The multimedia file I/O services provide support for the following file I/O operations:
Basic unbuffered and buffered file I/O
RIFF file I/O
Direct access to the file I/O buffer
Memory files
Custom storage system I/O using application-supplied I/O procedures
Most applications only need the basic file I/O services and the RIFF file I/O services. Applications sensitive to file I/O performance, such as applications that stream data from a CD-ROM in real time, can optimize performance by using services to directly access the file I/O buffer. Applications that access custom storage systems can provide their own I/O procedure that reads and writes elements of the storage system. A storage system is a method of physically storing data in a file, such as a file archival system or a database storage system.