Abstract: The invention provides a storage system, and a method for operating a storage system, that provides for relatively rapid and reliable takeover among a plurality of independent file servers. Each file server maintains a reliable communication path to the others. Each file server maintains its own state in reliable memory. Each file server regularly confirms the state of the other file servers. Each file server labels messages on the redundant communication paths, so as to allow other file servers to combine the redundant communication paths into a single ordered stream of messages. Each file server maintains its own state in its persistent memory and compares that state with the ordered stream of messages, so as to determine whether other file servers have progressed beyond the file server's own last known state.

Abstract: The invention provides a method and system for collaborative planning among multiple collaborators and multiple trading partners, in which individual collaborators and individual trading partners can both make use of global information regarding parties using the system, while still being able to maintain secure and separate information regarding how those individual parties treat their counterparts. The system includes a many-to-many hub at which multiple collaborators and multiple trading partners can exchange information, the hub including a global database having public information about those multiple collaborators and multiple trading partners; the system also includes within the hub a set of private databases having secure and separate information for individual collaborators or individual trading partners.

Abstract: The invention provides a method and system for dynamically controlling link parameters during communication between one or more receiver/transmitters. Transmissions are sent as frames from a Base Station Controller to one or more Customer Premises Equipment. Together with a payload, each frame contains a special control message that pre-announces to both the transmitter and receiver the link parameters to be used until changed. The receiving Customer Premises Equipment processes the link parameters and returns a payload of its own within the same frame. With this dynamic approach, link parameters may be changed as often as every frame.

Abstract: Various embodiments include methods and apparatuses limit connection resources at one or more first network nodes. In one method embodiment, at a second network node, a handshake message is detected; a pending network connection is randomly selected; and a message to end the randomly selected pending network connection is sent from the second node. Various embodiments have one or more elements that can begin if a total of pending network connections exceeds a threshold. In one apparatus embodiment, a packet sniffer component detects a handshake message; a random selection component is coupled to the packet sniffer and randomly selects a pending network connection; and a sending component is coupled to the random selection component and sends a message to end the randomly selected pending network connection. Various embodiments have one or more elements that can begin if a total of pending network connections exceeds a threshold.

Abstract: The invention provides a method and system for reducing RAID parity computation following a RAID subsystem failure. Ranges of RAID stripes are assigned to bits in a bitmap that is stored on disk. When writes to the RAID are in progress, the bit associated with the range of stripes in the bitmap is set. When a failure occurs during the write process, the bitmap is analyzed on reboot to determine which ranges of stripes where in the process of being written, and the parity data for only those ranges of stripes is recomputed. Efficiency is increased by use of an in-memory write counter that tracks multiple writes to each stripe range. Using the write counter, the bitmap is written to disk only after each cycle of its associated bitmap bit being set to a value of 1 and then returning to zero. The invention may be installed, modified, and removed at will from a RAID array, and this may be accomplished while the system is in operation.

Abstract: This invention comprises auto-diagnosis logic that can be implemented in operating systems in an appliance-like auto-diagnosis module coupled to the TCP receiver, the TCP sender or both. TCP events are sampled and a set of statistics on these events is maintained. Receiver side TCP diagnostic techniques include detecting sender's re-transmission timeouts, evaluating the average size of packets being received, determining if a receiver is a bottleneck, and performing other evaluations of an incoming data stream. Sender side diagnostic techniques include flagging transmission timeouts, monitoring the average size of a transmitted packet, evaluating if the advertised window accounts for the delay-bandwidth product of the network connecting the receiver and the sender systems, performing bottleneck checks, and other evaluations of an outgoing data stream. The results are aggregated using system attributes. Systems with common problem areas and attributes are grouped together.

Abstract: A is a method is disclosed for integrating a file system with a RAID array that exports precise information about the arrangement of data blocks in the RAID subsystem. The file system examines this information and uses it to optimize the location of blocks as they are written to the RAID system. Thus, the system uses explicit knowledge of the underlying RAID disk layout to schedule disk allocation. The method uses separate current-write location (CWL) pointers for each disk in the disk array where the pointers simply advance through the disks as writes occur. The algorithm used has two primary goals. The first goal is to keep the CWL pointers as close together as possible, thereby improving RAID efficiency by writing to multiple blocks in the stripe simultaneously. The second goal is to allocate adjacent blocks in a file on the same disk, thereby improving read back performance. The method satisfies the first goal by always writing on the disk with the lowest CWL pointer.

Abstract: A method and system for reliably performing extra-long operations in a reliable state-full system (such as a file system). The file system includes a separate portion of the file system reserved for files having extra-long operations in progress, including file deletion and file truncation. This separate portion of the file system is called the zombie file space; it includes a separate name space from the regular (“live”) file system that is accessible to users, and is maintained as part of the file system when recording a consistency point.

Abstract: A data storage system, such as RAID, upgraded dynamically including multiple stages, providing error checking data without taking the system off-line. Checksums are computed from the data and placed in block 63 of the same disk. The combination of parity bits across the parity disk, the remaining uncorrupted data in the data disks, and checksums within each disk includes sufficient information to enable restoration of corrupt data. The system is upgraded by reserving permanent checksum blocks, writing the checksums to a volume block number, and placing the checksums in permanently reserved checksum block locations after first moving data already there to unreserved blocks.

Abstract: The invention provides a method and system for performing a dump operation that preserves partial results of an aborted or interrupted dump, and allows restarting the dump from near where it was stopped. Thus, tapes from the original dump, plus tapes from the restarted dump, can be combined to provide a consistent subset of a filesystem. In a preferred embodiment, the dump operation is performed on a consistent recorded snapshot of the filesystem, so that the subset of the filesystem recorded on the tapes is itself consistent. As an emergent consequence, the dump operation is freely interruptable, restartable, and provides a set of tapes that maintain a consistent subset of the filesystem that is transparent to tape-restore operations and other operations to be performed on the filesystem as it was recorded on tape.

