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Write Inhibit a Single DASD Device at the System Level Using the Path Group Identifier

IP.com Disclosure Number: IPCOM000247896D
Publication Date: 2016-Oct-10
Document File: 1 page(s) / 43K

Publishing Venue

The IP.com Prior Art Database

Abstract

Disclosed is a method that enables a user to write inhibit a single device for a single host system using the path group identifier.

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Write Inhibit a Single DASD Device at the System Level Using the Path Group Identifier

A diagnostic control command (i.e., Dynamic Shared Object (DSO)) enables a user to write inhibit a Direct Access Storage Device (DASD). However, this command write inhibits all devices within the logical path that was used to

write-inhibit the device.

There are no known solutions within an enterprise operating system that write inhibit a single device within a single system. A method is needed to enable a user to write inhibit a single device for a single host system.

The novel method write inhibits the device by passing the path group identifier, along with the logical subsystem number (LSS) and channel connection address (CCA), to the storage control unit so that it can write inhibit the device at the path group ID level.

When a DASD volume is brought online to a host system, the method establishes a path group identifier for that device on that system. This path group identifier is unique for each system that has access to the device. This path group identifier can be obtained via the ICKDSF ANALYZE HOSTACCESS(ALL) command.

Figure: Example of the output

The method then passes this path group ID, along with the LSS and CCA, to the hardware via a new DSO command. This new command has the hardware just write inhibit the device for that path group ID, so that any write operations coming in from that path are command rejected.

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