NAME

     bt — Buslogic/Mylex MultiMaster SCSI host adapter driver

SYNOPSIS

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

           device isa
           device scbus
           device bt

           In /boot/device.hints:
           hint.bt.0.at="isa"
           hint.bt.0.port="0x330"

DEPRECATION NOTICE

     This driver is scheduled for removal prior to the release of FreeBSD 13.0.

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-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-545S      ISA     30           Fast SCSI-2
           BT-542D      ISA     30           Differential Fast SCSI-2
           BT-542B      ISA     30           SCSI-2 (542B revision H)

           MultiMaster "A" Series Host Adapters:

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

     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 certain 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.

HARDWARE

     The bt driver supports the following BusLogic MultiMaster “W”, “C”, “S”, and “A” series and
     compatible SCSI host adapters:

     •   BusLogic BT-445C
     •   BusLogic BT-445S
     •   BusLogic BT-540CF
     •   BusLogic BT-542B
     •   BusLogic BT-542B
     •   BusLogic BT-542D
     •   BusLogic BT-545C
     •   BusLogic BT-545S
     •   BusLogic/BusTek BT-640
     •   BusLogic BT-946C
     •   BusLogic BT-948
     •   BusLogic BT-956C
     •   BusLogic BT-956CD
     •   BusLogic BT-958
     •   BusLogic BT-958D
     •   Storage Dimensions SDC3211B / SDC3211F

SEE ALSO

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

HISTORY

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

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 revisions, with their otherwise undocumented quirks,
     would not have been possible without his efforts.