They provide more functionality and are easier to use than the MS-DOS servicesYou might ask why you need another set of file I/O services, when you already have the services of MS-DOS, the C run-time libraries, and Windows. The Multimedia file I/O services offer the following advantages over other file I/O services:
They provide more functionality and are easier to use than the MS-DOS services
They are a part of the system software, so they don't increase the size of your application, like linking to the C run-time libraries
They provide more functionality than the Windows services, such as support for buffered I/O, RIFF files, memory files, and custom storage systems
In addition, the Multimedia file I/O services are optimized for performance-intensive applications. The CPU overhead of using these services versus going directly to MS-DOS is very low.