title: Read and write hard disk sector directly and efficiently
body: <p>I have a special need for block data storage. My data are formatted data blocks in size of 4096. For high efficiency, I want to directly manipulate the block on hard disk sector and do not want to treat the data block as file. I think one way is to treat the device as a file such as /dev/sda1 and to use lseek() read() and write() to read and write data. However I do not know the whether the head of the file is the first sector of hard disk. I also suspect the efficiency of this method.</p>
  
  <p>I am working on Linux OS and C programming language.</p>
  
  <p>What is the most efficient way to handle the sector of hard disk? Should I write an block device module of linux. However, I do not know much about it. What kernel functions should I use to read and write on block device?</p>