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Symbios SCSI
Windows NT Driver Installation
This file describes the features and use of the Symbios SDMS device driver for the Windows NT 3.5x/4.x operating system environment. It is divided into the following sections:
Installing Your SYMC8XX.SYS Driver
New System Installation
Obtaining Drivers from Symbios Web
Site
Existing System Installation
Windows NT 4.x
Windows NT 3.5x
Performance Tuning for NT 4.0
Large Block Size Support
Maximum Number of Concurrent I/Os
Disk Mirroring
Command Line Options
Troubleshooting
Introduction for Windows NT 3.5x/4.x
Windows NT 3.5x/4.x is an operating system designed to run on
processors using current technology. It provides a graphical user interface environment
incorporating many high-level features (refer to the Microsoft Windows NT 3.5x/4.x
documentation for details). I/O requests in Windows NT 3.5x/4.x are handled by an I/O
manager. To address a SCSI peripheral, the I/O manager goes through the appropriate
drivers. Class drivers for hard disk, floptical, CD-ROM, printer, and scanner peripherals
are provided in Windows NT 3.5x/4.x. Other class drivers, provided by peripheral
manufacturers, may be added to support new devices. Tape device support is built into the
operating system itself and does not require a class driver. Symbios/Microsoft provide a
miniport driver, called SYMC8XX.SYS, to complete the path to a Symbios controller or
processor with an optional SDMS SCSI BIOS. The following sections describe this driver and
its installation.
Features
Description
SYMC8XX.SYS is designed to Microsoft's specification for miniport drivers. This driver allows connection of SCSI devices including disk drives, CD-ROMs, and tape drives for PCI-based machines. To support a new SCSI device, the Windows NT 3.5x/4.x architecture requires that a class driver for that type device be present (usually supplied by Microsoft, or possibly by the peripheral manufacturer). No changes to SYMC8XX.SYS are required. This driver is only supported under Windows NT 3.5 and later versions (including NT 4.0). It does not run under earlier versions of NT.
SCSI commands are passed directly from a Windows application to the SCSI devices by using the SCSI pass-through facility (refer to the Microsoft Windows NT 3.5x/4.x documentation for details). This facility allows applications to directly control and access SCSI devices by filling in a data structure and calling in to the port driver.
The SYMC8XX.SYS driver supports Ultra SCSI protocol, providing twice the raw data transfer rate of Fast SCSI for disk drives and Symbios host adapters that support Ultra SCSI. However, Ultra SCSI requires more stringent SCSI bus cabling setups than Fast SCSI.
Note!:
The Symbios driver bundled in Windows NT 3.51 is named NCRC810.SYS. When Windows NT selects the bundled Symbios driver during setup, the driver information (i.e., "NCR C810 PCI SCSI Host Adapter") is displayed. Although this implies that the driver only supports the 53C810, it actually supports the 53C810, 53C810A, 53C815, 53C825, and 53C825A. In fact, the Symbios driver controls all of these 53C8xx controllers that are in the system. Please keep in mind that Windows NT 3.51 setup only displays the driver information, not every controller found by that driver.
The Symbios driver bundled in Windows NT 4.0 is named
SYMC810.SYS.
When Windows NT selects the bundled Symbios driver during setup, the driver information
(that is, "Symbios C810 PCI SCSI Host Adapter") is displayed. Although this
implies that the driver only supports the 53C810, it actually supports the 53C810,
53C810A, 53C815, 53C825, 53C825A, 53C860, 53C875, and 53C876. In fact, the Symbios
driver controls all of the 53C8xx controllers
that are in the system. Please keep in mind that Windows NT 4.0 setup only displays the
driver information, not every controller found by that driver.
Installing Your SYMC8XX.SYS Driver
New System Installation
This procedure installs the SYMC8XX.SYS driver onto a Windows NT system. Use this procedure when installing NT onto an unused SCSI drive. NT automatically adds the driver to the registry and copies the driver to the appropriate directories.
