Hitachi Data Systems has announced that its new storage subsystems, the 7390 disk drive and 7490 cartridge tape subsystem, will be shipping in October and November this year, as has its sibling distributor, Comparex Informationssysteme GmbH (CI No 1,517). The company also added a 7390-F model which provides up to 22.7Gb and is format-compatible with the older 7380-Ks; 7390 models 1 and 2 are compatible with the IBM 3390, and Model 1 stores up to 946Mb, half the capacity of Models 2 and F; each frame contains four or eight volumes, and the Bs contain four, eight or 12; the volume size of a model 2 is 1.89Gb and frame capacities are 7.56Gb, 15.1Gb and 22.7Gb. Hitachi says a fully configured 60.5Gb string of 7390-2 occupies 55% of the space taken up by the 7380-K, which is half the size of IBM’s 3380-K; when compared with the 3390, the 7390 is claimed to require up to 19% less floor space and 70% less than 60Gb of 3380-K; the 7390-2 has an average seek time of 10mS, latency is 7.1mS, and the transfer rate is 4.2Mb per second. Actuator Level Cache reduces the effect of RPS missed reconnections: when a requested record is under the read-write head but there isn’t a free channel, the record is read into Actuator Level Cache and stored until a channel is free. The 7390-2 has a track capacity of 56,664 bytes, as opposed to the 3380’s 47,476 bytes, and migration requires re-blocking of data and changes to the Job Control Language; to assist in this process or run 3380 applications, customers can either use the 3380 Track Compatibility Mode or use the 7390-F; in the first option, a portion of the 56Kb 7390 track is reduced to the 47Kb of a 3380, but that results in a 16% loss of capacity. The F model has 2,655 cylinders, and in native mode it runs with 56Kb tracks and 2,226 cylinders; in full capacity compatibility mode, it uses 47Kb per track and 2,655 cylinders to provide 1.89Gb. Also to be available in the fourth quarter, the 7490 cartridge tape subsystem consists of a control unit containing one or two controllers per cabinet, and drive units with two or four transports per cabinet.
