfigure storage class memory increments;   based on the command code, initiating a deconfiguration process for deconfiguring the storage class memory, the process configured to deallocate the requested number of increments of storage class memory specified in the total size value, wherein the initiating comprises performing one or more validity checks;   continuing to perform the deconfiguration process of the storage class memory based on the one or more validity checks being successful, wherein the one or more validity checks comprises determining that the increments of storage class memory to be deconfigured are in a configured state; and   storing a response code in a response field of a response block, the response code indicating whether the deconfiguration process is initiated, the response block comprising a length code indicating a length of the response block.   
     
     
         2 . The method of  claim 1 , wherein the one or more validity checks further comprises a check of a length field of the request block; a check of whether the Deconfigure Storage Class Memory command is available to be executed; a check that the request block has a valid format; and a check that the I/O subsystem is able to perform the Deconfigure Storage Class Memory command, and wherein the deconfiguration process continues based on the one or more validity checks being successful. 
     
     
         3 . The method of  claim 1 , wherein the initiating further comprises commencing an asynchronous process to perform the deconfiguration of the storage class memory based on the one or more validity checks being successful, wherein deconfigured storage class memory content is initialized to zero and placed in a standby state. 
     
     
         4 . The method of  claim 3 , further comprising indicating completion of the asynchronous process in a notification response block. 
     
     
         5 . The method of  claim 4 , wherein the notification response block includes a response code that indicates results of the attempt to execute the Deconfigure Storage Class Memory command. 
     
     
         6 . The method of  claim 5 , wherein the notification response block is obtained via execution of a store event information command to obtain event information. 
     
     
         7 . The method of  claim 4 , wherein the request block is further configured to include an asynchronous completion correlator to be returned in the notification response block, the asynchronous completion correlator to be used to resume processing of the Deconfigure Storage Class Memory command. 
     
     
         8 . The method of  claim 1 , wherein the deconfiguration process includes:
 moving the increments of storage from a configured state to a reserved state;   zeroing contents of the increments of storage; and   placing the increments of storage in a standby state.