3rd paragraph The performance difference arises (we believe) because when working from an SQLite database, the open() and close() system calls are invoked only

3rd paragraph The performance difference arises (we believe) because when working from an SQLite database, the open() and close() system calls are invoked only once, whereas open() and close() are invoked once for each blob when using blobs stored in individual files. It appears that the overhead of calling open() and close() is greater than the overhead of using the database.