SCSI Adapter Technical Information

DP 6200 Series
On-Board SCSI Adapter

SCSI Device Installation

The Symbios SCSI adapter on the DP Series support:

SCSI 8 bit (narrow) - Devices 0-6 on J7 with a 50-pin standard ribbon cable.

SCSI 16 bit (wide) - Devices 0-6 and 8-15 on J2 with a 68-pin high density ribbon connector

Note: The SCSI adapter defaults to device 7.

The board is equipped with an integrated fast/wide SCSI adapter. The adapter is enabled or disabled via the Chipset option of the BIOS Setup utility and via a hardware jumper (see the Quick Reference Guide for jumper settings).

The SCSI adapter is a bus master device which gain control of the PCI bus to transfer data between the CPU memory and the SCSI devices. The I/0 base address and interrupts are set by the PCI plug and play BIOS at boot time.

A SCSI configuration utility is available on boot-up of the board. Shortly after the SCSI BIOS information displays, the configuration program can be accessed by pressing Control C. The configuration utility will allow you to scan the SCSI bus, change configuration options, and view a list of SCSI devices connected to the board. If the SCSI BIOS is inadvertently turned off in the SCSI configuration utility, turn it back on by holding <CTRL> A when the board is reset.

Termination - SCSI Adapter (external SCSI devices)

SCSI termination is controlled by dip switches 3-6 of switch 1 on the I/O board. The factory default is all switches OFF, which terminates connector J4 (on end bracket) as one end of the SCSI chain.

See figures 3-1 through 3-4 for termination switch settings.

Figure 3-1, 8 bit External OR Internal SCSI Devices

Figure 3-2, 8 bit External AND Internal SCSI Devices

Figure 3-3, 16 bit External OR Internal SCSI Devices

Figure 3-4, 16 bit External AND Internal SCSI Devices

Termination should also be configured as enabled if the SCSI interface is not used. The last device on the SCSI cable must also supply a termination load to the cable. SCSI devices not at the end of the cable must have their termination loads disconnected.

Enabling and disabling a SCSI device's termination may involve a switch or shunt setting or the installation or removal of resistive SIP or DIP packages on their circuit board. Consult the installation manual for the SCSI device to determine its termination options.

Symbios 825A Controller Features & Benefits

Performs wide high-speed SCSI bus transfers in single-ended mode up to 20 MB/s synchronous transfers and 14 MB/s asynchronous transfers
SCRIPTS Instruction Prefetch
536-byte buffer allows burst length of up to 128 transfers
Load and Store instruction
4 KB static RAM for SCRIPTS instruction storage
32 additional Scratchpad registers for user-defined functions
SDMS software supports the Advanced SCSI Protocol interface (ASPI)
Compiler-compatible with existing SYM53C7XX & SYM53C8XX SCRIPTS
BIOS and driver support for hard disk, tape, CD-ROM, and removable media peripherals for all of the major operating systems, including: DOS, Windows 3.X, Windows 95, Windows NT, OS/2 (including Warp), Novell NetWare, SCO Unix, UnixWare
Reduces PCI bandwidth requirements for execution of I/O

Driver Installation Guides

Quick Steps for NT 4.0	SCO Unix
Windows NT 3.51 & 4.0	UnixWare
Windows 95	NetWare
OS/2	MSDOS

Drivers

Symbios 825A SCSI drivers can be downloaded by clicking on the link below.

Symbios SCSI Drivers (SCSI-SYM.EXE)