Chris,

I have no microSD atm, so will need to buy one. Could you post a list of cards that are known to work?

I bought this one today, and it seems to work (well, I can read the directories and file names, but there seems to be a problem with reading file contents).

SanDisk Mobile microSD Card 2GB

$9.99 at Office Depot in the US.

Chris,
Thanks for looking into this. If you change to use ReadToEnd() the behavior is the same. So this might be memory leak inside the StreamReader itself.

I'm getting exactly the same error as Szymon when I try to read a file from the SD card. I actually wrote my sample before I saw this thread, but my code is almost the same.

Here's the sample code where I use a StreamReader object to get the first line of a text file:

using System;
using System.IO;
using System.Threading;
using Microsoft.SPOT;
using Microsoft.SPOT.Hardware;
using SecretLabs.NETMF.Hardware;
using SecretLabs.NETMF.Hardware.Netduino;

namespace SDCardSample
{
    public class Program
    {
        public static void Main()
        {
            string currentDir = Directory.GetCurrentDirectory();
            Debug.Print("Current directory: " + currentDir);

            string[] dirs = Directory.GetDirectories(currentDir);
            foreach (string d in dirs)
            {
                Debug.Print("dir: " + d);
                string[] files = Directory.GetFiles(d);
                foreach (string f in files)
                {
                    Debug.Print("file: " + f);
                    StreamReader reader = new StreamReader(f);
                    Debug.Print(reader.ReadLine());
                    reader.Close();
                }
            }
        }
    }
}

And the exception that gets thrown:

Current directory: \
dir: \SD
file: \SD\FOO.TXT
Failed allocation for 685 blocks, 8220 bytes

Failed allocation for 685 blocks, 8220 bytes

    #### Exception System.OutOfMemoryException - CLR_E_OUT_OF_MEMORY (1) ####
    #### Message: 
    #### System.IO.StreamReader::ReadLine [IP: 000a] ####
    #### SDCardSample.Program::Main [IP: 005e] ####
A first chance exception of type 'System.OutOfMemoryException' occurred in System.IO.dll
An unhandled exception of type 'System.OutOfMemoryException' occurred in System.IO.dll

Note that this happens for both ANSI and UTF-8 encoded files (I created the files on the PC).

We have posted updated firmware to address the SD card mounting and memory allocation issues.
http://forums.netdui...patch-4-beta-1/

SD card-related updates in the firmware update:
* Mounting invalid MicroSD cards now throws an exception
* Reduced memory usage when accessing SD cards

Please let me know if this new firmware fixes things for you...

Chris

Cool - thanks for getting the new firmware out so quickly!

This seems to fix the problem I was having with the StreamReader.ReadLine() method yesterday:

Current directory: \
dir: \SD
file: \SD\FOO.TXT
The quick brown fox jumps over the lazy dog.

Now I need to figure out what to do with 1.83 GB of storage.

That is pretty cool. Small and cheap enough to install in a dedicated project . This definitely gives me some ideas. Watch out