Configuration Table
Overview
Information on the VAXstation 4000 Model 90 devices is stored in
the system configuration tables during the power-up initialization.
The initialization code sizes the system by reading the ROM-based
device configuration tables (DCT) and builds a memory resident
configuration data structure. Figure 2–5 shows how the data
structures are linked together.
Figure 2–5 Model 90 Configuration Tables
M o d e l
9 0
N V R
S c r a t c h
R A M
M a i n
T a b l e
C o n f i g u r a t i o n
D e v i c e
C o n f i g u r a t i o n
T a b l e
D e v i c e
C o n f i g u r a t i o n
T a b l e
D e v i c e
C o n f i g u r a t i o n
T a b l e
L J - 0 1 8 2 9 - T I 0
The initialization code saves the pointer to the scratch RAM in
the Model 90 NVR in four consecutive bytes. The scratch RAM
contains a pointer to the main configuration table (MCT) at its
base address. The MCT contains pointers to the DCT.
Main
Configuration
Table
The main configuration table (MCT) contains a list of the devices
in the system and a pointer to the device configuration table
(DCT) for each device. The MCT is built when power is turned on
and resides in the diagnostic area in memory. The MCT gives the
test dispatcher a single interface into the various components of
the system. The MCT is shown in Figure 2–6.
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