1. A magnetic disk drive including a magnetic recording medium, a perpendicular magnetic recording head, and a positioning device for positioning the perpendicular magnetic recording head over the magnetic recording medium, said magnetic disk drive supplying write electrical current to the perpendicular magnetic recording head, said perpendicular magnetic recording head comprising:
a main pole including a magnetic multilayer composed of a high saturation flux density layer and a low saturation flux density layer;
a return path for supplying a magnetic flux to the main pole; and
a conductive coil for excitation of the return path,
wherein:
the high saturation flux density layer contains an Fe\u2014Co alloy,
a width of the main pole is 200 nanometers or less,
a direction of magnetization in a pair of the high saturation flux density layers of the magnetic multilayer facing each other with respect to the low saturation flux density layer is oriented in an antiparallel arrangement by magnetostatic coupling between magnetization of the high saturation flux density layers, and
a thickness of the high saturation flux density layer is thicker than the thickness of the low flux density layer.
2. A magnetic disk drive including a magnetic recording medium, a perpendicular magnetic recording head, and a positioning device for positioning the perpendicular magnetic recording head over the magnetic recording medium, said magnetic disk drive supplying write electrical current to the perpendicular magnetic recording head, said perpendicular magnetic recording head comprising:
a main pole including a magnetic multilayer composed of a high saturation flux density layer and a low saturation flux density layer;
a return path for supplying a magnetic flux to the main pole; and
a conductive coil for excitation of the return path,
wherein:
a width of the main pole is 200 nanometers or less,
a thickness of the high saturation flux density layer is thicker than the thickness of the low flux density layer, and
a direction of magnetization in a pair of the high saturation flux density layers of the magnetic multilayer facing each other with respect to the low saturation flux density layer is oriented in an antiparallel arrangement by magnetostatic coupling between magnetization of the high saturation flux density layers.
3. The magnetic disk drive according to claim 1, wherein said main pole is arranged at the trailing side of the return path, and said perpendicular magnetic recording head further comprises:
a yoke arranged between the main pole and the return path; and
a main pole taper section arranged between the yoke and the main pole.
4. The magnetic disk drive according to claim 2, wherein said main pole is arranged at the trailing side of the return path, and said perpendicular magnetic recording head further comprises:
a yoke arranged between the main pole and the return path; and
a main pole taper section arranged between the yoke and the main pole.
5. A magnetic disk drive including a magnetic recording medium, a thin film perpendicular magnetic recording head, a positioning device for positioning the thin film perpendicular magnetic recording head over the magnetic recording medium, and a device control portion for supplying a write electrical current to the thin film perpendicular magnetic recording head and encoding write data, said thin film perpendicular magnetic recording head comprising:
a main pole including a magnetic multilayer composed of a high saturation flux density layer and a low saturation flux density layer;
an auxiliary pole;
a return path for supplying a magnetic flux to the main pole; and
a conductive coil for excitation of the main pole and the return path,
wherein:
a width of the main pole is 200 nanometers or less,
a thickness of the high saturation flux density layer is thicker than the thickness of the low flux density layer, and
overshoot of the write electrical current is controlled less or equal to 100% by the device control portion.
6. A magnetic disk drive according to claim 5, wherein the overshoot of the write electrical current is controlled within a range of 50% to 100% by the device control portion.
7. A magnetic disk drive according to claim 5, wherein the magnetic recording medium comprises:
a recording layer comprising a ferromagnetic material with high coercivity and which retains written data through its uniaxial magnetic anisotropy; and
a flux keeper layer with low coercivity and which contributes to the generation of a magnetic recording field through interaction with a write element.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. A method for testing a computer system, the method comprising:
testing the computer system, by a sequencer, using test modules arranged in a first sequence, wherein each of the test modules is for testing at least a portion of the computer system;
generating an interrupt by a test module, wherein the interrupt is generated in response to encountering an error during testing, or in response to the test module requiring an operator to complete a particular portion of testing;
responsive to the interrupt generated by the test module in the modules, determining if the operator is available to respond to the interrupt;
responsive to determining that the operator is available to respond to the interrupt, arranging, by the sequencer, the test modules into a second sequence based on a first policy; and
responsive to determining that the operator is unavailable to respond to the interrupt, arranging, by the sequencer, the test modules into a third sequence based on a second policy.
