initializer, IECCINIT, which also serviced other DASD device types, and for the same purpose. It was at initialization-time that the OS learned that the 9340 has no non-volatile cache and the 9345 has a shorter than expected track capacity. The initializer, therefore, assigned a different device type than the 3990/3390. 9330 family of disk drives 9331 Diskette Unit models 1 and 11 contained one 8-inch FDD while the models 2 and 12 contained one 5-inch FDD. 9332 Direct Access Storage Device used the IBM 0667 HDD. 9333 High Performance Disk Drive Subsystem used the IBM 0664 or IBM 0681 HDDs depending upon subsystem model 9334 Disk Expansion Unit attaches from one to four SCSI HDDs to the RS/6000 system. 9335 Direct Access Storage Subsystem This HDD used in this subsystem was developed under the code name "Kestrel" at IBM Hursley, UK, and was an 850 MB HDD using three 14-inch disks with dual rotary actuators, each actuator accessing three surfaces with two heads per surface. The HDD was in the rack mountable 9335 announced as a part of the October 1986 IBM 9370 Information System announcement. There is no known OEM version of this HDD. 9336 Disk Unit used the IBM 0681 HDD (Redwing) 9337 Disk Array Subsystem used the IBM 0662 (Spitfire) or 0663 (Corsair) HDDs. HDDs offered for IBM small systems IBM 2310 The IBM 2310 Removable Cartridge Drive was announced in 1964 with the IBM 1800, and then in 1965 with the IBM 1130; it likely first shipped with the 1130 in late 1965. It could store 512,000 16-bit words (1,024,000 bytes) on an IBM 2315 cartridge. A single oxide-coated aluminum disk spun in a plastic shell with openings for the read/write arm and two heads. IBM 5444 The IBM 5444 was announced September 1969 as part of System/3. Developed at IBM's Hursley, England, laboratory under code name Dolphin it used the 5440 disk cartridge. The cartridge in turn contained one 14-inch disk. There were three models: Model 1 has one fixed disk and one removable disk each with 100 tracks per surface for a disk cartridge capacity of 1.23 MB Model 2 has one fixed disk and one removable disk each with 200 tracks per surface for a disk cartridge capacity of 2.46 MB Model 3 has only one removable disk with 200 tracks per surface for a disk cartridge capacity of 2.46 MB IBM 62GV