Magnetic Disk Post Code Writing and Seek Control Optimization
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In magnetic disk devices, switching between different track arrangement schemes (such as SMR and CMR) requires rewriting post codes for positional correction, which is time-consuming and inefficient, as existing methods often necessitate separate seek controls for writing post codes and user data.
Innovation Solution
The magnetic disk device implements a method where both post code writing and user data writing are performed under tracking control, reducing the number of seek control operations by executing them once per track, and utilizes a post code area to store pre-generated codes for different schemes, allowing for efficient switching between track arrangement schemes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If separate seek control operations are used for writing post codes and user data, then positioning accuracy is improved, but processing time increases
Solution Approach 1:
The patent combines the writing of post codes and user data into a single seek control operation. The magnetic head performs one seek movement to the target track, then writes both the post code (for positioning correction) and the user data sequentially without returning to the outer radius or performing a separate seek operation. This merging of operations maintains positioning accuracy through the post code while eliminating the time loss from multiple seek operations.
Solution Approach 2:
The post code is written first as a preliminary action before writing the user data. By pre-writing the positioning correction code in the initial seek operation, the system prepares the necessary positioning information in advance, allowing the subsequent user data writing to proceed without additional positioning operations or time delays.
2Adaptability or versatility
If post codes are rewritten when switching track arrangement schemes, then adaptability is improved, but processing time increases
Solution Approach 1:
Different post codes for different track arrangement schemes (SMR and CMR) are pre-generated and stored in a post code storage area before switching is needed. When a scheme switch occurs, the controller simply retrieves the appropriate pre-generated post code from storage and writes it to the magnetic disk, eliminating the time-consuming process of generating new post codes during the switching operation.
Solution Approach 2:
The system dynamically selects and switches between different pre-generated post codes based on the current track arrangement scheme. The controller adjusts which post code to use (SMR-specific or CMR-specific) according to the active scheme, enabling flexible adaptation while maintaining efficient processing by avoiding real-time post code generation during dynamic scheme transitions.
3Measurement precision
If multiple seek control operations are performed for formatting, then positioning precision is improved, but productivity decreases
Solution Approach 1:
The patent merges the post code writing operation and user data writing operation into a single seek control sequence during formatting. The magnetic head performs one seek movement to the target track and then sequentially writes both the post code and user data without returning to the outer radius or performing additional seek operations. This combining of operations maintains the positioning precision needed for correct data placement while significantly improving formatting speed by eliminating redundant seek movements.
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 significantly reduces the time required for processing post code and user data writing, improving efficiency by minimizing the number of seek control operations and eliminating the need for generating new post codes during scheme switching.
Implementation Method 1
a magnetic head including a write head that executes writing on the magnetic disk
Implementation Method 2
a read head that executes reading from the magnetic disk
Data Source
AI summary
According to one embodiment, a first storage area and a second storage area in which a plurality of tracks are set are provided in a radial direction of a magnetic disk. A plurality of post codes corresponding to the second storage area is stored in the first storage area. A controller controls first processing of reading a plurality of post codes from the first storage area and writing the plurality of read post codes in servo area of the second storage area. In the first processing, the controller controls both second processing and third processing in a state where a write head is located on a first track. The second processing is processing of writing a post code among the plurality of read post codes in a servo area. The third processing is processing of writing user data in a data area or reading user data from a data area.