arad is the device driver for
Adaptec 274x and 284x (7770 chip) SCSI host adapter cards.
It directly supports these host adapters:
This driver also supports the AIC-7770 chip on
Certified SCO OpenServer System platforms.
Refer to the
Compatible Hardware Web Pages.
to determine the support status of your host adapter, or
contact your system supplier.
Configuring the arad driver
You can configure the arad driver using entries in
/etc/conf/cf.d/mdevice and /etc/conf/sdevice.d/arad.
Changes to these files
take effect once you relink the kernel using
and reboot the system.
Configure arad driver-specific characteristics
by editing the /etc/conf/pack.d/arad/space.c file,
which controls parameters such as the SCSI ID,
the SCB handling mode,
parity checking, and timeouts.
Boot time configuration of SCSI
parameters to override
the default hardware configuration information.
Of special interest are the adapter= parameter
that specifies information for
the host adapter card
that plugs into or is part of the motherboard,
and the periph= parameter
that specifies information about the host adapter
being used by one of the generic peripheral interfaces
(Sdsk, Srom, or Stp).
Configuring twin channel adapters
If the adapter supports more than one SCSI bus (that is,
you have one of the twin channel adapters), you must ensure that
all installation devices are on the primary bus.
To use the secondary bus channel after installation, it must be configured
as an additional SCSI host adapter.
Note that there are only two channels (A and B) on the Adaptec
2740/2742T and 2740/2742AT cards.
These notes apply to the Adaptec host adapter BIOS:
If multiple 2740T host adapters are being used, under certain
conditions, disable all BIOSs except the boot host adapter.
If the BIOS of the 2740T/2742T or the
2740A/A-T/2742/A/A-T is disabled, the driver will use the
default setting configuration.
Adaptec 274x configuration utility notes
These notes apply to the Adaptec 274x configuration utility:
Save the configuration information before using the
When termination on Channel B is not set up properly or if
the 2740T/2740A-T/2742A-T is
not seated properly in the EISA slot, the
configuration utility might falsely detect those adapters
as 2740/42 or 2740W/2742W host adapters.
The following general notes apply.
The AHA-2740T/2742T and the
2740A/A-T/2742A/A-T do not support a
synchronous rate lower than 3.6MB/s.
The system might display a warning message if you try to perform a
fresh install of the driver at IRQ 10; this is
because of the possibility of an interrupt collision. Do
not use IRQ 10 for a fresh installation. The
IRQ can be changed to 10 for a previously installed driver.
When adding a host adapter, the lowest BIOS
address must correspond to the lowest EISA slot.
Some hard disk drives which initiate synchronous
negotiation will not be installed during BIOS
scan when synchronous negotiation is disabled on the host
adapter. It is recommended that synchronous negotiation be
left enabled (default) for hard disks.
The arad driver
supports all standard SCSI ioctls
that are defined in the <sys/scsicmd.h> header file
and documented on the
These error messages associated with arad may display on the console.
for general information about kernel error messages,
including a list of generic device driver errors.
WARNING: arad: Adapter diagnostic failure 0x%x: bus 0
arad was unable to initialize the hardware
that it found.
This often indicates a hardware error.
WARNING: arad: Cannot initialize drive ID:0
arad was unable to perform
SCSI commands on the boot drive
to determine its drive geometry.
This might indicate that not enough memory was available
to perform the operation.
WARNING: arad: CONFLICT-Disconnection must be enabled in order for tag-queuing to work
By definition, tag queuing requires that disconnection be enabled.
If tag queuing is enabled but disconnect is disabled,
then this message appears.
The solution is to either enable disconnection
or disable tag queuing in the driver's space.c file.
WARNING: arad: spurious interrupt arad_name.
An interrupt occurred but there was no pending command.
The source could be another driver,
such as a video driver,
that is sharing the same interrupt.
From the standpoint of the host adapter driver,
this message can be ignored.
Target Bus Phase Sequence Error
An error occurred in the SCSI phase.
Anything can cause this message,
including device firmware, the SCSI driver,
and bus resets.
Usually no user response is possible,
although you may want to avoid issuing the commands
that resulted in this error.
Auto-Request Sense Failed
When a check condition occurs,
the host adapter automatically performs a check condition
to obtain the sense key.
If that process also fails,
this message is displayed.
No user response required.
Host Adapter Hardware Error
Check the adapter and cabling.
Be sure that the host adapter is firmly seated in the slot.
The host adapter might be malfunctioning;
contact the host adapter manufacturer for assistance.