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ATA(4)			 BSD Kernel Interfaces Manual			ATA(4)

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

     For ISA based ATA/ATAPI support:
     device isa
     device ata0 at isa? port IO_WD1 irq 14
     device ata1 at isa? port IO_WD2 irq 15

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

     To	support	ATA compliant disk drives:
     device atadisk

     To	support	ATAPI CD-ROM, CDR, CDRW, DVD-ROM and DVD-RAM drives:
     device atapicd

     To	support	ATAPI floppy drives, such as the ZIP and LS120:
     device atapifd

     To	support	ATAPI tape drives:
     device atapist

     To	enable static controller and device numbering (see the NOTES section
     options ATA_STATIC_ID

     The following tunables are	setable	from the loader:

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

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

     set to 1 to enable	Write Caching, 0 to disable (default is	enabled)
     (WARNING might cause data loss on power failures)

     set to 1 to enable	Tagged Queuing support,	0 to disable (default is dis-
     abled) (only IBM DPTA and DTLA drives support that)

     This driver provides access to disk drives, ATAPI CD-ROM and DVD drives,
     ZIP drives	and tape streamers connected to	controllers according to the
     ATA and ATAPI standards.  These devices are also commonly known as	IDE or
     EIDE devices.

     The currently supported controllers with their maximum speed include:

     Acerlabs Aladdin		    Ultra DMA 33 (UDMA2), 33 MB/sec
     AMD 756			    Ultra DMA 66 (UDMA4), 66 MB/sec
     AMD 766			    Ultra DMA 100 (UDMA5), 100 MB/sec
     CMD 646			    DMA	2 (WDMA2), 16 MB/sec
     CMD 648			    Ultra DMA 66 (UDMA4), 66 MB/sec
     CMD 649			    Ultra DMA 100 (UDMA5), 100 MB/sec
     Cypress 82C693		    DMA	2 (WDMA2), 16 MB/sec
     HighPoint HPT366		    Ultra DMA 66 (UDMA4), 66 MB/sec
     HighPoint HPT370		    Ultra DMA 100 (UDMA5), 100 MB/sec
     Intel PIIX			    DMA	2 (WDMA2), 16 MB/sec
     Intel PIIX3		    DMA	2 (WDMA2), 16 MB/sec
     Intel PIIX4		    Ultra DMA 33 (UDMA2), 33 MB/sec
     Intel ICH0			    Ultra DMA 33 (UDMA2), 33 MB/sec
     Intel ICH			    Ultra DMA 66 (UDMA4), 66 MB/sec
     Intel ICH2			    Ultra DMA 100 (UDMA5), 100 MB/sec
     Intel ICH3			    Ultra DMA 100 (UDMA5), 100 MB/sec
     Promise Ultra/Fasttrak-33	    Ultra DMA 33 (UDMA2), 33 MB/sec
     Promise Ultra/Fasttrak-66	    Ultra DMA 66 (UDMA4), 66 MB/sec
     Promise Ultra/Fasttrak-100	    Ultra DMA 100 (UDMA5), 100 MB/sec
     ServerWorks ROSB4		    Ultra DMA 33 (UDMA2), 33 MB/sec
     SiS 5591			    Ultra DMA 33 (UDMA2), 33 MB/sec
     Cyrix 5530			    Ultra DMA 33 (UDMA2), 33 MB/sec
     VIA 82C586			    Ultra DMA 33 (UDMA2), 33 MB/sec
     VIA 82C686a		    Ultra DMA 66 (UDMA4), 66 MB/sec
     VIA 82C686b		    Ultra DMA 100 (UDMA5), 100 MB/sec

     All unknown chipsets can be supported at the maximum speed	of 16 MB/sec.

     The ata driver also allows	for changes to the transfer mode of the	de-
     vices at a	later time when	the system is up and running.

     The driver	attempts to set	the maximum performance	transfer mode on your
     disk drives by selecting the highest possible DMA mode.  ATAPI devices
     are left in PIO mode because DMA problems are common despite the device
     specifications.  You can always try to set	DMA mode on an ATAPI device
     using the sysctl method described here, but be aware that your hardware
     might not support it and can hang the system.

     To	see the	devices' current access	modes, use the command line:

	   sysctl hw.atamodes

     which results in the modes	of the devices being displayed as a string
     like this:

	   hw.atamodes:	dma,pio,---,pio,dma,---,dma,---, (--- =	no device)

     This means	that ata0-master is in DMA mode, ata0-slave is in PIO mode,
     and so forth.  You	can set	the mode with sysctl and a string like the
     above, for	example:

	   sysctl hw.atamodes=pio,pio,---,dma,pio,---,dma,---,

     The new modes are set as soon as the sysctl command returns.

     /dev/ad*		      ATA disk 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

     Static numbering (enabled with the	ATA_STATIC_ID kernel option) reserves
     a number for each possibly	connected disk,	even when not present.	This
     may result	in odd situations where, for example, ad0 and ad2 exist	in the
     absence of	ad1.  The advantage is that the	addition of the	formerly ab-
     sent drive	does not cause the numbers of the other	drives to change.

     The ata driver does not support MFM/RLL/ESDI (ST-506) style disks.

     Remember that in order to use UDMA4 (and above) mode you have to use a
     special 80	conductor cable, and the driver	tries to determine if you have
     such a cable attached before setting UDMA4	mode.

     The use of	UDMA4(66MHz) and higher	together with non-UDMA4	devices	on the
     same ATA channel is not recommended, unless they are run at the non-UDMA4
     device's lower speed.  The	driver has been	designed to handle that	kind
     of	setup but lots of older	devices	do not like this.

     The ata driver first appeared in FreeBSD 4.0.

     The ata driver was	written	by Soren Schmidt <>.

     This manual page was written by Jeroen Ruigrok van	der Werven
     <> and Soren Schmidt <>.

BSD			       January 27, 2000				   BSD


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