Abit LM6E Pentium II User Manual page 71

General Discussion about HDD Installation
Appendix B
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
General Discussion
About HDD Installation
B-1