What is the actual service running behind svchost.exe

I knew that a lot of Windows Services (available as DLLs) run under the host process svchost.exe during start-up. But is there any way to find out what is the actual mapping service behind each svchost.exe? Sometimes, the svchost.exe process occupies a lot of CPU/memory resources and we need to know the actual service behind it.

The answer is very simple on Windows 7. Press "Ctr+Shift+Esc" to open the Task Manager.
Click on "Show processes from all users". Just right click on any svchost.exe process and in the context menu, select "Go To Service". You would be redirected to the Services Tab, wherein the appropriate service would be highlighted.

Another nifty way is to use the following command on the cmd prompt:
tasklist /svc /fi "imagename eq svchost.exe"

Long file names on Windows

Just spend the last 30 mins in total frustration on the way Windows 7 handles long file names. I was essentially trying to copy "LifeRay Social Office" portal folder structure from one location to the other.

On my Windows 7 desktop, the copy command from Explorer won't just work ! No error message, no warning, just that the window disappears. I did a remote desktop to the server and tried to copy from there. On the Windows Server 2000 box, I atleast got an error message - "Cannot copy file". But that's it, no information on why copy did not work.

I debugged further and tried to copy each individual file and only then did I get a meaningful error message - "The file Name(s) would be too long for the destination folder." So essentially the total path (string-length) of the files were long enough for Windows to go awry.

A quick google search showed that this is a core windows problem. Windows Explorer (File Explorer in Windows 8 and Windows Server 2012) uses ANSI_API calls which is limited to 260 characters in the paths. There are some hot fixes available as a patch on windows, but did not try them yet.

So what are the options then? MS has released a tool called as RoboCopy that can handle this problem. Another popular tool is LongPathTool. In my case, fortunately I had JDK installed on my box. I used the jar command to inflate/deflate the folder structure between copying and it worked like a charm :) Strangely WinZip on Windows 7 did not work as it threw some weird error long file names.

There is another headache due to long file names. You also cannot delete such directories form the windows explorer !. I tried using the rmdir command from the command prompt and thankfully that worked !!!

Useful Command Line Tools for Windows 7

Jotting down some Win 7 commands that I often use for quick access to information. One can directly type these commands in the 'Run' window.

• msconfig: Get to know the programs that are configured to start during boot. Disable those programs that you are not interested in.
• msinfo32: Quick summary of your system information. Give detailed info on hardware resources, OS details, system properties, etc.
• control: Quick access to the Control Panel
• eventvwr: Quick access to the Event Viewer
• perfmon: Useful tool to monitor the performance of your system using performance counters.
• resmon: Great tool to check out the resource utilization of CPU, Memory and Disk IO.
• taskmgr: Quick access to Task Manager
• cmd: Opens the command prompt
• inetcpl.cpl : Opens the internet settings for proxy, security etc. 

Cold start Vs Warm start of programs

We often notice that if we start a Windows Forms application the first time after a system reboot, then the start-up time is quite long. But if I close and open the win-form application again, then the application start-up time is reduced drastically. This is true for all programs - Java. .NET, VB... not just WinForms. 

For e.g. open a 5 MB word doc right after reboot and then reopen it again. There would be a difference of 5x-10x in startup times.  This difference between start-up times is called as Cold start and Warm start.

This happens because of 'disk-cache'. The 'disk-cache' is part of RAM that is dedicated to caching disk pages into memory. So the next time, a program is accessed, the disk cache is hit first and if the required program is found there, then it is loaded into the program space. Hence expensive disk access is eliminated and hence the start-up time is much faster. The pages remain in disk cache as long as possible and are removed based on a FIFO principle.

Operating systems have started using this technique to make programs appear faster. 

For example superfetch service on windows vista (xp has prefetch) does this by putting your most frequent used applications into the ram, so when you launch them, they are actually launched not for the first, but second time. 

Disabling startup programs

In Windows XP, if you are getting annoyed by the number of programs that start-up when the OS loads, then there is an easy way to disable the programs we don't need.

Just type "msconfig" in the 'Run' window.  A window titled 'System Configuration Utility' would come up. Navigate to the 'StartUp' tab and uncheck those programs that need not be started at boot time.

What the hell are all those processes running in the taskbar?

Ever opened the TaskManager on windows and wondered why there are so processes running?
HowTo-Geek gives valuable information on some of the nagging questions:

1. juschedexe
2. ctfmonexe
3. rundll32
4. svchost