2. The method of claim 1, wherein the test modules are arranged into the second sequence based upon a degree of operator relevancy with respect to each of the test modules.
3. The method of claim 2, wherein the degree of operator relevancy comprises a degree of efficiency associated with the operator.
4. The method of claim 2, wherein the degree of operator relevancy comprises a degree of power requirements associated with the operator.
5. The method of claim 1, wherein arranging the test modules into the second sequence and the arranging the test modules into the third sequence comprises arranging critical test modules before non-critical test modules.
6. The method of claim 1, wherein arranging test modules into the second sequence and arranging the test modules into the third sequence is based on testing history statistics of each of the test modules and a failure rate of each of the test modules.
7. The method of claim 1, wherein arranging the test modules into the second sequence and arranging the test modules into the third sequence is based on an order dependency between at least two of the test modules.
8. A data processing computer system comprising:
a bus;
a communications unit connected to the bus;
a storage device connected to the bus, wherein the storage device includes program code; and
a processor unit connected to the bus, wherein the processor unit is configured to run the program code to test the computer system, by a sequencer, using test modules arranged in a first sequence, wherein each of the test modules is for testing at least a portion of the computer system; generate an interrupt by a test module, wherein the interrupt is generated in response to encountering an error during testing, or in response to the test module requiring an operator to complete a particular portion of testing; determine if the operator is available to respond to the interrupt in response to the interrupt generated by the test module in the modules; arrange, by the sequencer, the test modules into a second sequence based on a first policy in response to determining that the operator is available to respond to the interrupt; and arrange, by the sequencer, the test modules into a third sequence based on a second policy in response to determining that the operator is unavailable to respond to the interrupt.
9. The data processing computer system of claim 8, wherein the test modules are arranged into the second sequence based upon a degree of operator relevancy with respect to each of the test modules.
10. The data processing computer system of claim 9, wherein the degree of operator relevancy comprises a degree of efficiency associated with the operator.
11. The data processing computer system of claim 9, wherein the degree of operator relevancy comprises a degree of power requirements associated with the operator.
12. The data processing computer system of claim 8, wherein arranging the test modules into the second sequence and arranging the test modules into the third sequence comprises arranging critical test modules before non-critical test modules.
13. The data processing computer system of claim 8, wherein arranging the test modules into the second sequence and arranging the test modules into the third sequence is based on testing history statistics of each of the test modules and a failure rate of each of the test modules.
14. The data processing computer system of claim 8, wherein arranging the test modules into the second sequence and arranging the test modules into the third sequence is based on an order dependency between at least two of the test modules.
15. A computer program product for testing a computer system comprising:
a non-transitory computer readable storage device;
program code, stored on the computer readable storage device, for testing the computer system, by a sequencer, using test modules arranged in a first sequence, wherein each of the test modules is for testing at least a portion of the computer system;
program code, stored on the computer readable storage device, for generating an interrupt by a test module, wherein the interrupt is generated in response to encountering an error during testing, or in response to the test module requiring an operator to complete a particular portion of testing;
program code, stored on the computer readable storage device, for determining if the operator is available to respond to the interrupt in response to the interrupt generated by the test module in the modules;
program code, stored on the computer readable storage device, for arranging, by the sequencer, the test modules into a second sequence based on a first policy in response to determining that the operator is available to respond to the interrupt; and
program code, stored on the computer readable storage device, for arranging, by the sequencer, the test modules into a third sequence based on a second policy in response to determining that the operator is unavailable to respond to the interrupt.
16. The computer program product of claim 15 wherein the test modules are arranged into the second sequence based upon a degree of operator relevancy with respect to each of the test modules.
17. The computer program product of claim 16 wherein the degree of operator relevancy comprises a degree of efficiency associated with the operator.
18. The computer program product of claim 16 wherein the degree of operator relevancy comprises a degree of power requirements associated with the operator.
19. The computer program product of claim 15 wherein arranging the test modules into the second sequence and arranging the test modules into the third sequence comprises arranging critical test modules before non-critical test modules.
20. The computer program product of claim 15 wherein arranging the test modules into the second sequence and arranging the test modules into the third sequence is based on one or more of testing history statistics of each of the test modules, failure rate of each of the test modules, and an order dependency between at least two of the test modules.