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AHB(4)			     Kernel Interfaces Manual			  AHB(4)

NAME
     ahb -- Adaptec EISA SCSI host adapter driver

SYNOPSIS
     To compile this driver into the kernel, place the following lines in your
     kernel configuration file:

	   device scbus
	   device ahb

     Alternatively, to load the driver as a module at boot time, place the
     following line in loader.conf(5):

	   ahb_load="YES"

DESCRIPTION
     This  driver  provides  access  to  the  SCSI  bus  connected to an Adaptec
     AHA-174X host adapters in "enhanced" mode.  Tagged queueing and synchronous
     SCSI transfers are supported.

HARDWARE
     The ahb driver supports the following SCSI host adapters:

     *	 Adaptec AHA-1740
     *	 Adaptec AHA-1742
     *	 Adaptec AHA-1740A
     *	 Adaptec AHA-1742A

SEE ALSO
     aha(4), ahc(4), aic(4), cd(4), da(4), sa(4), scsi(4)

AUTHORS
     The ahb driver was written by Justin T. Gibbs.

CAVEATS
     The Adaptec 174X is very  sensitive  to  SCSI  bus  termination  and  cable
     length.   It  may also have difficulties operating with some modern devices
     that, due to their speed, expose timing problems in the controller.   There
     are no known mechanisms for working around device incompatibilities of this
     nature.

FreeBSD 9.1			  July 4, 2004				  AHB(4)

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