Sun Microsystems 2.1 Media File System MFS, Guaranteed stream delivery rate, Independent streams

With the exception of the APIs for the MSM and CM, the workings of the server’s software components are largely invisible to the user. This is particularly true of the MFS, access to which is exclusively throughout the MSM and CM.

The Sun MediaCenter software offers the following features:

Guaranteed stream delivery rate

Once a stream is accepted for delivery, the server delivers the stream contents at a guaranteed rate until the end of the stream content is reached, the server is asked to stop playing the stream, or server hardware fails.

Independent streams

Delivered streams are independent: they can be stopped and started individually; output streams might all be playing simultaneously from different portions of the same content stream or from different content streams.

Online loading

The server maintains delivery of streams as the highest priority task, so that as the server approaches its maximum bandwidth in stream delivery, any content loading taking place will slow and, at some point, stop, until such time as the server recovers sufficient resources to resume loading. (Note that you cannot load content if the server is reading data from the parity disk, which occurs following a disk failure.)

Playthrough

The server software supports a playthrough capability wherein a Sun MediaCenter server can deliver streams from a title as that title is stored. A given piece of content can be played from the server only five seconds after storage of it has begun.

The following subsections describe the components of the Sun MediaCenter software.

1.3.1Media File System (MFS)

The MFS is designed to deliver multimedia data from an array of attached disks to an output network. In addition to providing the foundation for all of the features listed above, the file system supports:

Recovery from single-disk failures

The MFS will recover from a single disk failure after a small start-up interval (less than 10 seconds). It uses a strategy similar to RAID-4. The number of content disks for each parity disk varies with the disk subsystem used for a particular server model.

Chapter 1 Introduction 1-5