Adaptec AHA-2940UW User Guide - Page 32

SCSI Device Configuration

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AHA-2940UW/OF and AHA-2944UW/OF User's Guide SCSI Device Configuration The next four options allow you to configure certain parameters for each SCSI device on the SCSI bus. The settings apply to all SCSI IDs, even if they have not been assigned to a device. If you are configuring the active device, use the SCSI Disk Utilities option, which is explained on page 3-10, to determine which SCSI IDs are assigned to which devices. s Initiate Sync Negotiation- This option determines if the single-chip host adapter initiates synchronous negotiation with each SCSI device. When Initiate Sync Negotiation is set to Yes, the single-chip host adapter initiates synchronous negotiation with the SCSI device. When the option is set to No, the single-chip host adapter does not initiate synchronous negotiation. The default setting is Yes for all SCSI devices because most SCSI devices support synchronous negotiation and because a Yes setting may allow faster data throughput. The single-chip host adapter always responds to synchronous negotiation if the SCSI device initiates it; however, data is transferred in asynchronous mode if neither the single-chip host adapter nor the SCSI peripheral negotiates for synchronous data transfers. Note: Some older SCSI-1 devices do not support synchronous negotiation while Initiate Sync Negotiation is set to Yes, causing the computer to operate erratically or hang. If you use these devices, set Initiate Sync Negotiation to No. s Maximum Sync Transfer Rate- This option determines the maximum synchronous data transfer rate that the single-chip host adapter can support for a given device. The single-chip host adapter supports rates up to the UltraSCSI maximum of 20.0 MB/sec. UltraSCSI host adapters attached to a Wide SCSI bus support an effective maximum synchronous transfer rate of 40.0 MB/sec. The default setting is the maximum rate supported by the single-chip adapter: - 40.0 MB/sec for Wide UltraSCSI - 20.0 MB/sec for Narrow UltraSCSI or Wide SCSI 3-8 Downloaded from www.Manualslib.com manuals search engine

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3-8
AHA-2940UW/OF and AHA-2944UW/OF User’s Guide
SCSI Device Configuration
The next four options allow you to configure certain parameters for
each SCSI device on the SCSI bus. The settings apply to all SCSI IDs,
even if they have not been assigned to a device. If you are
configuring the
active device
, use the SCSI Disk Utilities option,
which is explained on page 3-10, to determine which SCSI IDs are
assigned to which devices.
■
Initiate Sync Negotiation
— This option determines if the
single-chip host adapter initiates synchronous negotiation
with each SCSI device. When Initiate Sync Negotiation is set to
Yes
, the single-chip host adapter initiates synchronous
negotiation with the SCSI device. When the option is set to
No
,
the single-chip host adapter does not initiate synchronous
negotiation. The default setting is
Yes
for all SCSI devices
because most SCSI devices support synchronous negotiation
and because a
Yes
setting may allow faster data throughput.
The single-chip host adapter always responds to synchronous
negotiation if the SCSI device initiates it; however, data is
transferred in asynchronous mode if neither the single-chip
host adapter nor the SCSI peripheral negotiates for
synchronous data transfers.
Note:
Some older SCSI-1 devices do not support
synchronous negotiation while Initiate Sync Negotiation is
set to
Yes
, causing the computer to operate erratically or
hang. If you use these devices, set Initiate Sync Negotiation
to
No
.
■
Maximum Sync Transfer Rate
— This option determines the
maximum synchronous data transfer rate that the single-chip
host adapter can support for a given device. The single-chip
host adapter supports rates up to the
Ultra
SCSI maximum of
20.0 MB/sec.
Ultra
SCSI host adapters attached to a Wide SCSI
bus support an effective maximum synchronous transfer rate
of 40.0 MB/sec. The default setting is the maximum rate
supported by the single-chip adapter:
–
40.0 MB/sec for Wide
Ultra
SCSI
–
20.0 MB/sec for Narrow
Ultra
SCSI or Wide SCSI
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