Browse Prior Art Database

Advanced Error Management for DASD

IP.com Disclosure Number: IPCOM000104215D
Original Publication Date: 1993-Mar-01
Included in the Prior Art Database: 2005-Mar-18
Document File: 2 page(s) / 40K

Publishing Venue

IBM

Related People

Chesarek, DJ: AUTHOR

Abstract

Disclosed is a DASD error recovery process which utilizes a "service reference cylinder" concurrently with in-line diagnostics tests to direct the error recovery process.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 75% of the total text.

Advanced Error Management for DASD

      Disclosed is a DASD error recovery process which utilizes a
"service reference cylinder" concurrently with in-line diagnostics
tests to direct the error recovery process.

      The Advanced Error Management (AEM) process invokes a set of
diagnostic function tests as part of the recovery process before
posting a permanent I/O error condition or before taking any
resources off line as part of error management damage control.  AEM
does not depend on customer production I/O to generate the sense data
used in the prior art error management process.  It ensures that
sufficient information is available by the use of diagnostic tests.

      A key element of the proposed process is the Servo Reference
Cylinder (SRC) located on each DASD device.  Each SRC contains known
good test data, and space which will allow the AEM diagnostic
function tests to write data on the DASD device without impacting
customer data.

      To summarize, the SRC has the following attributes.  It
contains known test data which can be read free of repeatable checks,
at least at the last time media maintenance was performed on that
cylinder.  It also contains space for the data to be written on media
maintained tracks, and data which was accurately aligned with the
heads when it was written.  The SRC is located on a physical cylinder
which has a maximum bit density for any data under the actuator which
will process its data.

      The AEM pr...