Shadow MBR Update Mechanism Using Partial Sector Copying
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Solution Overview
Problem
The Trusted Computing Group (TCG) standard for updating a shadow master boot record (MBR) lacks specific implementations, leading to inefficiencies and potential timeouts due to the requirement of copying all sectors, even when only a portion of the MBR needs to be updated, as it allocates a large 128 MB space which is often not fully utilized.
Innovation Solution
A storage device uses two storage areas to efficiently update the shadow MBR by determining the highest written sector and copying only non-updated sectors up to that point, avoiding unnecessary data copying and timeouts, while maintaining compliance with the TCG standard through atomic transactions and special commands.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If all sectors are copied from the first storage area to the second storage area during shadow MBR update, then the TCG standard requirement for atomic update is met, but unnecessary data copying occurs leading to potential timeouts and reduced efficiency
Solution Approach 1:
The patent applies partial action by determining the highest written sector in the first storage area and copying only the non-updated sectors up to that point, rather than copying all sectors. This partial copying approach maintains atomic update compliance while significantly reducing unnecessary data transfer and preventing timeouts during the shadow MBR update process.
2Reliability
If a large 128 MB storage space is allocated for the shadow MBR as per TCG standard, then sufficient space is provided for updates, but most of the space remains unused leading to wasted resources
Solution Approach 1:
The patent implements partial action by allocating and utilizing only the necessary portion of the 128 MB storage space based on the actual shadow MBR size and update requirements. By determining the highest written sector and copying only up to that point, the system maintains sufficient update capability while avoiding the waste of allocating unused storage resources.
3Reliability
If the shadow MBR is implemented as read-only for security reasons, then security is maintained, but update operations require special read/write commands which complicate the update process
Solution Approach 1:
The patent applies segmentation by dividing the shadow MBR update process into distinct phases: determining the highest written sector, copying only non-updated sectors up to that point, and designating the second storage area as the current version. This segmented approach maintains security through controlled access while simplifying the update process by reducing the scope of operations required.
Data Source
AI summary
A storage device and method for updating a shadow master boot record (MBR) are provided. In one embodiment, a storage device is provided having a memory with a first storage area and a second storage area. The storage device receives updated sectors of the shadow MBR from a host device and writes the updated sectors in the second storage area. The storage device determines a highest written sector in the first storage area that is occupied by the shadow MBR. The storage device copies the non-updated sectors of the shadow MBR from the first storage area to the second storage area, wherein only the non-updated sectors up to the highest written sector are copied. Accordingly, any non-updated sectors above the highest written sector are not copied from the first storage area to the second storage area. The storage device then designates the second storage area as storing a current version of the shadow MBR.