>* I don't mind HDIO_DRIVE_TASK nearly as much as HDIO_DRIVE_CMD,
 >* since the command protocol is available.

That's not HDIO_DRIVE_TASKFILE, by the way..  a different beast there.

HDIO_DRIVE_TASK is just a slightly different form of HDIO_DRIVE_CMD
for non-data commands (specifically, some SMART commands),
with a more complete register set being exchanged.

Cheers
-- 
Mark Lord
(hdparm keeper & the original "Linux IDE Guy")