Limitations of the Existing System Interface

Currently, all client interaction to a pvfs2-server is done through the System Interface API. This interface provides a set of file system and I/O operations to be performed against the pvfs2-server(s), but suffers from several major limitations in its current state. These limitations can be described briefly as:

• Semantic Limitations: the current implementation provides a blocking interface to all operations. We already know that a non-blocking interface is required for efficient access through other existing non-blocking iterfaces such as ROMIO.
• Reusability Limitations: the current implementation performs many blocking operations. This cannot be used as is in the proposed non-blocking state-machine oriented architecture of the pvfs2-client.

A proposed redesign of the System Interface implemented in terms of reusable state machines can solve these limitations, as discussed below.