ad(4) generic ATA/ATAPI disk controller driver

Other Alias

ata, ar, acd, afd, ast


For ISA based ATA/ATAPI support: device isa device ata

In /boot/device.hints hint.ata.0.port=0x1f0 hint.ata.0.irq=14 hint.ata.1.port=0x170 hint.ata.1.irq=15

For PC98 based ATA/ATAPI support: device isa device ata

In /boot/device.hints hint.atacbus.0.port=0x640 hint.atacbus.0.irq=9

For PCI based ATA/ATAPI support: device pci device ata

To support ATA compliant disk drives: device atadisk

To support ATA software RAID's: device ataraid

To support ATAPI CDROM, DVD and CD/DVD burner drives: device atapicd

To support ATAPI floppy drives: device atapifd

To support ATAPI tape drives: device atapist

To turn ata(4) subsystem controller drivers into cam(4) interface modules (disables all native ata(4) APIs and periperal drivers): options ATA_CAM

The following tunables are settable from the loader:

set to 1 for DMA access, 0 for PIO (default is DMA).
set to 0 to disable the 80pin cable check (default is 1, check the cable)
set to 1 for DMA access, 0 for PIO (default is DMA).
set to 1 to enable Write Caching, 0 to disable (default is enabled). WARNING can cause data loss on power failures and crashes.
set to 1 to allow Message Signalled Interrupts (MSI) to be used by specified PCI ATA controller, if supported.
limits initial ATA mode for specified device on specified channel.
limits initial ATA mode for every device on specified channel.
controls SATA interface Power Management for specified channel, allowing to save some power by the cost of additional command latency. Possible values:

interface Power Management is disabled, default value.
device is allowed to initiate PM state change, host is passive.
host initiates PARTIAL PM state transition every time port becomes idle.
host initiates SLUMBER PM state transition every time port becomes idle.

Modes 2 and 3 are implemented only for AHCI driver now.


The driver provides access to ATA (IDE) and SerialATA disk drives, ATAPI CDROM/DVD drives, ZIP/LS120 ATAPI drives and ATAPI tape drives connected to controllers according to the ATA/ATAPI standards.

The currently supported ATA/SATA controller chips are:

ATP850P, ATP860A, ATP860R, ATP865A, ATP865R.
M5228, M5229, M5281, M5283, M5287, M5288, M5289.
AMD756, AMD766, AMD768, AMD8111, CS5536.
IXP200, IXP300, IXP400, IXP600, IXP700, IXP800.
CMD646, CMD646U2, CMD648, CMD649.
Cypress 82C693.
Cyrix 5530.
HPT302, HPT366, HPT368, HPT370, HPT371, HPT372, HPT372N, HPT374.
6300ESB, 31244, PIIX, PIIX3, PIIX4, ESB2, ICH, ICH0, ICH2, ICH3, ICH4, ICH5, ICH6, ICH7, ICH8, ICH9, ICH10, SCH, PCH.
IT8211F, IT8212F, IT8213F.
JMB360, JMB361, JMB363, JMB365, JMB366, JMB368.
88SX5040, 88SX5041, 88SX5080, 88SX5081, 88SX6041, 88SX6042, 88SX6081, 88SX6101, 88SX6102, 88SX6111, 88SX6121, 88SX6141, 88SX6145, 88SX7042.
NC3000, NC5000.
nForce, nForce2, nForce2 MCP, nForce3, nForce3 MCP, nForce3 Pro, nForce4, MCP51, MCP55, MCP61, MCP65, MCP67, MCP73, MCP77, MCP79, MCP89.
PDC20246, PDC20262, PDC20263, PDC20265, PDC20267, PDC20268, PDC20269, PDC20270, PDC20271, PDC20275, PDC20276, PDC20277, PDC20318, PDC20319, PDC20371, PDC20375, PDC20376, PDC20377, PDC20378, PDC20379, PDC20571, PDC20575, PDC20579, PDC20580, PDC20617, PDC20618, PDC20619, PDC20620, PDC20621, PDC20622, PDC40518, PDC40519, PDC40718, PDC40719.
HT1000, ROSB4, CSB5, CSB6, K2, Frodo4, Frodo8.
Silicon Image:
SiI0680, SiI3112, SiI3114, SiI3124, SiI3132, SiI3512.
SIS180, SIS181, SIS182, SIS5513, SIS530, SIS540, SIS550, SIS620, SIS630, SIS630S, SIS633, SIS635, SIS730, SIS733, SIS735, SIS745, SIS961, SIS962, SIS963, SIS964, SIS965.
VT6410, VT6420, VT6421, VT82C586, VT82C586B, VT82C596, VT82C596B, VT82C686, VT82C686A, VT82C686B, VT8231, VT8233, VT8233A, VT8233C, VT8235, VT8237, VT8237A, VT8237S, VT8251, CX700, VX800, VX855, VX900.

Unknown ATA chipsets are supported in PIO modes, and if the standard busmaster DMA registers are present and contain valid setup, DMA is also enabled, although the max mode is limited to UDMA33, as it is not known what the chipset can do and how to program it.

The driver can change the transfer mode and various other parameters when the system is up and running. See atacontrol(8).

The driver sets the maximum transfer mode supported by the hardware as default. However the driver sometimes warns: ``DMA limited to UDMA33, non-ATA66 cable or device. '' This means that the driver has detected that the required 80 conductor cable is not present or could not be detected properly, or that one of the devices on the channel only accepts up to UDMA2/ATA33. The hw.ata.ata_dma_check_80pin tunable can be set to 0 to disable this check.

Unknown ATAPI devices are initialized to DMA mode if the hw.ata.atapi_dma tunable is set to 1 and they support at least UDMA33 transfers. Otherwise they are set to PIO mode because severe DMA problems are common even if the device capabilities indicate support. You can always try to set DMA mode on an ATAPI device using atacontrol(8), but be aware that your hardware might not support it and can potentially hang the entire system causing data loss.


ATA disk device nodes
ATA RAID device nodes
ATAPI CD-ROM device nodes
ATAPI floppy drive device nodes
ATAPI tape drive device nodes
sample generic kernel config file for based systems


Please remember that in order to use UDMA4/ATA66 and above modes you must use 80 conductor cables. Please assure that ribbon cables are no longer than 45cm. In case of rounded ATA cables, the length depends on the quality of the cables. SATA cables can be up to 1m long according to the specification.

Static device numbering (enabled with the ATA_STATIC_ID kernel option) reserves a number for each possibly connected disk, even when not present. This is useful in hotswap scenarios where disks should always show up as the same numbered device, and not depend on attach order.

Native Command Queuing (NCQ) on SATA drives is not yet supported.


The driver first appeared in Fx 4.0 .


An Søren Schmidt Aq [email protected] .