User Guide

46 ASUS PCI-SC875 User’s Manual

VII. WINDOWS NT

(Features)

VII. WINDOWS NT DRIVERS

Features

• Synchronous negotiation (including Fast/Ultra SCSI)

• Wide negotiation

• Tagged command queuing

• 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])

• Supports disk array configurations with no LUN 0

• Supports disk array configurations with non-contiguous LUNs

• Ultra SCSI (Fast 20) support (20 MB/s narrow, 40 MB/s wide)

• User selectable enabling/disabling of 8xx chip’s scripts prefetch option

• User selectable enabling/disabling of PCI Cache Line support for thePCI com-

mands Read Line, Read Multiple and Write-and -Invalidate.

Description

SYMC8XX.SYS 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 NT 3.5x/

4.x 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.SYS are required. This driver is only supported under Windows NT 3.5

and later versions (including NT 4.0). It does not run under earlier versions of NT.

SCSI commands are passed directly from a Windows application to the SCSI de-

vices by using the SCSI pass-through facility (refer to the Microsoft Windows NT

3.5x/4.x 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.SYS driver supports Ultra SCSI protocol, providing twice the raw

data transfer rate of Fast SCSI for disk drives and Symbios Logic host adapters that

support Ultra SCSI. However, Ultra SCSI requires more stringent SCSI bus cabling

setups than Fast SCSI.