Fiber optic interconnects for the IBM S/390 Parallel Enterprise Server G5

Abstract

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