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			95.TXT
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INSTALLATION GUIDE FOR THE SDMS DRIVER SYMC8XX.MPD V2.00.00

This file describes the features and use of the Symbios Logic SDMS device 
driver for the Windows 95 operating system environment. It is divided 
into the following sections:

Introduction for Windows 95
	Features
	Description
Installing Your SYMC8XX.MPD Driver
	Preparing a Symbios Driver Diskette
	New System Installation
	Existing System Installation
	Verifying Correct Driver Installation
	Command Line Options
	Troubleshooting
Important Additional Information
	Enabling/Disabling Fast 20 Support
	Multiple Symbios Logic Host Adapter Considerations

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***************** Introduction for Windows 95 *******************

Windows 95 is an operating system designed to run on Intel processors 
using current technology. It provides a graphical user interface 
environment incorporating many high-level features 
(refer to the Microsoft Windows 95 documentation for details). 
I/O requests in Windows 95 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 95. Other
class drivers, provided by peripheral manufacturers, are added to 
support new devices. Symbios Logic/Microsoft provides a miniport 
driver, called SYMC8XX.MPD, 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
 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])
 Fast 20 Support (20 MB/s narrow, 40 MB/s wide)
 SCAM Support (SCSI Configured AutoMatically)


* Description *

SYMC8XX.MPD 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 95 architecture requires 
that a class driver for that type device is present (usually 
supplied by Microsoft, or possibly by the peripheral manufacturer). 
No changes to SYMC8XX.MPD are required.  This driver is only supported
under Windows 95. 

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 95 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.MPD 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.MPD 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.MPD
SYMC8XX.INF


* New System Installation *

This procedure installs the SYMC8XX.MPD driver onto a Windows 95 
system. Use this procedure when initially upgrading to Windows 95. 
Windows 95 automatically adds the driver to the registry and 
copies the driver to the appropriate directories.

NOTE:  Some Symbios Logic PCI SCSI host adapters are supported by a
driver bundled in Windows 95.  For these adapters, the bundled driver
is automatically installed during Windows 95 Setup.  To change to
the SYMC8XX.MPD driver, follow the instructions for Existing System
Installation after Windows 95 installation is completed.

1. Initiate Windows 95 Setup according to the Microsoft instructions.

2. Setup enters the hardware detection phase after a system reboot.
     ("Setting up Hardware" message box is displayed.)  If the message 
     "NCR PCI SCSI Host Adapter" is displayed, then the host adapter is 
     supported by the bundled driver, and it is installed 
     automatically.  After Windows 95 installation completes, you can install 
     the SYMC8XX.MPD driver according to the "Existing
     System Installation" instructions.

3. If the host adapter is not supported by the bundled driver, Setup 
     displays a New Hardware Found - PCI SCSI Bus Controller dialog box.  
     Select "Driver from disk provided by hardware manufacturer" and 
     click OK.

4. Insert the Symbios Driver diskette into drive A: (or B:) and click OK.  If
     using drive B:, you must select it from the pick list.

5. Windows 95 automatically copies the appropriate driver files and
 rebuilds its driver database.

6. Sometimes a "System Settings Change" dialog box is displayed (if the boot
     device is the adapter controlled by the new driver).  Remove the flex
     disk from the drive and click Yes to restart the computer.


At this point, Windows 95 Setup completes and the new driver is  
operational.  To verify this, see the section "Verifying Correct Driver
Installation"

NOTE:  At driver 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 installs the SYMC8XX.MPD driver onto an existing 
Windows 95 system.

1. Boot Windows 95.

2. Click Start.  Move to Settings, Control Panel, and click.

3. Double-click on the System icon.

4. Click on the Device Manager tab.  

5. Either double-click on the SCSI controllers entry, or click once on
     the plus sign to the left of it.

6. Select the PCI NCR C8xx SCSI Host Adapter entry.  Click the Properties
     button.

7. Click the Driver button.  The version of the currently active driver
     should display in the File details section.

8. Click the Change Driver... button.

9. Even though you have previously installed the SYMC8XX.MPD driver, 
     click the Have Disk... button to install a newer version.

10. Insert the Symbios Driver diskette in drive A: (or B:) and click OK.  If
     using drive B:, you must select it from the pick list.

11. The Select Device dialog box should display "Symbios Logic 8xxxx PCI
     SCSI Host Adapter", where 8xxxx matches the installed adapter.
     Click OK.

12. The Driver tab is updated to display the new driver files.
     To install these driver files, click OK.  [Do NOT click the Change
     Driver... button.]  The driver files is copied and a new
     driver database is built.

13. Sometimes a "System Settings Change" dialog box is displayed (if the boot
     device is the adapter controlled by the new driver).  Remove the flex
     disk from the drive and click Yes to restart the computer.

