This read-only integer reports the size, in kilobytes, of a partition on the printer's storage device, and on the CLJ8500 it always returns the same number as hrdiskstoragecapacity since the whole disk is treated as one partition. It gives an admin the partition-level size figure without needing to separately track how the disk is divided. For example, an admin who already read hrdiskstoragecapacity for a disk would see hrpartitionsize return that identical KB value rather than a smaller subdivided figure.