i. For devices which have queue depth greater than 1 (TCQ devices) and
support ordered tags, block layer can just issue the barrier as an
ordered request and the lower level driver, controller and drive
-itself are responsible for making sure that the ordering contraint is
+itself are responsible for making sure that the ordering constraint is
met. Most modern SCSI controllers/drives should support this.
NOTE: SCSI ordered tag isn't currently used due to limitation in the
of ii. Just keeping issue order suffices. Ancient SCSI
controllers/drives and IDE drives are in this category.
-2. Forced flushing to physcial medium
+2. Forced flushing to physical medium
Again, if you're not gonna do synchronization with disk drives (dang,
it sounds even more appealing now!), the reason you use I/O barriers
i. No write-back cache. Keeping requests ordered is enough.
ii. Write-back cache but no flush operation. There's no way to
-gurantee physical-medium commit order. This kind of devices can't to
+guarantee physical-medium commit order. This kind of devices can't to
I/O barriers.
iii. Write-back cache and flush operation but no FUA (forced unit