Abstract: An application programming interface (API) is described that allows creating or destroying one or more pairs of data structures for asynchronously passing between the operating system and a network application pointers to packet buffers mapped to both parties.

Abstract: A uniform application programming interface (API) provides efficient generation and control of resource reservations so as to ensure a desired quality of service (QoS) for applications running on an operating system of a computer system. The uniform API is based on a hierarchical file system which associates resource reservations with references to shared objects, rather than with the objects themselves. The uniform API permits the use of a variety of different proportional share schedulers for controlling access to physical resources, e.g., CPU, memory, disk, network interfaces, etc. of the computer system. The hierarchical file system includes a separate directory for each independently-scheduled physical resource of the computer system. A parent of the resource reservation in the hierarchical file system is either a root node of the file system or another reservation for the same resource.

Abstract: A computer operating system that allows legacy applications to be run automatically with quality of service (QoS) guarantees matching required QoS performance levels. In accordance with the invention, files have QoS requirement attributes that can be set-by users. Additionally, users may interpose a requirement broker between a given legacy application and the operating system. The requirement broker may be in the form of a modified version of a library that is dynamically linked with applications at load time. The requirement broker intercepts certain system calls and automatically requests from the system QoS guarantees in accordance with the QoS requirement attributes of the accessed files, whether local or remote.

Abstract: Received packets are processed utilizing protocol processing stages in an operating system, in accordance with a technique referred to as signaled receiver processing (SRP). A given protocol processing stage uses a next stage submit (NSS) function to pass a packet to a subsequent protocol processing stage. Each protocol processing stage is associated with one or more sockets. Each socket is associated with the input function of a protocol processing stage, an unprocessed input queue (UIQ) that contains packets destined to the socket but not yet processed by the socket's input function, and a list of owner processes, which expect input from the socket. NSS uses a multi-stage early demultiplexing (MED) function, which determines a packet's next destination socket, based on the stage currently processing the packet and on information contained in the packet.

Abstract: A computer operating system in which transfer of control of executing threads between protection domains is implemented using specific portals dedicated to the particular transfer of control between two protection domains. The transfer of control may also include parameter manipulation. A server registers a portal specification with a portal manager, the portal specification defining the behavior of portals which transfer control to the server. Thereafter, when a client application desires service from the server, the client application requests instantiation of a portal which will transfer control of an execution thread from the client application protection domain to the server protection domain. Upon receipt of the request, the portal manager dynamically generates portal code and updates a portal table associated with the client application, thus instantiating the portal.

Abstract: A method and system for servicing disk I/O requests from domains which have been guaranteed minimum quality of disk service maintains I/O requests for each domain are in separate queues. The queues are serviced by a disk scheduler which selects requests from the queues in accordance with a fair queuing scheduling algorithm that considers the estimated time required to service the request at the head of a queue with regard for the size of the input or output associated with the request, the proportion of disk bandwidth assigned to the particular domain, and the state of the other queues.