The AlphaServer 2100 I/O Subsystem

The AlphaServer 2100 I/O subsystem contains a dual-level I/O structure that includes the high-powered PCI local bus and the widely used EISA bus. The PCI bus is connected to the server's multiprocessing system bus through the custom-designed bridge chip. The EISA bus supports eight general-purpose EISA/ISA connectors, providing connections to plug-in, industry-standard options. Data rate isolation, disconnected transaction, and data buffer management techniques were used to ensure bus efficiency in the I/O subsystem. Innovative engineering designs accomplished the task of combining Alpha CPUs and standard-system I/O devices.