Surveying the New Win32 Driver Model for Windows 98 and Windows NT 5.0

摘要

WDM expands on the driver/minidriver model that has proven so successful with SCSI and NDIS drivers. A developer who understands the issues of a hardware bus or a class of device builds a class driver. Other developers (like you and me) write minidrivers that handle specific hardware. The Win32~® Driver Model (WDM), a new feature planned for the upcoming releases of Windows 98 (codenamed Memphis) and Windows NT~® 5.0, encompasses four distinct areas of functionality. First, both operating systems have a new, common set of interfaces based on the Windows NT 4.0 driver model which allow binary compatibility between Windows 98 and Windows NT 5.0. Unfortunately, drivers for standard Windows-based devices must fit into an older architecture that's incompatible with this new kernel-mode support. Keyboards, mice, displays, disk and tape drives, serial and parallel port devices, and multimedia devices fall into the standard category if they plug into an ISA, EISA, PCI, or MCA bus. But, if you have a specialized device for which you previously wrote both VxD and monolithic kernel-mode drivers, WDM will let you discard (or at least stop enhancing) the VxD.