Aaeon MB-562 Manual page 98

These four lines set the hard disk PIO transfer mode, which affects
the hard disk data transfer rate. The system will auto-detect the
PIO mode of a device in any of these positions when they are set to
'Auto', the recommended setting. Alternatively, you can set the
mode manually. Modes 0 to 4 are supported.
These four lines enable hard disk UltraDMA transfer mode, which
requires a drive that supports this data transfer method. The
system will auto-detect an UltraDMA device in any of these four
positions when they are set to 'Auto', the recommended setting.
The other setting is 'Disabled'. You can leave these set to Auto
without effect if there are no UltraDMA devices installed.
When this item is Enabled, the system will support burst data
transfer mode to increase HDD transfer speed.
90 MB-562 User's Manual