Driver Descriptor
Overview
Any device that provides a shared port driver or shared class
driver must provide a descriptor that supplies the Model 90 base
system firmware, system test monitor, and any other piece of
software specific information about the drive. The format for a
driver descriptor is shown in Figure 2–8.
Figure 2–8 Driver Descriptor Data Structure
LJ-00106-TI0
Address of IO Segment Table
Address of Driver Data Area
Size of Driver Data Area
Entry Point of Driver
Length of Driver
Address of Driver
Device ID
0
4
8
C
10
14
18
The fields of the driver descriptor are as follows:
Name
Description
Device ID
Ensures that the driver descriptor
ID matches the function block ID.
This allows a function the ability
to determine if it is being used
correctly.
Address of driver
Contains the address of the device
driver. This address may be ROM or
memory address.
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