[ The PC Guide | Systems and Components Reference Guide | Motherboard and System Devices | System Chipset and Controllers | Chipset Functions and Features | Chipset Peripheral and I/O Bus Control ]

IDE/ATA Hard Disk Controller

Almost all motherboards now have integrated into them support for four IDE (ATA) hard disks, two on each of two channels. The IDE/ATA interface is discussed in considerable detail here. Integrating this support makes sense for a number of reasons, among them the fact that these drives are on the PCI bus, so this saves an expansion slot (and hence reduces cost).

There are several features related to the IDE interface and its use of the PCI bus that are controlled by the chipset. The data transfer rate of IDE drives is based on their using programmed I/O (PIO) modes, and use of the fastest of these modes depends on support from the PCI bus and chipset. The ability to set a different PIO mode for each of the two devices on a single IDE channel, called independent device timing, is also a chipset feature. Without this, both devices must run at the slower of the two devices' speed. PIO modes are discussed in detail in the section on hard disk interfaces.

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