Win2000 device driver Tutorial 1

Introduction
A Device Driver is an executor arm of the Operating System that is in charge of the communication between a peripheral device and its user programs.
The Operating System must have resources for application programs to access i/o devices. It must also be able to expose relevant portions of the machine\'s hardware to those applications. For example, if you connect an USB mouse into your computer, the Operating System must make that mouse available to its desktop and to all applications that need mouse control. The Operating System may also decide to give you access to specific portions of the hardware, for example, it may let you query or modify PCI or AGP bus registers, hardware configuration settings, or interrupt priorities and disciplines.

The original Operating System you get in a CD from the supplier already includes a fair number of device drivers. These drivers define all the peripherals and hardware features that the OS supports. The OS package in fact will include way more drivers than those required to run your machine: for example, it may include a SCSI driver even though you don\'t have a SCSI hard drive or CDROM in your system. However, that driver will not be installed in your system. If tomorrow you buy yourself a SCSI CDROM, you will have to install a driver for that CDROM before your OS and your applications can use it.

The driver to be installed can come from three places. The OS may have already installed it, or that functionality may be already part of an existing driver that encompasses a wider spectrum of peripherals which include your CDROM. Alternatively, the driver may be in your OS\'s CDROM but not yet installed - that is, the peripheral is supported by your OS but you didn\'t as yet install that support. Finally, the manufacturer of your peripheral will typically ship all drivers required to run that peripheral in some sort of removable media packaged with the hardware. In this last case, your manufacturer may or may not support your OS, or the specific version you\'re running. However, even then, the manufacturer may have a driver available on their web site, or you may be able to find drivers written by third party developers by going to the appropriate places in the internet. For example, http://www.winfiles.com and http://www.linux.org will both point you to a wealth of drivers.

And, of course, you can write your own driver ! With the knowledge accumulated in this course, you should be able to start such a project.

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