1. Start the NT installation by booting from the Microsoft Setup floppy disk.
2. Press Enter when the Welcome to Setup screen appears.
3. On the Setup Method screen, choose Custom Setup by pressing C. (If Express Setup is chosen, the installation program scans for SCSI adapters and finds the Symbios PCI (53C810) driver (NCRC810.SYS for NT 3.5x, SYMC810.SYS for NT 4.0), which is an older version of the SYMC8XX.SYS driver. Let the installation continue. When installation completes, change the driver. To change the driver, see the "Existing System Installation" section.)
4. Press S to skip mass storage device detection. (If Enter is pressed, the installation program scans for SCSI adapters and finds the Symbios PCI (53C810) driver (NCRC810.SYS for NT 3.5x, SYMC810.SYS for NT 4.0), which is an older version of the SYMC8XX.SYS driver. Let installation continue. When the installation completes, change the driver. To change the driver, see the "Existing System Installation" section.)
5. When a screen displays the SCSI adapters found, choose S to configure additional SCSI adapters.
6. Move the highlight bar to Other and press Enter.
7. When prompted for the manufacturer-supplied hardware support disk, insert your Symbios Driver diskette containing the Windows NT driver and press Enter. The diskette is distributed with the board. To obtain the Windows NT driver from the Symbios Web Site to use as the installation disk, see "Obtaining Drivers from Symbios Web Site" for more information.
8. The Symbios PCI (53C8XX) Miniport driver, Symbios PCI <53C8XX>, is shown highlighted. Press Enter to proceed.
9. NT should now recognize the Miniport driver and the SCSI hardware. Press Enter to continue.
At this point, simply follow the Microsoft Windows NT
installation procedure.
Obtaining Drivers from Symbios Web Site
Symbios provides updated Windows NT drivers on their web site. To access this web site and download the driver, follow these steps:
1. Open your browser and follow the menu path: File --> Open.
2. Enter the URL in the Open field, which is: http://www.symbios.com. The Symbios Home Page appears.
3. Scroll down to the PCI SCSI driver software link and double click on this link. The Technical Support page appears.
4. Scroll down to the bottom of this page to locate the bulleted item: "Current versions of Symbios SDMS device drivers for specific operating systems", where the word versions is highlighted as a link.
5. Double click on versions and the Customer Hardware/Software License Agreement appears with text to read and Agree/Disagree buttons at the end.
6. Read the agreement terms and click on the Agree button. If you click on the Disagree button, the system returns to the Symbios Home Page.
7. After clicking on the Agree button, a screen appears with the current Symbios drivers for various operating systems. Scroll down to locate the Windows NT driver. The filename will be ntxxx.zip, where xxx represents the current version number.
8. To download this file, highlight the filename and follow the menu path: File --> Save As File and save it to the directory of your choice. The file may appear as a shortcut item on your desktop after the download.
9. Unzip the file to a blank flex disk and use the -d option
(or equivalent to maintain the directory hierarchy. The flex disk is now the driver
installation disk.
Existing System Installation
This procedure installs the SYMC8XX.SYS driver onto an existing Windows NT system.
NOTE: Windows NT 4.x uses the Windows 95 user interface, resulting
in minor changes to the procedure for updating SCSI
drivers. Procedures for both NT 4.x and NT 3.5x are listed.
Windows NT 4.x
1. Boot NT and log on as Administrator.
2. Click the Start button, move to Settings, then to Control Panel, and click.
3. Double-click on SCSI Adapters.
4. Click the Drivers tab. If NCRSDMS.SYS, NCRC810.SYS, NCRC8XX.SYS, or SYMC8XX.SYS drivers are listed, select the driver(s) and choose Remove before adding the new driver. Select OK when the Remove Driver message prompts, "Are you sure you want to remove this driver?". Another message may display saying "The SCSI Adapter has been marked as a boot device ...". Click OK.
5. Click Add. A list of installed adapters is displayed.
6. Click the Have Disk button.
7. When prompted, insert your Symbios Driver diskette containing the
Windows NT driver. For the path to copy manufacturer's files from, enter
A:\WINNT\MINIPORT and select OK.
