Windows NT 4.0 and earlier operating systems
In Windows NT 4.0 and in earlier operating systems, the driver model for the SCSI adaptor is also applied to the IDE controllers. The miniport driver that is written by the OEMs is linked to the Microsoft-supplied Scsiport.sys driver to make up the complete port driver. The Atapi.sys driver in Windows NT 4.0 is a SCSI miniport driver for the IDE controllers.
Windows 2000 and later operating systems
In Microsoft Windows 2000 and in later operating systems, the driver model has changed. The Atapi.sys driver is a port driver
like the Scsiport.sys driver. Atapi.sys supports all IDE devices that use the
specifications for advanced technology attachment packet interface
(ATA/ATAPI-5). The OEMs may write a MiniIDE driver to perform minimal
functionality that
is specific to their IDE controller, such as direct memory access [DMA] or bus mastering setup.
Windows 2000, Windows XP, and Windows Server 2003 include documentation about the MiniIDE driver model in the Driver Development
Kit (DDK). The DDK also contains a sample MiniIDE driver. You can find the sample
MiniIDE driver in the following folder:
\Src\Storage\Miniide\Pciide