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ATA(4)			     Kernel Interfaces Manual			  ATA(4)

NAME
     ata, 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 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

     The following tunables are setable 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: might cause data loss on power failures.)

     hw.ata.tags
     set to 1 to enable Tagged Queuing support, 0 to disable (default is
     disabled).  (Only IBM DPTA, DTLA, ICxxxxxxAT, ICxxxxxxAV drives support
     that.)

DESCRIPTION
     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	100  (UDMA5), 100 MB/sec
					    (depending on model, max  stated  at
					    boot)
     AMD 756				    Ultra DMA 66 (UDMA4), 66 MB/sec
     AMD 766				    Ultra DMA 100 (UDMA5), 100 MB/sec
     Acard ATP850			    Ultra DMA 33 (UDMA2), 33 MB/sec
     Acard ATP860			    Ultra DMA 66 (UDMA4), 66 MB/sec
     Acard ATP865			    Ultra DMA 133 (UDMA6), 133 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
     Cyrix 5530 			    Ultra DMA 33 (UDMA2), 33 MB/sec
     HighPoint HPT366			    Ultra DMA 66 (UDMA4), 66 MB/sec
     HighPoint HPT370			    Ultra DMA 100 (UDMA5), 100 MB/sec
     HighPoint HPT372			    Ultra DMA 133 (UDMA6), 133 MB/sec
     HighPoint HPT374			    Ultra DMA 133 (UDMA6), 133 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
     Intel ICH4 			    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
     Promise Ultra/Fasttrak-100 TX2/TX4     Ultra DMA 100 (UDMA5), 100 MB/sec
     Promise Ultra/Fasttrak-133 TX2/TX2000  Ultra DMA 133 (UDMA6), 133 MB/sec
     ServerWorks ROSB4			    Ultra DMA 33 (UDMA2), 33 MB/sec
     ServerWorks CSB5			    Ultra  DMA	100  (UDMA5), 100 MB/sec
					    (depending on model, max  stated  at
					    boot)
     Sil 0680				    Ultra  DMA	133  (UDMA6), 133 MB/sec
					    (depending on model, max  stated  at
					    boot)
     SiS 5591				    Ultra  DMA	100  (UDMA5), 100 MB/sec
					    (depending on model, max  stated  at
					    boot)
     VIA 82C586 			    Ultra DMA 33 (UDMA2), 33 MB/sec
     VIA 82C596 			    Ultra DMA 66 (UDMA4), 66 MB/sec (de-
					    pending  on  model,  max  stated  at
					    boot)
     VIA 82C686a			    Ultra DMA 66 (UDMA4), 66 MB/sec
     VIA 82C686b			    Ultra DMA 100 (UDMA5), 100 MB/sec
     VIA 8233/8235			    Ultra DMA 133  (UDMA6),  133  MB/sec
					    (depending	on  model, max stated at
					    boot)

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

     The ata driver also allows for changes to the transfer mode of the  devices
     at a later time when the system is up and running, see atacontrol(8).

     The  driver  attempts  to set the maximum performance transfer mode on your
     disk drives by selecting the highest possible DMA mode.   However	the  ata
     driver sometimes issues the message "DMA limited to UDMA33, non-ATA66 cable
     or  device",  if the cable is ATA66 (or above) compliant, it is because the
     other device on this channel states it can only accept  up  to  UDMA2/ATA33
     signals.	ATAPI devices are left in PIO mode because DMA problems are com-
     mon despite the device specifications.  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 hang the system.

FILES
     /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
			     systems

NOTES
     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 ab-
     sence of ad1.  The advantage is that the addition of  the	formerly  absent
     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 spe-
     cial 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.

SEE ALSO
     atacontrol(8), burncd(8)

HISTORY
     The ata driver first appeared in FreeBSD 4.0.

AUTHORS
     The ata driver was written by Soren Schmidt <sos@FreeBSD.org>.

     This  manual  page  was  written  by  Jeroen   Ruigrok   van   der   Werven
     <asmodai@FreeBSD.org> and Soren Schmidt <sos@FreeBSD.org>.

FreeBSD 5.0			January 27, 2000			  ATA(4)

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