Abstract: Approaches for retrieving files from a replicated file system. A component receives, from a requestor, a request for a copy of a data unit. The component identifies a plurality of storage nodes that each stores a complete copy of the data unit. The component sends, to the plurality of storage nodes, an instruction to retrieve a copy of the data unit within a specified period of time. At each storage node receiving an instruction, a determination of whether the copy of the data unit may be retrieved within the specified period of time is made, and if so, the copy of the data unit is provided to the component only if the copy of the data unit was actually retrieved within the specified period. The component provides the first copy of the data unit it receives to the requestor and discards any subsequently received copies of the data unit.

Abstract: A method and a storage system are provided for implementing a sustained large block random write performance mechanism for shingled magnetic recording (SMR) drives in a redundant array of inexpensive disks (RAID). A Solid State Drive (SSD) is provided with the SMR drives in the RAID. The SSD is used in a hot spare mode, which is activated when a large block random-write event is identified for a SMR drive in the RAID. In the hot spare mode, the SSD temporarily receives new incoming writes for the identified SMR drive. Then the identified SMR drive is updated from the SSD to restore the state of the identified SMR drive, and operations continue with normal writing only using the SMR drives in the RAID.

Abstract: Systems and methods to understand how commercial-off-the-shelf (COTS) software components interact with a system when the COTS components are integrated into a system. A software wrapping technology is utilized to encase the COTS software components such that a wrapper isolates the COTS components during testing.

Abstract: Fault tolerance is improved in a computing system which includes one or more computing machines by (i) executing a control thread or other control program in conjunction with a fault tolerance software system running on at least one of the machines, and (ii) initiating via the control program a test script program which sends one or more requests to a monitored program. The test script program also processes corresponding responses to the one or more requests, and generates a return value utilizable by the control program to indicate a failure condition in the monitored program. The computing system may be configured in accordance with a client-server architecture, with the fault tolerance software system and the monitored program both running on a server of the system.

Abstract: A method for detecting intrusions that employ messages of two or more protocols is disclosed. Such intrusions might occur in Voice over Internet Protocol (VoIP) systems, as well as in systems in which two or more protocols support some service other than VoIP. In the illustrative embodiment of the present invention, a stateful intrusion-detection system is capable of employing rules that have cross-protocol pre-conditions. The illustrative embodiment can use such rules to recognize a variety of VoIP-based intrusion attempts, such as call hijacking, BYE attacks, etc. In addition, the illustrative embodiment is capable of using such rules to recognize other kinds of intrusion attempts in which two or more protocols support a service other than VoIP. The illustrative embodiment also comprises a stateful firewall that is capable of employing rules with cross-protocol pre-conditions.

Abstract: A method for Real-time Transport Protocol (RTP) packet authentication on a packet data network. In particular, the invention relates to a method for preventing toll fraud, privacy compromise, voice quality degradation, or denial of service (DoS) on Voice over IP networks. The Real-time Transport Protocol (RTP) is susceptible to several security attacks, including thirdparty snooping of private conversations, injection of forged content, and introduction or modification of packets to degrade voice quality. The Secure Real-time Transport Protocol (SRTP) provides confidentiality, message authentication, and replay protection for RTP traffic. However, SRTP incurs an additional overhead to verify the HMAC-SHA1 message authentication code for each packet. SRTP+ significantly decrease the verification overhead compared to SRTP and thereby increases the number of faked packets required to mount a successful denial of service attack. SRTP+ provides packet authentication but not integrity.

Abstract: A method and apparatus for automatically determining whether a security vulnerability alert is relevant to a device (e.g., personal computer, server, personal digital assistant [PDA], etc.), and automatically retrieving the associated software patches for relevant alerts, are disclosed. The illustrative embodiment intelligently determines whether the software application specified by a security vulnerability alert is resident on the device, whether the version of the software application on the device matches that of the security vulnerability alert, and whether the device's hardware platform and operating system match those of the security vulnerability alert.

Abstract: Fault tolerance is improved in a computing system which includes one or more computing machines by (i) executing a control thread or other control program in conjunction with a fault tolerance software system running on at least one of the machines, and (ii) initiating via the control program a test script program which sends one or more requests to a monitored program. The test script program also processes corresponding responses to the one or more requests, and generates a return value utilizable by the control program to indicate a failure condition in the monitored program. The computing system may be configured in accordance with a client-server architecture, with the fault tolerance software system and the monitored program both running on a server of the system.

Abstract: A method and apparatus for a fault injection tool having greater flexibility, ease and portability in realizing the basic functionality of the fault injection. The basic functionality of the fault injection process is abstracted into three base classes, namely, a fault injector (FI), a workload generator (WG) and a data collector (DC). A control class performs configuration and management of the objects that are instantiated from the base classes. The control class also implements a graphical user interface. For each base class there is a corresponding core class that performs control and management of a so-called associated “plugin”. Each of the core classes can be implemented as a single class or as a pair of distributed classes. If a core class is implemented as a pair, the FI, WG, or DC object controls operation of the FIRemote, WGRemote or DCRemote object, respectively. For each core class, the associated plugin performs the actual functionality.

Abstract: The invention provides a software instrumentation tool operative to control the execution of a target program, and to execute user-specified instrumentation actions upon occurrence of corresponding user-specified events during target program execution. Advantageously, the instrumentation tool permits the instrumentation actions to be implemented without modification of the target program code, and can be used to provide any desired type of instrumentation on any target program. In an illustrative embodiment, the instrumentation tool includes a frontend portion which provides a creation graphical user interface (GUI) to the tool, and a backend portion which controls execution of the target program and executes the user-specified actions. The frontend portion also includes, for a given target program, a created GUI which is created by a user for providing selected instrumentation functions for the given target program.

Abstract: Fault tolerance is provided in a computing system using a technique referred to as indirect instrumentation. In one embodiment, a number of different copies of a given target program are executed on different machines in the system. Each of the machines includes a controller for controlling the execution of the copy of the target program on that machine. The controllers communicate with a user interface of an instrumentation tool on another machine. A user specifies variables to be monitored, breakpoints, voting and recovery parameters and other information using the user interface of the instrumentation tool, and the tool communicates corresponding commands to each of the controllers for use in executing the copies. A fault is detected in one of the copies by comparing values of a user-specified variable generated by the different copies at the designated breakpoints.

Abstract: An exposure feedback apparatus is disclosed that includes a comparison unit for receiving and comparing image data with a predetermined exposure level and generating a comparison signal indicative thereof, and a multiplexing unit responsive to the comparison signal for supplying the image data to a display output line when the image data is within a desired exposure range and for alternatingly supplying the image data and preselected display data to the output line when the image data is outside of a desired exposure range. In operation, the alternating supply of the image data and preselected display data to the display output line causes portions of a display unit coupled thereto to "blink" when areas of the imaged scene exceed the predetermined exposure level. Thus, the user is supplied with visual feedback that is indicative of the exposure conditions of the captured image.