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US 10,971,187 B2Granted
Constant-density writing for magnetic storage media
AssigneeMarvell Asia Pte Ltd
InventorSupaket Katchmart
Life of this patent
Estimating the term…
Abstract
The present disclosure describes aspects of constant-density writing for magnetic storage media. In some aspects, a constant-density writer delays transitions between bits within write data to enable constant-density writing. The write data has an initial bit period based on a constant clock signal, which is generated based on the rotation of a media disk. The constant-density writer modifies the write data to generate phase-delayed write data, which has a bit period that is greater than or equal to the initial bit period. To realize this bit period, the constant-density writer changes write phases of bit transitions within the write data. The constant-density writer can also insert stretch bits, filter single-bit transitions, and mitigate glitches within the phase-delayed write data.
Claims20
A method for constant-density writing to magnetic storage media, the method comprising:
- accepting write data from a host, the write data having an initial bit period associated with a period of a clock signal, the period of the clock signal being fixed according to an angular velocity of a disk of the magnetic storage media;
- determining respective bit periods for ones of multiple concentric tracks of a disk of magnetic storage media, each bit period of the respective bit periods associated with a particular concentric track of the multiple concentric tracks, the respective bit periods representing periods of time that vary based on respective radiuses of the multiple concentric tracks;
- the respective bit periods being configured to maintain a particular bit density across the multiple concentric tracks;
- selecting, for the write data, a concentric track from among the multiple concentric tracks, the concentric track being associated with a bit period of the respective bit periods;
- prior to writing along the concentric track, generating phase-delayed write data by delaying transitions between bits of the write data according to the bit period associated with the concentric track, the delaying of the transitions being effective to cause bits of the phase-delayed write data to have the bit period associated with the concentric track, the bit period associated with the concentric track being different than the initial bit period associated with the clock signal;
- and
- writing the bits of the phase-delayed write data along the concentric track such that the concentric track has the particular bit density.
4 more elements
An apparatus for constant-density writing, the apparatus comprising:
- a disk of magnetic storage media to store write data, the disk including multiple concentric tracks;
- an interface to receive the write data from a host, the write data having an initial bit period associated with a period of a clock signal, the period of the clock signal being fixed according to an angular velocity of the disk of magnetic storage media;
- a magnetic media writer configured to write phase-delayed write data to the magnetic storage media as data bits;
- and
- a constant-density writer configured to:
- determine respective bit periods for ones of the multiple concentric tracks, each bit period of the respective bit periods associated with a particular concentric track of the multiple concentric tracks, the respective bit periods representing periods of time that vary based on respective radiuses of the multiple concentric tracks;
- the respective bit periods being configured to maintain a particular bit density across the multiple concentric tracks;
- select, for the write data, a concentric track from among the multiple concentric tracks, the concentric track being associated with a bit period of the respective bit periods;
- generate the phase-delayed write data by delaying transitions between bits of the write data according to the bit period associated with the concentric track, the delaying effective to cause bits of the phase-delayed write data to have the bit period associated with the concentric track, the bit period associated with the concentric track being different than the initial bit period associated with the clock signal;
- and
- transmit, to the magnetic media writer, the phase-delayed write data to enable the concentric track to have the particular bit density.
8 more elements
A System-on-Chip (SoC) for constant-density writing to magnetic storage media, the SoC comprising:
- an interface to a host from which write data is received for writing to magnetic storage media, the write data having an initial bit period associated with a period of a clock signal, the period of the clock signal being fixed according to an angular velocity of a disk of the magnetic storage media;
- an interface to a media writer of the magnetic storage media;
- and
- a constant-density writer implemented at least partially in hardware, the constant-density writer configured to:
- determine respective bit periods for ones of the multiple concentric tracks, each bit period of the respective bit periods associated with a particular concentric track of the multiple concentric tracks, the respective bit periods representing periods of time that vary based on respective radiuses of the multiple concentric tracks;
- the respective bit periods being configured to maintain a particular bit density across the multiple concentric tracks;
- select, for the write data, a concentric track from among the multiple concentric tracks, the concentric track being associated with a bit period of the respective bit periods;
- generating phase-delayed write data by delaying transitions between bits of the write data according to the bit period associated with the concentric track, the delaying of the transitions being effective to cause bits of the phase-delayed write data to have the bit period associated with the concentric track, the bit period associated with the concentric track being different than the initial bit period associated with the clock signal;
- and
- transmit, to the magnetic media writer, the phase-delayed write data to enable the concentric track to have the particular bit density.
7 more elements
Dependencies are inferred from the claim text.