Abit IT5A User Manual page 69

General Discussion about HDD Installation
Appendix E
Most recent HDDs use IDE interface. Installing an IDE hard disk does not
require a lot of knowledge like installing the driver for a SCSI hard disk, but this
means that the user must install the hard disk by themselves and cope with all the
problems they may encounter. Here, we will try to help you solve these potential
problems.
The data stored on the hard disk is accessed through the chipset located on
the mainboard. You might have heard about the PIO mode, Master mode or
DMA mode of HDD. These modes reflect the way data is transferred to and
from the IDE drive and the mainboard.
What is the PIO mode? When the system needs to access hard disk data,
the CPU delivers input/output (I/O) orders through the chipset on the mainboard
to the hard disk drive, and then puts this data into the system memory. This is
the PIO mode.
What is the Master mode? When the system needs to access hard disk data,
this data is directly accessed from the hard disk by the chipset on the mainboard
(using a DMA or a PIO mode), and then the data is put into the memory. In this
case, the CPU does not participate in the data transfer.
What is the DMA mode? Usually, DMA mode refers to accessing the hard
disk data by the chipset, it does not refer to the data transfer mode.
Here are some examples of data transfer rates for IDE HDD with PIO
interface:
PIO Mode 0 The fastest data transfer rate reaches 3.3Mbyte/sec
PIO Mode 1 The fastest data transfer rate reaches 5.2Mbyte/sec
PIO Mode 2 The fastest data transfer rate reaches 8.3Mbyte/sec
PIO Mode 3 The fastest data transfer rate reaches 11.1Mbyte/sec
PIO Mode 4 The fastest data transfer rate reaches 16.6Mbyte/sec
General Discussion
About HDD Installation
E-1