-> I finally got fed up with the burner I have now and went out
-> and bought one of those 'double layer' DVD RW burners that also
-> does CDRs and CDRWs. 

-> Won't work here. Either it's my BIOS (Award) or my boot manager
-> but something gives me a "DMI pooling data" message and the
-> boot process stops before ever accessing the bootmanager's
-> files on the hard drive. :-\ 

I've the same reservations about trying one here.
Even the Belkins BIOS'ed I/O card I'm contemplating purchasing
only mentions CD-ROMs and burners but no DVD burners.

I've seen the DMI error myself some time ago
when attempting to use a freeware DOS C compiler and
a DOS MPEG player.
SimTel had a program that fixed that but I've no recollection
what it's called.

-> Tried several combinations as master, as slave, etc. Only the
-> DVD burner and hard drive - and a few other combinations. 

I think you may have overtaken your legacy hardware :-(
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