O'Reilly logo
  • Ivan Petrov thinks this is interesting:

Providing the O_DIRECT flag to open( ) instructs the kernel to minimize the presence of I/O management. When this flag is provided, I/O will initiate directly from user-space buffers to the device, bypassing the page cache. All I/O will be synchronous; operations will not return until completed.

From

Cover of Linux System Programming

Note

Direct IO