AT&T 3B2 Off-Line Diagnostic Manual page 536

Phase Descriptions - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
Phase #21
Phase Name:
Type:
Function:
Tests:
Time:
Warnings:
Notes:
HDC XD Read/Write Tests
Data Read/Write Tests (xdc_7)
Demand
This phase performs a Read/Write test on the diagnostic cylinder.
Test 1 - uses the specify command to initialize the NEC chip.
Test 2 - moves the heads to cylinder O.
Test 3 - reads the physical drive information and defect table.
Test 4 - writes the diagnostics cylinder with data.
Test 5 - returns the heads to cylinder
o.
Test 6 - uses the check command to verify the correct generation of the CRC
code for the data.
Test 7 - returns the heads to cylinder
o.
Test 8 - reads data from the diagnostic cylinder and compares it to data in a
buffer.
Test 9 - returns the heads to cylinder
o.
Tests 10 through 100 - no tests run.
Tests 101 through 109 - are identical to Tests 1 through 9 except disk1 is
tested.
50 seconds
None
This phase is designed to test the read/write capabilities of the disk. A
complete cylinder will be written and read. The tests are done over the
diagnostic cylinder. During the course of this phase, the check command is
used to verify that the CRC bytes are correct. The verify data command is
used to check the data. The test sequence is as follows:
Write - Write data to the disk.
Check - Check that CRC bytes are correct.
Verify - Verify data written against the buffers.
Read - Read the data and then compare.
Error Detection - Read the data with induced errors.
CRC - Check CRC Error Detection.
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