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It looks like Patric gave you a pretty good explanation on this one. As to your other question regarding multi-CPU and multi-core CPUs, they really didn't become a factor until fairly recently. I'm not exactly sure what you mean by "multi-CPU" other than to say 2 or more physical CPU chips on one board. In that scenario, you are "technically" running a parallel processing system, although I'm not sure the OS really treats it as such. It can schedule processes to run on one CPU or the other but I don't believe you (as the programmer) have control through the OS as to what gets scheduled where, etc.
Multi-core CPUs muddy the waters even further, as they are physically one chip and each core generally shares the same memory. Theoretically you could treat it as 2 CPUs, but I think you still end up with the same issues of context switches, etc.
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As previous comments have stated, threading is not equivalent to paralellel processing. Currently MS operating systems do not choose a processor for a thread or a process to run on. That has to be done in the application by the application. If you would like to further investigate this, MSDN has some examples and I am not certain that CP does or does not.
Phil
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pbraun wrote: Currently MS operating systems do not choose a processor for a thread or a process to run on. That has to be done in the application by the application.
That seems to conflict with what Patrick and Scott are saying. Are you sure about this?
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Unless they've changed the scheduler in XP SP? and Vista for user processes, user processes are only scheduled on CPU 0. You can check this by writing a simple process that displays the CPU identifier and makes the CPU busy. Then run a few instances of the process to see which CPU they end up on. I don't have the source code for the test program I used to check that with anymore. It will take some time to re-create it.
Phil
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I just built a test app that uses spawns a new thread to do lots of work. I've got a dual core CPU here and I see that both cores are kept partially busy while the thread runs. In other words, the OS is scheduling both cores to bear the load of a single thread.
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in my opinion i wouldnt consider parallel programming to be the same as threading, purely because with parallel programming you need dedicated memory per processor.
If you really want to experiment with parallel programming then I would recommend investigating a new framework for .NET from microsoft which utilises GPGPU concepts. The framework is called Microsoft Research Accelerator.
In a nutshell GPGPU concepts utilises the graphic processor units parallel processing ability.
http://channel9.msdn.com/wiki/default.aspx/Accelerator.HomePage[^]
http://research.microsoft.com/act/[^]
Accelerator is very exciting because it gives you an idea the future path the .net framework itself may take, add to that the advent of multicore processors.
This is as close as you will get to true parallel programming in c#
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Very interesting, thanks.
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Parallel programming is not the same as multi-threading. In a parallel processing system you have multiple processors each with their own memory. These processors can run the same computational process, different processes, or parts of a single process independently and simulataneously without requiring context switching.
Multi-threading allows multiple threads of execution to occur on a single processor and requires context switching to move between the threads.
A single (physical) processor system can perform multi-threaded activities but not parallel processing, which a parallel processing system can be both multi-threaded and parallel.
As to being able to do parallel processing in C#, it currently isn't really possible. You need specific compilers and language instructions that allow you to take advantage of a parallel processor system. These are not available in C# or any of the .NET languages.
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Scott Dorman wrote: These are not available in C# or any of the .NET languages.
I wonder how hard it would be to wrap MPI in C# wrappers?
We only use it at a very high level at my job, so I don't know the vagaries and minuscule details of how it works, but I imagine it would be quite the undertaking, if it's even possible.
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I'm sure it's possible but probably not worth the effort it would take to get everything right. There are a lot of concepts that are present in single processor systems that take on entirely new meanings in the world of parallel processors.
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Scott Dorman wrote: As to being able to do parallel processing in C#, it currently isn't really possible.
Parallel processing to a certain degree is possible in C# see my post above for the link.
That is the entire purpose of the Accelerator framework to bring parallel processing (of a certain degree) into the .net platform based upon the current GPU hardware. Its work inprogress but a step in the right direction. There is also a video on channel9 on which two developers talk about Accelerator in great detail.
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Interesting link and some pretty cool research. My point still stands, however, in that it isn't possible to do parallel processing in C#...unless you are willing to install the research software, which most companies wouldn't allow.
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I have some dll that when the are deployed they will need to
be registered with regasm.exe. The question is how/where in
a standard 'Setup Project' do I accomplish this.
God Bless,
Jason
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Hi all,
I use the .Net 3 framework and VS 2005 But my Windows Forms look like old ones, I mean like MFC applications or windows 95  .
Any ideas how to fix this?
Thanks in advance
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Either convert to WPF or make sure to set Application.EnableVisualStyles(); in your program's Main() function.
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That's how they should look. 
