Scsiselect Settings - Adaptec AHA-1510B Installation Manual

SCSISelect Settings

Basic Host Adapter Settings
The following settings are the SCSISelect settings most
likely to require any modification.
Host Adapter Interrupt (IRQ) Channel—This option
sets the host adapter's IRQ. Each add-in card installed
in your system, including the host adapter, must have
a unique IRQ. In Plug and Play systems, the IRQ is set
automatically. In non-Plug and Play systems you must
set the IRQ manually.
Host Adapter SCSI ID— This option sets the host
adapter's SCSI ID. We recommend that you leave the
host adapter set to SCSI ID 7, which gives the host
adapter the highest priority on the SCSI bus.
SCSI Parity Checking—This option determines
whether the host adapter verifies the accuracy of data
transfer on the SCSI bus. You should disable SCSI
Parity Checking on the host adapter and all SCSI
devices if any SCSI device connected to the host
adapter does not support SCSI parity; otherwise, set it
to Enabled. Most SCSI devices do support SCSI par-
ity. If you are not sure whether a device supports
SCSI parity, consult the documentation for the device.
Host Adapter SCSI Termination—This option sets
termination on the host adapter. You can set it to
Enabled, Disabled, or Automatic. Automatic works
like this:
– If the host adapter detects that a cable is con-
nected to either its internal or external SCSI con-
nector, then it enables its terminators (the host
adapter is at the end of the SCSI bus).
– If the host adapter detects that a cable is con-
nected to both its internal and external SCSI con-
nector, then it disables its terminators (the host
adapter lies between the ends of the SCSI bus).
We recommend that you set the host adapter to
Automatic termination.
SCSI Device Settings
The SCSI device settings allow you to configure certain
parameters for each device on the SCSI bus. To configure
settings for a specific device, you must know the SCSI ID
assigned to that device. If you are not sure of the SCSI ID,
see Using the SCSI Disk Utilities on page 8.
Initiate Sync Negotiation—This option determines
whether synchronous data transfer negotiation (Sync
Negotiation) between the device and host adapter is
initiated by the host adapter. Normally, the Initiate
Sync Negotiation setting should be enabled, because
most SCSI devices support synchronous negotiation
and because it allows for faster data transfer.
Maximum Sync Transfer Rate—This option sets the
maximum synchronous data transfer rate that the host
adapter supports. The host adapter supports rates up
to the Fast SCSI maximum of 10.0 MBytes/sec. In
most cases, you can use the maximum value of 10.0.
Enable Disconnection—This option determines
whether the host adapter allows the SCSI device to
disconnect from the SCSI bus (sometimes called
Disconnect/Reconnect). If you have only one device
on the SCSI bus, disabling disconnection will give a
slight performance increase. If you have more than
one device on the SCSI bus, disconnection should be
enabled to allow multithreaded SCSI operation.
Advanced Host Adapter Settings
The advanced host adapter settings should not be
changed unless absolutely necessary.
ISA Plug and Play Support—This option determines
whether the host adapter supports Plug and Play
functionality. When Plug and Play Support is
enabled, the host adapter will work fine in both Plug
and Play and Legacy (non-Plug and Play) systems.
The only time you should disable Plug and Play Sup-
port is when you have an "ill-behaved" Plug and
Play system. If you cannot get your host adapter
working in a Plug and Play system, as a last resort,
try disabling this setting.
Plug and Play SCAM Support—This option deter-
mines whether the host adapter automatically assigns
SCSI IDs to SCSI devices that support the SCAM pro-
tocol (see Using Your Host Adapter on page 6). Most
non-SCAM devices tolerate the SCAM protocol, so
you can enable this option even if you have a non-
SCAM device.
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