Magnetic Disk Write Buffer for Consecutive WRITE SAME Commands
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Solution Overview
Problem
Magnetic disk devices experience delays when receiving consecutive WRITE SAME commands due to waiting for disk rotation, which affects write performance.
Innovation Solution
Implementing a buffer memory and controller system that allows for sequential writing of data to the disk without waiting for disk rotation by determining if the Logical Block Addresses (LBAs) are consecutive, enabling simultaneous processing and writing of multiple WRITE SAME commands.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the magnetic disk device executes processing for each WRITE SAME command sequentially, then data integrity and encryption are ensured, but write performance deteriorates due to disk rotation waiting time
Solution Approach 1:
The patent applies preliminary action by pre-positioning data on the disk surface before the write head arrives. The controller predicts the write head position based on disk rotation speed and pre-loads data into the buffer memory in advance, so that when the write head reaches the target position, data is already ready for immediate writing without waiting for disk rotation cycles.
Solution Approach 2:
The patent implements dynamics by making the buffer memory size and data pre-loading strategy adaptive to disk rotation speed variations. The controller dynamically adjusts the amount of data to pre-load and the timing based on real-time disk rotation speed measurements, optimizing the balance between data integrity assurance and write performance across different operating conditions.
2Manufacturing precision
If the magnetic disk device waits for disk rotation to complete before writing each command, then data writing accuracy is maintained, but processing time increases
Solution Approach 1:
The controller performs preliminary positioning calculations based on the predicted write head position and pre-loads the corresponding data into the buffer memory before the write head arrives at the target location. This eliminates the need to wait for disk rotation to complete full cycles, maintaining writing accuracy while reducing processing time.
3Productivity
If the magnetic disk device processes multiple WRITE SAME commands consecutively, then initialization efficiency in RAID environments improves, but disk rotation waiting delays accumulate
Solution Approach 1:
The patent enables continuous useful action by maintaining a pipeline of data pre-loading and write operations. While one data set is being written to the disk, the controller simultaneously pre-loads the next data set into the buffer memory. This continuous overlapping of operations eliminates idle waiting time between commands, allowing multiple WRITE SAME commands to be processed efficiently in RAID initialization scenarios.
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
Improves write performance by allowing continuous writing operations without waiting for disk rotation, enhancing efficiency in RAID environments and similar scenarios.
Implementation Method 1
a head configured to write data to the disk
Data Source
AI summary
According to one embodiment, a magnetic disk device including a disk, a head configured to write data to the disk, a buffer memory configured to temporarily hold data to be written to the disk, a recorder configured to temporarily hold data to be input from the buffer memory, and a controller configured to transfer first data from the buffer memory to the recorder and to transfer second data corresponding to the first data from the recorder.