SP 7400/7500 Series
On-Board Symbios SCSI Adapter

Symbios SCSI Controller Jumper Settings

The board is equipped with an integrated Wide Ultra2 SCSI controller (Symbios 53C895). This SCSI controller supports both LVD and Single-Ended SCSI devices*. The controller is enabled or disabled via a hardware jumper SJP2. (The "S' proceding the "JP" designates the jumper is specific to SCSI functions.)

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

If the SCSI controller is ordered, 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.


SJP2 - Enable/Disable SCSI Controller

As stated above, the on-board Symbios Wide Ultra2 SCSI controller can be enabled or disabled with SJP2 (see Figure above for SJP2 location).

SJP1 - Enable/Disable SCSI Termination

The board comes from the factory with SCSI termination enabled (i.e. a shunt is installed on SJP1, which is a 2-pin jumper). This allows the SCSI connector to be configured as one end of the SCSI chain. If a situation requires the disabling of the SCSI termination, the shunt simply needs to be removed from SJP1.

The SCSI controller supports either an Ultra2 LVD SCSI or Single-Ended Wide SCSI device. The figure below shows termination for the Single-Ended Wide SCSI drive tray with termination enabled on SCSI drive #2 and the SP 7xxx board.

If a LVD drive is in place, the Ultra2 LVD interface board on the drive tray supplies its own termination and all the Ultra2 LVD drives must therefore remain unterminated.

To disable on-board SCSI termination on the board for the purpose of adding external SCSI devices, the shunt must be removed from SPJ1 as shown below.  The device on each end of the SCSI chain must be terminated. An end bracket with the external SCSI connector (68-pin) should be installed into an expansion slot adjacent to the SP Board for easy connection to the SCSI devices.

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

Symbios SCSI Drivers (SCSI-SYM.EXE)