Table 2–6 (Cont.) PARAMS Configuration Utility HSD05 Array Controller
Parameters
Parameter
Name
Definition
SYSTEMID
Specifies the lower order 32 bits of the 48-bit system identification
number. The factory default for this identifier is the same as
specified by the NODENAME parameter.
DISK_ALCS
Determines the device allocation class for all disk devices connected
to HSD05 array controller. If disks are to be served to other nodes
within the VAXcluster, this parameter must be non-zero and match
the ALLOCLASS SYSGEN parameter on connected systems. The
factory default for this parameter is zero.
TAPE_ALCS
Determines the device allocation class for all tape devices connected
to the HSD05 array controller. If tapes are to be served to other
nodes within the VAXcluster, this parameter must be non-zero and
match the ALLOCLASS SYSGEN parameter on connected systems.
The factory default for this parameter is zero.
INTERVAL
Controls the rate at which SCSI device scanning is done. This value
is only used if SCANNING is enabled. The factory default for this
parameter is 60 seconds.
NUMPOLL
Controls the number of SCSI devices to look for during each
INTERVAL. This parameter is currently not implemented but
may be activated in a future revision of the firmware. The factory
default for this parameter is 7, which scans for all available units at
each interval.
UNIT_OFFSET
Helps to differentiate devices when a system has two DSSI buses.
Unit offset is specified as the value to be used in the thousands
position of the MSCP unit ID, such as x for DIAx210. This offset is
automatically created by the system. The unit offset values must
be unique for each DSSI bus on the system. The factory default for
this parameter is 0.
SYNC_RATE
The rate in MHz that data is transferred during the data
transmission phase between target and host. The factory default for
this parameter is 7 MHz.
MAX_HOSTS
Determines the maximum number of hosts with which the HSD05
array controller will communicate. This parameter is primarily
used for disk and tape credit allotment. For best performance, set
this parameter to the maximum number of hosts to be used. Digital
supports up to three hosts (the factory default) in a multihost
HSD05 array controller configuration.
FASTSCAN
Reduces the SCSI SELECT timeout to a much smaller value, with
the default timeout set at 250 milliseconds. This parameter is
currently not implemented. The factory default for this parameter
is 0 (disabled).
SCANNING
Enables/disables the HSD05 array controller’s ability to scan for
newly connected devices. If scanning is disabled, the HSD05 array
controller only does one scan for devices at power up, and will not
look for new devices every INTERVAL seconds. The factory default
for this parameter is 1.
DISCONNECT
Enables/disables the ability to disconnect all SCSI devices connected
to the HSD05 array controller. When only one device is connected
to the HSD05 array controller, this parameter should be disabled
for better performance. The factory default for this parameter is 1.
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Preparing to Use the HSD05 Array Controller 2–13
