Phase #(20)23 - Hard Disk Media Check; Phase #(20)23 Test - AT&T 3B2 Off-Line Diagnostic Manual

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Phase #(20)23 - Hard Disk Media Check
Phase Name:
Type:
Function:
Test:
Warnings:
Hard Disk Media Phase (mecLtst)
Demand
This phase verifies that the Cyclic Redundancy Check (CRC) codes for both
data and addresses are correct over the entire disk media. This phase also
verifies that the address returned by the Hard Disk Controller (HDC) is the
next expected address.
Test 1 - uses the check command to verify that the CRC codes for both the
address and data are correct. For all CRC errors that are detected, the failing
address is printed in absolute form (that is, cylinder, head, and sector).
The address returned by the HDC is compared with an expected value to
ensure that the HDC knows where it is on the disk. An error message is
displayed if a mismatch occurs.
Any error detected during a seek, recalibrate, or when the operational mode of
the controller is specified will result in the termination of the test. If a failure
occurs, the Hard Disk Interface (Phase 18) diagnostic should be run to
determine the problem.
This test code assumes that the demand phase of the Hard Disk Interface
diagnostic runs ATP (All Tests Passed). It also assumes the disk is formatted
and that known defects have been mapped to alternate sectors.
Phase #(20)23 Test
Test Number: 1
Function: This test checks the entire surface of the disk with the check command.
Procedure: The CRC for both the address and data is verified by the check command.
Defect management is used to avoid known media defects. In addition to the
CRC, the address returned by the HDC is checked to verify that the controller
knows the portion of the disk it is checking.
Hardware Tested: The surface of the hard disk is tested.
Data Returned: The failing disk address of the error and any disk address mismatches are
returned.
Supplemental Data: The controller status for fatal controller errors is returned.
SYSTEM BOARD DIAGNOSTICS 3-65