Ide Installation Guide; Ide Transfer Modes - Abit PR5 User Manual

IDE Installation Guide

This section is a guide to installing IDE devices in your
computer system. It covers installing devices you con-
nect to the mainboard' s onboard Enhanced IDE control-
ler. The main hard disk drive used in most systems is an
IDE device. In addition to this, however, you may want
to install more hard disks, a CD-ROM drive or combina-
tion of these. The onboard controller supports up to four
devices. The purpose of this section is to provide some
background information regarding the process and give
some example configurations.

IDE Transfer Modes

Hard disk read/write operations are performed via the
mainboard' s chipset. The transfer of data between the
hard disk and the system takes place via one of several
transfer modes – PIO mode, Master mode or DMA mode.
Master Mode
In Master mode, when the system reads data, the
mainboard chipset performs hard disk read opera-
tions directly using either PIO or DMA and places
retrieved data in the system memory.
PIO Mode– Programmed Input/Output
In PIO mode, to read data, the CPU issues I/O com-
mands to the mainboard chipset to perform hard
disk read operations and place retrieved data di-
rectly in the system memory. There are several PIO
modes, categorized as Mode 0 ~ 4.
DMA Mode – Direct Memory Access
The direct transfer of data between the system
memory and the hard disk where the mainboard
chipset performs hard disk read operations directly
and places retrieved data in the system memory
independent of the CPU.
All of these modes provide faster data transfer.