8. On the Install Driver menu, the Miniport driver, Symbios PCI (53C8XX), is shown highlighted. If it is not highlighted, select it. Choose OK.
At this point, the following message may occur:
"The driver(s) for this SCSI Adapter are already
on the system. Do you
want to use the currently installed driver(s) or install new one(s)?"
Selecting Current uses the driver already on the
system, and selecting New
uses the driver on the floppy disk. Unless you want to use the older
version already on the system, choose New. If you chose Current, go to
step 10.
9. For the path to the OEM SCSI Adapter files, A:\WINNT\MINIPORT should be displayed. Select Continue.
10. A System Settings Change message displays "You must restart your computer before the new settings take effect. Do you want to restart your computer now?" Choose OK to restart and reboot NT. If you choose Cancel, remember that you must restart before the new driver is loaded.
11. Rebooting loads your new Miniport driver.
Windows NT 3.5x
1. Boot NT and log on as Administrator.
2. Open the Main window in the Program Manager.
3. Double-click on Windows NT Setup.
4. Choose Options, then choose Add/Remove SCSI Adapters.... If NCRSDMS.SYS, NCRC810.SYS, NCRC8XX.SYS, or SYMC8XX.SYS drivers are listed, select the driver(s) and choose Remove before adding the new driver. Select OK when the Setup Message prompts, "Are you sure you want to remove the selected SCSI Adapter?"
5. Then choose Add, and select OK when the Setup Message prompts, "Are you sure you want to add a SCSI Adapter?"
6. On the SCSI Adapter list, go to the bottom and choose Other.
7. When prompted, insert your Symbios Driver diskette containing the Windows NT driver. For the path to copy manufacturer's files from, enter
A:\WINNT\MINIPORT and select OK.
8. On the Select OEM Option menu, the Miniport driver, Symbios PCI (53C8XX), is shown highlighted. If it is not highlighted, select it. Choose OK.
9. On the Select SCSI Adapter Option menu, choose Install with the SYMBIOS, Inc. PCI (53C8XX) driver highlighted.
At this point, the following message may be displayed:
"The driver(s) for this SCSI Adapter are already
on the system. Do you
want to use the currently installed driver(s) or install new one(s)?"
Selecting Current uses the driver already on the
system, and selecting New
uses the driver on the floppy disk. Unless you want to use the older
version already on the system, choose New. If you chose Current, go to
step 11.
10. For the path to the OEM SCSI Adapter files, A:\WINNT\MINIPORT should be displayed. Select Continue.
11. On the SCSI Adapter Setup menu, choose Close.
12. Rebooting loads your new Miniport driver.
Performance Tuning for NT 4.0
NT 4.0 has registry entries that can be used to increase the
performance of SCSI I/O for certain configurations. The tunable parameters are large
transfer block size support and a guaranteed number of concurrent I/O's for a particular
SCSI bus.
Large Block Size Support
The SYMC8XX.SYS driver can support up to a 1MB transfer size in NT 4.0 and a 256K transfer size in NT 3.5x. In NT 3.5x this larger transfer size is enabled by default and cannot be changed. However, in NT 4.0 the default transfer size is 64K. To enable a larger transfer size, an entry must be added to the registry, using the file sym_256K.reg. This file will set a 256K maximum, but it can be edited to set other desired maximum transfer sizes.
There are two methods to add this registry setting. One is to locate the sym_256K.reg data file (supplied with the driver files) using Windows Explorer and double-click the file. The other method is to type at the command prompt:
regedit sym_256K.reg
This will insert an entry in the registry to enable 256K block size support.
Any maximum block size between 64K and 1MB (-8KB) can be set by editing the sym_256K.reg file. The formula to calculate the proper value for MaximumSGList is:
MaximumSGList = (Maximum Block Size)/4K +1
For 256K: 256K/4K = 64, add 1 for 65 (decimal) or 0x41. The maximum value allowed for MaximumSGLIst is 255 or 0xFF. This denotes an absolute maximum transfer size of 1040384, which is 8K less than 1MB (1040384/4K = 0xFE, add 1 for 0xFF or 255). Be sure to read the information in the sym_256K.reg data file before editing it.
