windows系统编程 源代码

[上一页 [下一页] 前言 Windows Driver Model(WDM)的根源可追溯到几年前一种叫做Windows for Workgroups 3.10的操作系统。那时候我们努力地支持无数不同的SCSI控制器，我长期地注意WindowsNT开发组创建的小端口驱动程序类型。不久就认识到重新构造必要的映象加载器(image loader)和小端口驱动程序需要的执行环境比把这些小端口驱动程序重写成某些VXD形式的驱动程序并调试完毕所花费的努力要少得多。 不幸的是,Windows from Workgroups 3.10已经停止发行带有SCSI小端口支持的版本,主要是由于象ASPI(高级SCSI编程接口)这样的外围问题。然而，跨Windows和windows NT操作系统共享同样的驱动程序执行映象的基础是适当的并且可以在win95中见到，它(win95)可以与NT共享SCSI和NDIS小端口驱动程序二进制代码。 共享驱动程序模式的潜在意义是重大的。驱动程序开发人员感兴趣的是支持双平台，共享驱动模式能降低开发和调试的一半开消。对微软来说，共享模式意味着更容易地从win9x迁移到Windows2000或这个平台的未来版本。对最终用户来说，大量不同种类 的稳定驱动程序可以在这个家族中的所有成员之间通用。 下一个(逻辑)步骤是 The next logical step, then, was to create a driver model with the ability to share general purpose drivers across both platforms. But what form should it take? Three requirements were immediately obvious: it must be multiprocessor-capable, it must be processor-independent, and it must support Plug and Play (PnP). Fortunately, the Windows NT 4.0 driver model met the first two requirements, and it seemed clear that the next major release of Windows NT would support PnP as well. As a result, WDM can be considered a proper subset of what is now the Windows NT driver model. The potential benefits of a shared driver model can be realized today for many classes of devices, and choosing the WDM driver model will continue to pay dividends in the future. For example, a correctly written WDM driver requires only a recompile before functioning in an NT 64-bit environment prototype. WDM will continue to evolve as new platforms and device classes are supported. Future versions of Windows 9x and Windows 2000 will contain upwardly revised WDM execution environments. Fortunately, WDM is designed to be "backward compatible," meaning that WDM drivers written according to the Windows 2000 DDK and designed to work for the intended environment will continue to work in a subsequent WDM environments. There is a lot to WDM, and in this book Walter does an excellent job in offering an in-depth tour of every aspect as well as the philosophy of the Windows Driver Model. Forrest Foltz 微软公司Windows开发体系结构设计者