Fiber optic interconnects for the IBM S/390 parallel enterprise server G5

Fiber optic interconnections ("interconnects") have become an increasingly important part of System/390(R) over the years. With the introduction of th e Generation 5 Parallel Enterprise Server in May 1998, a number of importan t new fiber optic features and enhancements to existing features were made available for applications in input/output device attachment, networking, a nd parallel sysplex coupling. In this paper, we describe the main applicati ons of fiber optic data links on System/390, with emphasis on the new featu res announced with the G5. In particular, we describe the fiber connection (FICON(TM)) links, the Gigabit Ethernet interface for the open systems adap ter (OSA Express), the Fiber Transport Services fiber quick connect system featuring a new type of small-form-factor fiber optic connector, and the Ge ographically Dispersed Parallel Sysplex using the 9729 Optical Wavelength D ivision Multiplexer. We also describe the use of optical mode-conditioning patch cables in FICON, Gigabit Ethernet, and Parallel Sysplex(R) data links as a way to reuse an installed multimode cable infrastructure at higher da ta rates, and to overcome distance-limiting phenomena such as differential mode delay associated with modal power distribution. Technical data is pres ented for each of these applications, and we discuss how the new fiber opti c interconnects fit into the overall IBM strategy for future large systems.