XTEST label Word Comment
--------------- ------- -----------------------------------------------------
Config 0 General configuration bit field
NumCyls 1 Number of cylinders
res0 2 Reserved
CurCyls 54 Number of current cylinders
CurHeads 55 Number of current heads
CurSPT 56 Number of current sectors (per track)
SecCapLo 57 Device sector capacity low byte
SecCapHi 58 Device sector capacity high byte