Soumitra Sarkar

Multiprotocol transport networking: eliminating application dependencies on communications protocols

The Multiprotocol Transport Networking (MPTN) architecture is a general solution that breaks the binding between distributed applications and communications protocols. The MPTN architecture enables existing applications to run unmodified over any communications protocol. In this paper, we first present the trends in networking that resulted in todays networks supporting multiple communications protocols. Next, we describe the classes of problems this support causes. The MPTN architecture is described and presented as a solution to many of these problems. We also present several alternative solutions to the multiple communications protocol problem and compare them to the MPTN solution. Last, we describe the IBM AnyNet™ family of products that implement the MPTN architecture.

A language-based approach to building CSCW systems

An architecture is given for computer supported cooperative work (CSCW) systems that maintains and executes an explicit model of a project-specific process to provide customized support for enforcing the team coordination policies that are represented in the process model. One focus of this research has been the design of a process programming language for building executable process models. The language provides features for data, activity and user role modelling. A process program executed by a generic virtual machine is the basis of a customized CSCW system. The authors present a characterization of the different dimensions of a CSCW system, describe the proposed process programming language and evaluate the expressibility of the language by demonstrating, with examples, how it can be used to generate CSCW systems with different characteristics.<<ETX>>

Characteristics of document similarity measures for compliance analysis

Due to increased competition in the IT Services business, improving quality, reducing costs and shortening schedules has become extremely important. A key strategy being adopted for achieving these goals is the use of an asset-based approach to service delivery, where standard reusable components developed by domain experts are minimally modified for each customer instead of creating custom solutions. One example of this approach is the use of contract templates, one for each type of service offered. A compliance checking system that measures how well actual contracts adhere to standard templates is critical for ensuring the success of such an approach. This paper describes the use of document similarity measures - Cosine similarity and Latent Semantic Indexing - to identify the top candidate templates on which a more detailed (and expensive) compliance analysis can be performed. Comparison of results of using the different methods are presented.

CARP: Handling Silent Data Errors and Site Failures in an Integrated Program and Storage Replication Mechanism

This paper presents CARP, an integrated program and storage replication solution. CARP extends program replication systems which do not currently address storage errors, builds upon a record-and-replay scheme that handles nondeterminism in program execution, and uses a scheme based on recorded program state and I/O logs to enable efficient detection of silent data errors and efficient recovery from such errors. CARP is designed to be transparent to applications with minimal run-time impact and is general enough to be implemented on commodity machines. We implemented CARP as a prototype on the Linux operating system and conducted extensive sensitivity analysis of its overhead with different application profiles and system parameters. In particular, we evaluated CARP with standard unmodified email, database, and web server benchmarks and showed that it imposes acceptable overhead while providing sub-second program state recovery times on detecting a silent data error.

Multiprotocol transport networking: a general internetworking solution

The multiprotocol transport networking (MPTN) architecture proposed in this paper is a general solution to providing interconnectivity for applications. The MPTN architecture provides a protocol-independent system interface that includes most functions provided by existing transport protocols. As a result, the MPTN architecture decouples higher-layer protocols, application programming interfaces, and applications from protocols at the transport layer and below. Using the MPTN architecture, current and new applications can function unmodified over any transport supported under the MPTN interface. In addition, MPTN transport-layer gateways provide an end-to-end communication facility across a number of networks running different protocols. Therefore, a collection of networks running different protocols can serve as a single logical network.<<ETX>>

Cotools: a tool composition mechanism for object-based environments

Most environments provide mechanisms for <italic>tool integration</italic> to reuse existing tools in flexible ways to build composite tools. A common approach is to model tools as <italic>stream transformers</italic> and to provide <italic>channel-oriented</italic> composition mechanisms which connect output streams of tools to the inputs of other tools to form tool configurations. This approach is inappropriate for environments centered around an <italic>environment database</italic>, where tools communicate with each other by manipulating <italic>database views</italic>. This paper proposes a composition mechanism called <italic>cotools</italic>, which models the cooperation of a set of tools via database objects that are concurrently accessed by members of a cotool. Details of the cotool model, an example of its use, and related ideas are presented in this paper.

Transaction mechanisms for software environment databases

Databases for software environments have a set of requirements that are fundamentally different from conventional databases. Besides requiring an object-oriented or semantic data model, CASE databases need to support interactive design transactions, trigger facilities and a application model for integrating software tools. Design transactions are necessary for interactive applications where the duration of a transaction may last days or months. Triggers are useful for incremental data derivation and constraint maintenance. Composite tools, built by reusing tool components, require a multithreaded transaction facility where changes made by one member tool are immediately visible to other members, and the entire complex tool executes as one transaction. The authors describe design transactions, multithreaded transactions, the interaction between the transaction model and triggers, and the rationale for including these features in an environment database.<<ETX>>

Towards More Effective Solution Retrieval in IT Support Services Using Systems Log

Technical support agents working in the IT support services field resolve IT problems. They are often faced with the daunting task of identifying the correct solution document through a search system from large corpora of IT support documents. Based on the observation that system logs may contain critical information for identifying the root cause of IT problems, we explore the idea of automatic query expansion by using system logs as a bridge to link queries with the most relevant documents. Given the original query from a user such as a technical support agent, an intermediate query is first formed by adding key terms extracted from system logs using domain-specific rules. Based on topic models, further key terms are selected from corpora of IT support documents, which are combined with the intermediate query to form the final query. Our experimental results show that expanding queries using system logs together with topic models yields better performance in retrieving relevant IT support documents than using topic models only.

Measuring Compliance and Deviations in a Template-Based Service Contract Development Process

Asset-based approaches, involving the use of standardized reusable components (as opposed to building custom solutions), are increasingly being adopted by IT service industries to achieve higher standardization, quality and cost reduction goals. In this paper, we address issues related to the use of an asset-based approach for authoring service contracts, where standard templates are defined for each type of service offered. The success of such an approach relies on a compliance checking system. We focus on three key components of such a system. The first measures how well actual contracts comply with the standard templates. The second analyzes compliant contracts containing moderate deviations and reports on the consistent patterns of deviations observed for each template to help identify necessary modifications required in templates to keep them up-to-date with evolving business requirements and customer needs. The third analyzes noncompliant contracts and identifies groups within them such that members of each group have enough similarity to each other to warrant consideration for development of new templates for each group. We describe the architecture of the proposed system, our experience in the use of various text analysis techniques to prototype different system components, and the lessons learned.