Patent ID: 7380088

Claim:
A data storage system, comprising: a plurality of virtual storage device units, each including: a storage device sled; a plurality of physical storage devices interconnected to said storage device sled, wherein no virtual storage device includes physical storage devices interconnected to different ones of said storage device sleds; a controller; a system enclosure, wherein said plurality of virtual storage device units are housed within said system enclosure, wherein any one virtual storage device unit can be removed from said system enclosure as a single field replaceable unit, wherein for each virtual storage device unit including more than one physical storage device said controller concatenates data on said plurality of physical storage devices, wherein each virtual storage device unit effectively operates as if it were comprised of a single physical storage device, wherein a first physical storage device in a first virtual storage device unit provides a first range of storage addresses, wherein a second physical storage device in said first virtual storage device unit provides a second range of storage addresses, and wherein data is not stored in said second range of storage addresses until data has been written to all storage addresses included in said first range of storage addresses; a power supply, wherein in a first mode of operation while storing data to said first virtual storage device unit, power is supplied to said first physical storage device and not to said second physical storage device while a first number of addresses included in said first range of addresses are not full of data, wherein in a second mode of operation after said first number of addresses included in said first range of addresses are full of data but before all of said first range of storage addresses are full of data, while power continues to be supplied to said first physical storage device and while storing data to said first virtual storage device unit, power is supplied to said second physical storage device, wherein said first number of storage addresses is less than all of said storage addresses included in said first range of storage addresses, and wherein in a third mode of operation after all of said storage addresses included in said first range of storage addresses are full of data and while storing data to said first virtual storage device unit, power is supplied to said second physical storage device and not to said first physical storage device.