Method for improving processing speed of input and output related to writing in operating system

A method of processing input and output in an operating system, the method comprising:

• performing an I/O preparation process and an I/O request for a data block in an application program thread;
• activating, by the application program thread, a journaling thread;
• waiting for completion of an I/O for the data block and waiting for a commit of the journaling thread;
• preparing an I/O for the journal block and requesting the I/O for the journal block at a same time as the waiting for the completion of the I/O for the data block and the waiting for the commit of the journaling thread, in the journaling thread;
• preparing an I/O for a journal commit block, before waiting for completion of the I/O for the journal block after the requesting of the I/O for the journal block;
• after waiting for the completion of the I/O for the journal block, requesting the I/O for the journal commit block;
• and
• waiting for completion of the I/O for the journal commit block.