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Storage and Key Move

IP.com Disclosure Number: IPCOM000120707D
Original Publication Date: 1991-May-01
Included in the Prior Art Database: 2005-Apr-02
Document File: 1 page(s) / 48K

Publishing Venue

IBM

Related People

Brey, TM: AUTHOR [+7]

Abstract

A storage key protects data (4K page) associated with the key from being used per the value and conditions of the key. If the key is broken, then a machine check is generated and no task can access the data. If the data is changed and critical to the task or system, then the task is aborted and/or the system is aborted.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 77% of the total text.

Storage and Key Move

      A storage key protects data (4K page) associated with the key
from being used per the value and conditions of the key. If the key
is broken, then a machine check is generated and no task can access
the data.  If the data is changed and critical to the task or system,
then the task is aborted and/or the system is aborted.

      This design allows the machine check to be generated; however,
it is intercepted by the Recovery Module of the System Control
Program.  The Recovery Module is modified to issue a new instruction.

      When this condition of key error is detected, this Recovery
Module then looks for an unused, unassigned page wherein the data
with the bad key can be moved.  The instruction provides a source
address and a destination address.  The processor will then, upon
decode of the new instruction, signal the Service Processor to have
the system move the data.

      In this design, another element is used to do the data move.
Unlike the CP, this element can move data without being signalled of
a key error.

      The Service Processor then retrieves from the Hardware System
Area (HSA) the copy of the storage key that is the good copy of the
key.  (When the key was last altered, a copy was put in the HSA for
recovery of soft errors.)  The good copy of the source key is then
written in the destination address.  The processor is then signalled
of the success of the move and the new instruction is allowed to
pro...