Patent ID: 7761284

Claim:
A data storage system comprising: one or more disk drives; an interface configured to emulate a tape drive and to receive data for storage on said one or more disk drives using tape format data storage commands and tape storage data formats; and a storage controller configured to pre-allocate a portion of the storage space on said one or more disk drives to a tape storage volume that receives data via said interface, wherein said storage controller is further configured to automatically change the amount of storage space pre-allocated to said tape storage volume in response to tape format data storage commands received via said interface, and wherein the pre-allocated portion comprises both free portions of the pre-allocated portion of the storage space and used portions of the pre-allocated portion of the storage space wherein said storage controller is configured to decrease the amount of storage space pre-allocated to said tape storage volume if a write command to overwrite a logical block address corresponding to a tape record number below a threshold is received.