X-Git-Url: https://git.openpandora.org/cgi-bin/gitweb.cgi?p=pandora-kernel.git;a=blobdiff_plain;f=Documentation%2FABI%2Ftesting%2Fsysfs-block;h=cbbd3e0699453391a461bff35431df5f0ee0d53e;hp=44f52a4f5903359eda2f2ffafff2d3341e437e62;hb=f27884aeadff9654f4a1e8a05dd92f4b140afe29;hpb=1e24b15b267293567a8d752721c7ae63f281325a diff --git a/Documentation/ABI/testing/sysfs-block b/Documentation/ABI/testing/sysfs-block index 44f52a4f5903..cbbd3e069945 100644 --- a/Documentation/ABI/testing/sysfs-block +++ b/Documentation/ABI/testing/sysfs-block @@ -60,3 +60,62 @@ Description: Indicates whether the block layer should automatically generate checksums for write requests bound for devices that support receiving integrity metadata. + +What: /sys/block//alignment_offset +Date: April 2009 +Contact: Martin K. Petersen +Description: + Storage devices may report a physical block size that is + bigger than the logical block size (for instance a drive + with 4KB physical sectors exposing 512-byte logical + blocks to the operating system). This parameter + indicates how many bytes the beginning of the device is + offset from the disk's natural alignment. + +What: /sys/block///alignment_offset +Date: April 2009 +Contact: Martin K. Petersen +Description: + Storage devices may report a physical block size that is + bigger than the logical block size (for instance a drive + with 4KB physical sectors exposing 512-byte logical + blocks to the operating system). This parameter + indicates how many bytes the beginning of the partition + is offset from the disk's natural alignment. + +What: /sys/block//queue/logical_block_size +Date: May 2009 +Contact: Martin K. Petersen +Description: + This is the smallest unit the storage device can + address. It is typically 512 bytes. + +What: /sys/block//queue/physical_block_size +Date: May 2009 +Contact: Martin K. Petersen +Description: + This is the smallest unit the storage device can write + without resorting to read-modify-write operation. It is + usually the same as the logical block size but may be + bigger. One example is SATA drives with 4KB sectors + that expose a 512-byte logical block size to the + operating system. + +What: /sys/block//queue/minimum_io_size +Date: April 2009 +Contact: Martin K. Petersen +Description: + Storage devices may report a preferred minimum I/O size, + which is the smallest request the device can perform + without incurring a read-modify-write penalty. For disk + drives this is often the physical block size. For RAID + arrays it is often the stripe chunk size. + +What: /sys/block//queue/optimal_io_size +Date: April 2009 +Contact: Martin K. Petersen +Description: + Storage devices may report an optimal I/O size, which is + the device's preferred unit of receiving I/O. This is + rarely reported for disk drives. For RAID devices it is + usually the stripe width or the internal block size.