same enumeration, different results?

[CCodeNewbie]

Still not perfect - but it works (Improvements very welcome)

TimeSpan uptime = TimeSpan.Zero;
using (PerformanceCounter ut = new PerformanceCounter("System", "System Up Time"))
{
ut.NextValue();
uptime = TimeSpan.FromSeconds(ut.NextValue());
}
Console.WriteLine(uptime.ToString());
//result - 03:53:39.7870000

Process[] processlist = Process.GetProcesses();
foreach (Process procs in processlist)
{
if (procs.ProcessName == "System")
{
long st = procs.StartTime.ToFileTime();
DateTime stDt = new DateTime(1601, 1, 1).AddSeconds(st);
float Days = (Environment.TickCount / 86400000);
int dd = (int)Days;
float Hours = (Environment.TickCount / 3600000 % 24);
int HH = (int)Hours;
float Mins = (Environment.TickCount / 60000 % 60);
int mm = (int)Mins;
float Secs = (Environment.TickCount / 1000 % 60);
int ss = (int)Secs;
DateTime result = DateTime.Now - new TimeSpan(dd, HH, mm, ss);
}
}
//result - 20/03/2012 08:31:33

code run @ ~ 12:24 pm

[CCodeNewbie]

Hi Luc, Got it working but wanted to say thank you for your help (code is in my reply to PIEBALDconsult). Would welcome your thoughts and comments...

[PIEBALDconsult]

For what purpose? Task Manager says mine started in 2009 which is certainly untrue. So I don't see how you can do better. P.S. Even as the administrator on my home system (Win 7) I still get the access violation when I try to get the StartTime of the System process.

[Alan N]

I'm glad you've come to a solution that you are happy with. One point that I'm not sure you appreciate is that the up time obtained from the performance counter and the TickCount are essentially the same value.

private void CompareCounterAndTickCount() {
  using (PerformanceCounter ut = new PerformanceCounter("System", "System Up Time")) {
    ut.NextValue();
    TimeSpan counterUpTime = TimeSpan.FromSeconds(ut.NextValue());
    TimeSpan tickCountUpTime = TimeSpan.FromMilliseconds(Environment.TickCount);
    Console.WriteLine("Up Time");
    Console.WriteLine("  from performance counter {0}", counterUpTime);
    Console.WriteLine("  from tickcount           {0}", tickCountUpTime);
  }
}

On my system the duration reported by TickCount is ~0.2s longer than the performance counter's value which presumably just means the two counters do not share the same origin. Also note the use of the FromMilliseconds method to convert the TickCount to a TimeSpan, much simpler than your multistep calculation! Alan.

[CCodeNewbie]

You need to run it as System (mine impersonates System to get the info, Administrator doesn't have enough privileges) The purpose is a) because it completes the Process listing and allows me to cross-reference against netstat & system boot-time.

[CCodeNewbie]

Yes, but I am not trying to get the system start-time. I can already get that using Ravi's post (see my previous question). I explicitly want the System process's start-time.

[Alan N]

I can't understand your reasoning in this matter. The SystemUp Time performance counter description is System Up Time is the elapsed time (in seconds) that the computer has been running since it was last started. This counter displays the difference between the start time and the current time. The Environment.TickCount description is A 32-bit signed integer containing the amount of time in milliseconds that has passed since the last time the computer was started. Subtracting either from the current time gets the time when the computer was started. I don't see why (or how) you differentiate the system start time and the "System" process start time. Alan.

[PIEBALDconsult]

CCodeNewbie wrote:

because it completes the Process listing

Then just display what the StartTime property tells you and leave it at that.

[CCodeNewbie]

Hi Alan, The reason(s) for wanting the System process start-time never had anything to do with getting the PCs boot-time. It had to do with being able to complete a running-processes table, x-reference against 2 other sql tables that form part of the project and possibly because I saw so many forum postings that said it can't be done :) Thanks for all your help with this & when I have completed phase 2 and/or 3 I will probably post the whole thing as an article and look forward to your comments.

[CCodeNewbie]

The StartTime property, once manipulated to reveal a value, tells you 1601/1/1 00:00:00. That wasn't good enough for me. I wanted the actual StartTime but didn't have the syntactical knowledge of how to get it even if I did have rough idea of how it could be retrieved. Thanks to you, Alan, Ravi & Luc, I (and anybody else Googling "get Window's System process starttime" or something similar), instead of hitting dozens of sites saying it can't be done, now have a solution. I would like to think that's what boards like this are for. Thank you once again for your input.