ESCON (Enterprise Systems Connection) is a data connection created by
IBM, and is commonly used to connect their
mainframe computers to peripheral devices such as
disk storage,
tape drives and
IBM 3270 display controllers. ESCON is an
optical fiber
An optical fiber, or optical fibre in Commonwealth English, is a flexible, transparent fiber made by drawing glass ( silica) or plastic to a diameter slightly thicker than that of a human hair. Optical fibers are used most often as a mea ...
,
half-duplex
A duplex communication system is a point-to-point system composed of two or more connected parties or devices that can communicate with one another in both directions. Duplex systems are employed in many communications networks, either to allow ...
,
serial interface. It originally operated at a rate of 10MB/s, which was later increased to 17MB/s. The current maximum distance is 43 kilometers.
IBM introduced ESCON in September 1990 as part of its System/390 announcement.
[
] It replaced the older, slower (4.5MB/s), copper-based, parallel,
IBM System/360 Bus and Tag channels technology of 1960-1990 era mainframes. Optical fiber is smaller in diameter and weight, and hence could save installation costs. Space and labor could also be reduced when fewer physical links were required - due to ESCON's switching features. ESCON is being supplanted by the substantially faster
FICON
FICON (Fibre Connection) is the IBM proprietary name for the ANSI ''FC-SB-3 Single-Byte Command Code Sets-3 Mapping Protocol'' for Fibre Channel (FC) protocol. It is a FC layer 4 protocol used to map both IBM's antecedent (either ESCON or para ...
, which runs over
Fibre Channel.
ESCON allows the establishment and reconfiguration of channel connections dynamically, without having to take equipment off-line and manually move the cables. ESCON supports channel connections using serial transmission over a pair of fibers. The ESCON Director supports dynamic switching (which could be achieved prior to ESCON, but not with IBM-only products). It also allows the distance between units to be extended up to 60 km over a dedicated fiber. "Permanent virtual circuits" are supported through the switch.
ESCON switching has advantages over a collection of point-to-point links. A peripheral previously capable of accessing a single mainframe can now be connected simultaneously to up to eight mainframes, providing peripheral sharing.
The ESCON interface specifications were adopted in 1996 by
ANSI
The American National Standards Institute (ANSI ) is a private non-profit organization that oversees the development of voluntary consensus standards for products, services, processes, systems, and personnel in the United States. The organi ...
X3T1 committee as the SBCON standard, which is now managed by
X3T11.
See also
*
Direct access storage device (DASD)
* Most important DASD (
disk arrays) with ESCON interfaces:
**
EMC Symmetrix
The Symmetrix system was an EMC's enterprise storage array. It combined dozens of hard drives into a single virtual device that was then shared on a local area network. It was the flagship product of EMC in the 1990s and 2000s.
History
Sym ...
, DMX and VMAX families.
**
Hewlett Packard Enterprise XP Storage family.
**
Hitachi Data Systems
Hitachi Data Systems (HDS) was a provider of modular mid-range and high-end computer data storage systems, software and services. Its operations are now a part of Hitachi Vantara.
It was a wholly owned subsidiary of Hitachi Ltd. and part of ...
Lightning
**
IBM Enterprise Storage Server (Shark)
** IBM
Storage DS8000
**
Sun StorageTek SVA
References
Computer storage devices
Fiber-optic connectors
Mainframe computers
IBM System/360 mainframe line
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