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BT(4)			     Kernel Interfaces Manual			   BT(4)

NAME
     bt -- Buslogic/Mylex MultiMaster SCSI host adapter driver

SYNOPSIS
     device bt0 at isa? port ? irq ?
     device scbus0 at bt0

DESCRIPTION
     This  driver  provides access to the SCSI bus connected to a Buslogic/Mylex
     MultiMaster or compatible controller:

	   MultiMaster "W" Series Host Adapters:

	   Adapter   Bus   Commands  Description
	   BT-948    PCI     192     ULtra SCSI-3
	   BT-958    PCI     192     Wide ULtra SCSI-3
	   BT-958D   PCI     192     Wide Differential ULtra SCSI-3

	   MultiMaster "C" Series Host Adapters:

	   Adapter   Bus   Commands  Description
	   BT-946C   PCI     100     Fast SCSI-2
	   BT-956C   PCI     100     Wide Fast SCSI-2
	   BT-956CD  PCI     100     Wide Differential Fast SCSI-2
	   BT-445C   VLB     100     Fast SCSI-2
	   BT-747C   EISA    100     Fast SCSI-2
	   BT-757C   EISA    100     Wide Fast SCSI-2
	   BT-757CD  EISA    100     Wide Differential Fast SCSI-2
	   BT-545C   ISA      50     Fast SCSI-2
	   BT-540CF  ISA      50     Fast SCSI-2

	   MultiMaster "S" Series Host Adapters:

	   Adapter   Bus   Commands  Description
	   BT-445S   VLB      30     Fast SCSI-2
	   BT-747S   EISA     30     Fast SCSI-2
	   BT-747D   EISA     30     Differential Fast SCSI-2
	   BT-757S   EISA     30     Wide Fast SCSI-2
	   BT-757D   EISA     30     Wide Differential Fast SCSI-2
	   BT-545S   ISA      30     Fast SCSI-2
	   BT-542D   ISA      30     Differential Fast SCSI-2
	   BT-742A   EISA     30     SCSI-2 (742A revision H)
	   BT-542B   ISA      30     SCSI-2 (542B revision H)

	   MultiMaster "A" Series Host Adapters:

	   Adapter   Bus   Commands  Description
	   BT-742A   EISA     30     SCSI-2 (742A revisions A - G)
	   BT-542B   ISA      30     SCSI-2 (542B revisions A - G)

     AMI FastDisk Host Adapters that are true BusLogic	MultiMaster  clones  are
     also supported by this driver.

     Tagged  queueing  is  supported on 'W' series adapters, 'C' series adapters
     with firmware of rev 4.42 and higher, and 'S' series adapters with firmware
     of rev 3.35 and higher.

     Boards with certain firmware revisions may lock up under heavy load to cer-
     tain devices, especially if tagged queueing is used.  Should you  encounter
     a problem with your adapter, contact Mylex technical support and ensure you
     have the latest firmware for your controller.

SEE ALSO
     cd(4), da(4), sa(4), scsi(4)

AUTHORS
     Julian  Elischer  wrote a driver for the Multimaster cards that appeared in
     the 386BSD patch kit.  The driver was rewritten by Justin T. Gibbs to  take
     advantage	of  new  board	features and work with the CAM SCSI framework in
     FreeBSD 3.0.

     Special thanks to Leonard N. Zubkoff for writing such a complete  and  well
     documented  Mylex/BusLogic  MultiMaster  driver for Linux.  Support in this
     driver for the wide range of MultiMaster  controllers  and  firmware  revi-
     sions, with their otherwise undocumented quirks, would not have been possi-
     ble without his efforts.

FILES
     sys/dev/buslogic/bt.c	   Core Driver Implementation
     sys/dev/buslogic/btreg.h	   MultiMaster Register Set and Core Driver Data
				   Structures
     sys/pci/bt_pci.c		   PCI Bus Driver Attachment
     sys/i386/eisa/bt_eisa.c	   EISA Bus Driver Attachment
     sys/i386/isa/bt_isa.c	   ISA/VL Bus Driver Attachment

HISTORY
     The bt driver first appeared in the 386BSD patch kit.

FreeBSD 4.7			October 16, 1998			   BT(4)

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