Subject: Addition Unit Directory entries

From: "Hattig, Myron" <[email-masked]>
Date: Wed, 13 Jan 1999 11:01:45 -0800

What additional unit directory entries other than Unit_Spec_Id and
Unit_Sw_Version are needed?

Joseph suggested the model_id. Here is the text defining the
model id:

---------------------------------------------------------
17h is the concatenation of key_type and key_value for
the Model_ID entry.

YYY is a vendor-specified ID that uniquely identifies this model
for the vendor whose Vendor_ID is specified in the root directory
 (the Vendor_ID MUST be specified in the root directory). The
Model_ID entry must be immediately followed by a textual descriptor
leaf entry. This associates an ASCII string with the Model_ID that will
be used to identify the vendor- and model-specific software driver to
associate with this particular IEEE 1394 networking hardware implementation.

The Model_ID, although optional, is recommended, because it associates
 a Model_ID with the IEEE 1394 networking h/w that is distinct from the
Model_ID of the root or of any other logical devices that may be present
on the node. This will enable a PnP-enabled operating system to load
h/w-specific drivers for IP/1394 networking if there is a need to do so.

---------------------------------------------------------

I wonder about the value of model_id because I can't imagine
any hardware specific drivers that are necessary for IP/1394
networking. The IP/1394 drivers will reside at the same layer
as other drivers for protocols like SBP-2, AV/C, and CIP.
I would expect that all these drivers feed into a common
interface/driver that abstracts away any vendor specific 1394
hardware issue. Is this correct?

-myron