2,146 research outputs found
Software engineering and middleware: a roadmap (Invited talk)
The construction of a large class of distributed systems can be simplified by leveraging middleware, which is layered between network operating systems and application components. Middleware resolves heterogeneity and facilitates communication and coordination of distributed components. Existing middleware products enable software engineers to build systems that are distributed across a local-area network. State-of-the-art middleware research aims to push this boundary towards Internet-scale distribution, adaptive and reconfigurable middleware and middleware for dependable and wireless systems. The challenge for software engineering research is to devise notations, techniques, methods and tools for distributed system construction that systematically build and exploit the capabilities that middleware deliver
A Compiler and Runtime Infrastructure for Automatic Program Distribution
This paper presents the design and the implementation of a compiler and runtime infrastructure for automatic program distribution. We are building a research infrastructure that enables experimentation with various program partitioning and mapping strategies and the study of automatic distribution's effect on resource consumption (e.g., CPU, memory, communication). Since many optimization techniques are faced with conflicting optimization targets (e.g., memory and communication), we believe that it is important to be able to study their interaction.
We present a set of techniques that enable flexible resource modeling and program distribution. These are: dependence analysis, weighted graph partitioning, code and communication generation, and profiling. We have developed these ideas in the context of the Java language. We present in detail the design and implementation of each of the techniques as part of our compiler and runtime infrastructure. Then, we evaluate our design and present preliminary experimental data for each component, as well as for the entire system
Multi-Threaded Actors
In this paper we introduce a new programming model of multi-threaded actors
which feature the parallel processing of their messages. In this model an actor
consists of a group of active objects which share a message queue. We provide a
formal operational semantics, and a description of a Java-based implementation
for the basic programming abstractions describing multi-threaded actors.
Finally, we evaluate our proposal by means of an example application.Comment: In Proceedings ICE 2016, arXiv:1608.0313
Considerations on command and response language features for a network of heterogeneous autonomous computers
The design of a uniform command language to be used in a local area network of heterogeneous, autonomous nodes is considered. After examining the major characteristics of such a network, and after considering the profile of a scientist using the computers on the net as an investigative aid, a set of reasonable requirements for the command language are derived. Taking into account the possible inefficiencies in implementing a guest-layered network operating system and command language on a heterogeneous net, the authors examine command language naming, process/procedure invocation, parameter acquisition, help and response facilities, and other features found in single-node command languages, and conclude that some features may extend simply to the network case, others extend after some restrictions are imposed, and still others require modifications. In addition, it is noted that some requirements considered reasonable (user accounting reports, for example) demand further study before they can be efficiently implemented on a network of the sort described
Declarative Ajax Web Applications through SQL++ on a Unified Application State
Implementing even a conceptually simple web application requires an
inordinate amount of time. FORWARD addresses three problems that reduce
developer productivity: (a) Impedance mismatch across the multiple languages
used at different tiers of the application architecture. (b) Distributed data
access across the multiple data sources of the application (SQL database, user
input of the browser page, session data in the application server, etc). (c)
Asynchronous, incremental modification of the pages, as performed by Ajax
actions.
FORWARD belongs to a novel family of web application frameworks that attack
impedance mismatch by offering a single unifying language. FORWARD's language
is SQL++, a minimally extended SQL. FORWARD's architecture is based on two
novel cornerstones: (a) A Unified Application State (UAS), which is a virtual
database over the multiple data sources. The UAS is accessed via distributed
SQL++ queries, therefore resolving the distributed data access problem. (b)
Declarative page specifications, which treat the data displayed by pages as
rendered SQL++ page queries. The resulting pages are automatically
incrementally modified by FORWARD. User input on the page becomes part of the
UAS.
We show that SQL++ captures the semi-structured nature of web pages and
subsumes the data models of two important data sources of the UAS: SQL
databases and JavaScript components. We show that simple markup is sufficient
for creating Ajax displays and for modeling user input on the page as UAS data
sources. Finally, we discuss the page specification syntax and semantics that
are needed in order to avoid race conditions and conflicts between the user
input and the automated Ajax page modifications.
FORWARD has been used in the development of eight commercial and academic
applications. An alpha-release web-based IDE (itself built in FORWARD) enables
development in the cloud.Comment: Proceedings of the 14th International Symposium on Database
Programming Languages (DBPL 2013), August 30, 2013, Riva del Garda, Trento,
Ital
Duck Futures: A Generative Approach to Transparent Futures
Futures offer a convenient abstraction for encapsulating delayed computation. It is a mechanism to introduce concurrency through a rewrite of the sequential program. However, managing futures is tedious and requires knowledge of concurrency and its concerns. The notion of transparent futures is used to hide the complexity of futures from developers. A number of techniques based on transparency have been proposed to create and manage futures. Previous techniques make use of reflection. In this paper, we propose duck futures that use a generative approach. We show that duck futures are much more efficient compared to previous notions of transparent futures. We also present the first large scale study of the applicability and utility of duck futures in practice using the Boa infrastructure for mining large scale open source repositories. Our study finds that transparent futures, despite their limitations, can be very useful in practice
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