Method and apparatus for magneto-optical recording and reading using optimized laser powers

A magneto-optical recording apparatus for recording information to and reading information from a rotating disk comprising a magnetic medium with a plurality of zones, the recording apparatus comprising:

• an interface controller that controls communication with a host device;
• a drive controller coupled to the interface controller that controls rotation of the disk, the drive controller comprising;
• a microprocessor that executes programs defining operation of the drive controller;
• and
• a memory subsystem coupled to the microprocessor comprising a memory device that stores information used by the programs during operation of the recording apparatus, the information comprising:
• an identifier that matches an identifier stored on the magnetic medium;
• a set of constant values associated with the magnetic medium comprising constant values denoted by h, k, s, c, .alpha., .beta. and .delta.;
• and
• a set of equations that determine optimum write powers as functions of linear velocity, v, of the magnetic medium, comprising:
• Ph(v)=hv.sup..alpha.,where Ph(v) is a preheat power;
• Pk(v)=kv.sup..beta.,where Pk(v) is a peak power;
• Pm(v)=Pk(v)+s, where Pm(v) is a maintenance power;
• and
• Pc(v)=cv.sup..delta., where Pc(v) is a cooling power;
• a disk drive mechanism and circuit coupled to the drive controller that causes the disk to rotate in response to signals from the drive controller;
• and
• a laser control mechanism and circuit coupled to the drive controller and comprising a laser source directed toward the disk, the laser control mechanism and circuit operating the laser source in response to signals from the drive controller.

A magneto-optical disk drive, comprising:

• a drive controller that controls operation of a laser source and a disk drive mechanism, the drive controller comprising:
• a microprocessor;
• and
• a memory subsystem coupled to the microprocessor that stores programs executed by the microprocessor and data used by the programs, the memory subsystem comprising at least one memory device, the memory subsystem produced by:
• storing on the memory device a plurality of identifiers each corresponding to a disk drive medium having a particular structure;
• storing on the memory device a plurality of sets of constant values each associated with one of the plurality of identifiers, each set of constant values comprising constant values denoted by h, k, s, c, .alpha., .beta. and .delta.;
• and
• storing on the memory device a set of equations that determine optimum write powers as functions of linear velocity, v, of the magnetic medium, comprising:
• Ph(v)=hv.sup..alpha., Ph(v) is a preheat power;
• Pk(v)=kv.sup..beta., where Pk(v) is a peak power;
• Pm(v)=Pk(v)+s, where Pm(v) is a maintenance power;
• and
• Pc(v)=cv.sup..delta., where Pc(v) is a cooling power.

A magneto-optical disk drive, comprising:

• a drive controller that controls operation of a laser source and a disk drive mechanism, the drive controller comprising:
• a microprocessor;
• and
• a memory subsystem coupled to the microprocessor that stores programs executed by the microprocessor and data used by the programs, the memory subsystem comprising at least one memory device;
• the magneto-optical disk drive produced by:
• storing on the memory device a plurality of identifiers each corresponding to a disk drive magnetic medium having a particular structure;
• storing on the memory device a plurality of sets of constant values each associated with one of the plurality of identifiers, each set of constant values comprising constant values denoted by h, k, m, c, .alpha., .beta., .gamma. and .delta.;
• and
• storing on the memory device a set of equations that determine optimum write powers as functions of linear velocity, v, of the magnetic medium, comprising:
• Ph(v)=hv.sup..alpha., where Ph(v) is a preheat power;
• Pk(v)=kv.sup..beta., where Pk(v) is a peak power;
• Pm(v)=mv.sup..gamma., where Pm(v) is a maintenance power;
• and
• Pc(v)=cv.sup..delta., where Pc(v) is a cooling power.

In a magneto-optical (MO) recording system for recording information on a disk, the disk comprising a medium having a plurality of zones, a method for recording information on the disk, comprising the steps of:

• storing a plurality of identifiers on a storage device of the recording system, each of the plurality of identifiers corresponding to a medium;
• for each of the plurality of identifiers, storing on a storage device of the recording system a set of constant values denoted by h, k, c, s, .alpha., .beta. and .delta.;
• reading a disk including comparing an identifier stored on the disk with the plurality of identifiers to find a match;
• and
• when a match is found, calculating a set of optimum write powers corresponding to the identifier on the disk, the set of optimum write powers comprising optimum preheat power Ph(v), optimum peak power Pk(v), optimum maintenance power Pm(v) and optimum cooling power Pc(v) for each of the plurality of zones, the set of optimum write powers calculated according to a set of equations:
• Ph(v)=hv.sup..alpha. ;
• Pk(v)=kv.sup..beta. ;
• Pm(v)=Pk(v)+s;
• and
• Pc(v)=cv.sup..delta. ;
• where v is a linear velocity of the medium.

In a magneto-optical (MO) recording system for recording information on a disk, the disk comprising a medium having a plurality of zones, a method for recording information on the disk, comprising the steps of:

• storing a plurality of identifiers on a storage device of the recording system, each of the plurality of identifiers corresponding to a medium;
• for each of the plurality of identifiers, storing on a storage device of the recording system a set of constant values denoted by h, k, m, c, .alpha., .beta., .gamma. and .delta.;
• reading a disk including comparing an identifier on the disk with the plurality of identifiers to find a match;
• when a match is found, calculating a set of optimum write powers corresponding to the identifier on the disk, the set of optimum write powers comprising optimum preheat power Ph(v), optimum peak power Pk(v), optimum maintenance power Pm(v) and optimum cooling power Pc(v) for each of the plurality of zones, the set of optimum write powers calculated according to equations:
• Ph(v)=hv.sup..alpha. ;
• Pk(v)=kv.sup..beta. ;
• Pm(v)=mv.sup..gamma. ;
• and
• Pc(v)=cv.sup..delta. ;
• where v is a linear velocity of the medium;
• and
• storing the set of optimum write powers on the storage device.

In a magneto-optical (MO) recording system for recording information on a disk, the disk comprising a magnetic medium having a plurality of zones, a method for recording information on the disk, comprising the steps of:

• performing a write operation on a first zone including the steps of:
• applying a laser beam to the zone having a preheat power Ph;
• applying a laser beam to the zone having a peak power Pk;
• applying a laser beam to the zone having a maintenance power Pm;
• and
• applying a laser beam to the zone having a cooling power Pc;
• empirically determining first optimum powers at which an optimum jitter margin is attained, including a first optimum preheat power Ph(v.sub.0), a first optimum peak power Pk(v.sub.0), a first optimum maintenance power Pm(v.sub.0), and a first optimum cooling power Pc(v.sub.0);
• performing a write operation on a second zone;
• empirically determining second powers at which an optimum jitter margin is attained, including a second optimum preheat power Ph(v.sub.1), a second optimum peak power Pk(v.sub.1), a second optimum maintenance power Pm(v.sub.1), and a second optimum cooling power Pc(v.sub.1);
• calculating a value .alpha. according to ##EQU3## calculating a value a value h according to ##EQU4## calculating a value .beta. according to ##EQU5## calculating a value k according to ##EQU6## calculating a value .gamma. according to ##EQU7## calculating a value m according to ##EQU8## calculating a value .delta. according to ##EQU9## calculating a value c according to ##EQU10##