Marshaler

Moving to a new Blog Site!!

2005-06-15T01:51:00.000-07:00

Hi - I am moving to a new Blog site, so i'll be blogging there now! View my new Blog

Cryptanalysis of SHA-1

2005-02-24T01:56:00.000-08:00

Read Cryptanalysis of SHA-1 by Bruce Schneier.

WaitForSingleObject(Handle, Timeout)

2005-02-11T00:52:00.000-08:00

Recently I was working on a problem where I had to create new process on a click of a button. With this, I needed some callback or signal when this new process terminates. This new process was launched on a new thread. I looked into the Thread Class but there was no out of box functionality to achieve this. So I end up writing this code.

Here is the PInvoke Declaration

[DllImport("Kernel32.dll", CharSet=CharSet.Unicode,SetLastError=true)]
static extern uint WaitForSingleObject(
IntPtr HANDLE,
uint Timeout);

Creating a new Thread to start our process…

newThread = new Thread(new ThreadStart(StartNewApplication));
newThread.Name = "ClientApplication";
newThread.Start();

private void StartNewApplication()
{
//Declarations...
const uint INFINITE = 0xFFFFFFFF;
uint returnValue;
int error;

//Creating a new process
Process pr = new Process();
pr.StartInfo.FileName="RemotingServer.exe";
pr.StartInfo.WindowStyle = ProcessWindowStyle.Normal;
pr.Start();

//Using WaitForSingleObject to wait till the threads give a
//signal. As we want to get signaled when the thread gets
//terminated, we set timeout time as "Infinite".
IntPtr HANDLE = pr.Handle;
returnValue = WaitForSingleObject(HANDLE,INFINITE);
if (returnValue == 0xFFFFFFFF)
{
//Getting error code...
error = Marshal.GetLastWin32Error();
}
else
{
//Code which we want to execute after the thread has been terminated
}
}

.NET Framework Resource Management

2005-01-26T05:16:00.000-08:00

This white paper discusses details of resource management in components written for the Common Language Runtime (CLR). Click here to view.

CLR and its relationship to MemToLeave

2005-01-06T05:34:00.000-08:00

Larry Chesnut talks about "CLR and its relationship to MemToLeave" in Yukon.

GAC Structure

2004-10-31T02:10:00.000-08:00

Everyone knows now that GAC physically have directories for each version of assembly. Now what happens when Whidbey Beta 1 is released as it supports both 32 bit platform and 64 bit platform. So if we have directory for each assemblies, there can be problem because both assemblies for 32 bit and 64 bit will have same assemblies unless Microsoft make them with different versions. This obviously is not the right way. We make an application on 32 bit platform using some assembly and then when we want to port it to 64 bit platform; we need to use assemblies with different version. Its not an easy and friendly way.

Before Whidbey, we had only one directory “GAC” which further had directories named after assemblies and they further had directories with respect to version. It was something like this “WinDir”\assembly\GAC\“AssemblyName”\ “VersionNumber”__“PublicKeyToken”. So what Microsoft has done is they have reorganised the directory structure a bit. They have new directories named “GAC_32” for 32 bit and something similar for 64 bit in future like “GAC_64”. This structure can be viewed by disabling the Cache Viewer. To do this, go to registry editor, HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Fusion and change value for "DisableCacheViewer" to 1. If its not present, then create a DWORD value for it and set its value to 1. Now open explorer and see "WinDir"\assembly folder. You'll be able to see the physical structure of GAC.

Now after we install framework 2.0 Beta 1, we have 3 GACs in all. One is for “specific to 32 bit system” which is “GAC_32”, one for portal assemblies “GAC_MSIL” and the last one is for v1.0 and v1.1 called “GAC”.

Also, when we see the assembly folder in explorer, we see another column which tells us about the process architecture. It shows “MSIL” or “x86” or nothing. MSIL is for Portable Assemblies, x86 ones are 32 bit platform specific and the ones which don’t have anything are v1.0 or v.1.1 assemblies.

Note: The above implementation is for Framework 2.0 Beta 1. It might change in future releases.

.NET Memory Management and GC Myths

2004-10-13T04:37:00.000-07:00

Just came across this series of post by Paul Wilson on .NET Memory Management and GC Myths. He talks about how to handle large objects and how .NET Framework internally manages memory when Object.Dispose() is called. Beside the post, the comments section is also good where they had good discussion on some points.

Ensuring all applications run on latest CLR

2004-09-29T07:08:00.000-07:00

If you want to ensure that all applications run on the latest CLR installed on your system, you just need to change some registry settings or set a flag in VS.NET 2005 (Beta 1). There is a switch in VS.NET 2005 (Beta 1) which does this.

Doing it with registry:

To turn on the switch
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft
\.NETFramework\OnlyUseLatestCLR=dword:00000001

To turn off the swtich
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft
\.NETFramework\OnlyUseLatestCLR=dword:00000000

Reverse

2004-09-27T07:26:00.000-07:00

Try this game- Reverse. Its awesome . Got it from Eric's Blog. I'm done with it...and still moving the mouse in opposite direction. :P

Monad September 2004 release available

2004-09-23T05:55:00.000-07:00

Monad September 2004 (Partner Drop 3) release is available for download at MS Beta Site with some new features in it :)

More on HashCode...

