The IBM 7137 Disk Array Subsystem is a state-of-the-art storage solution designed to support applications needing expanded storage capacity and enhanced availability. All 7137 models contain a base configuration of three drives, a high-performance controller card and redundant power supplies. They attach to the RS/6000, the NCR Model 3455 and 3555, Hewlett-Packard (HP) 9000 700 and 800 Series, Sun SPARCstation, Sun SPARCcenter, and Sun SPARCserver through a fast and wide (16 bit) SCSI-2 differential interface. The standard configuration for each model may be expanded to a maximum of eight drives by adding additional feature drives. Virtual partitioning allows the array to be addressed as multiple smaller disk units.The 7137 is available with a new enhanced controller which provides up to a 20% performance improvement over the current controller, primarily when using large sequential data transfer workloads.The Model 414 utilizes 4.3 GB disk drives and features a 1 MB standard write cache or a 4 MB optional write cache.