Adaptec AHA-2742T User Manual - Page 66

SCSI Device Configuration

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Configuring the Host Adapter Configuration Setting for SCSI Devices (1x8) Channel A Device ID #0 #1 #2 #3 #4 #5 #6 #7 Enable Disconnection yes yes yes yes yes yes yes yes Initiate Sync Negotiation yes yes yes yes yes yes yes yes Maximum Sync Xfer Rate 10.0 10.0 10.0 10.0 10.0 10.0 10.0 10.0 Include in BIOS Scan yes yes yes yes yes yes yes yes Error if Device Not Found no no no no no no no no Send Start Unit Command no no no no no no no no OK Figure 3-13. SCSI Device Configuration Enable Disconnection This option is used to determine whether or not the host adapter will allow a SCSI device to disconnect from the SCSI bus (sometimes referred to as disconnect/reconnect). This allows the host adapter to perform other operations on the SCSI bus while the SCSI device is temporarily disconnected. When set to yes, the SCSI device may disconnect from the SCSI bus. The SCSI device, however, may choose not to disconnect, even if allowed to by the host adapter (this is usually configurable on the SCSI device). When set to no, the SCSI device will not be allowed to disconnect from the SCSI bus. The default setting is yes. In general, disconnect should be allowed for the most efficient SCSI bus utilization and highest overall system performance. If only one SCSI device is attached to the SCSI host adapter, disconnects are not required for efficient SCSI bus utilization since only one SCSI device is using the SCSI bus. A slight performance increase may be realized if disconnect is not allowed in this case, due to the decreased SCSI overhead. In multi-device environments, disconnect should normally be enabled to take advantage of the disconnect/reconnect feature. If a particular SCSI device does not support disconnect/reconnect, then Enable Disconnection should be disabled (set to no). If a particular SCSI device does support disconnect/reconnect, then Enable Disconnection should be enabled (set to yes). Most SCSI devices today do support disconnect/reconnect. 3-15 Adaptec AHA-2740 Series User's Manual Stock Number: 510381-00 / Rev. C (Page 3-15) Print Spec Number: 491709-00 Rev C Current Date: 9/1/93 ECN Date: 9/14/93

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Enable Disconnection
This option is used to determine whether or not the host adapter
will allow a SCSI device to disconnect from the SCSI bus (some-
times referred to as disconnect/reconnect). This allows the host
adapter to perform other operations on the SCSI bus while the
SCSI device is temporarily disconnected.
When set to
yes
, the SCSI device may disconnect from the SCSI
bus. The SCSI device, however, may choose not to disconnect,
even if allowed to by the host adapter (this is usually configurable
on the SCSI device). When set to
no,
the SCSI device will not be
allowed to disconnect from the SCSI bus. The default setting is
yes
.
In general, disconnect should be allowed for the most efficient
SCSI bus utilization and highest overall system performance. If
only one SCSI device is attached to the SCSI host adapter, discon-
nects are not required for efficient SCSI bus utilization since only
one SCSI device is using the SCSI bus. A slight performance
increase may be realized if disconnect is not allowed in this case,
due to the decreased SCSI overhead. In multi-device environ-
ments, disconnect should normally be enabled to take advantage
of the disconnect/reconnect feature.
If a particular SCSI device does not support disconnect/reconnect,
then Enable Disconnection should be disabled (set to
no
). If a
particular SCSI device does support disconnect/reconnect, then
Enable Disconnection should be enabled (set to
yes
). Most SCSI
devices today do support disconnect/reconnect.
Configuration Setting for SCSI Devices
(1x8)
Channel A Device ID
Enable Disconnection
Initiate Sync Negotiation
Maximum Sync Xfer Rate
Include in BIOS Scan
Error if Device Not Found
Send Start Unit Command
OK
<ESC>
<DEFAULT>
#0
yes
yes
10.0
yes
no
no
#1
yes
yes
10.0
yes
no
no
#2
yes
yes
10.0
yes
no
no
#3
yes
yes
10.0
yes
no
no
#4
yes
yes
10.0
yes
no
no
#5
yes
yes
10.0
yes
no
no
#6
yes
yes
10.0
yes
no
no
#7
yes
yes
10.0
yes
no
no
Figure 3-13.
SCSI Device Configuration
Adaptec AHA-2740 Series User’s Manual
Stock Number:
510381-00
/
Rev. C
(Page 3-15)
Print Spec Number:
491709-00 Rev C
Current Date:
9/1/93
ECN Date:
9/14/93
Configuring the Host Adapter
3-15