C# reading multiple files by multiple thread issue

[Mou_kol]

Here is two approaches to read multiple files by a multiple threads but getting problem. please tell me what is the problem in the below code

for (int i = 0; i < counter; i++)
{
var thread = new Thread(() => GenerateVirusFile(i));
thread.Start();
}

please see the full code and tell me what is wrong there.

class Program
{
static string folderPath;
static readonly string fileContent = @"X5O!P%@AP[4\PZX54(P^)7CC)7}$EICAR-STANDARD-ANTIVIRUS-TEST-FILE!$H+H*";

    static void Main(string\[\] args)
    {
        folderPath = "F:\\VirusScan";

        int counter = 1000;
        for (int i = 0; i < counter; i++)
        {
            var thread = new Thread(() => GenerateVirusFile(i));
            thread.Start();
        }

        Console.ReadKey();
    }

    static void GenerateVirusFile(int i)
    {
        string filePath = $@"{folderPath}\\TestForVirusScan\_{i}\_{DateTime.Now.ToString("yyyyMMddHHmmssffff")}.txt";

        try
        {
            using (StreamWriter writer = new StreamWriter(filePath))
            {
                writer.WriteLine(fileContent);
            }

            var timer = Stopwatch.StartNew();
            while (true)
            {
                if (!File.Exists(filePath))
                {
                    Console.WriteLine($"{i}: File was removed in {timer.ElapsedMilliseconds}ms");
                    break;
                }
                else
                {
                    Thread.Sleep(1);
                }
            }
        }
        catch (Exception ex)
        {
            Console.WriteLine($"{i}: Exception {ex.GetType().Name} occurred: {ex.Message}");
        }
    }
}

doing same job Using task

class Program
{
static string folderPath;
static readonly string fileContent = @"X5O!P%@AP[4\PZX54(P^)7CC)7}$EICAR-STANDARD-ANTIVIRUS-TEST-FILE!$H+H*";

        static void Main(string\[\] args)
        {
            folderPath = "F:\\VirusScan";
    
            int counter = 1000;
            List tasks = new List();
    
            for (int i = 1; i <= counter; i++)
            {
                Task

[Member_15329613]

What is wrong?

[Lost User]

Hello, Windows Defender will detect and block the EICAR test file[^]. If you need to write this to disk then you will need to add an exclusion. Configure and validate exclusions based on extension, name, or location | Microsoft Docs[^] Best Wishes, -David Delaune

[Lost User]

Reading multiple files at the same time is slower than reading them one after another. Limited channels. Context / thread switching. HDD head contention.

It was only in wine that he laid down no limit for himself, but he did not allow himself to be confused by it. ― Confucian Analects: Rules of Confucius about his food

[primem0ver]

If I were you and for some reason I needed to read/write multiple files in parallel (though Gerry is right when it comes to writing files to traditional hard disk drives), instead of the methods you use, I would simplify things by using the Parallel.For or the Parallel.Foreach method.