OS/2 BusLogic Switches
MultiMaster Device Drivers
Drive Power Connector
Primary Controller in Non-IML System
Term Power Fuse
When power is first applied to the BT-640A, an on-board diagnostic routine
is run to verify that the major functional components of the board are
operating correctly. The bus master chip, the SCSI controller chip, the
firmware PROM, the local RAM and internal data buses are tested. Results of the
tests are indicated by an LED on the board.
The LED will first turn on when power is applied. If the diagnostics find no
malfunctions, the LED will then go off. In normal operation, the LED will be
illuminated when command or SCSI bus activity occurs on the board. If an error
is detected by the diagnostics, the LED will repeatedly flash a specific number
of times, with a long pause between flashes, to indicate the board function
which failed. This will continue until the board is powered down or reset.
Failure interpretation from the number of flashes is as follows:
||Not operating/missing terminator
||Firmware ROM checksum failure
||Local RAM test failure
||SCSI controller / interface failure
||Internal data bus failure
||Internal address bus failure
||Bus master chip failure
||SCSI drive type mismatch*
* Applicable to the BT-646 when SE SCSI drivers are connected to the
differential SCSI bus.
Disk Drive Power Connector
A 4-pin disk drive power connector (J4) is located at the top edge of the
BT-64x board next to the SCSI connector Jl. This connector provides +12V and
Note: The BT-64x brings the 12 volt power supply
to the 4-pin power connector (14) via three gold fingers on the edge connector.
The power rating of the Micro Channel edge connector on the12 volt is one
ampere per finger. Consequently, the maximum power allowed from the 12 volts
(Pin 1 of J4) is three amperes. Because certain large SCSI drives may require
more than three amperes when their motors are spinning up, BusLogic recommends
that this connector not be connected to these large SCSI drives.
Based on the power rating of the SCSI drives, if is recommended that this
power connector not be daisy chained to multiple drives.
Term Power Fuse
SDCxx11x and BT-64x use a Microlite Little Fuse 27301.5 125 V 1.5 A (or
equivalent micro fuse). It is difficult to see that the fuse is blown so you
will need to use a VOM to test for continuity. The fuse can blow if termination
power settings are not correct on the SCSI devices or if you disconnect the
SCSI cables while the card or SCSI devices have power.
(Ed. Sure ain't kidding!)
Primary Controller in Non-IML System
Enable the BIOS. Set your boot drive to ID0 or the BT-64x will not be able
to boot from it. Also, you should set the boot drive to "autostart" so it spins
up as soon as the system is turned on. I had a 0662 set to ID0, but the BT-646
complained about Target 0, LUN 0 not being detected, but then showed the 0662
at ID0, then the CD at 6,0. After jumpering the 0662 to autostart, everything
For operating systems such as UNIX, NetWare, and OS/2, the mailbox protocol
of the BT-64x provides true multitasking operation. Through the use of a
mailbox structure, the BT-64x can support up to 255 tasks with minimum host
processor intervention. Onboard firmware controls all of the SCSI activity that
a task requires, including the Arbitration, Selection, Disconnection,
Reconnection, and command completion status. This same mailbox protocol
supports both initiator and target mode operation permitting high speed
host-to-host communication and scatter-gather data transfers.
Disk > 1 GB and not SC0 UNIX
In the DOS environment, INT 13 calls are routed through the BT-64xA/S/D’s
ROM BIOS. This on-board BIOS intercepts host interrupt 13H calls and dispatches
a command to the BT-64x for all host to SCSI disk accesses. When the >lGB
option is turned on, the BT-64x BIOS can access up to 8 GBytes per disk.
Otherwise, it can only access the first 1 GBytes even if the formatted disk
capacity is greater than 1GByte. This 1GByte restriction does not apply to
other operating systems, such as NetWare, UNIX, SC0 UNIX 3.2.4, or OS/2 if the
operating system can boot without accessing > 1 GBytes. If the operating
system’s bootable image resides below 1 GBytes then it can boot via Interrupt
13H. Once any of these operating systems are booted, the disk accesses are not
routed through Interrupt 13H and the operating system can access the entire
disk space even if the > 1 GB option is not turned on.
Under SC0 UNIX 3.2.2, the >lGB option must be turned off because the
operating system itself has a 1 GByte limitation. Otherwise, disk images may be
corrupted when the 1 GByte boundary is reached. For SC0 UNIX 3.2.4, the
operating system does not impose the 1 GByte limit, and this option can be
turned on or off accordingly. Consequently, the >lGByte support must be
turned on under the following two conditions: (1) the combined space of all the
DOS partitions exceeds lGByte, or (2) >lGByte disk accesses are required to
boot the operating system. To enable the > 1 GB support, turn on this
option. Warning: If this option is changed, you must
reformat the disk to avoid corrupting the existing file system.
Ed. The >1GB translation scheme is
incompatible with IBM SCSI controllers. After formatting a DPES-13080 1.08GB
drive on a BT-646S (>1GB translation enabled), I was unable to access it
after then attaching the drive to a Corvette. I had to reformat the drive with
Note: Earlier ADF versions may have "Slot Data
Width". The function of this bit was changed. The data width function is
detected by the host adapter and this switch was ignored.
CONFG243.EXE - (111k) ADF files for all
Storage Dimensions SCSI adapters. Buslogic drivers are the same. The
Micro Channel RAIDCard - v2.0 (269K) all
the required files to support the -002 Micro Channel RAIDCard for OS/2 and
NetWare. For use under NetWare, you must also have the LANStor Plus software. When unarchiving this file,
use the "-D" option to restore the directory structure.
LANStor5 - v6.10 (109k) SCSI NLM for
NetWare v3.11 - supports the SDC1611/3211x under NetWare versions 3.11. Not
tested or certified using NetWare v3.12 or v4.xx.
LANStor Plus - v2.50 (114k) SCSI NLM for
NetWare v3.12 and v4.xx most current version of LANStor for the SDC1611/3211x,
and the SDC3231WS SCSI Adapters. It includes LAPIS Plus which which is Artecon'
ASPI layer (manager).