Reglamento 1371/2007

This section describes theSYMMPI.SYS driver for the Windows 2000 operating system and includes these topics:

• Section 7.6.1, “Installing the SYMMPI.SYS Driver”

• Section 7.6.2, “Performance Tuning”

This driver supports only Windows 2000.

7.6.1 Installing the SYMMPI.SYS Driver

The following procedures install theSYMMPI.SYSdriver onto a new or existing Windows 2000 system.

7.6.1.1 New System Installation

This procedure installs theSYMMPI.SYSdriver onto a new

Windows 2000 system. Windows 2000 automatically adds the driver to the registry and copies the driver to the appropriate directory.

The method for installing Windows 2000 on a new system involves using a CD-ROM. Refer to the Microsoft document for installing Windows 2000 using boot floppy diskettes.

Step 1. Start the Windows 2000 installation by booting from the Windows 2000 CD-ROM.

The system BIOS must support booting from a CD-ROM. BIOS

Step 2. Press F6 to install the SYMMPI.SYS driver when the screen displays:

“Press F6 if you need...”

Note: You must press F6 for the system to recognize the new driver. Otherwise, the system does not recognize the devices controlled by the driver during the Windows 2000 setup.

Step 3. Choose S to specify an additional device when the screen displays:

“Setup could not determine the type of one or more mass storage devices...”

Note: If this screen is not displayed as the first user input, then pressing F6 was not seen by the setup program. Reboot the system and return to Step 2.

Step 4. The system prompts for the manufacturer-supplied hardware support disk. Insert the driver diskette containing the

Windows 2000 device driver and press Enter.

Step 5. Select the Windows 2000 device driver from the menu by highlighting it and press Enter.

Step 6. Press Enter to proceed.

Step 7. Return to the Windows 2000 Setup screen.

Step 8. Press Enter to proceed.

Step 9. Follow the Microsoft Windows 2000 installation procedure at this point.

Step 10. Repeat this process for the second channel, if one is present.

7.6.1.2 Existing System Installation

This procedure installs or upgrades theSYMMPI.SYS driver onto an existing Windows 2000 system.

Step 1. Boot Windows 2000.

The Found New Hardware Wizard begins.

Step 2. Click on the Next button.

Step 3. Click on the“Search for a suitable driver...”

button to select it, and then click on the Next button.

Step 4. Click on the Next button.

Step 5. Check the specify location box, uncheck all other boxes, and click on the Next button.

Step 6. TypeA:\W2K and click on the OK button.

Step 7. Click on the Next button on the Driver Files Search Results window.

Step 8. Click on the Finish button to complete the driver installation.

Step 9. Repeat this process for the second channel, if one is present.

7.6.2 Performance Tuning

The Windows 2000 operating system has registry entries that you can use to tune the performance of SCSI I/O for certain configurations. The tunable parameters are the large transfer block size support and the guaranteed number of concurrent I/Os for a particular SCSI bus.

7.6.2.1 Large Block Size Support

TheSYMMPI.SYSdrivers can support up to a 1 Mbyte transfer size in a Windows 2000 system; however, the default Windows 2000 transfer size is 64 Kbytes. To enable better performance, the driver installation process adds a registry entry to enable 256 Kbytes transfer sizes.

Programmers can also use thempi_256K.regfile to set or re-enable the maximum transfer size. There are two methods to add this registry setting. The first method is to locate the mpi_256K.regdata file using Windows Explorer, double-click on the file, and edit it. The second method is to type at the command prompt:

regedit mpi_256K.reg

This command inserts an entry in the registry to enable 256 Kbytes block size support.

Editing the MPI_256K.REGdata file can set any maximum block size between 64 Kbytes and 1 Mbyte. The formula to calculate the proper value for MaximumSGList is:

As an example, to determine the MaximumSGList value for 256 Kbytes, take [(256 Kbytes/4 Kbytes) +1] = 65 (or 0x41 in hexadecimal).

The maximum value allowed for MaximumSGList is 255 or 0xFF. For the particular value of 0xFF, the internal value passed to Windows 2000 is increased to 0x101, allowing support for a full 1 Mbyte transfer.

Read the information in thempi_256K.regdata file before editing it.

The system must reboot for the new registry setting to be effective. To reset the maximum block size to the default of 64 Kbytes, follow the instructions above, except use mpidfblk.reg as the data file.

7.6.2.2 Maximum Number of Concurrent I/Os (Guaranteed)

Windows 2000 guarantees a maximum of 32 concurrently active I/Os on a particular SCSI bus. Due to the method of memory allocation, the actual limit of concurrent I/Os can vary between various drivers or versions of drivers. This can have a significant impact on performance benchmarking between different driver versions or adapter vendors. In effect, one adapter could support 80 outstanding I/Os, while another adapter could only support 32 outstanding I/Os.

To enable better performance, the driver installation process adds a registry entry to support 128 concurrent I/Os. If a different maximum value is desired, programmers can use the mpi100io.regdata file to add a registry entry that set the maximum numbers of concurrent I/Os. There are two methods to add this registry setting. One method is to locate the mpi100io.regdata file using Windows Explorer, double-click on the file, and edit it. The other method is to type at the command prompt:

regedit mpi100io.reg

This command inserts an entry in the registry to guarantee a maximum of 100 concurrent I/Os per adapter.

Note: Setting this value to a high number uses increasing amounts of nonpaged pool memory, which is a critical Windows 2000 resource. High values for this setting can degrade system performance.

Be sure to read the information in thempi100io.reg data file before editing it. You must reboot system for the new registry setting to take effect. To reset the guaranteed number of concurrent I/Os to the Windows 2000 default of 32, follow the instructions above but use mpidefio.regas the data file.