Service manual

<REFERENCE>(XMI) has three types of nodes: processor nodes, memory

nodes, and I/O adapter nodes.

A processor node, consists of a single-board VAX processor. It contains

a central processor unit (CPU) chip, a ﬂoating-point processor, a primary

and secondary cache, a writable EEPROM for system parameters, and a

communication path to the XMI bus. The <REFERENCE>(XRP) has a

chip that communicates with an optional vector processor.

Processors communicate with main memory over the <REFERENCE>(XMI).

The system supports multiprocessing with up to six processors. One pro-

cessor becomes the boot processor during power-up and handles all system

communication. The other processors become secondary processors and re-

ceive system information from the primary processor (see Section 3.4 and

Section 4.4).

The <REFERENCE>(rigel) has an optional vector processor, the

<REFERENCE>(xrv), which executes VAX vector instructions. This

processor is tightly coupled to the <REFERENCE>(XRP) through a Vector

Interface Bus (VIB) cable connecting the two modules. They occupy

adjacent <REFERENCE>(XMI) slots.

A memory node is an <REFERENCE>(XMA2). In <REFERENCE>(2x)

MS62A may also be installed. See Section 6.14, Mixing MS65A and MS62A

Memory Modules for details. Memory is a global resource and may be

reached by all processors on the <REFERENCE>(XMI). There are three

variants of the <REFERENCE>(xma2); 32-Mbyte, 64-Mbyte, and 128-

Mbyte. Each memory module has ECC and control logic. The console

program automatically interleaves the memory for maximum performance.

An optional battery backup unit protects all data in case of power failure.

The XMI I/O adapters include the DEMNA, the CIXCD, and the KDM70.

The DEMNA is an Ethernet adapter, the CIXCD is a CI adapter, and the

KDM70 is a disk adapter.

An optional <REFERENCE>(XMI)-to-VAXBI adapter, called a <REFER-

ENCE>(XBI_plus), is a 2-module adapter that maps data between these

two buses. I/O adapters on the VAXBI pass data between the system

and peripheral devices. The <REFERENCE>(XBIA_plus) module is in-

stalled on the <REFERENCE>(XMI) bus; it communicates with the <REF-

ERENCE>(XBIB_plus) module on the VAXBI using a 120-pin cable. The

in-cabinet version of the VAXBI in the XMI-2 platform has 12 slots. Each

VAXBI channel must have one <REFERENCE>(xbi_plus) connecting it to

the <REFERENCE>(XMI).

System error messages and self-test results refer to the pair of DWMBB

modules as XBI.

Introduction 1–5