At this point, the new driver is operational.  To verify this, see 
the section "Verifying Correct Driver Installation"

NOTE:  At driver 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.



* Verifying Correct Driver Installation *

After installing/updating with the SYMC8XX.MPD driver, you should verify 
proper operation of the driver.

1. Check that all devices on the SCSI bus are available via My Computer.
     Double-click on the My Computer icon.  Check that all logical SCSI hard 
     drives and CD-ROM drives are shown.

2. Click the Start button, move to Settings, Control Panel, and click.
     Double-click on the System icon.  Click the Device Manager tab.
     Check that no host adapter is displayed with a yellow or red symbol under 
     the SCSI controllers entry.  If there is, continue with the 
     steps below to help determine the problem.

3. Either double-click on the SCSI controllers entry, or click once on
     the plus sign to the left of it.  One entry for each host adapter
     installed in the system is displayed.  Select an entry, then
     click the Properties button.  The Device Status message should read
     "This device is working properly."  If any other messages appear,
     continue with the steps below to get more information on the problem.

4. Click the Driver tab.  Two entries should appear, one for SYMC8XX.INF
     and one for SYMC8XX.MPD.  The INF file does not contain embedded
     version information, so the File Details are all Not Available.
     Select the SYMC8XX.MPD file.  The file version of the driver is displayed.

5. Click Cancel to leave the Host Adapter Properties dialog box. Click on
     the Performance tab.  A list of performance attributes is displayed.
     Below the list, you should see the message "Your system is
     configured for optimal performance."  If any other messages appear,
     select each message and click the Details button.  This provides
     more information on why the system is not performing optimally and
     methods to correct the problem.

If no problems are encountered in the above steps, the new driver is
operating properly.  Otherwise, consult the section on Troubleshooting
for additional information.



* Command Line Options *


There are no command line options with the Windows 95 device driver.



* Troubleshooting *


DURING INSTALLATION, NO SCSI DEVICES ARE FOUND.

a. Insure that all devices are powered on and terminated correctly.

b. Check that no devices have duplicate SCSI Ids.

c. 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.


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.MPD 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 to Windows 95, hold down F8 when Starting 
    Windows 95... is displayed.  At the menu, select Safe Mode.  Once the 
    system is booted, disable Fast 20 support using the procedure
    described above.

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.MPD driver is installed, support for Fast 20 is
enabled or disabled using the Device Manager.  Fast 20 is enabled/disabled
on a per adapter basis.

Use this procedure for enabling/disabling Fast 20 Support:

1. Click the Start button, move to Settings, Control Panel, and click.
     Double-click on the System icon.  Click the Device Manager tab.

2. Either double-click on the SCSI controllers entry, or click once on
     the plus sign to the left of it.  One entry for each host adapter
     installed in the system is displayed.  Select the adapter 
     desired, then click the Properties button.  Click the
     Settings tab.

3. The Adapter settings entry will display "Fast20_Support=x;", where 
      x is 0 or 1.  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

4. Click OK to exit the Settings tab.

5. Click OK again.  If the entry was changed, the "System Settings 
     Change" dialog box is displayed.  Click Yes to restart the 
     computer.

After the system reboots, the new setting for Fast 20 is in effect.


* Multiple Symbios Logic Host Adapter Considerations *

If multiple Symbios Logic PCI SCSI host adapters are installed in the
system, special actions are sometimes required to install or change drivers.
This is due to the fact that some Symbios Logic host adapters are
supported by the bundled driver, and also that one Symbios driver 
supports all Symbios host adapters installed in the system.

With multiple Symbios adapters, it is possible to have a situation
where one adapter is assigned to one driver, and another is assigned to
a different driver.  This can cause conflicts which may cause the system
to switch to real-mode drivers, affecting performance and access to
CD-ROM or tape drives.

There are two methods for ensuring that all Symbios Logic host adapters
are controlled by only one driver (when installing additional boards or 
updating drivers).

Method 1

Using the Device Manager, change the driver for a particular host adapter
to the desired driver, but when asked to reboot the system for the new
settings to take effect, click No. Change drivers for all
Symbios Logic host adapters in the system to the new driver, and reply 
No to rebooting until the final adapter is changed.  If booting  
from a SCSI device, check that the adapter controlling this device is
the last one changed.

Method 2

Determine which driver file is active for all adapters through the 
Properties tab in Device Manager.  Go to the \WINDOWS\SYSTEM\IOSUBSYS
directory and rename the driver file to an extension other than MPD.
Reboot the system.  While booting, the system may ask to load the
bundled driver file from the Windows 95 installation disk.  Click OK,
then when the system says it can't find the file, click Skip File.  Do
this for all adapter messages while booting.  After the system is
booted, use the Device Manager to change the driver for each adapter 
to the desired driver.  Do not reply Yes to reboot the system until 
the final adapter has been changed.
  
