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Browse Prior Art Database

Error Protection for Data Transfers between Hard Disk and Host

IP.com Disclosure Number: IPCOM000106704D
Original Publication Date: 1993-Dec-01
Included in the Prior Art Database: 2005-Mar-21
Document File: 2 page(s) / 42K

Publishing Venue

IBM

Related People

Gonzalez, JP: AUTHOR

Abstract

Described is a technique for use in a computer system for checking data transfer synchronization between a disk drive and the host.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 81% of the total text.

Error Protection for Data Transfers between Hard Disk and Host

      Described is a technique for use in a computer system for
checking data transfer synchronization between a disk drive and the
host.

      The technique disclosed herein is implemented as part of the
device driver (software) for the hard disk.

On any data transfer, the device should proceed with the steps as
follows:

1.  Keep track of the number of data words (bytes) being transferred.

2.  Continue the transfer as usual until the word next to last has
    been transferred.  In other words, do not complete the transfer;
    pause before transferring the last word.

3.  At this critical point, check the data request (DRQ) bit in the
    disk drive status register.  This bit should be set to 1,
    indicating that the drive is ready for more data transfer.  If it
    is not a 1, a synchronization error has been detected in this
    transfer, and appropriate error correction and/or reporting
    should be performed at this point.

4.  If the DRQ bit was set in step 3, then the remaining word is
    transferred.

5.  At this (also critical) point, the DRQ bit should be checked once
    again.  This time DRQ should be 0, indicating that the drive does
    NOT expect any more transfers.  If it is set to 1, it is an
    indication of a synchronization error.  Correction or reporting
    should be made as appropriate.

6.  If the transfer passes both DRQ tests, it...