Abit BX6, User Manual

Page: 67 / 103

General Discussion about HDD Installation B-1
Appendix B General Discussion About
HDD Installation
Most of the present 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 often must install the hard disk by himself and cope with all
the problems they may encounter. Here, we will try to help you solve these
potential problems.
The data stored in the hard disk are accessed through the chipset located on the
motherboard. You might often hear about the PIO mode, Master mode or DMA
mode of HDD. These modes reflect the way data is transferred from and to the
IDE drive and the motherboard.
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 motherboard 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 motherboard
(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
The higher the MODE value is, the best is the hard disk data transfer rate. But this
does not mean that you can select the highest mode value as you like. You must
be sure that your hard disk supports that type of fast data transfer, otherwise your
hard disk will not be able to operate correctly.
Here are some examples of data transfer rates for IDE HDD with DMA mode:
DMA Mode 0: The fastest data transfer rate reaches 4.16Mbyte/sec
DMA Mode 1: The fastest data transfer rate reaches 13.3Mbyte/sec
DMA Mode 2: The fastest data transfer rate reaches 16.6Mbyte/sec