Magnetic Disk Controller Buffer Encoding for Write Latency
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Solution Overview
Problem
Magnetic disk controllers face delays in writing data and error check codes due to the need to wait for the sector to return to the magnetic head, which increases the time required for data transfer and storage.
Innovation Solution
A magnetic disk controller with multiple buffers and an encoding unit that encodes data in real-time, allowing simultaneous reading and writing operations, ensuring that data and error check codes can be written immediately after generation, without relying on sector position alignment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the magnetic disk controller waits for the sector to return to the magnetic head position before writing data, then the data can be written to the correct sector location, but the writing time is significantly delayed
Solution Approach 1:
The patent applies preliminary action by calculating the error check code in advance while the sector is rotating away from the head position. The controller computes the error check code during the sector's absence, so that when the sector returns to the head position, both the data and error check code are ready for immediate writing, eliminating the waiting time while maintaining position accuracy
Solution Approach 2:
The patent segments the data writing process into two independent phases: (1) error check code calculation phase that occurs while the sector is rotating away, and (2) data writing phase that occurs when the sector returns to the head position. This segmentation allows the error check calculation to be performed in parallel with sector rotation, reducing overall writing time without compromising position accuracy
2Reliability
If the magnetic disk controller holds data until the sector returns to the magnetic head, then data integrity is ensured, but data transfer efficiency decreases
Solution Approach 1:
The patent implements continuity of useful action by maintaining continuous data processing operations. While one sector is being written to, the controller continuously calculates error check codes for subsequent sectors and prepares data for the next write operations. This continuous processing eliminates idle waiting time and maintains high data transfer efficiency while ensuring data integrity through proper error check code generation
3Device complexity
If the controller uses a single buffer for data storage, then the device complexity is reduced, but concurrent read-write operations cannot be performed
Solution Approach 1:
The patent applies segmentation by dividing the buffer memory into multiple separate buffers (first buffer and second buffer). This allows the controller to perform concurrent operations: while data is being written to one buffer, error check codes can be calculated and data prepared in another buffer. The multiple buffers enable parallel processing streams without increasing overall system complexity significantly
Solution Approach 2:
The patent uses an intermediary approach by introducing a buffer control unit that manages data flow between multiple buffers and the encoding unit. This intermediary controller coordinates the concurrent read-write operations, allowing efficient utilization of multiple buffers while maintaining system simplicity through centralized control logic
Data Source
AI summary
Methods and apparatus describe processing of data for recording to a storage device. An apparatus includes, in at least one aspect, a plurality of buffers and circuitry configured to encode data stored in one buffer of the plurality of buffers concurrently with storing data in another buffer of the plurality of buffers and to write the encoded data from the one buffer to a storage device concurrently with encoding the stored data in the other buffer.