Browse Prior Art Database

Data-mirroring in PCI bus

IP.com Disclosure Number: IPCOM000014658D
Original Publication Date: 2001-Sep-01
Included in the Prior Art Database: 2003-Jun-20
Document File: 2 page(s) / 71K

Publishing Venue

IBM

Abstract

Disclosed is a hardware function to mirror a PCI storage device. The hardware monitors "write" data transferred to the target PCI device with storage and derives the data into own "redundant" storage simultaneously.

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Data-mirroring in PCI bus

    Disclosed is a hardware function to mirror a PCI storage device. The hardware monitors "write" data transferred to the target PCI device with storage and derives the data into own "redundant" storage simultaneously.

    In present computer system, to preserve stored data is one of most important matters. the disclosure realizes low-cost, easy-to-develop and better performed data mirroring. Using the disclosed hardware functions, following points are advantage: - the disclosure can be implemented in general purposed PCI bus, not a special bus. - the disclosed hardware only monitors PCI bus, so performance load for software or hardware is very little.

    The disclosed hardware function consists of simple hardware logic and firmware. As shown in Figure, suppose a PCI storage device such as SCSI controller and RAID controller as Device A and that Device B has the disclosed logic and sufficient storage. Device B monitors "memory write to device A".

Device B works in following procedures:
1. After the system boot up and PCI bus initialized, Device B gets "PCI Address" of Device A by searching "Vender ID" and "Device ID" of Device A.
2. Similarly, Device A gets "Memory Base Address" of Device A and monitors PCI data that are accessed to the "Memory Base Address" of Device A.
3. If memory addresses of Device A are accessed "Write", Device B derives the data. and stores these to own storage. Following is in details:

3.1 Device B monitors and derives every...