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					INTRO.TXT
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This file presents general information about the Symbios SDMS software 
product. Symbios is a registered trademark and SDMS is a trademark
of LSI Logic Corporation.

This file is divided into the following sections:

General Description
Overview
	SCSI BIOS
	SCSI Device Drivers
Before You Begin
	Basic Rules For SCSI Host Adapter and Device Installation
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*************************** General Description **************************

The Symbios Storage Device Management System (SDMS) is a complete software 
package that solves the increasingly complex problem of managing system
I/O. It seamlessly addresses hardware and software interfaces by supporting
LSI Logic's family of Symbios SCSI processors and controllers, and a wide
range of SCSI peripheral devices, while offering interoperability across 
application programs, operating systems, and host platforms. SDMS consists
of a resident SCSI BIOS that manages all SCSI controller or processor 
specific functions, and a series of SCSI device drivers that provide 
operating system and peripheral specific support.

SDMS provides a standard method to interface SCSI I/O subsystems with
devices, operating systems, and application software. It also enhances
system capabilities already provided by SCSI controllers and processors
by facilitating multi-threaded I/O support, system-wide SCSI device access,
and creation of new applications.


******************************** Overview ********************************

A Symbios SCSI controller or processor can control peripherals such as 
hard disk drives, CD-ROM drives, tape drives, and removable media. SCSI 
peripherals are intelligent devices that do not need the constant attention 
required by non-intelligent devices. Up to 15 SCSI peripheral devices can 
be connected (by using the SCSI bus) to a SCSI host bus adapter card on 
which the SCSI controller or processor resides.

A SCSI host bus adapter can also function as a secondary adapter in a system 
which already has a primary hard drive controller card (IDE, ESDI, ST506). 
Only SCSI host bus adapters will do this, expanding the possibilities for 
system configuration.

* SCSI BIOS *

A SCSI BIOS is the bootable ROM code that manages SCSI hardware resources. It 
is specific to a family of Symbios SCSI controllers or processors. A Symbios 
SCSI BIOS integrates with a standard system BIOS, extending the standard disk 
service routine provided through INT13h. It is also responsible for processing
and executing SCSI requests communicated from a SCSI device driver or 
application.

An important feature of the SCSI BIOS is that it is completely operating 
system independent. All ROM-based SCSI BIOS support booting from a SCSI hard 
disk and can be ported to a variety of hardware platforms. They also support 
16-bit and 32-bit operating systems running under real or protected addressing 
modes.

The Symbios SCSI BIOS provides a hardware independent interface which 
isolates the operating system drivers and SCSI application programs from the 
underlying hardware. This enables a single driver to work with any host 
adapter or SCSI controller which has a Symbios SCSI BIOS.

During its boot time initialization, the SCSI BIOS determines if another hard 
disk is already installed. If there is, the SCSI BIOS will map any SCSI drives 
it finds behind the drive already installed. Otherwise, the SCSI BIOS will 
install drives starting with the system boot drive. In this case, the system 
will boot from a drive controlled by the SCSI BIOS. For more information on 
SCSI BIOS control of hard disk drives, see Chapter 2, "SCSI BIOS" in the
PCI Storage Device Management System SDMS 4.0 User's Guide. 

* SCSI Device Drivers *

The SCSI device drivers translate an operating system I/O request into a data 
structure, and transport the structure to the SCSI BIOS. A Symbios SCSI device
driver is operating system specific, but completely hardware independent. The
hardware specifics are addressed by the SCSI BIOS.

Although a driverless solution exists for some operating systems, and 
provides adequate support for many applications, loading a driver (or drivers 
in some cases) will provide additional features. Connecting peripherals other 
than hard disk drives, for example, requires loading the appropriate 
driver(s). 


**************************** Before You Begin ****************************

SDMS 4.0 software requires an IBM PC/AT or compatible computer with an 80386 or 
higher microprocessor. An understanding of basic operating system commands is 
assumed. For background information on this subject, refer to the 
SCSI-2 specification or the book SCSI: "Understanding the Small Computer 
System Interface". Sources for these publications are listed in the preface of 
the PCI Storage Device Management System SDMS 4.0 User's Guide. 

Before using the SDMS 4.0 software, the Symbios SCSI controller should be 
configured into your system, taking into account the configuration of other 
host bus adapters and system resources (see Basic Rules... listed below).

LSI Logic recommends that all data be backed up before making any changes 
or installing any software, including Symbios SCSI controllers and software.
Failure to adhere to this accepted computer practice may lead to loss of data.

*  *  * Basic Rules For SCSI Host Bus Adapter and Device Installation *  *  *

Both ends of the SCSI bus must be terminated. Refer to the hardware manuals 
for the devices and the host adapter to determine what the terminators 
are, and where they are located.

Each SCSI device must be configured with a different ID number. Refer to the 
hardware manuals for the devices and the host adapter to locate where the 
jumpers or dip switches are for setting ID numbers. Usually the host   
adapter is ID 7. The devices are then set at IDs 0 through 6 (plus 8 through 
15 for wide SCSI). The bootable hard drive must have the lowest numerical ID. 

The red or blue line on a standard SCSI cable (or the black line on one end 
of a multicolored SCSI cable) designates pin one on the cable connector and 
must connect to pin one on the device or host bus adapter connector. Refer to 
the hardware manuals for the devices and the controller to locate pin one of 
the connector.

If the system already has an internal bootable hard drive (IDE, ESDI, ST506), 
the drivers for the SCSI device(s) must reside on the internal bootable hard 
drive.



