Question

I have written a small WPF widget using C# that displays the current CPU activity, RAM used and disk activity as three small percentage type bars. I have used the following PerformanceCounters for this: (diskCounter PerformanceCounter returns current total disk activity in bytes per second)

private void InitialisePerformanceCounters()
{
    cpuCounter = new PerformanceCounter("Processor", "% Processor Time", "_Total", true);
    totalRam = (int)(new Microsoft.VisualBasic.Devices.ComputerInfo().TotalPhysicalMemory / 1024 / 1024);
    ramCounter = new PerformanceCounter("Memory", "Available MBytes");
    diskCounter = new PerformanceCounter("PhysicalDisk", "Disk Bytes/sec", "_Total", true);
}

The problem is that although I have discovered how to get the total available RAM to calculate a used percentage from, I cannot find out how to read the disk’s ‘theoretical’ maximum data transfer rate. I need this to calculate the percentage of disk transfer rate used.
Any help would be greatly appreciated.

Answer 1

The only way to do this would be to test it yourself. You could do something like this at the beginning of your application:

byte[] data = new byte[1024];

string path = System.IO.Path.GetTempFileName();

int bytesPerSecond = 0;

using (System.IO.FileStream fs = new System.IO.FileStream(path, System.IO.FileMode.Create))
{
    System.Diagnostics.Stopwatch watch = new System.Diagnostics.Stopwatch();

    watch.Start();

    for (int i = 0; i < 1024; i++) fs.Write(data, 0, data.Length);

    fs.Flush();

    watch.Stop();

    bytesPerSecond = (int)((data.Length * 1024) / watch.Elapsed.TotalSeconds);
}

System.IO.File.Delete(path);

This does, however, assume that the Temp directory is on the disk in question. If not, you’ll have to create a path on the disk you want to measure. Note that this is measuring write speed, not read speed.

This is somewhat contrived since 1MB is not much data to write, but you could try it with a larger amount of data; the concept is the same.