A distributed object platform for multimedia applications

2007

This document defines a Remote Direct Memory Access Protocol (RDMAP) that operates over the Direct Data Placement Protocol (DDP protocol). RDMAP provides read and write services directly to applications and enables data to be transferred directly into Upper Layer Protocol (ULP) Buffers without intermediate data copies. It also enables a kernel bypass implementation. Recio, et al.

Computing Research Repository, 2003

Message passing programs commonly use buffers to avoid unnecessary synchroniza- tions and to improve performance by overlapping communication with computation. Unfortunately, using buffers makes the program no longer portable, potentially un- able to complete on systems without a sufficient number of buffers. Effective buffer use entails that the minimum number needed for a safe execution be allocated. We explore a

2011 17th IEEE Real-Time and Embedded Technology and Applications Symposium, 2011

Real-time systems and applications are becoming increasingly complex and often comprise multiple communicating tasks. The management of the individual tasks is well-understood, but the interaction of communicating tasks with different timing characteristics is less well-understood. We discuss several representative inter-task communication flows via reserved memory buffers (possibly interconnected via a real-time network) and present RAD-Flows, a model for managing these interactions. We provide proofs and simulation results demonstrating the correctness and effectiveness of RAD-Flows, allowing system designers to determine the amount of memory required based upon the characteristics of the interacting tasks and to guarantee real-time operation of the system as a whole.

Multimedia, IEEE, 2002

Proceedings Third IEEE International Symposium on Object-Oriented Real-Time Distributed Computing (ISORC 2000) (Cat. No. PR00607), 2000

In this paper we highlight major technical requirements for designing and developing future distributed multimedia information system using Internet technology. The key requirements of this system are t o a llow users to access and search and to communicate multimedia documents consisting of text, audio, video, and image. We emphasize the role of object-oriented technology for information management and real-time communication protocols to guarantee QoS. We present a r eference a r chitecture for Web-based r eal-time distributed multimedia system which integrates enabling technologies including real-time streaming, multimedia indexing and searching, and distributed object management.

Lecture Notes in Computer Science, 2006

One of the most challenging aspects to designing a Java messaging system for HPC is the intermediate buffering layer. The lower and higher levels of the messaging software use this buffering layer to write and read messages. The Java New I/O package adds the concept of direct buffers, which-coupled with a memory management algorithm-opens the possibility of efficiently implementing this buffering layer. In this paper, we present our buffering strategy, which is developed to support efficient communications and derived datatypes in MPJ Express-our implementation of the Java MPI API. We evaluate the performance of our buffering layer and demonstrate the usefulness of direct byte buffers.

Multimedia Tools and Applications, 2000

Continuous media servers manage delay sensitive data such as audio and video clips. Once a server initiates the display of a clip on behalf of a client, it must deliver the data to the client in a manner that prevents data starvation. Otherwise, its display may suffer from disruptions and delays, termed hiccups. A hiccup-free display is important to a number of applications such as video-on-demand for entertainment, distance learning, news dissemination, etc. Buffer sharing enables a server to trade memory for disk bandwidth to service multiple clients by sharing data in memory, using a single disk stream. However, an uncontrolled buffer sharing scheme may reduce system performance.

1998

Multimedia database systems (MMDBSs) have to be capable to handle efficiently time-dependent and timeindependent data, and to support Quality-of-Service (QoS). To support continuous playout of time-dependent data, reservations of the limited resources disk I/O bandwidth and network bandwidth have to be combined with appropriate buffer management. Based on the special requirements of the DEDICATION pre-study, i.e., building a cheap prototype system for asynchronous distance education, we have designed the buffer management mechanism Q-L/MRP. Q-L/MRP is a buffer preloading and page replacement mechanism for multimedia applications with heterogeneous QoS requirements. Q-L/MRP extends L/MRP with two features: (1) it supports multiple concurrent users, and (2) it supports QoS with a dynamic prefetching daemon. This dynamic prefetching daemon is able to dynamically adapt to the changes in network and disk I/O load. Furthermore, QoS requirements from the users like frame rate are mapped into the buffer mechanism. Our performance analysis shows that Q-L/MRP is very suitable for the special environment in DEDICATION and outperforms other buffer management mechanisms. Since we have implemented Q-L/MRP in software only, it is also suitable for other multimedia applications on other systems with different hardware configurations and workloads.

Digest of Papers. COMPCON Spring 89. Thirty-Fourth IEEE Computer Society International Conference: Intellectual Leverage, 1989

... reference net-work communication and extensible memory ob-jwts. transparcnt shared libraries to supply binary com. patibility and an object programming facility integrated with transparent network communication. Page 2. 2.1. ...

Proceedings of the 2nd Annual ASCI Conference, 1996

Abstract. Current paradigms for interprocess communication are not sufficient to describe the exchange of information at an adequate level of abstraction. They are either too low-level, or their implementations cannot meet performance requirements. As an alternative, we propose distributed shared objects as a unifying concept. These objects offer user-defined operations on shared state, but allow for efficient implementations through replication and distribution of state. In contrast to other object-based models, these implementation ...

ABC++ is a portable object-oriented type-safe class library for parallel programming in C++. It supports active objects, synchronous and asynchronous object interactions, and object-based shared regions on both shared- and distributed-memory parallel computers. ABC++ is written in, and compatible with, standard C++: no language extensions or pre-processors are used. This paper focuses on its use of an object-oriented technique called smart messages to support object interactions. Smart messages demonstrate the effectiveness of object-oriented programming in encapsulating low-level details of concurrency and in improving software portability.

IEEE/ACM Transactions on Networking, 2020

Buffering architectures and policies for their efficient management are core ingredients of a network architecture. However, despite strong incentives to experiment with and deploy new policies, opportunities for changing anything beyond minor elements are limited. We introduce a new specification language, OpenQueue, that allows to express virtual buffering architectures and management policies representing a wide variety of economic models. OpenQueue allows users to specify entire buffering architectures and policies conveniently through several comparators and simple functions. We show examples of buffer management policies in OpenQueue and empirically demonstrate its impact on performance in various settings.

2000

Multimedia networking refers to the transfer of related audio, video, images, text and/or data among networked computers. Because of their very large filesize and their continuous nature, these transfers are problematic. Unlike the majority of proposed solutions for transmitting continuous media, which either request a dedicated connection or use connectionless protocols, we propose a solution which uses a connection-oriented protocol (TCP/IP). A dynamic feedback and buffering mechanism allows us to continue with the transmission even in the case that the network load increases, decreasing the necessary bandwidth by gradually reducing the quality of the transmitted stream. Transmission quality is restored when the network traffic reduces. An object-oriented approach is used to build both server and client, allowing easier system debugging and expansion. Multithreading is used to solve some problems which require concurrent solutions.

1991

ACM SIGARCH Computer Architecture News, 1991

We describe the rationale for the design and the architecture of a Memory Management Unit (MMU) for object-oriented systems. The CAMOES 1 MMU supports arbitrary size protected objects mapped on a single virtual address space. Support for object invocations is provided in the form of an operations cache closely coupled with the addressing hardware. The MMU only executes in hardware those functions crucial for performance; other functions and, namely, the management of internal buffers and associative memories, and object management policies, are handled in software. This functional organisation is suitable for current generation processors based on RISC principles and is able to support open multi-lingual environments.