FreeBSD Man Pages

acd(4)

NAME

     ata, ar, acd, ad, afd, ast -- generic ATA/ATAPI disk controller driver

SYNOPSIS

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

     In /boot/device.hints:
     hint.ata.0.at="isa"
     hint.ata.0.port="0x1f0"
     hint.ata.0.irq="14"
     hint.ata.1.at="isa"
     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.at="isa"
     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

     The following tunables are settable from the loader:

     hw.ata.ata_dma
     set to 1 for DMA access, 0 for PIO (default is DMA).

     hw.ata.atapi_dma
     set to 1 for DMA access, 0 for PIO (default is PIO).

     hw.ata.wc
     set to 1 to enable Write Caching, 0 to disable (default is enabled).
     WARNING: can cause data loss on power failures.

DESCRIPTION

     AMD:	     AMD756, AMD766, AMD768, AMD8111.
     CMD:	     CMD646, CMD648, CMD649.
     Cypress:	     Cypress 82C693.
     Cyrix:	     Cyrix 5530.
     HighPoint:      HPT302, HPT366, HPT366, HPT368, HPT370, HPT371, HPT372,
		     HPT374.
     Intel:	     PIIX, PIIX3, PIIX4, ICH, ICH0, ICH2, ICH3, ICH4, ICH5.
     ITE:	     IT8212F.
     National:	     SC1100.
     nVidia:	     nForce, nForce2, nForce3.
     Promise:	     PDC20246, PDC20262, PDC20263, PDC20265, PDC20267,
		     PDC20268, PDC20269, PDC20270, PDC20271, PDC20275,
		     PDC20276, PDC20277, PDC20318, PDC20319, PDC20371,
		     PDC20375, PDC20376, PDC20377, PDC20378, PDC20379,
		     PDC20617, PDC20618, PDC20619, PDC20620.
     ServerWorks:    ROSB4, CSB5, CSB6.
     Silicon Image:  SiI0680, SiI3112, SiI3114, SiI3512.
     SiS:	     SIS5513, SIS530, SIS540, SIS550, SIS620, SIS630, SIS630S,
		     SIS633, SIS635, SIS730, SIS733, SIS735, SIS745, SIS961,
		     SIS962, SIS963, SIS964
     VIA:	     VT82C586, VT82C586B, VT82C596, VT82C596B, VT82C686,
		     VT82C686A, VT82C686B, VT8231, VT8233, VT8233A, VT8233C,
		     VT8235, VT8237.

     Unknown ATA chipsets are supported in PIO modes, and if the standard bus-
     master 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 ata driver can change the transfer mode and various other parameters
     when the system is up and running.  See atacontrol(8).

     The ata driver sets the maximum transfer mode supported by the hardware
     as default.  However the ata driver sometimes warns: ``DMA limited to
     UDMA33, non-ATA66 cable or device''.  This means that the ata 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.

     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.  Other-
     wise 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.

FILES

     /dev/ad*		     ATA disk device nodes
     /dev/ar*		     ATA RAID device nodes
     /dev/acd*		     ATAPI CD-ROM device nodes
     /dev/afd*		     ATAPI floppy drive device nodes
     /dev/ast*		     ATAPI tape drive device nodes
     /sys/i386/conf/GENERIC  sample generic kernel config file for ata based
			     systems

NOTES

     Please remember that in order to use UDMA4/ATA66 and above modes you must
     show up as the same numbered device, and not depend on attach order.

SEE ALSO

     atacontrol(8), burncd(8)

HISTORY

     The ata driver first appeared in FreeBSD 4.0.

AUTHORS

     Soren Schmidt <sos@FreeBSD.org>.

FreeBSD 5.4			March 23, 2005			   FreeBSD 5.4

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