This read-write Counter reports (or, if auto-calc is off, lets the admin manually set) the upper word of the short-term average write rate used to characterize recent drive usage. An admin combines this with the lower-word counterpart to see the actual write-rate figure feeding the short-term wearout date projection. For example, if write-rate auto-calc is disabled, the admin would need to manually calculate and write a value here for the short-term projection to be meaningful.