2004-09-17T03:50:00.000-07:00

Continuing to my previous post, I was wondering how this HashCode is calculated. On what basis this hashcode is returned.
Here are my conclusions::
Object.GetHashCode returns an index to an internal SyncBlock table that CLR maintains for object synchronization. Each element of this internal table is reference of the SyncBlock for an object.
Also I gave some logical reasons why we get a duplicate HashCode. After knowing how the HashCode is calculated, I deduced that when the object is alive in memory, HashCode functions returns the index of the internal table where the SyncBlock reference is stored. Now when the object is dead or is not in memory any more, this table entry gets empty or null. When new object is created, its SyncBlock reference is also needed to be stored in this table. System might use the same table entry to store the SyncBlock reference for this new object. This is the reason why we get duplicate HashCode for different objects.

Object.GetHashCode()

2004-09-11T03:37:00.000-07:00

Object.GetHashCode () gives us the hash code for an object. But as the documentation says, we should not use it for uniqueness. Because every object will give a hashcode and it will be same till the object lives. There can be cases where two different objects have same hashcode. This is very much possible. This is because Object.GetHashCode () returns an integer which contains a 32 bit value. And if there are more than 2^32 objects living in memory, then the hash code tends to repeat thought they are different objects if checked using Object.Equals() method. I’m not saying that only after 2^32 objects in memory, the hash code will repeat, but this is one case where the hash code can repeat. Also hashcode is an integer and it can have at the most 2^32 values. So, the hashcode can repeat. I tried to make the hashcode repeat on my system. Here is the code for it.

Hashtable hsTable = new Hashtable ();
while (true)
{
object obj1 = new object ();
int _hashCode = obj1.GetHashCode ();
if (hsTable.ContainsKey(_hashCode))
{
Debug.Write("Duplicate Hashcode: " + _hashCode);
break;
}
hsTable.Add(_hashCode, null);
}

Result:
Duplicate Hashcode: 65193

So, we do get same hashcode for different objects. MSDN says: “The default implementation of GetHashCode does not guarantee uniqueness or consistency; therefore, it must not be used as a unique object identifier for hashing purposes”. Hence proved :)

There are more things to talk about Object.GetHashCode(), but I’m still working on them!

What is WOW64?

2004-09-09T06:28:00.000-07:00

I was searching some information when i came across Josh's blog.
What is WOW64 and what does it mean to managed applications that run on 64 bit machine?

um...pretty interesting :)

WinFS, Avalon, Indigo... on WinXP and Windows 2003

2004-08-30T21:57:00.000-07:00

Just read this news, MS is planning to bring WinFS, Avalon, Indigo... on Windows XP and Windows 2003.

"Windows WinFX Developer Technologies Will Be Made Available For Windows XP and Windows Server 2003"

Read it here

Monad Download problem

2004-08-24T07:26:00.000-07:00

While downloading "Monad" from Microsoft Beta Site, i faced some problems. When clicked the download page, the page appeared blank except the header and footer. Nothing happening. Got the solution after 2 days. The problem was that my system didn't had Microsoft's "File Transfer Manager". I downloaded this "FTM" and after that when i clicked on the download page, it started downloading. Read about this FTM, how to install it and how to remove it from your system.

CLR - What happens behind the scene?

2004-08-10T01:26:00.000-07:00

Ever wondered when we click on a managed "exe", what happens. Yes, ofcourse, our application starts, but what are things happening behind the scene. This is the main objective of my latest article. Read it here. Comments/suggesstions are welcome. Email me

Distributed GC

2004-08-09T04:06:00.000-07:00

Was reading about Remoting, saw this article which gives a brief overview about "Mysteries of Distributed Garbage Collection".

Gravitation cannot be held responsible for falling in love

2004-08-08T22:04:00.000-07:00

"Gravitation cannot be held responsible for falling in love", said by Albert Einstein. I really like these words :). In an article, Albert Einstein describes "Why it hurts to fall". And he describes his theory why we are hurt when we fall on ground in comparison with love. Nice to read. Read it here

Size of the Managed Object

2004-07-26T23:53:00.000-07:00

I was trying to get the managed size of the objects, but was stuck. Then after searching, i found this blog of Chris Brumme. He says that "We don't expose the managed size of objects because we want to reserve the ability to change the way we lay these things out". Got another interesting post from the same post. Its from Sam Gentile's Blog. He Says that we can get the size of the Managed Value Types and not Managed Reference Types. Haven't tried myself, but sounds interesting!!

Monad - new Microsoft Command Shell

2004-07-01T03:04:00.000-07:00

Microsoft new Command Shell - codenamed Monad, will be available with Longhorn. I'm not lucky till now to get my hands on it...but after reading Pooja's Blog, it seems pretty cool. Waiting to get my hands on it!!

I'm in Hyderabad :)

2004-06-22T21:10:00.000-07:00

Hi!
I'm in Hyderabad, working here in India Delivery Center, Accenture. I reached here on June 15, 2004. Had induction for 2 days. Went good. And then on the weekend, had lot of work...find house and stuff..and I found one. i'll be shifting this weekend.

Hyderabad city is good. It's clean and the weather (as of now) is good...I'm enjoying.

Have lots of stuff to write...but will do later.

Cya till then :)

My First Blog

2004-06-02T02:48:00.000-07:00

Hi!
This is my First Blog...i have been reading blogs so today today thought start blogging myself. About me, i'm Rupreet from Chandigarh and soon will be joining Accenture @ Hyderabad. I have been working in .NET for quite some time.

Well guys, i'll get back soon...till then cya :)