SMI-S Disk Partition Subprofile¶

Profile adjustment¶

The Disk Partition Subprofile does not reflect real-world MBR partition tables:

• The profile specifies, there can be up to 4 primary partitions (correct), one of them can be extended (correct) and up to 4 logical partitions can be instantiated on this extended partition (wrong, number of logical partitions is not limited).
• The profile specifies that logical partition metadata is on the beginning of the extended partition (see Figure 7 in the profile). In reality, each logical partition has its own metadata sector just before the partition. In addition, there can be number of empty sectors between the logical partition metadata and the partition beginning, which are left as result of alignment rules.

As result of this deficiency, some adjustments were necessary:

• The LMI_DiskPartition representing a logical partition includes the metadata sector and any alignment sectors.

• NumberOfBlocks property includes the metadata and any alignment sectors.
• ConsumableBlocks includes only the real usable data on partition.

Correct overview of logical partitions.

GPT partition tables do not have these issues and are generally preferred over MBR ones.

Implementation¶

All mandatory classes are implemented. However, CreateOrModifyPartition method is not implemented. This function might be added in future.

The only way, how to create partitions is proprietary LMI_CreateOrModifyPartition, which fits actual partitioning better.