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    <p>A <code>FileStream</code> will allow you to seek to the portion of the file you want, no problem. It's the recommended way to do it in C#, and it's fast.</p> <p>Sharing between threads: You will need to create a lock to prevent other threads from changing the FileStream position while you're trying to read from it. The simplest way to do this:</p> <pre><code>// This really needs to be a member-level variable; private static readonly object fsLock = new object(); // Instantiate this in a static constructor or initialize() method private static FileStream fs = new FileStream("myFile.txt", FileMode.Open); public string ReadFile(int fileOffset) { byte[] buffer = new byte[bufferSize]; int arrayOffset = 0; lock (fsLock) { fs.Seek(fileOffset, SeekOrigin.Begin); int numBytesRead = fs.Read(bytes, arrayOffset , bufferSize); // Typically used if you're in a loop, reading blocks at a time arrayOffset += numBytesRead; } // Do what you want to the byte array and return it } </code></pre> <p>Add <code>try..catch</code> statements and other code as necessary. Everywhere you access this FileStream, put a lock on the member-level variable fsLock... this will keep other methods from reading/manipulating the file pointer while you're trying to read.</p> <p>Speed-wise, I think you'll find you're limited by disk access speeds, not code.</p> <p>You'll have to think through all the issues about multi-threaded file access... who intializes/opens the file, who closes it, etc. There's a lot of ground to cover.</p>
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    1. COI think he should have multiple `FileStream` instances (one for each thread) rather than using locking to share it among threads.
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    2. CO@Gabe, could you elaborate a little? Wouldn't you get a IOExeption if you try to stream the same file multiple times?
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      1. USjoe_coolish
    3. CO@joe_coolish: As long as your file is open with shared (rather than exclusive) access, there's no reason you can't access it from multiple streams simultaneously.
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