On 01/03/2013 12:57 PM, dmccunney wrote: > On Wed, Jan 2, 2013 at 7:57 PM, Jim Lemon<j...@bitwrit.com.au> wrote: > >> If there was a Linux kernel in which the user could turn off everything that >> isn't in DOS, that would be a way out. > > If you could turn off everything that *isn't* in DOS, you might have > fun running the Linux kernel. You run DOS in an emulator on top of > Linux because you can't *get* DOS to run native on that hardware. > Drivers are needed that don't exist. > > What you probably want is a flavor of Linux modified for use in an > RTOS, where a user process can preempt the kernel itself. > Exactly. I intend to try out RTLinux at some point.
> But on modern hardware, "other time-critical programs that will carve > out slices of CPU time" are likely a "Who cares?" issue. Commonly > used hardware is orders of magnitude faster than the machines DOS was > made to run on, and there are cases like games where you might > specifically *want* to steal CPU slices, because otherwise your game > runs *too* fast and is unplayable. . > I have had to do this once, when writing an assembly code driver for a digital rotation encoder. The read cycle had to be slowed down by a specified number of NOPs to allow the register to load. The problem is that when a program is monitoring response devices such as the mouse and keyboard and presenting an animated display to the user, even a millisecond lost to some other program is a disaster. As I can often see the system "blink" on modern PCs running Windows and even Linux, I'm reasonably certain that I can't trust them to be accurately recording reaction times. One of my colleagues thought that she had solved the problem by buying an expensive test battery until I showed her the "uncertainty" factor that came with every response recorded. Jim ------------------------------------------------------------------------------ Master Visual Studio, SharePoint, SQL, ASP.NET, C# 2012, HTML5, CSS, MVC, Windows 8 Apps, JavaScript and much more. Keep your skills current with LearnDevNow - 3,200 step-by-step video tutorials by Microsoft MVPs and experts. ON SALE this month only -- learn more at: http://p.sf.net/sfu/learnmore_122712 _______________________________________________ Freedos-user mailing list Freedos-user@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/freedos-user
