Specifications

1-6 Overview
tion to two 10BaseT Ethernet ports, one FDDI port, and three FWD and
one single-ended SCSI ports.
The DWLMA is the interface between a hose and a 14-slot XMI bus. It
manages data transfer between XMI adapters and the I/O port.
The DWLAA is the interface between a hose and a 10-slot Futurebus+ card
cage. It manages data transfer between Futurebus+ adapters and the I/O
port.
The DWLPA is the interface between a hose and a 12-slot, 32-bit PCI bus.
It manages data transfer between PCI adapters and the I/O port. The PCI
is physically implemented as three 4-slot PCI buses, but these appear logi-
cally to software as one 12-slot PCI bus. The PCI also supports the EISA
bus.
The Memory Channel interface connects a hose to a 100 MB/sec Memory
Channel bus. This bus is a memory-to-memory computer system intercon-
nect, and supports up to 8 nodes. With appropriate fiber optic bridges, this
can be expanded to 64 nodes.
The TLSB supports up to three I/O ports of either type. The first (or only)
I/O port in the system is installed in the dedicated I/O TLSB slot (slot 8).
Any latency-sensitive devices should be configured to this I/O port. The
second I/O port, if present, should be installed in the highest number slot
accommodating an I/O port.
The I/O port uses mailbox operations to access CSR locations on the remote
I/O bus. Mailbox operations are defined in the Alpha System Reference
Manual. For PCI buses, direct-mapped I/O operations are also supported.
1.6 Software
The system software consists of the following components:
• Console
• OpenVMS Alpha operating system
• Digital UNIX operating system
• Diagnostics
The following subsections provide brief overviews of the system software
components.
1.6.1 Console
The console firmware supports the two operating systems as well as the
following system hardware:
• DECchip 21164 processor
• One or two processors per CPU module and up to 12 processors per
system
• Multiple I/O ports per system
• PCI I/O bus and peripherals
• Memory Channel
The console supports boot devices on the following I/O port adapters: