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Non-volatile cache for providing data integrity in operation with a volatile demand paging cache in a data storage system

  • US 5,732,238 A
  • Filed: 06/12/1996
  • Issued: 03/24/1998
  • Est. Priority Date: 06/12/1996
  • Status: Expired due to Term
First Claim
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1. A non-volatile cache mechanism for use in a mass storage mechanism connected from a host computer system for storing data operated upon by the host computer system, the mass storage mechanism including a plurality of mass storage devices, a bus connected from the host computer system for conducting write addressed and data from the host computer system to the mass storage devices, a volatile cache connected from the bus for storing data to be written to the mass storage devices, and a cache control processor connected from the bus and responsive to write operations on the bus, each write operation including a write address and at least one data word, for writing the data to be written into the mass storage devices into the volatile cache mechanism, the non-volatile cache mechanism comprising:

  • a non-volatile memory connected from the bus for receiving and storing the data words,a cache control connected from the bus and to the non-volatile memory and responsive to the write operations for controlling write operations of the non-volatile memory for writing the data words into the non-volatile memory in parallel with receipt of the data words into the volatile cache mechanism,a cache index connected from the cache control for storing index entries relating write addresses of write operations on the bus with corresponding storage addresses of the data words in the non-volatile memory,the cache control being responsive to a current write operation for reading the write address of the write operation, reading the index entries stored in the cache index to identify and select at least one available storage address in the non-volatile memory for storing the at least one data word of the current write operation, generating at least one index entry relating the write address of the current write operation and a selected at least one storage address in the non-volatile memory, and generating write control signals controlling the non-volatile memory to write the at least one data word of the current write operation into the selected at least one storage address in the non-volatile memory.

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