Magnetic Disk Device Parallel Write Read Servo Timing
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Solution Overview
Problem
In magnetic disk devices, the separation of write and read heads by a predetermined distance leads to an area that cannot be used for data storage, as data writing must stop before servo data can be read, resulting in inefficient use of the disk space.
Innovation Solution
The magnetic disk device enables simultaneous data writing and servo data reading by adjusting the timing of power save and servo gate signals, allowing the read head to read servo data during data writing, thereby extending the data area and optimizing disk usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If data writing is stopped before servo data reading to ensure accurate servo data acquisition, then servo data reading accuracy is improved, but the usable data area is reduced
Solution Approach 1:
The system performs preliminary separation of servo data and user data in the signal domain before writing to the magnetic disk. By using a servo extraction filter to separate servo data from user data in advance, the system can then write both types of data simultaneously without interference, allowing the data writing process to extend into the area previously reserved for servo data reading.
Solution Approach 2:
The patent replaces the mechanical/time-based sequential operation (stop writing, then read servo data) with a signal processing-based parallel operation. By using frequency domain filtering and signal separation techniques, the system can distinguish and process servo data and user data simultaneously, eliminating the need to stop data writing for servo data reading.
2Reliability
If write and read heads are separated by a predetermined distance to prevent interference, then write/read operation reliability is improved, but the head gap area cannot be used for data storage
Solution Approach 1:
The patent transitions from spatial separation management to frequency domain separation. Instead of trying to utilize the head gap area by moving heads closer (spatial dimension), the system separates servo data and user data in the frequency domain using filtering techniques. This allows simultaneous writing in the same spatial location without interference, effectively adding a frequency dimension to the data storage capability.
Solution Approach 2:
The system changes the operational parameters by using different frequency ranges for servo data and user data. By allocating specific frequency bands to each data type and using filtering to maintain separation, the system can write both data types simultaneously in the same physical area, effectively increasing the usable data area while maintaining reliability through frequency-based parameter separation.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach allows for parallel data writing and reading, effectively increasing the usable data area and improving the accuracy of servo data reading, reducing the unutilized space between the write and read heads.
Implementation Method 1
a write head configured to write data to the magnetic disk
Implementation Method 2
a read head configured to read data from the magnetic disk
Data Source
AI summary
According to one embodiment, a magnetic disk device includes a magnetic disk section and a control section. The magnetic disk section includes a magnetic disk, a magnetic head, and a preamplifier. The control section included a processing section configured to cause the preamplifier to execute processing of generating the recording current used by a write head to write data to the magnetic disk, and processing of receiving an output reproduced from the magnetic disk by a read head, and configured to control the magnetic disk section. In the preamplifier, processing of reading data from the magnetic disk is executed by the read head in parallel with processing of writing data transferred from the control section to the magnetic disk by means of the write head.