tree-wide: fix assorted typos all over the place

[safe/jmp/linux-2.6] / Documentation / ABI / testing / sysfs-block

diff --git a/Documentation/ABI/testing/sysfs-block b/Documentation/ABI/testing/sysfs-block
index cbbd3e0..d2f9033 100644 (file)
--- a/Documentation/ABI/testing/sysfs-block
+++ b/Documentation/ABI/testing/sysfs-block
@@ -4,7 +4,7 @@ Contact:        Jerome Marchand <jmarchan@redhat.com>
 Description:
                The /sys/block/<disk>/stat files displays the I/O
                statistics of disk <disk>. They contain 11 fields:
-                1 - reads completed succesfully
+                1 - reads completed successfully
                 2 - reads merged
                 3 - sectors read
                 4 - time spent reading (ms)
@@ -94,28 +94,37 @@ What:               /sys/block/<disk>/queue/physical_block_size
 Date:          May 2009
 Contact:       Martin K. Petersen <martin.petersen@oracle.com>
 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.
+               This is the smallest unit a physical storage device can
+               write atomically.  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.  For stacked block
+               devices the physical_block_size variable contains the
+               maximum physical_block_size of the component devices.
 
 What:          /sys/block/<disk>/queue/minimum_io_size
 Date:          April 2009
 Contact:       Martin K. Petersen <martin.petersen@oracle.com>
 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.
+               Storage devices may report a granularity or preferred
+               minimum I/O size which is the smallest request the
+               device can perform without incurring a performance
+               penalty.  For disk drives this is often the physical
+               block size.  For RAID arrays it is often the stripe
+               chunk size.  A properly aligned multiple of
+               minimum_io_size is the preferred request size for
+               workloads where a high number of I/O operations is
+               desired.
 
 What:          /sys/block/<disk>/queue/optimal_io_size
 Date:          April 2009
 Contact:       Martin K. Petersen <martin.petersen@oracle.com>
 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.
+               the device's preferred unit for sustained I/O.  This is
+               rarely reported for disk drives.  For RAID arrays it is
+               usually the stripe width or the internal track size.  A
+               properly aligned multiple of optimal_io_size is the
+               preferred request size for workloads where sustained
+               throughput is desired.  If no optimal I/O size is
+               reported this file contains 0.