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Dynamic Allocation of High Availability Storage

IP.com Disclosure Number: IPCOM000091527D
Original Publication Date: 1968-Mar-01
Included in the Prior Art Database: 2005-Mar-05
Document File: 2 page(s) / 44K

Publishing Venue

IBM

Related People

Hackl, FJ: AUTHOR [+2]

Abstract

The possibility that a malfunction within a computer storage causes it to be unavailable for data processing can be decreased. This is realized by setting aside certain blocks of storage such that two or more physical storage units are actually addressed each time an address is referenced. In the event that one storage unit fails, the needed data can be fetched from the other.

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Dynamic Allocation of High Availability Storage

The possibility that a malfunction within a computer storage causes it to be unavailable for data processing can be decreased. This is realized by setting aside certain blocks of storage such that two or more physical storage units are actually addressed each time an address is referenced. In the event that one storage unit fails, the needed data can be fetched from the other.

In a system in which not all data need be placed in such high availability storage, storage can be allocated by having the Central Processing Unit CPU use the group of lines A. CPU brings up the Allocate Line and at the same time activates the Address Prefix Bus and the Unit Bus. The Address Prefix indicates which high-order storage address bits are to select the storage units indicated by the Unit Bus. When the Allocate Line is up, the Storage Configuration and Selection Control Unit SCS constructs a table of storage unit numbers specified by the Address Prefix bits.

To use a storage unit after it has been allocated, CPU activates the Storage Select Lines signalling either for a read or a write. At the same time, it puts a virtual address on the Virtual Address Bus and either puts write data on the Read-Write Bus or anticipates data coming from it. The SCS translates high- order bits of the virtual address into one or more storage unit selects. It also transmits the low-order address bits and the select lines to the appropriate storage units....