The system must be rebooted for the new registry setting to be effective.
To reset the maximum block size to the default of 64K, follow the
instructions above, except use symdfblk.reg as the data file.
Maximum Number of Concurrent I/O's (Guaranteed)
NT (both 3.51 and 4.0) only guarantee a maximum of 32 concurrent I/O's active on a particular SCSI bus. However, due to the method of memory allocation, the actual limit of concurrent I/O's can vary greatly between various drivers or versions of drivers. This can have a huge impact on performance benchmarking between different driver versions or adapter vendors. In effect, one adapter may actually be able to have 70 or 80 I/O's outstanding, while another adapter could only have 32. This can also affect systems with high performance storage subsystems, such as disk arrays.
Note: NT 3.51 cannot be tuned for this parameter. Only NT 4.0 uses this setting.
In order to have a guaranteed number of concurrent I/O's, an entry must be added to the registry, using the file sym100io.reg.
There are two methods to add this registry setting. One is to locate the sym100io.reg data file (supplied with the driver files) using Windows Explorer and double-click the file. The other method is to type at the command prompt:
regedit sym100io.reg
This will insert an entry in the registry to guarantee a maximum of 100 concurrent I/O's per adapter.
If a maximum other than 100 is desired, the sym100io.reg file can be edited. However, setting this value to a high number uses increasing amounts of non-paged pool memory, a critical NT resource. High values for this setting can degrade system performance. Be sure to read the information in the sym100io.reg data file before editing it.
The system must be rebooted for the new registry setting to be effective.
To reset the guaranteed number of concurrent I/O's to the default of
32, follow the instructions above, except use symdefio.reg as the data file.
Auto Request Sense
Enabling and Disabling Auto Request Sense is found in the section titled "Troubleshooting."
Disk Mirroring
Note: This section applies only to Intel x86-platforms where the Symbios 4.xx PCI SCSI BIOS is used.
Symbios 4.xx PCI SCSI BIOS loads only one image in the memory when the system boots regardless of how many host bus adapters (HBAs) are used in the system. All of the disk drives on all HBAs will be recognized through the INT13h function call. Because of this implementation, disk mirroring under NT needs to be done via the following instructions which might be different from Microsoft's documentation.
Here's how to create an NT Fault Tolerant (FT) floppy so that you can boot from the mirrored partition in case the primary partition fails.
1. Format a floppy disk in drive A: using NT (File Manager or Windows Explorer) for use as a Fault Tolerant boot floppy.
2. From the root directory of the primary partition, copy NTLDR, NTDETECT.COM, and BOOT.INI to this floppy disk.
3. Temporarily remove the read-only attribute of the BOOT.INI file so that it can be modified and saved.
4. Edit BOOT.INI on the FT floppy and modify the following line where you want to boot the mirrored partition.
multi(0)disk(0)rdisk(x)partition(y)\<winnt_directory>
where
multi(0) and disk(0) should always remain same.
x = (the drive number of the mirrored
partition in the INT13
chain - 80h).
The drive number of the mirrored partition
can be found during system
bootup of the Symbios 4.xx PCI SCSI BIOS when the primary
partition does
not exist. It should say either BOOT (=80h), 81h, 82h, and
higher.
Therefore the value of x would be 0 when BOOT, 1 when 81h, 2 when
82h, etc.
