Quantum Trailblazer 420/850AT

The following values are used to set the PC/AT CMOS Table:

Drive		420AT	850AT

Cylinder	1010	1647

Heads		16	16

Sectors		51	63

Write Precomp	65535*	65535*

Landing Zone	1010	1647

*= The Quantum Trailblazer does not require Write Pre compensation, your CMOS setting should be set to reflect that this feature is not enabled. A value of 65535 is a number that many BIOS manufactures use to disable this feature if the value 'none' is not present.

Jumper Settings

The Trailblazer 420/850AT has three drive mode jumper options; DS, SP and CS.

• The MASTER of a two drive configuration or as the only drive: Jumper DS only, SP and CS open.
• A SLAVE drive in a two drive configuration: Remove any jumpers across DS, SP or CS.
• A MASTER drive in a two drive configuration if the SLAVE drive does not use DASP: Jumper DS and SP only.
• CS not used, DO NOT install a jumper across this position.

The SP jumper is only used when the second drive in a two drive configuration does not support DASP. DASP (Drive active / drive 1 present) is a CAM (Common Access Method) defined signal that indicates the presence of a second drive, DASP is used during power on initialization and after a reset. Prior to this definition, products were introduced which did not utilize this method to detect the presence of a second drive. The SP jumper is only used on the MASTER drive, with the DS jumper, when the second drive does not support DASP.

The CS (Cable Select) jumper is only used in systems that support this feature. Cable Select allows for each IDE disk drive to be jumped the same and the position on the cable determines the ID. This requires special cable and both drives on the interface would have to support this feature.