Magnetic Disk Controller Index Detection and Adjacent Sector Writing
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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 magnetic head to return to a sector's previous position, which increases the time required for data transfer and storage.
Innovation Solution
A magnetic disk controller with an index detecting unit, error check code generating unit, and writing control unit that allows for immediate writing of error check codes and data into adjacent sectors, eliminating the need for the head to return to the previous position by generating error check codes based on the physical address of subsequent sectors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the magnetic disk controller waits for the magnetic head to return to the sector's previous position before writing data and error check code, then the data can be written at the correct physical location, but the writing time is delayed
Solution Approach 1:
The controller performs preliminary actions by calculating the physical address and generating the error check code immediately upon receiving write data, before the magnetic head returns to the original sector position. This allows the data to be written as soon as the head reaches the calculated position, eliminating the waiting time while ensuring accurate positioning through pre-computed addresses.
Solution Approach 2:
Instead of writing data to the same sector after a full rotation, the invention writes data to a different sector (sector N+1 or later) based on calculated physical addresses. This dimensional change in the writing location allows the system to bypass the waiting time for head return while maintaining precise control over where data is stored on the disk.
2Reliability
If the magnetic disk controller calculates error check code based on sector address and data, then data integrity can be ensured, but the controller cannot write data immediately after obtaining the sector address
Solution Approach 1:
The controller performs preliminary calculation of the physical address based on the logical sector address and determines the target write position in advance. The error check code is generated immediately upon receiving the data, without waiting for the magnetic head to return. This preliminary action ensures data integrity through error check codes while enabling immediate writing to the pre-calculated position, thus improving productivity.
3Manufacturing precision
If the magnetic disk controller holds writing of data until the sector comes back to the magnetic head position, then data can be written at the correct location, but the data transfer efficiency is reduced
Solution Approach 1:
The controller calculates the physical address and determines the exact write location in advance, before the magnetic head completes its return rotation. This preliminary determination of the write location allows the system to immediately write data when the head reaches that position, eliminating the need to wait for the original sector to return, thus maintaining location accuracy while improving transfer efficiency.
Solution Approach 2:
The invention changes the writing dimension from the original sector (after full rotation) to a different sector (N+1 or later) based on calculated physical addresses. This allows data to be written to a different location on the disk without waiting for the head to return to the original position, maintaining precise location control while significantly improving data transfer efficiency.
Data Source
AI summary
Among other disclosed subject matter, a magnetic disk controller can include an index detecting unit to detect an index of the magnetic disk, an error check code generating unit to, after the index detecting unit detects the index, generate a first error check code for first write data based on the first write data and a first physical address of a first sector subsequent to the detected index, and a writing control unit to cause the first error check code generated by the error check code generating unit, the first write data and the first physical address to be written into a second sector subsequent to the first sector.