Installation guide

4 – Windows NT Driver Installation QLDIRECT
FC0153302-00 F 4-3
4.3.3
Updating the Windows NT Driver
Perform the following steps if a Windows NT driver is already installed and you want
to install an updated version of the driver.
NOTE: This procedure does not modify the current registry parameters for the
QLA22xx Windows NT driver.
1. Open a DOS command prompt window.
2. Change the current directory to the Windows NT driver directory. For
example:
CD \WINNT\SYSTEM32\DRIVERS
3. Make a backup copy of the old driver. You can copy the file into the same
directory with a .SAV extension indicating that it is the saved file. For
example:
COPY QL2200.SYS QL2200.SAV
4. Insert the disk that contains the updated QLogic driver into an appropriate
drive.
5. Copy the new driver over the old driver. For example:
COPY A:\NT\QL2200.SYS
6. Remove the disk that contains the QLogic driver.
7. Reboot your system to load the updated driver.
4.3.4
Enabling Enhanced Scatter/Gather
Windows NT 4.0 includes enhanced scatter/gather list support for handling very
large SCSI I/O transfers. Version 4.0 supports up to 256 scatter/gather segments
of 4096 bytes each, allowing transfers of up to 1,048,576 bytes. For some disk
drives, it is better to reduce the transfer size to 65, 536 bytes. To reduce the transfer
size, change the subkey value in the registry (see the QLogic README.TXT file for
more information).
4.4
QLDIRECT
The QLDIRECT driver, coupled with the QLogic Windows NT enhanced miniport
driver, provides the following features.
■ A highly optimized I/O path for normal read and write operations with reduced
CPU utilization and increased parallelization
■ Failover and failback features to reroute I/O operations to the correct path
See appendix A for further information.