windowswinapistoragehard-drivesector

LogicalBytesPerSector vs PhysicalBytesPerSector


When I do the command fsutil fsinfo sectorInfo c:, I receive this output:

LogicalBytesPerSector :                                 512
PhysicalBytesPerSectorForAtomicity :                    4096
PhysicalBytesPerSectorForPerformance :                  4096
FileSystemEffectivePhysicalBytesPerSectorForAtomicity : 4096 Device
Alignment :                                      Aligned (0x000)
Partition alignment on device :                         Aligned
(0x000) No Seek Penalty Trim Supported Not DAX capable Not
Thinly-Provisioned

I'm worried about the difference between LogicalBytesPerSector and PhysicalBytesPerSectorForAtomicity.

As LogicalBytesPerSector is less than PhysicalBytesPerSectorForAtomicity, will every block of 512 bytes I write actually be written atomically? On the other hand, will every block of 4096 bytes I write actually be written atomically?

Also, will the read/write of 512 bytes be slow, as if I understand well, the system will need to read 4096 physical bytes just to write my 512 bytes?


Solution

  • does every block of 512 bytes I will wrote will be wrote atomically ? on the other way does every block of 4096 Bytes I will wrote will be wrote atomically?

    4096 will write atomically.

    512 will write atomically with possibly writing other data to complete to 4096.

    Also does the read/wrote of 512 bytes will be not too much slow as, if I understand well, the system will need to read 4096 Physical bytes just to wrote my 512 bytes?

    Yes, at least write by PhysicalBytesPerSectorForPerformance. By more may be still faster due to more efficient commands utilization.