Perhaps not x86-64 specific ... I'm trying to write a DVD with dvdrecord. 
cdrecord works fine on this drive, but dvdrecord always fails with

cd0(viaide0:1:1):  Check Condition on CDB: 0x28 00 00 00 00 00 00 00 01 00
     SENSE KEY:  Illegal Request
                 Incorrect Length Indicator Set
      ASC/ASCQ:  Illegal Mode For This Track

Can someone please sell me a clue or a pointer? I'm trying to write pretty full 
DVDs (the ISO image is 4461133824 bytes). I was disappointed to discover that 
the ISO 9660 file system forces me to break my large data file into smaller ones...

Thanks.