title: What is the fastest way to write a large file on the iPhone?
body: <p>This app I'm working on allows the user to take pictures, and saves them locally (a small thumbnail image via Core Data, and the full-size image in the documents directory).</p>
  <p>I'm finding that writing the image file to the documents directory takes a long time, though -- 8 seconds on my iPhone 3GS, even longer on my iPhone 3G, and on the first-gen iPod touch.</p>
  <p>I write the file this way:</p>
  <pre><code>[imgData writeToFile:imagePath atomically:YES];
  </code></pre>
  <p>Is there a faster way to do this?</p>
  <p>The iPhone's camera app seems to write the images to the filesystem very quickly. I could do the writing in a thread, but I'm concerned about the user possibly quitting my app before the thread finishes.</p>