The problem is , that is is hard to insure the wanted order of writes
This is needed for journalled/logged filesystems for example.
IDE drives don't provide write order controls. End of story. Ext3 doesn't
care about this providing the drive isn't caching writes, it just wants to
be sure that an I/O completed before it is told it has. You control that
with hdparm to alter write caching if you are really paranoid.