Apparatus for a host central processor with associated controller to capture a selected one of a number of memory units via path control commands

• US 5,630,169 A
• Filed: 03/29/1996
• Issued: 05/13/1997
• Est. Priority Date: 09/24/1992
• Status: Expired due to Term

• Current Assignee: Unisys Corporation
• Original Assignee: Unisys Corporation
• Inventors: Jackson, Gary E.
• Primary Examiner(s): Lee, Thomas C.
• Assistant Examiner(s): PERVEEN, REHANA
• Application Number:
  US08/625,662
• Time in Patent Office: 410 Days
• Field of Search: 395/825, 395/856, 395/475, 395/200.01, 395/725, 395/439
• US Class Current: 710/5
• CPC Class Codes: G06F 13/1657 Access to multiple memories
• CPC Class Codes: G06F 3/0601 Interfaces specially adapted for storage systems
• CPC Class Codes: G06F 3/0607 by facilitating the process of upgrading existing storage systems, e.g. for improving compatibility between host and storage device
• CPC Class Codes: G06F 3/0608 Saving storage space on storage systems
• CPC Class Codes: G06F 3/0635 by changing the path, e.g. traffic rerouting, path reconfiguration
• CPC Class Codes: G06F 3/0673 Single storage device
• CPC Class Codes: G06F 3/0689 Disk arrays, e.g. RAID, JBOD

Abstract

A pair of data processing systems, each of the data processing system having a host central processor and an associated controller including memory, both of the data processing systems to be cooperatively associated with a number of disk drive memory units, each of the disk drive memory unit coupled to both said controllers. Either one of the host central processors can appropriate any one of the disk drive memory units as a selected disk drive memory unit by propagating path-control-data to the memory in both of the controllers and in the selected disk drive memory unit.

Claims

1. An arrangement for allocating a disk drive memory unit to a selected controller in a pair of data processing systems, each said data processing system having a host central processor and an associated controller including memory, both said data processing systems to be cooperatively associated with a number of disk drive memory units, each said disk drive memory unit coupled to both said controllers, whereby either one of said host central processors can appropriate any one of said disk drive memory units as a "selected" disk drive memory unit by propagating "path-control-data" to the memory in both said controllers and in the selected disk drive memory unit, the arrangement further comprising:

propagate means for propagating command signals and said "path control data" from one of said host central processors to the associated controller as the "selected" controller to allocate one of said disk drive memory units as the "selected" disk drive memory unit;

store means for storing said "path control data" in said memory of said selected controller in response to said command signals;

first read means for reading by the selected disk drive memory unit, in response to signals from said "selected" controller and said path control data from the memory of the selected controller and for storing said path-control data in said selected disk drive memory unit;

interrupt means for interrupting the other controller by sending a command from said selected controller via said selected disk drive memory unit;

second read means for reading said path control data by said other controller from said selected disk drive memory unit and storing the path control data into its own memory; and

to accommodate

transmit means for sending a command by said other controller via said selected disk drive memory unit to said selected controller indicating that the information is received; and

signal means for indicating successful allocation by said selected controller to said one of said host central processors.

2. An array for allowing a selected controller in a pair of data processing systems to take over a disk drive memory unit, each said data processing system having a host central processor and an associated controller including memory, both said data processing systems to be cooperatively associated with a number of disk drive memory units, each said disk drive memory unit coupled to both said controllers, wherein either one of said host central processors can appropriate any one of said disk drive memory units as a "selected" disk drive memory unit by propagating "path-control-data" to the memory in both said controllers and in the selected disk drive memory unit, this array further comprising:

propagate means for propagating command signals and said "path control data" from one of said host central processors to the associated controller as the "selected" controller to allocate a predetermined one of said disk drive memory units as the "selected" disk drive memory unit;

store means for storing said "path control data" in said memory of said selected controller in response to said command signals;

first read means for reading by the "selected" disk drive memory unit, in response to signals from said selected controller and said "path control data" from the memory of the selected controller, and for storing said "path control data" in said "selected" disk drive memory unit, and also for acknowledging said predetermined selection to said selected controller;

interrupt means for interrupting the other controller by sending a command from said selected controller via said selected disk drive memory unit;

second read means for reading said "path control data" by said other controller from said "selected" disk drive memory unit and storing the "path control data" into its own memory;

transmit means for sending a command by said other controller via said "selected" disk drive memory unit to said "selected" controller indicating that the information is received; and

indicate means for indicating successful take-over by said "selected" controller to said one of said host central processors.

3. An arrangement for taking over a "selected" disk drive in a system comprised of a pair of host computer systems, each of the said host computer systems with an associated controller and controller memory, there being N such disk drives, each being similar and coupled to both said computer systems, this arrangement further comprising:

initiate means for causing a selected one of said host computer systems to propagate first signals and "path control data" to a said associated controller by way of indicating this as the "selected" controller and of designating one of said disk drives as the "selected" disk drive, with said "path control data" being stored in said memory of said "selected" controller;

read means for causing said "selected" disk drive to read said "path control data" from said memory of said selected controller, and to store said "path control data";

responsive to second signals from said selected controller;

interrupt means for causing the other controller to be interrupted by third signals from said "selected" controller, said third signals being sent via said selected disk drive, to read said "path control data" from said selected drive and to store said path control data, and also to acknowledge receipt of said path control data to said selected controller via said selected disk drive; and

signal means for causing said selected controller to indicate successful drive allocation to its own host system.