BladeCenter midplane and media interface card

This paper describes the electrical architecture and design of the IBM eServere BladeCentert midplane and media interface card. The midplane provides the redundant interconnects among processor blades, switch modules, media interface card, and management modules. It also serves as the redundant power distribution medium from the power modules to all blades and other devices. A major attribute of the BladeCenter electrical design is the redundant nature of the interconnects, which gives this product superior reliability and availability. The media interface card provides the interface between the CD-ROM and floppy disk drives and the blades that share these devices. The sharing of these devices was a key BladeCenter innovation. Also, to ensure that the architecture will be flexible enough to support multiple input/output fabric protocols, SerDes (serialized/deserialized) is used as the internal high-speed communication electrical interface. Since highspeed designs can easily result in higher implementation costs, a significant predesign simulation effort was undertaken to analyze and prioritize design guidelines in order to develop a high-speed midplane at a competitive cost. This paper highlights how we reduced board costs by finding solutions that overcame some of the challenges of 2.5-Gb/s data transmission over multiple printed circuit boards and connectors.