WITETM Revision 1.4

Release Notes

 

Introduction

This document contains the release notes for WITE revision 1.4 from Guzik Technical Enterprises. The highlights of revision 1.4 include:

  • Track profile test that calculates read width, write width and read-to-write offset
  • Correctly functioning production scanning mode
  • Support for new head amplifiers, head stacks and PRML chips
  • Performance enhancements for head stack testing
  • Bug fixes

All discussion of features and bugs in this document uses WITE version 1.31 as a baseline for comparison. For information about features and modifications prior to 1.31, please refer to the WITE user's manual and to the release notes for previous revisions of WITE.

New Features in WITE 1.4

Enhancements to the track profile test

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Track profile test algorithm

The track profile test has been enhanced to measure the write width, read width and read-to-write offset. The test also optionally measures bitshift and comparator error rate as a function of the offset from the track center.

The following algorithm is used to perform width and offset calculations:

  1. The track profile is measured according to the range and increment parameters.
  2. The peak of the measured track profile taken as 100% amplitude and the lowest TAA in the specified range as 0% amplitude (floor level).
  3. Two interpolation lines are built from the lower interpolation limit to the upper interpolation limit using the least squares fit method.
  4. The distance between the interpolation lines at the write width threshold (default 50%) is reported as the write width ("TPWrWidth").
  5. The distance between the continuation of the interpolation lines to the floor level minus the calculated write width is reported as the read width ("TPRdWidth").
  6. The read-to-write offset is calculated as the distance between the center of the write width and the zero offset in the track profile plot. Please note that this algorithm is different from the one used in the standalone WROffset test. These tests may give different values for read-to-write offset.

Track profile test configuration

To configure the track profile test, select "Tests | Composite Tests | Track Profile" from the dashboard.

You will see the following track profile test configuration dialog box:

The "Iterations" box specifies the number of iterations. TAA measurements will be performed iterations times at each offset position.

The "Filter" box allows selection of the filter to read the signal through. Please note that if the overwrite option is selected, the overwrite filter specified for the current zone in "Control|Filters" will be used.

The "microInch Range" frame specifies the starting and ending offset and increment between measurements in microinches. The device step shows the minimum step size of the current device in microinches.

The "Write" frame controls the write operation, allowing selection of the pattern or flux to be written.

The "Interpolation" frame allows enabling and disabling of slope interpolation. When interpolation is enabled, the interpolation lines will be built between upper and lower thresholds specified and the write width, read width and read-to-write offset will be measured and saved to the database. To apply the measured read-to-write offset value to subsequent tests, select the "Program WROffset" option. Note that the "Program WROffset" option can be used only when both the "Write" and "Interpolation" options are enabled. "Write width threshold" specifies the level at which the write width is to be measured.

The "Attenuator control" frame allows manual adjustment of the attenuator and freezing of its automatic adjustment during the test.

The "Test Selection" frame allows enabling and disabling of bitshift and comparator error rate measurements. Use of the fast offset operation for TAA measurements is also controlled within this frame. Note that the fast offset operation can not be used if the bitshift or comparator error rate tests are enabled. Enabling the "Backward TAA" option will cause track profile measurements to be taken both forward and backward. The "Average forward and backward TAA" option enables reporting of the average TAA. This option is available only when "Backward TAA" is enabled.

The "Table Data" frame specifies whether the track profile should be plotted and/or written to the database.

Conversion program for new database format

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To avoid frequent changes to the RWA.MDB database, the PRML read channel parameters have been separated into their own database, ERA.MDB. When WITE 1.4 is run for the first time on a product created using WITE 1.31 or earlier, this database file will be created automatically. A standalone conversion utility is provided to convert products without using WITE. This is useful, for example, for converting files stored on a central server and distributed to multiple machines where they are actually used.

In normal operation, running the conversion program will be unnecessary as updates will be made transparently. This section covers how to manually convert database files.

The conversion program is called ERA_TRAN.EXE. When run, the WITE directory found in WITE.INI and all products in this directory are selected by default. You can select or deselect WITE directories and products in them before starting transfer.

  1. To select additional WITE and/or product directories: select your choices in the left frame labeled "find for conversion". Press the "Add to list ->" button to add them to the conversion list.
  2. To remove products and/or directories from the conversion list: select the product or product directory in the "WITE directories" or "products" frame. Press the "Remove from list ->" button to remove the selected product(s) from the conversion list.
  3. Press the "Convert!" button to convert the product(s) on the conversion list to the new database format.