y = the partition number on the drive
(starts at 1 which equals single
partition on the drive)
For example, let's say there are two Symbios 8xx HBAs
in the system. The
first HBA, HBA #0 which is the boot path, has two SCSI hard drives on ID 0
and ID 5. The second HBA, HBA #1, has two SCSI hard drives on ID 2 and ID
4. Assuming that the SCSI bus scan starts from ID 0 and goes up, the drive
number of INT13h will look like this:
HBA #0, ID 0= BOOT (which is
80h)
HBA #0, ID 5= 81h
HBA #1, ID 2= 82h
HBA #1, ID 4= 83h
Now NT is installed on the boot drive, HBA #0 ID 0, and
a mirrored
partition is established on HBA #1 ID 2. If the primary partition fails,
for example due to power failure, then the drive number of INT13h will
change:
HBA #0, ID 5= BOOT (which is
80h)
HBA #1, ID 2= 81h
HBA #1, ID 4= 82h
Therefore, the following line should be used in the
BOOT.INI on the NT
Fault Tolerant boot floppy to boot from the mirrored partition, HBA #1
ID 2. Note that rdisk(1) was calculated from x=81h-80h.
multi(0)disk(0)rdisk(1)partition(1)\<winnt_directory>
5. Save the BOOT.INI and restore the "read-only"
attribute.
Troubleshooting
The following are some potential problems and their suggested solutions:
Problem
During installation, no SCSI devices are found.
Solution
a. Ensure that the custom setup is chosen on the Setup Method screen.
b. Ensure that all devices are powered on and terminated correctly.
c. Check that no devices have duplicate SCSI IDs.
d. Make sure INT A is assigned for the PCI slot(s) where your SCSI
host
adapter(s) are installed.
Problem
System crashes during installation with a message indicating
inaccessible
boot device.
Solution
a. This error is usually associated with an IRQ, DMA channel, I/O
(chip)
address, or BIOS address conflict. Set the SCSI host adapter to use a
different interrupt.
b. This error is sometimes caused by a virus infecting the Master
Boot Record
of the boot device. Use a write-protected DOS bootable flex containing
virus scanning and cleaning software to check for any viruses on the boot
device, and remove if any are found.
Problem
A disk drive is recognized as seven different devices when only one
is
physically connected to the SCSI bus.
Solution
a. This error is usually caused by older SCSI devices incorrectly
indicating
to NT that they support multiple LUNs. Contact the device manufacturer for
a firmware upgrade.
Problem
Problems with SCSI devices installation or operation
Solution
a. If a SCSI device is not operating properly (either the device is
not found
or a SCSI interface error occurs during scanning), it is possible that the
third-party device drivers do not support the auto request sense feature
of Symbios host adapters. Disable the auto request sense feature as
described below and try the device operation again.
b. Using the file "symno_ar.reg" (supplied with the
Symbios NT driver
files), either double click the file in Windows Explorer or File Manager
or type "regedit symno_ar.reg" at the command prompt. This inserts
a
registry entry that disables the auto request sense feature. The system
system must be rebooted for this change to take effect.
c. To re-enable the auto request sense feature, use the file
"sym_auto.reg"
and perform one of the update methods in step b. above.
Problem
Problems with certain SCSI devices when using an Ultra SCSI adapter.
Solution
a. Some SCSI devices do not function properly when the adapter
attempts to
negotiate Ultra SCSI transfer rates. If a device is not operating
properly, check the transfer speed setting using the 4.xx PCI BIOS
Configuration Utility (press Control-C when the Symbios PCI BIOS
banner is displayed during the system boot process). Devices that do not
support Ultra SCSI should be set to a maximum of 10 MB/sec for narrow (8
bits), 20 MB/sec for wide (16 bits).
Problem
Problems with Ultra SCSI devices using Ultra SCSI protocol.
Solution
a. If the system is configured with a Symbios host adapter that
supports Ultra
SCSI and an Ultra SCSI device is on the SCSI bus, intermittent problems and
possible system crashes can occur if the SCSI bus cable and terminators do
not conform to the Ultra SCSI specification.
b. Disable Ultra SCSI support for all devices via the SDMS 4.xx PCI
BIOS
Configuration Utility (press Control-C when the Symbios PCI BIOS banner is
displayed during the system boot process).
c. If the system operates properly without Ultra SCSI enabled, it is
highly
likely that the SCSI bus cable and terminators are not configured
correctly for Ultra SCSI. See the Symbios host adapter User's Guide
for information on Ultra SCSI cabling requirements.
