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			NT.TXT
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INSTALLATION GUIDE FOR THE SDMS DRIVER SYMC8XX.SYS V2.00.00

This file describes the features and use of the Symbios Logic SDMS device 
driver for the Windows NT 3.5x operating system environment. It is divided 
into the following sections:

Introduction for Windows NT 3.5x
	Features
	Description
Installing Your SYMC8XX.SYS Driver
	Preparing a Symbios Driver Diskette
	New System Installation
	Existing System Installation
	Command Line Options
	Troubleshooting
Important Additional Information
	Enabling/Disabling Fast 20 Support

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***************** Introduction for Window NT 3.5x *******************

Windows NT 3.5x 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 documentation for details). 
I/O requests in Windows NT 3.5x 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. 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 Logic/Microsoft 
provides a miniport driver, called SYMC8XX.SYS, to complete the path 
to a Symbios Logic  controller or processor with an optional SDMS SCSI BIOS. 
The following sections describe this driver and its installation.



* Features *

 Synchronous negotiation (including Fast/Fast20 SCSI) 
 Wide negotiation
 Tagged command queuing
 Supports multiple host adapters
 Supports multiple Logical Unit Numbers (LUNs)
 Disconnect/Reselect
 Scatter-Gather
 Differential Support
 Supports SCSI pass-through functionality
 BUS device reset
 Scan order change (scans the bus from SCSI ID 0 to MAX SCSI ID [7 or 15])
 Supports disk array configurations with no LUN 0
 Supports disk array configurations with non-contiguous LUNs
 Fast 20 Support (20 MB/s narrow, 40 MB/s wide)


* 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 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.  It will 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 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 Fast 20 SCSI protocol, providing twice the
raw data transfer rate than Fast SCSI for disk drives and Symbios Logic 
host adapters that support Fast 20.  However, Fast 20 requires more 
stringent SCSI bus cabling setups than Fast SCSI.




************** Installing Your SYMC8XX.SYS Driver ****************


* Preparing a Symbios Driver Diskette *

Copy the files listed below (supplied to you on diskette) to the root directory 
of a clean floppy diskette, and use this Symbios Driver diskette during
installation:

SYMC8XX.SYS
SYMC8XX.TAG
OEMSETUP.INF
TXTSETUP.OEM


* 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 off 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 Logic PCI (53C810) driver 
     NCRC810.SYS, which is an older version of the SYMC8XX.SYS driver.  
     Let 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 Logic PCI (53C810) driver NCRC810.SYS, which is an older 
     version of the SYMC8XX.SYS driver.  Let installation continue.  When 
     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 Manufacturer-supplied hardware support disk, 
     insert your Symbios Driver diskette and press Enter. 

8. The Symbios Logic  PCI (53C8XX) Miniport driver, 
     Symbios Logic 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.

NOTE:  For a new system installation, the Symbios Logic PCI (53C8XX) 
Miniport driver defaults to Fast 20 support turned OFF.  To enable Fast 20
support, see Enabling/Disabling Fast 20 Support below.


* Existing System Installation *

This procedure will install the SYMC8XX.SYS driver onto an existing 
Windows NT system.

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. For the path to the
     files, leave a:\ and select OK.

8. On the Select OEM Option menu, the Miniport driver, 
     Symbios Logic 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 LOGIC Inc. PCI (53c8XX) driver highlighted.

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 will use the driver already on the system, and 
selecting New will use 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, leave a:\ and select 
      Continue.

11. A Setup Message will display giving you the option of enabling Fast 20
      support.  To enable Fast 20 support, choose OK.  To leave Fast 20
      disabled, choose Cancel.

12. On the SCSI Adapter Setup menu, choose Close.

13. Rebooting will load your new Miniport driver.



* Command Line Options *


There are no command line options with the Windows NT 3.5x device driver.





* Troubleshooting *


DURING INSTALLATION, NO SCSI DEVICES ARE FOUND.

a. Insure that the custom setup is chosen on the Setup Method screen.

b. Insure 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.


SYSTEM CRASHES DURING INSTALLATION WITH A MESSAGE 
INDICATING INACCESSIBLE BOOT DEVICE.

a. This error is usually associated with an IRQ, DMA channel, I/O (chip) 
    address, or BIOS address conflict. Set the SCSI host bus adapter  
    board to use a different interrupt.


A DISK DRIVE IS RECOGNIZED AS SEVEN DIFFERENT DEVICES 
WHEN ONLY ONE IS PHYSICALLY CONNECTED TO THE SCSI BUS.

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.

PROBLEMS WITH FAST 20 DEVICES USING FAST 20 PROTOCOL

a. If the system is configured with a Symbios Logic host adapter that
    supports Fast 20, a Fast 20 device is on the SCSI bus, and Fast 20
    support by the SYMC8XX.SYS driver is enabled, intermittent problems
    and possible system crashes can occur if the SCSI bus cable and
    terminators do not conform to the Fast 20 specification.

b. If the system is bootable, disable Fast 20 support using the procedure
    described above.

c. If the system is not bootable, use the Emergency Repair Disk to restore
    the system to a previously working configuration (with Fast 20 disabled).

d. If the system operates properly without Fast 20 enabled, it is highly
    likely that the SCSI bus cable and terminators are not configured
    correctly for Fast 20.  See the Symbios Logic host adapter hardware
    manual for information on Fast 20 SCSI cabling requirements.




*************** Important Additional Information ********************


* Enabling/Disabling Fast 20 Support *

Once the SYMC8XX.SYS driver is installed, support for Fast 20 is
enabled or disabled using the Registry Editor.  

CAUTION:  Incorrect modifications to the registry can disable the system .  
Before making any changes to the registry, insure that you
have an Emergency Repair Disk available.  An Emergency Repair Disk is
created either during Windows NT installation, or by running the RDISK
program.

Use this procedure for enabling/disabling Fast 20 Support:

1. Run the REGEDT32.EXE program (using either File, Run or through File
      Manager).

2. Select the HKEY_LOCAL_MACHINE window.

3. Open the following folder tree:  SYSTEM\CurrentControlSet\Services.

4. From this tree, open the Symc8XX folder, then the Device folder.

5. In the right-hand window, double-click on the Driver Parameter entry.

6. In the String Editor dialog box, do not change anything but the number
      just to the right of the equal sign.  Set this number to:

      1 for Fast 20 enabled
      0 for Fast 20 disabled

7. Click OK.

8. Exit the Registry Editor program.  Any change in this registry entry
      does not take effect until the system is rebooted.

