Sun Microsystems, Inc.

Counterpoint Computers, Inc.

J Kent Peacock

James Gregory Hanko

Robert J Block

Sangeeta Varma

The present invention provides a method and apparatus for making a computational service highly available in a multiple server computer environment. In the thin client computing paradigm, end user terminals rely on remote server computers for operation of most functions traditionally associated with personal computing. If the remote server computer fails, all of the users' computers will likewise fail. The present invention provides a solution by implementing a redundant server strategy and a redirection process. One or more servers hosting a communication to the terminal do not contain the only copy of permanent user data. This makes all session hosting servers interchangeable. If a server fails, the failure is detected and the terminal switches to another host server.

Method and apparatus for making a computational service highly available

A method for grouping Human Interface Devices (HIDs) into a multi-head display is provided. The HIDs are identified as either 'primary' or 'secondaries'. A computational-service policy module is consulted when a new HID connects to the network. If the HID is identified as a secondary, the module consults all servers within a group to see if the primary presently has an active session connected to any of the servers. If the primary is being controlled by the same server to which the secondary is connected, the session connection information for the primary is augmented to indicate that the secondary is attached to the same session, and this information is disseminated to the interested software entities. The associated session may then provide multi-head outout to the secondary. If the primary is being controlled by another server in the group, the secondary re-attaches to the server that is hosting the primary.

Associating multiple display units in a grouped server environment

The present invention provides a method and apparatus for distributing load in a multiple server computer environment. In one embodiment, a group manager process on each server periodically determines the server's capacity and load (i.e., utilization) with respect to multiple resources. The capacity and load information is broadcast to the other servers in the group, so that each server has a global view of every server's capacity and current load. When a given terminal authenticates to a server to start or resume one or more sessions, the group manager process of that server first determines whether one of the servers in the group already is hosting a session for that user. If that is the case, one embodiment of the present invention redirects the desktop unit to that server and the load-balancing strategy is not employed. Otherwise, for each resource and server, the proper load balancing strategies are performed to identify which server is best able to handle that particular session.

Method and apparatus for distributing load in a computer environment

A method and system for managing control information associated with a file is disclosed. According to the method, a cache is established in a first file block for storing a second type of file control data. The cache has a cache range. In response to receiving a command to write the file, a first and second type of file control data is generated. The second type of file control data has a logical block number identifying a location in the second file block where the second type of file control data is to be stored. The first type of file control data is stored in the first file block. If the logical block number is within the cache range, then the second type of file control data is stored in the cache. If the logical block number is outside the cache range, then the cache is flushed by copying the previously stored second type of file control data in the cache to a second file block. The second type of file control data is then written into the cache.

Method and apparatus for caching file control information corresponding

A multiple processor (CPU) computer system, each CPU having a separate, local, random access memory means to which it has direct access. An interprocessor bus couples the CPUs to memories of all the CPUs, so that each CPU can access both its own local memory means and the local memories of the other CPUs. A run queue data structure holds a separate run queue for each of the CPUs. Whenever a new process is created, one of the CPUs is assigned as its home site and the new process is installed in the local memory for the home site. When a specified process needs to be transferred from its home site to another CPU, typically for performing a task which cannot be performed on the home site, the system executes a cross processor call, which performs the steps of: (a) placing the specified process on the run queue of the other CPU; (b) continuing the execution of the specified process on the other CPU, using the local memory for the specified process's home site as the resident memory for the process and using the interprocessor bus to couple the other CPU to the home site's local memory, until a predefined set of tasks has been completed; and then (c) placing the specified process on the run queue of the specified process's home site, so that execution of the process will resume on the process's home site.

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Menlo Park, CA, United States of America

J Kent Peacock