A Hole In My Head

I have been getting quite a few personal emails with specific questions on how to write a driver or how to a specific technology works or how to fix a particular problem. I welcome the emails, but I want these discussions to be public so that they are...

Jake Oshins wanted to write about IRQLs and I am gladly letting him use my blog as a platform. Here it is… I’ve found myself explaining IRQL a lot lately, sometimes to people who want to know because they’re trying to write Windows drivers and sometimes...

Yesterday I wrote about the two methods I use to refactor a virtual function and make sure that I find all of the derived implementations. In the entry I lamented that I would like to have the C# keyword override implemented in C++. Well, apparently it...

If you are using DbgPrint for your debug output in Vista you may have noticed that you cannot see anything in the debugger. That is because DbgPrint now defaults to the DEFAULT debug component (you can read about the change here ) and the default settings...

One of the WDM escapes in KMDF is EvtDeviceWdmIrpPreprocess (or EvtDevicePreprocessWdmIrp in the API in which you register it) which you can register for by calling WdfDeviceInitAssignWdmIrpPreprocessCallback .  This function allows you to process...

Here at Microsoft, we have a central fax number and a fax "secretary" which routes the fixes as TIF files as email to the appropriate recipient. The TIF format allows for multiple pages embedded in one file so each faxed page is a different embedded page...

Let's define this simple worker function which registers for device interface arrival notifications for a given handle (either an HWND or service HANDLE): HDEVNOTIFY RegisterInterfaceNotificationWorker( HANDLE Recipient, LPCGUID Guid, DWORD Flags ...

/FASTDETECT is a command line flag in a boot.ini entry. It started showing up in Windows 2000 (W2K) by default. Why does this flag exist? Previous to W2K ntdetect.com performed a tremendous amount of device detection since PnP did not exist previous...

A lot of developers have a great experience with KMDF, but then they sometimes hit a wall. They add a chunk of code and the drivers start failing because something in the new code was not implemented correctly. The first question that comes to mind is...

For those of you who are trying to find the WDK download link on WHDC, it is not longer there. It has moved to the Microsoft Connect site. Peter Wieland previously described how to get the WDK Beta 2 ISO from this site and nearly the same instructions...

In the past if you wanted to delcare a UNICODE_STRING and buffer on the stack, you had to manually declare the buffer and then initialize all the fields in the UNICODE_STRING, basically something like this #define SOME_SIZE WCHAR stringBuffer[SOME_SIZE...

A few people have emailed me over the past few days how they can see the contents of the KMDF v1.1 ISO (or any other ISO for that matter) without having to burn it to a disc or telling me about the virtual CD tool on http://www.microsoft.com . I am sure...

If you would like me to write about a topic that relates to WDM, the kernel, debugging, WDF, KMDF, UMDF, or anything that I have refered to in other entries, please add a comment to this entry. Comments will be cleared out periodically if there is enough...

Yeah! The book is now back in print (see Amazon )

I saw a book, Advanced Windows Debugging , in the Microsoft company store and quickly read through it. It looked pretty awesome in the level of detail and breadth that it covered. I ordered my own copy and I think it would be an invaluable resource for...

Over the next few days I'll talk about different debugger commands which I use to make driver development easier, especially when debugging my driver. Today I'll talk about how to find your driver, the devices you created and any device object that any...

One thing that I have always found clunky is stack frame navigation in windbg/kd. Previously, I thought you had only a couple of options. The first option, if you are using WinDBG, is that you can bring up the call stack window. I have found that...

Let's say that you allocated a PIRP and sent it down your device stack. You free the PIRP in the completion routine and then return STATUS_MORE_PROCESSING_REQUIRED. To make life more fun, you decide that you want to be able to cancel the sent IRP after...

Looks like the going price on Amazon is >$250 :(. The good news is that you can still get the book as an e-book at O'Reilly, http://oreilly.com/catalog/9780735623743/ , or at Safari, for around $50. Not as convenient as a hard copy IMHO, but it is...

After a long wait (thank you for your patience!), the WDF 1.7 coinstallers are now up on the connect site. To get the bits go to http://connect.microsoft.com Log in using your passport account Navigate to the WDF page (I don't know where it...

For kernel mode code, if I have choice between using a #define or a FORCEINLINE function, the FORCEINLINE function wins every time. #defines have their place, especially for quotifying (the # operator) or concatenating (the ## operator), but they have...

One of the first things I do when I get a new desktop machine or install a new build of Windows is to map the Sleep button on my keyboard to hibernate instead of suspend. Hibernate makes more sense for these machines because they will never run on...

This has been asked quite a few times and is a major point of confusion for KMDF developers. The KMDF coinstaller comes in 2 flavors, chk and fre. Both flavors reside in the same directory in the WDK (winddk\6000\redist\wdf\<arch>) and have their...

I am not a big fan of the C/C++ preprocessor directives #ifdef or #ifndef . I am not denying that they certainly have their place and usage in the language. I'll first write about where I think they are useful and then about the situations where...

In my last post I described why a WDFREQUEST is unique to a particular WDFDEVICE.  There is one particular programming pattern where this is not the behavior you want.  This pattern is when you have each PDO accepting IO requests which it then...