title: how can I hold initial data when introducing an iPhone app?
body: <p>I am developing an iPhone app which retrieves information via NSUrlRequest and displays through UIWebView.</p>
  
  <p>I want to hold initial data (such as HTML pages, images) as a cache so that users of my app can access to data without network costs at the first time.
  Then, if data on my web server are updated, I would download them and update the cache.
  For performance issues, I think it is better to store data on file system than on core data.
  Yet, I think it's not possible to release a new app writing data on disk.</p>
  
  <p>So, I am about to store initial data(or initial cache) at Core Data, and when users launch my app for the first time, I would copy the data to disk (like /Library folder).</p>
  
  <p>Is it, do you think, a good approach?
  Or,...hmm, can I access to Core Data using NSUrlRequest?</p>
  
  <p>One more question,
  I might access to file system using NSURL, which is the same as to data on the Web. (right?)
  My app would compare version of the cache with version of data on my web server, and if it's old, retrieve new data.
  and my app will access only to file system.
  All data are actually HTML pages including script, and images. And, I want to cache them.</p>
  
  <p>could you suggest a better design?</p>
  
  <p>Thank you.</p>