Abstract: The invention provides a method and system in which a node in a 2-node high availability cluster can declare itself impaired. In doing so, an impaired node can self diagnose or request another node in the cluster assist in diagnosing the problem. An impaired node can then request another node takeover the impaired node's tasks whereby the impaired node is able to shut down gracefully.

Abstract: The invention provides interactive streaming mixed media production. A mixed media content creation tool includes a resource-computation element that computes the likely resource load to be imposed on a server, communication link, and client device, when sent by the server to the client and presented to a user at the client. The resource-computation element is responsive to amounts of communication bandwidth available using the communication link, presentation buffer space and computing resources available at the client, and other measures of resource load. The resource-computation element attempts to optimize resource usage by the mixed media content. The system also includes a presentation element that responds to the resource-computation element, and to user requests, and interactively presents measures of projected resource usage by the mixed media content, comparisons of that projected resource usage with available resources, and comparisons of that projected resource usage before and after optimization.

Abstract: The present invention provides a method for keeping a file system in a consistent state and for creating read-only copies of a file system. Changes to the file system are tightly controlled. The file system progresses from one self-consistent state to another self-consistent state. The set of self-consistent blocks on disk that is rooted by the root inode is referred to as a consistency point. To implement consistency points, new data is written to unallocated blocks on disk. A new consistency point occurs when the fsinfo block is updated by writing a new root inode for the inode file into it. Thus, as long as the root inode is not updated, the state of the file system represented on disk does not change. The present invention also creates snapshots that are read-only copies of the file system. A snapshot uses no disk space when it is initially created. It is designed so that many different snapshots can be created for the same file system.

Abstract: A method and system for operating multiple communicating caches. Between caches, unnecessary transmission of repeated information is reduced. Pairs of communicating caches compress transmitted information, including noncacheable objects. A first cache refrains from unnecessarily transmitting the same information to a second cache when each already has a copy. This includes both maintaining a record at a first cache of information likely to be stored at a second cache, and transmitting a relatively short identifier for that information in place of the information itself. Caches are disposed in a graph structure, including a set of root caches and a set of leaf caches. Both root and leaf caches maintain noncacheable objects beyond their initial use, along with a digest of the non-cacheable objects. When a server devices returns identical information to a root cache, root caches can transmit only a digest to leaf caches, avoiding re-transmitting the entire noncacheable object.

Abstract: The invention provides a method and system for routing or switching file system requests in a mass storage system. The mass storage system includes multiple storage devices coupled using fiber channel to a routing or switching device disposed internally within each shelf of mass storage devices in the mass storage system, and coupled directly to each individual mass storage device in that shelf. The switching device receives requests, identifies an individual target storage device for each such request, and sends each such request to its designated target storage device. The switching device also receives responses to such requests from each individual storage device within the shelf, and sends those responses from the storage device to an external medium with which the response can be delivered to the original requester.

Abstract: A technique wherein the number and position of a quantization parameter node is determined in response to the quantization parameters and a preselected error. The size of scene graph and the corresponding amount of memory required to store the scene graph can be reduced by selective placement of quantization parameter nodes in a scene graph. The scene graph is traversed depth first to establish an order and then traversed in reverse. At each node, a calculation relating to (1) the relative cost of inserting a quantization parameter node and (2) the relative savings that result from insertion of a quantization node is performed. Quantization parameter nodes are selectively placed in response to a result of these calculations. The maximum degree of acceptable error value is chosen for each quantization type. This error value limits the number of quantization parameter nodes that can be placed in a scene graph.

Abstract: This invention provides a method of pixel data compression in which sets of adjacent pixels are compressed in a manner which is sometimes lossy but which reserves the greatest loss of accuracy for circumstances where loss is masked by high frequency components of the original pixel data.

Abstract: Apparatus and methods, and computer program products are disclosed that accepts time-stamped information and feeds that information to a buffered system that consumes the information. The invention accepts an initial interval of the time-stamped information and when a pre-fill limit is reached, starts consumption of the data. The pre-fill limit is determined by monitoring the time stamp on the data that is ready to be consumed and the time stamp of data that has just been accepted. The difference between these time stamps provides an interval that represents the amount of time related to the data associated with the time-stamped information. Once the interval exceeds a pre-fill limit, the invention allows the buffered time-stamped information to be consumed. As the time-stamped information is consumed, the invention monitors the interval (other embodiments use the time stamp of data that is in the process of being consumed, or data that has just been consumed).

Abstract: The invention provides a method and system for entry and editing of multimedia objects for communication and presentation, associating multimedia objects with received sequences of keystroke or mouse action abbreviations. When an abbreviation is detected, the abbreviation is replaced with the associated multimedia object. Each multimedia object has editable properties, and each set of multimedia objects can be collected into an ensemble, which itself can have editable properties. One such ensemble property is a “theme,” which presents a variant of each multimedia object consistent with the theme.

Abstract: The present invention increases the difficulty of reverse engineering sensitive information protected by an encryption algorithm by increasing the difficulty associated with tracing the code that generates the key or the encryption algorithm. This is accomplished by generating the key, used to encrypt and decrypt the sensitive information, as a function of the program instruction values of the procedures used to generate the key and perform the decryption of the sensitive information. Thus, if the key generation code or the decryption code is modified (such as (but without limitation) by placement of a breakpoint, a trace function, or a halt instruction in the code) the resulting key will be different from the key used to encrypt the sensitive information and the decryption attempt will fail.