>  6.17.21 Words (46:27): Model number
> 
>  This field contains the model number of the device. The contents of this
>  field is an ASCII character string of forty bytes. The device shall pad
>  the character string with spaces (20h), if necessary, to ensure that
>  the string is the proper length. The combination of Serial number (words
>  (19:10)) and Model number (words (46:27)) shall be unique for a given
>  manufacturer (See 3.2.9).
> 
> So, while there's nothing in there to suggest that either is optional, 
> as a matter of fact, many manufactures apparently leave the serial 
> number blank, putting the "vendor" and "model number" into the model 
> number field, nor is it uncommon to leave the model number field 
> blank, and only put the "model number" into the "serial number" field.

I tried to use these fields to determine whether a CF card had been
changed while a system was asleep.
However all the CF cards we had (in a batch) had the same value for
both the 'model number' and 'serial number'.

We also tried to send some cards back because one failed to respond
to the identify request, and another had the disk size (in sectors)
in the wrong place.
Both were returned unchanged - except for a nice shiny new DOS filesystem
(which we weren't using)

	David

-- 
David Laight: david@l8s.co.uk