Drivers & Windows

[ACM]

In several definitions that I've read it says that for Windows to perform I/O to a device (such as a sound card), it gives control to the driver for that device and the driver actually communicates with the device in its own special language. Now for the driver to do this it would need to know the I/O address and the memory address of this device (since that's the only way data is transferred). Is this the case, or does the driver communicate under Windows (like any other program), telling Windows "send this to sound card", and then Windows worrying about what I/O address to activate?

[andyms18a]

win 3.1 to win me, let the driver talk to the hardwair
win nt to xp use hal, ( hardwair abstract layer) and dont let the drivers talk to the hardwair that is how win nt 2k and xp are more stable than the win 3.1 95 98 and me systems

[GaryRouth]

Sounds like perhaps you'd like some detailed articles, so let's see if we can get you started.
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First, the definitions (from Cnet's glossary):

HAL = hardware abstraction layer:
A hardware abstraction layer is a component of an operating system that functions something like an API. (In strict technical architecture, hardware abstraction layers reside at the device level, a layer below the standard API level.) It allows programmers to write applications and game titles with all the device-independent advantages of writing to an API, but without the large processing overhead that APIs normally demand.

API = application programming interface:
An API is a series of functions that programs can use to make the operating system do their dirty work. Using Windows APIs, for example, a program can open windows, files, and message boxes--as well as perform more complicated tasks--by passing a single instruction. Windows has several classes of APIs that deal with telephony, messaging, and other issues.
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Now, the details:
"Windows Driver Model Technology"
http://www.microsoft.com/hwdev/driver/wdm/default.asp

...this site has a brief blurb with a nice graph showing the system architecture of Win2000 (also similiar to XP's). They are a training site that offers courses (for a fee). You can read the blurb and study the graph for free, however:
http://tutorials.findtutorials.com/r...gory/97/id/379

And here's a link to an "Overview of the Windows I/O Model": if you look in the pane to the left, you'll notice that this article is part of a whole world of information on Windows architecture from msdn (completely free and as many details as anyone can stand):
http://msdn.microsoft.com/library/de.../irps_0rhj.asp

Happy Reading
. . . Gary

[Cricket]

I thought DirectX had something to do with how Windows communicates or interacts with multimedia hardware?

Cricket

[GaryRouth]

The way I think it works is that DirectX-compatible drivers operate at the device end, and can communicate directly with hardware, but commands are passed to them in WDM drivers through a Microsoft-written layer, which relieves the multimedia programmers of needing nVidia or ATi or Matrox hardware-specific commands, etc. And I think that in Win9x, this can take place on a lower level than in the NT/2000/XP model, where the Kernel is more protected by the HAL.

Maybe we should have Hal post a clearer picture of HAL for us
. . . Gary