SD File Create DateTime?

I am working on a program which logs data to a SD. The filename contains the date and time.

When looking at the files on the SD I noticed that while the filename was correct, the creation date of the that showed up on a PC was wrong.

I also noticed that when creating a file on the SD, captialization is required for the filesystem name. \sd\ does not work. \SD\ does?

Following is a code sample which demonstrates how I am setting the real-time and .NETMF clock, writting to the SD, and looking at the resultant times for the new file.

using System;
using System.IO;
using System.Threading;
using Microsoft.SPOT;
using Microsoft.SPOT.Hardware;
using Microsoft.SPOT.IO;
using GHIElectronics.NETMF.IO;
using GHIElectronics.NETMF.Hardware;

namespace SDTests
    public class Program
        public static void Main()
            // see if real-time clock has been set
            if (!RealTimeClock.IsTimeValid)
                Debug.Print("Setting real-time clock");
                RealTimeClock.SetTime(new DateTime(2010, 07, 03, 21, 30, 00));  
                Debug.Print("Real-time clock is valid");
            // set the NETMF clock from the real-time clock

            Debug.Print("Current time is " + DateTime.Now.ToString());

            // wait for sd to be recognized
            while (!PersistentStorage.DetectSDCard())

            // mount sd
            PersistentStorage sdPS = new PersistentStorage("SD");

            //StreamWriter wr = new StreamWriter("\\sd\\Test.txt", false); // causes exception
            StreamWriter wr = new StreamWriter("\\SD\\Test.txt", false);
            // write to file
            for (int i = 1; i <= 10; i++)
                wr.WriteLine("Line " + i.ToString());

            // close file

            // see what is on SD
            String[] files = Directory.GetFiles("\\SD\\");
            for (int i = 0; i < files.Length; i++)
                FileInfo info = new FileInfo(files[i]);
                Debug.Print(files[i] + " CreationTime: " + info.CreationTime.ToString());
                Debug.Print(files[i] + " LastAccessTime: " + info.LastAccessTime.ToString());
                Debug.Print(files[i] + " LastWriteTime: " + info.LastWriteTime.ToString());


The program output:

Real-time clock is valid
Current time is 07/03/2010 22:19:33
\SD\Test.txt CreationTime: 01/01/1985 00:28:49
\SD\Test.txt LastAccessTime: 01/01/1985 00:00:00
\SD\Test.txt LastWriteTime: 01/01/1985 00:28:48

What have I done wrong?


Yes, you need to have the “SD” in all caps. This is normal.

I did squawk a while back about the creation date given to files a while back, but it never really got answered.

As far as I can tell, you are doing everything right, or at least this is how I set a similar application up.

Hi Chris:

In the Microsoft world filenames are case insensitive. So, the capitial SD is not normal, just different. :expressionless:

I had did a search before posting, but did not see your prior post on the creation date issue.

Maybe we will get an answer this time :stuck_out_tongue:

Hi Mike,

The SD card creation date thing was in a private email, so that’s why it didn’t show up.

No response from ghi on this issue.

The question was asked on weekend and today is a holiday in USA so most engineers are not here. You will get an answer tomorrow from our file system expert, Mike!

Sorry, I did not realize that you guys were allowed to take time off. :stuck_out_tongue:

The date/time is not correct. We are working with Microsoft on a fix.

Great, thanks Mike!

Thanks Mike!