Back to results
US 10,832,716 B2Granted
Zone self servo writing with synchronized parallel clocks
AssigneeMarvell Asia Pte Ltd
InventorSupaket Katchmart
Life of this patent
Estimating the term…
Abstract
Zone self-servo write (SSW) technology is disclosed that leverages two clock signals synchronized in parallel to transition between zones to write servo patterns at different frequencies while minimizing error rate despite the different frequencies. Two separate clock signals (“clocks”) are used to locate and lock to different reference spirals. By updating both clocks in parallel instead of in series, error rate for writing while stepping up frequency across zones is reduced.
Claims20
A storage device comprising:
- a first phase lock loop (PLL) and a second PLL in parallel,
- the first PLL configured to receive a reference clock input and a first input and configured to output a first clock signal;
- the second PLL configured to receive the reference clock input and a second input and configured to output a second clock signal;
- a synchronization logic connected to output a first frequency multiplier and a frequency offset as the first input to the first PLL and connected to output a second frequency multiplier and the frequency offset as the second input to the second PLL, wherein the synchronization logic is configured to synchronize output to the first PLL with output to the second PLL;
- and
- a controller configured with program code executable by the controller to cause the storage device to write concentric servo tracks on a machine-readable medium at successively increasing clock frequencies while using the second clock signal for position feedback.
3 more elements
A storage device comprising:
- a read/write head assembly;
- a set of one or more machine-readable media;
- a first read channel and a second read channel;
- a first clock generator and a second clock generator connected in parallel to a synchronization logic, the first clock generator coupled to supply a first clock signal to the first read channel and the second clock generator coupled to supply a second clock signal to the second read channel,
- the synchronization logic configured to receive frequency multipliers and a frequency offset and connected to supply the frequency offset and a first frequency multiplier to the first clock generator and to supply the frequency offset and a second frequency multiplier to the second clock generator, wherein the synchronization logic is also configured to synchronize supplying of the frequency offset and the first frequency multiplier to the first clock generator with supplying of the frequency offset and the second frequency multiplier to the second clock generator;
- and
- a controller comprising self-servo writing program code executable to control the read/write head assembly to write a set of zoned intermediate reference spirals onto the set of one or more machine-readable media while using a set of coarse reference spirals for positional feedback and a set of zoned servo wedges onto the set of one or more machine-readable media while using the set of zoned intermediate reference spirals for position feedback.
4 more elements
A method of self-servo writing comprising:
- repeatedly synchronizing supplying of frequency multipliers and a frequency offset for generating a first clock signal and a second clock signal in parallel;
- and
- writing onto a machine-readable medium of a storage device servo wedges while using coarse reference spirals to move between zones and intermediate reference spirals in each zone for position feedback,
- wherein the coarse reference spirals are located and tracked based, at least in part, on the first clock signal,
- wherein the intermediate reference spirals are written and tracked based, at least in part, on the second clock signal.
2 more elements
Dependencies are inferred from the claim text.