ABCs of z/OS System Programming Volume 3 - IBM Redbooks

operating system point of view, device types always will be 3390s, sometimes with much
higher numbers of cylinders, but 3390s nonetheless.
ESS technology
The IBM TotalStorage Enterprise Storage Server (ESS) is the IBM disk storage server,
developed using IBM Seascape architecture. The ESS provides functionality to the family of
e-business servers, and also to non-IBM (that is, Intel®-based and UNIX-based) families of
servers. Across all of these environments, the ESS features unique capabilities that allow it to
meet the most demanding requirements of performance, capacity, and data availability that
the computing business requires. See 8.4, “Enterprise Storage Server (ESS)” on page 453 for
more information about this topic.
Seascape architecture
The Seascape architecture is the key to the development of the IBM storage products.
Seascape allows IBM to take the best of the technologies developed by the many IBM
laboratories and integrate them, thereby producing flexible and upgradeable storage
solutions. This Seascape architecture design has allowed the IBM TotalStorage Enterprise
Storage Server to evolve from the initial E models to the succeeding F models, and to the
later 800 models, each featuring new, more powerful hardware and functional enhancements,
and always integrated under the same successful architecture with which the ESS was
originally conceived. See 8.3, “Seascape architecture” on page 450 for more information.
Note: In this publication, we use the terms disk or head disk assembly (HDA) for the real
devices, and the terms DASD volumes or DASD devices for the logical 3380/3390s.
Chapter 8. Storage management hardware 447