# US 8,570,678 B2 · Determining tape head condition

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- Number: US 8,570,678 B2
- Document ID: US8570678B2
- Status: Granted
- Kind: B2
- Application number: 13/299,602
- Filed: 2011-11-18
- Published: 2013-05-23
- Granted: 2013-10-29
- Earliest claimed: 2011-11-18
- Assignees: Hewlett-Packard Development Company, L.P.
- Applicants: Brian Brong; Mike Alan Holmberg; Steven L. Brittenham; Michael Anthony Ellis; Saiman Kusin; Geoff Spratt
- Inventors: Brian Brong; Mike Alan Holmberg; Steven L. Brittenham; Michael Anthony Ellis; Saiman Kusin; Geoff Spratt
- Web page: https://patentgrep.com/patent/US8570678B2

## CPC

- G11B 5/455: Arrangements for functional testing of heads; Measuring arrangements for heads
- G11B 5/00813: {magnetic tapes}
- G11B: INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER (recording measured values in a way that does not require playback through a transducer G01D9/00; recording or playback apparatus using mechanically marked tape, e.g. punched paper tape, or using unit records, e.g. punched or magnetically marked cards G06K; transferring data from one type of record carrier to another G06K1/18; circuits for coupling output of reproducer to radio receiver H04B1/20; gramophone pick-ups or like acoustic electromechanical transducers or circuits therefor H04R)

## Abstract

Techniques to use a model associating condition of a tape head with tape head usage are described. The tape head is for use in a magnetic tape drive. In examples, a condition of the tape head is determined using a model. In examples, the model fits determined values of the condition parameter.

## Claims

### Claim 1

A method for predicting condition of a tape head for use in a magnetic tape drive, the method comprising:
determining a condition of the tape head using a model associating a condition parameter with tape head usage, the condition parameter being related to performance of the tape head, the model fitting pre-determined values of the condition parameter, and the model being a representation of the tape head that allows for determining tape head condition after a specific tape head usage without having to measure an actual value of the condition parameter.

### Claim 2 (depends on 1)

The method of claim 1, wherein the condition parameter is associated with at least one of a tape head wear, a magnetic spacing, and an error rate.

### Claim 3 (depends on 1)

The method of claim 1, wherein the model is a pre-determined model constructed by fitting a parameterized function with values of the condition parameter determined during a test procedure performed on a test tape head.

### Claim 4 (depends on 3)

The method of claim 3, wherein the parameterized function includes the function:
y=Mx−p,
y corresponding to a rate of the condition parameter,
x corresponding to a number of written cartridges, and
M and p corresponding to parameters for fitting the parameterized function.

### Claim 5 (depends on 3)

The method of claim 3, wherein:
the test procedure includes writing data on a plurality of fresh tapes using the test tape head; and
determining values of the condition parameter at selected intervals during the test procedure.

### Claim 6 (depends on 3)

The method of claim 3, wherein the values of the condition parameter are determined using atomic force microscopy measurements.

### Claim 7 (depends on 1)

The method of claim 1, wherein the determined condition of the tape head includes an expected operating life of the tape head.

### Claim 8 (depends on 1)

The method of claim 1 further comprising determining an actual value of the condition parameter over a lifetime of the tape head.

### Claim 9 (depends on 8)

The method of claim 8, wherein the actual value is determined using a magnetic spacing measurement, an error rate drift measurement, a tape head resistance measurement, or a combination thereof.

### Claim 10 (depends on 8)

The method of claim 8, further including using the determined actual value for comparing an actual condition of the tape head with the model to determine whether the actual condition of the tape head is abnormal.

### Claim 11 (depends on 8)

The method of claim 8, wherein:
the model is pre-determined using a plurality of test tape heads;
the model includes a lower limit and an upper limit for values of a condition parameter at a specific usage interval of the tape head; and
the method further includes determining an abnormal condition of the tape head when an actual value of the condition parameter is outside of the lower limit and the upper limit.

### Claim 12

An apparatus comprising:
a magnetic tape drive including is tape head to access content of a storage tape;
a processing circuit to determine whether an actual value of a condition parameter related to performance of the tape head is outside a range using a model associating tape head condition with tape head usage,
wherein the model fits pre-determined values of the condition parameter, and wherein the model is a representation of the tape head that allows for determining tape head condition after a specific tape head usage without having to measure an actual value of the condition parameter.

### Claim 13 (depends on 12)

The apparatus of claim 12, wherein the condition parameter is associated a tape head wear, a magnetic spacing, or an error rate.

### Claim 14 (depends on 12)

The apparatus of claim 12, the processing circuit to periodically determine actual values of the condition parameter by processing a magnetic spacing measurement or an error rate drift.

### Claim 15 (depends on 12)

The apparatus of claim 12, the processing circuit to generate an alert signal upon determining that an actual value of the condition value is outside the range.

### Claim 16 (depends on 12)

The apparatus of claim 12, wherein the model is a pre-determined model constructed by fitting a parameterized function with values of the condition parameter from a test procedure performed on a test tape head.

### Claim 17 (depends on 12)

The apparatus of claim 12, wherein:
the model is pre-determined using a plurality of test tape heads
the model includes a lower limit and an upper limit for values of the condition parameter at a specific usage interval of the tape head; and
the processing circuit to determine an abnormal condition of the tape head when an actual value of the condition parameter is outside the lower wear rate limit and the upper wear rate limit.

### Claim 18

A non-transitory tangible computer readable storage medium storing instructions that when executed by a computer cause the computer to implement a method to:
determine a cumulative rate associated with a parameter of the tape head, the tape head being for use in a magnetic tape drive, the parameter being a tape head wear, a magnetic spacing, or an error rate;
determine whether the cumulative rate is within a selected range using a model associating the tape head parameter with the parameter value, wherein the model fits pre-determined values of the condition parameter, and wherein the model is a representation of the tape head that allows for determining tape head condition after a specific tape head usage without haying to measure an actual value of the condition parameter; and
signal an abnormal condition of the tape head upon determining that the cumulative rate is outside the selected range.

### Claim 19 (depends on 18)

The medium of claim 18, wherein:
the model is pre-determined using a plurality of test tape heads;
the model includes a lower limit and an upper limit for values of a condition parameter at a specific usage interval of the tape head; and
the method further includes determining an abnormal condition of the tape head when an actual value of the condition parameter is outside of the lower limit and the upper limit.

### Claim 20 (depends on 18)

The medium of claim 18, wherein the model is a pre-determined model constructed by fitting a parameterized function in the form:
y=Mx−p,
y corresponding to the cumulative rate associated with the parameter of the tape head,
x corresponding to a number of written cartridges, and
M and p corresponding to parameters for fitting the parameterized function.