Support for new head amplifiers

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The following new head amplifiers are supported:

  • IBM36M551108C4
  • TLS24F556A
  • TS24M558 + 2212MR
  • TS24M558 + 2412MR
  • VM6202
  • VM620212

The following new head stack is supported:

  • HSA_81M3006

Other new features

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The spectral SNR test has been made simpler to use. The options have been changed from "background" and "after erasing" to "without erasing" and "with erasing." It is no longer necessary to calculate the harmonic frequencies for an arbitrary selected pattern. Instead, a flux with known harmonics is always written, allowing simple entry of any desired flux rate.

The Track Width parameter in the track profile test is now normalizable.

The spectrum analyzer self-calibration procedure features more descriptive error messages.

Support for the new TSA cartridge with on-board head amplifier was improved. It is no longer necessary to recalibrate TAA after changing the cartridge.

Bugs Fixed in WITE 1.4

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If an analog box equipped with an equalizer was replaced by an analog box without an equalizer, the nonexistent equalizer could still be selected, which would result in no signal passing through. In WITE 1.4, an additional diagnostic procedure was introduced to validate the hardware configuration.

A "Failure to communicate with spinstand" error often occurred due to errors in module initialization. WITE 1.40 will automatically reinitialize the appropriate module(s).

Previous revisions of WITE did not detect short circuits in the UP6 +5V power line. WITE 1.4 checks for shorts and presents the error message "UP power off" when one is detected.

The following errors were corrected in the track profile test:

  • The write width value was shown correctly in the track profile plot, but the value written to the database was incorrect. In version 1.4, the reported value is correct.
  • The track profile test crashed if a new operation was started before the previous one finished. WITE 1.4 disables buttons during operation, so no two operations can be started concurrently.
  • WITE crashed if the Redraw button was pressed immediately after the Clear button was pressed. This no longer causes an error.

When the "Control Head Amplifier" menu was opened, the head amplifier type was always displayed in blue, implying that its value from different from the value in the database. In WITE 1.4, the color of the combo box depends on whether it has the same value as stored in database or not.

For some HSAs, the chip name was not displayed under the "Configure|Preamp" menu. WITE 1.4 correctly displays the chip name.

The "Save all Iterations Data" option in the Production setup did not retain its value between WITE sessions. Now this option is saved in database.

A "Product not found" error message appeared after deleting any product in the product list. Now this message pops up only on deletion of the last product in the list.

The Spectral SNR test changed the selected overwrite filter value in the "Control|Filter" menu to the value specified for slot 1. In version 1.4, the spectral SNR test does not alter the default zone parameters.

The popcorn test crashed if write time, read time, or delay were too small. In release 1.4, additional validation procedures were added to verify user input.

A "Subscript out of Range" error message appeared during the execution of production tests with partially populated head stacks. WITE 1.4 operates correctly with partially populated head stacks.

The following errors were corrected in the scanning test:

  • Production scanning scanned only one track. WITE 1.4 correctly scans the specified tracks.
  • The first result displayed by the production scanning test was actually a result from a previous test run, not the test run just completed. WITE 1.4 correctly displays the results from the current test run.
  • Engineering scanning performance degraded dramatically if the track increment was over 400 microinches. WITE 1.4 performance does not suffer with large track increments.

Write current and read bias could not be set correctly for TLS24506 and TLS24S508 head amplifiers. WITE 1.4 allows these parameters to be set correctly.

Head selection did not work correctly for MR04B0C0 head amplifier. In WITE 1.4, head selection functions correctly.

Known bugs in WITE 1.4

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Some bugs were found too late to be fixed for the 1.4 release and will be fixed in a later release. This section contains all known bugs that you are likely to encounter. A bug’s presence here means that we are aware of the problem and actively working to solve it. If you encounter a problem not on this list, please report it to Guzik customer support.

The "retest with next setup" option in the "Production | Grd/Norm" menu does not register results to the database after the first setup. It should not be used.

Some DOS applications interfere with communication with Guzik hardware and can result in unstable test results. Please exit all DOS applications before running WITE.

WITE hangs up if a head amplifier different than the one actually present is selected in the "Control|Head Amplifier" menu.

Immediately after running a production sequence which includes scanning, an attempt to delete a zone may result in an "Operation not supported in transactions" error message. Retrying the zone deletion will work correctly.

A "Cannot sort zones" error message appears intermittently when zone execution order is changed in the production test. Retrying the operation will succeed.

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