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Posted:7/24/2012 5:08:00 PM |
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Many recent HDD models are of the "Advanced Format" kind: they are low-level formatted using 4 KiB (4096 bytes) sectors, instead of using the traditional sector size of 512 bytes. In order to not break compatibility with older computer firmwares and disk tools, these drives report a "logical" sector size of 512 bytes, and permit data transfers of that size. However, write performance is negatively affected when data writes are not properly aligned with the physical sectors of 4 KiB.
In order to avoid this problem with write performance, two conditions are required:
- Size of data transfers must be a multiple of 4 KiB.
- All partitions must begin aligned with a physical sector (i.e. 4 KiB) boundary (or with a logical -512 bytes- sector number multiple of eight).
The first condition is easy to met, because practically all file systems employ a cluster size that is a multiple of 4 KiB. However, the second requirement must be carefully fulfilled when creating the partitions. And, unfortunately, the partitions created on the internal HDD by the O!Play TV Pro software DO NOT meet that requirement, at least with the 2.2.607S version.
I verified that the first partition created by the TV Pro begins at (logical) sector 63, which obviously is not a multiple of eight. Beginning the first partition at sector 63 was customary and unfortunately many disk tools still follow that convention, which has its origin in the outdated concept of hard disk geometry (usually a disk track comprised 63 sectors).
The O!Play TV Pro disk partitioning routine should be modified as soon as possible in order to align all the partitions with 4 KiB sectors (or a sector number multiple of eight). In this way write performance should be optimal for Advanced Format HDDs (and the same for traditional format HDDs).
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