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lkort wrote: I use the .Net 3 framework and VS 2005 But my Windows Forms look like old ones, I mean like MFC applications or windows 95 .
Any ideas how to fix this?
Are you using the Zune desktop theme under Windows XP? That theme specifically is not supported by the WPF default styles, causing all the controls to look square and bland.
This is a good start for forcing your WPF app to use a particular Windows theme set:
http://notstatic.com/archives/56[^]
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I have to bind a Rectangle's Fill to a Brush ,both of them being declared in '<'App.Resources'>'
It is a easy task using StaticResource for the Fill property
So I've something like this:
I'm using quotes sign so the code can be viewed
'<'Application.Resources'>'
'<'DrawingBrush x:Key="id" x:Name="name"/'>'
'<'DataTemplate DataType="item"'>'
'<'Rectangle Width="30" Height="30" Fill="{StaticResource id}"/'>'
'<'/DataTemplate'>'
'<'/Application.Resources'>'
The hard part is that I want to bind the name of the Brush to the item's BrushID attribute ( as item is a XML element ) ... the name of the brush I want to use is accesible by XPath=@Brush.
so the code should look like this
'<'Application.Resources'>'
'<'DrawingBrush x:Key="id" x:Name="name"/'>'
'<'DataTemplate DataType="item"'>'
'<'Rectangle Width="30" Height="30" Fill="{StaticResource XPath=@BrushID}"/'>'
'<'/DataTemplate'>'
'<'/Application.Resources'>'
BUT
It seems that StaticResource doesn't support XPath.
How should I do this ?
Can anyone help me?
I'm looking forward to your reply.
Mihai
modified 30-Nov-21 21:01pm.
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want to design USB ocilloscope for PC.
I m learning the AT89C51 SERIES. I KNOW BASIC OF c# AND ANALOG ELECTRONICS.
Q:DID I NEED TO KNOW HIGHER TOPICS OF C#, i.e. MULTI-THREADING AND OTHERS?
Q:WHAT WILL BE THE FIRST STEP FOR THIS PROJECT, SHOULD I START WRITING CODE FIRST OR SHOULD I DECIDE WHICH CONTROLLER TO USE AND THEN DESIGN MY H/W, OR SHOULD I PRACTICE ON WINDOWS APPLICATION USING C#?
/////////BOTTOM LINE IS THAT I DON'T KNOW HOW TO BEGIN
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Hi,
first thing you MUST do is unlock the shift key.
then solve the communication problems:
1. what software will you need on PC side to work over USB
2. what software will you need on target side to work over USB
then pay attention to real-time behavior:
3. for the maximum sample rate, bits per sample, and trace duration, figure out
how much data is generated in what time; then try to figure out if a PC can swallow
this in real-time (most likely NO), then decide how much memory you will need
on target side to remedy that.
If and when you have concepts for these three, you can start implementing.
Luc Pattyn [Forum Guidelines] [My Articles]
this weeks tips:
- make Visual display line numbers: Tools/Options/TextEditor/...
- show exceptions with ToString() to see all information
- before you ask a question here, search CodeProject, then Google
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And just to add to Luc's small list, you will definitely need to know multi-threading since you'll want to display graphical data on the UI while mainting a running capture of the data.
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I keep getting the error "Unable to find entry point named "FindUser" in DLL.
Even though dumpbin says it exists.. as entry point 1
C++ DLL Declaration (WN_USER_SECURITY.dll):
extern "C" BOOL FindUser(CString csPassword,
CString &csUserName,
CString &csUserPriveledge,
BOOL &bUserActive)
{
return bFound;
}
C++ .def file:
; WN_USER_SECURITY.def : Declares the module parameters for the DLL.
LIBRARY "WN_USER_SECURITY"
DESCRIPTION 'WN_USER_SECURITY Windows Dynamic Link Library'
EXPORTS
FindUser @1
C# Declaration:
namespace Material_OIT
{
public class RijndaelDLL
{
[DllImport("WN_USER_SECURITY.dll")]
static public extern bool FindUser(StringBuilder password,
ref StringBuilder username,
ref StringBuilder userPriveledge,
ref StringBuilder userID,
ref StringBuilder userComments,
ref bool userActive);
}
}
C# Call:
RijndaelDLL.FindUser(password1,
ref username,
ref userPriv,
ref userID,
ref userCom,
ref userActive);
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BOOL is typically an Int32.
Also dont use ref on a StringBuilder, it's already a pointer :p
Also the 1st parameter should be only a 'string'. StringBuilder could work, but its overkill.
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