Disk Access Delay Time; Maximum Tag Count - Asus PCI-DA2100 User Manual

3.5.3

Disk Access Delay Time

Sets the delay time before the controller tries to access the hard drives after
power-on. The default is 15 seconds.
3.5.4 SCSI I/O Timeout
The "SCSI I/O Timeout" is the time interval that the controller waits
for a drive to respond. If the controller attempts to read data from or
write data to a drive, but the drive does not respond within the SCSI
I/O timout value, the drive will be judged to be a failed drive.
When the drive itself detects a media error while reading from the
drive platter, it will retry the previous reading or recalibrate the
head. When the drive has encountered a bad block on the media, it
has to reassign the bad block to another spare block. However, all of
this takes time. The time to perform these operations can vary
between different brands and models of drives.
During SCSI bus arbitration, a device with higher priority can utilize
the bus first. A device with lower priority will sometimes get a SCSI
I/O timeout when higher priority devices keep utilizing the bus.
The default setting for "SCSI I/O Timeout" is 7 seconds. It is highly
recommended not to change this setting. Setting the timeout to a
lower value will cause the controller to judge a drive as failed a drive
is still retrying or while a drive is unable to arbitrate the SCSI bus.
Setting the timeout to a greater value will cause the controller to
keep waiting for a drive, and it may sometimes cause a host timeout.
3.5.5

Maximum Tag Count

The maximum number of tags that can be sent to each drive at the
same time. A drive has a built-in cache that is used to sort all of the
I/O requests ("tags") which are sent to the drive, allowing the drive
to finish the requests faster. The cache size and maximum number of
tags varies between different brands and models of drive. Using the
default setting – "32" – is highly recommended. Changing the
maximum tag count to "Disable" will cause the internal cache of the
drive to be ignored (i.e., not used).
ASUS PCI-DA2100/PCI-DA2200 User's Manual
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