Technical information

Chapter 1
Base System Description
This chapter describes the VAX 4000 Model 200 base system, including the
following:
• Power-up self tests
• Digital Storage Systems Interconnect (DSSI) architecture
• Specifications for the KA660-AA/BA CPU and MS650-BA/BB memory
1.1 System Overview
The VAX 4000 Model 200 base system components are housed in two
different enclosures: the BA430 enclosure, which contains a 12-slot Q-
bus backplane, and the BA215 enclosure, which contains a 6-slot Q-bus
backplane.
Each base system contains the following:
• A KA660–AA/BA (M7626–A/–B) central processing unit (CPU) module
• From one to four MS650–Bx memory modules.
The base system modules are located in the following card slots:
• MS650–Bx memory modules are installed in slots 2 through 5.
• The KA660 CPU module is installed in slot 1.
The base system operates from the KA660 CPU firmware and the controls
on the CPU cover panel. The firmware is described in Section 1.2. Base
system operation also integrates Digital Storage Systems Interconnect
(DSSI) technology, which is discussed in Section 1.5.
Figure 1–1 is a block diagram of the VAX 4000 Model 200 system.
Base System Description 1–1