Physical memory is not virtual address space. In my opinion, this is another non sequitur. I'm not sure what logical process led to this myth. It can't be a misapprehension of a 1-1 mapping between physical memory and virtual memory, because that mapping is blatantly not one-to-one. You typically have far more virtual memory than physical memory...

Virtual memory is not virtual address space (part 2). This myth is being perpetuated even as I write this series of articles. The user-mode virtual address space is normally 2GB, but that doesn't limit you to 2GB of virtual memory. You can allocate memory without it being mapped into your virtual address space. (Those who grew up with Expanded ...

Virtual memory is not virtual address space (part 1). I don't know where this myth comes from; it's a non sequitur. Virtual address space describes how addresses are resolved, but since each process has its own virtual address space, the amount consumed by one program has no effect on that consumed by another program. Say you have ...

One of the adverse consequences of the /3GB switch is that it forces the kernel to operate inside a much smaller space. One of the biggest casualties of the limited address space is the video driver. To manage the memory on the video card, the driver needs to be able to address it, and the apertures required are typically quite large. When...

It's simple to explain what it does, but people often misunderstand. The /3GB switch changes the way the 4GB virtual address space is split up. Instead of splitting it as 2GB of user mode virtual address space and 2GB of kernel mode virtual address space, the split is 3GB of user mode virtual address space and 1GB of kernel mode virtual ...

One of the big no-no's in dialog box management is disabling the control that has focus without first moving focus somewhere else. When you do this, the keyboard becomes dead to the dialog box, since disabled windows do not receive input. For users who don't have a mouse (say, because they have physical limitations that confine them to the ...

Many people will recommend using shared data sections as a way to share data between multiple instances of an application. This sounds like a great idea, but in fact it's a security hole. Proper shared memory objects created by the CreateFileMapping function can be secured. They have security descriptors that let you specify which users are ...

Yesterday, I got a 419 scam via the contact form. This is a new low for spam stupidity. You'd think people who blog are more likely to be aware of Internet scams because they're reading the news, are clearly more comfortable with technology, and often make fun of news stories about 419 scammers. But if you're for real, I have this to say ...

Robert Scoble blogs from the Microsoft company picnic. Although he writes, "Microsoft holds a picnic for its employees every year," this suggests that the picnic is organized by Microsoft. It isn't. The company picnic is run by a professional company picnic company. They also do the Alaska Airlines company picnic, and probably ...

Setting focus in a dialog box is more than just calling SetFocus. A dialog box maintains the concept of a "default button" (which is always a pushbutton). The default button is typically drawn with a distinctive look (a heavy outline or a different color) and indicates what action the dialog box will take when you hit Enter. Note that this is ...