Abstract: One method for managing encryption includes identifying an available or a secure mode. During restarts a passphrase must be entered in secure mode but not in available mode. Further, a master key is created for encrypting volume keys, where master and volume encryption keys are not stored in non-volatile memory (NVRAM) nor in disk storage. A half-key is created by encrypting the master key with a secure key, the secure key and the encrypted volume encryption keys being stored in disk storage. The half-key is stored in NVRAM only in available mode but not in secure mode. The master key is recreated during a restart when operating in the available mode by decrypting the NVRAM half-key with the secure key from disk storage. Further, the passphrase must be entered by an operator to recreate the half-key and the master key during a restart in the secure mode.

Abstract: One method for managing encryption includes identifying an available or a secure mode. During restarts a passphrase must be entered in secure mode but not in available mode. Further, a master key is created for encrypting volume keys, where master and volume encryption keys are not stored in non-volatile memory (NVRAM) nor in disk storage. A half-key is created by encrypting the master key with a secure key, the secure key and the encrypted volume encryption keys being stored in disk storage. The half-key is stored in NVRAM only in available mode but not in secure mode. The master key is recreated during a restart when operating in the available mode by decrypting the NVRAM half-key with the secure key from disk storage. Further, the passphrase must be entered by an operator to recreate the half-key and the master key during a restart in the secure mode.

Abstract: In one embodiment, an apparatus for avoiding packet losses is provided. The apparatus includes a first communication device that is configured to receive packets of data over a network from a second communication device and to store information indicative of a sliding window that corresponds to a predetermined number of packets of data. The first communication device is further configured to determine a number of lost packets of data from within the sliding window in response to receiving the packet of data and to determine a maximum value from the sliding window. The maximum value corresponding to a maximum number of lost packets of data for a number of sliding windows. The first communication device is further configured to control the second communication device to adjust a bandwidth rate at which the packets of data are transmitted over the network based on at least the maximum value.

Abstract: An apparatus including a first computer for detecting a scrolling event is provided. The first computer is configured to store a destination array including pixels corresponding to a present set of data for a second computer and to store a source array including pixels corresponding to an expected set of data for a display on the second computer after a scrolling event. The first computer is configured to determine hash values of pixel pairs for the pixels of the destination array and to determine hash values of pixel pairs for the pixels of the source array. The first computer is configured to determine a final scroll offset between the pixels in the destination array and the source array based on the hash values. The first computer is configured to transmit pixels indicative of the expected set of data to the second computer based on the final scroll offset for display.

Abstract: An apparatus including a first computer for detecting a scrolling event is provided. The first computer is configured to store a destination array including pixels corresponding to a present set of data for a second computer and to store a source array including pixels corresponding to an expected set of data for a display on the second computer after a scrolling event. The first computer is configured to determine hash values of pixel pairs for the pixels of the destination array and to determine hash values of pixel pairs for the pixels of the source array. The first computer is configured to determine a final scroll offset between the pixels in the destination array and the source array based on the hash values. The first computer is configured to transmit pixels indicative of the expected set of data to the second computer based on the final scroll offset for display.

Abstract: In one embodiment, an apparatus for avoiding packet losses is provided. The apparatus includes a first communication device that is configured to receive packets of data over a network from a second communication device and to store information indicative of a sliding window that corresponds to a predetermined number of packets of data. The first communication device is further configured to determine a number of lost packets of data from within the sliding window in response to receiving the packet of data and to determine a maximum value from the sliding window. The maximum value corresponding to a maximum number of lost packets of data for a number of sliding windows. The first communication device is further configured to control the second communication device to adjust a bandwidth rate at which the packets of data are transmitted over the network based on at least the maximum value.

Abstract: A first data communication device (e.g., a thin client) receives data from a second communication device (e.g., a server or central computer) over a network. The first data communication device detects an actual bandwidth associated with receiving data from the second data communication device. Based on an actual detected bandwidth associated with receiving the data, the first data communication device generates a bandwidth metric identifying a proposed data rate for transmitting future data from the second communication device to the first data communication device. The first communication device transmits the bandwidth metric to the second data communication device for future data transmissions. Based on use of this technique, the second communication device transmits at or near a maximum possible bandwidth supported by a network link supporting transmission of data to the first data communication device.

Abstract: The present invention manages memory buffers in a computer network system. In one embodiment, a managing system on a thin client unit modifies an amount of central processing unit (CPU) resource on the thin client unit that is granted to a server application (e.g., a X server application). The modification is based on a function of how many network information packets are in a packet queue of the thin client unit. By dropping the amount of CPU resource granted lower and lower as the queue gets more and more full, the server application reduces the rate at which it sends commands, thus giving the thin client unit the opportunity to catch up in processing the commands already in the queue. When the number of packets in the queue passes a high critical threshold, the granted CPU resource is dropped to zero, effectively shutting off the server application.

Abstract: The present invention provides methods and apparatus for a computer network system to provide compact and efficient representations of graphics commands on drawing/displaying lines, circles, etc. The methods and apparatus exploit the redundancies and/or relations of the information in drawing/displaying lines, circles, etc. and allow for fewer bytes and faster transmission rate (e.g., more graphics primitives per second) to a client tier (e.g., to a thin client appliance and/or a display on the desktop appliance). For example, one embodiment of the present invention uses commands that take advantage of the structure of spans created by drawing commands to send a base fill command, followed by fills whose locations and size are expressed as deltas with respect to each previous fill in the list. The deltas may comprise a difference between two commands, a difference between a command and another difference, a difference between two differences, and/or a plurality of differences.

Abstract: The present invention manages memory buffers in a computer network system. In one embodiment, a managing system on a thin client unit modifies an amount of central processing unit (CPU) resource on the thin client unit that is granted to a server application (e.g., a X server application). The modification is based on a function of how many network information packets are in a packet queue of the thin client unit. By dropping the amount of CPU resource granted lower and lower as the queue gets more and more full, the server application reduces the rate at which it sends commands, thus giving the thin client unit the opportunity to catch up in processing the commands already in the queue. When the number of packets in the queue passes a high critical threshold, the granted CPU resource is dropped to zero, effectively shutting off the server application.

Abstract: The present invention provides methods and apparatus for a computer network system to provide compact and efficient representations of graphics commands on drawing/displaying lines, circles, etc. The methods and apparatus exploit the redundancies and/or relations of the information in drawing/displaying lines, circles, etc. and allow for fewer bytes and faster transmission rate (e.g., more graphics primitives per second) to a client tier (e.g., to a thin client appliance and/or a display on the desktop appliance). For example, one embodiment of the present invention uses commands that take advantage of the structure of spans created by drawing commands to send a base fill command, followed by fills whose locations and size are expressed as deltas with respect to each previous fill in the list. The deltas may comprise a difference between two commands, a difference between a command and another difference, a difference between two differences, and/or a plurality of differences.