Acer AcerAltos 21000 System Manual page 101

Hard Disk 32-bit Access
Enabling this parameter improves system performance by allowing
the use of the 32-bit hard disk access. This enhanced IDE feature
works only under DOS, Windows 3.x, Windows 95, and Novell
NetWare. If your software or hard disk does not support this function,
set this parameter to .
Disabled
CD-ROM Drive DMA Mode
This parameter allows you to enable or disable the CD-ROM drive
DMA mode. Set this parameter to to enable the DMA mode
Enabled
for the CD-ROM drive. This improves the system performance since
it allows direct memory access to the CD-ROM. To deactivate the
function, set the parameter to .
Disabled
BIOS Utility 4-15