From furm@npac.syr.edu Mon May 2 14:27:50 1994 Date: Mon, 2 May 1994 13:15:26 -0400 From: Wojtek Furmanski To: paulc@npac.syr.edu Cc: furm@npac.syr.edu Subject: text System Integration Tools and Interactive User Interfaces For HPCC Recent advances in parallel programming languages such as High Performance Fortran are expected to accelerate the process of integrating parallel processing into industry. However, a generic "real world" computationally intensive industrial applications in areas such as fluid dynamics, product design or concurrent engineering require even more powerful and versatile tools. Such applications typically contain several modules with varying degree of inter-modular interaction. Some modules such as digital signal processors, 3D renderers or PDE solvers map naturally onto the HPF programming model, while some others are inherently sequential. Also, a realistic application contains typically several data parallel modules, some of them interacting in the data parallel mode as well, for example different layers of a multigrid PDE algorithm, or subsequent filters in the machine vision systems. Finally, the process of integrating individual components into the full application is a complex task itself, and so is the process of module synchronization, interactive debugging and fine-tuning the parameters of a prototype. New generation HPDC software integration tools, required to handle this type of computational complexity, are currently being constructed. We summarize here recent activities in this area at NPAC. Currently popular approach, exploited in a series of recent projects at NPAC, is based on dataflow visualization systems such as AVS. This model supports a network of computational modules, implemented as individual UNIX processes, and interacting via the RPC protocol under control of the AVS kernel. Individual modules can be placed on different machines and hence the model provides support for heterogeneous distributed computing. Some of these modules can be also installed on parallel platforms, thereby extending the paradigm to the HPDC level. Visual editing tools for such a network are also offered by the system which facilitiate application prototyping, integration, monitoring and fine-tuning. Finally, several default visualization modules come with the system and allow for sophisticated data visualization and rendering tasks. AVS is most adequate for relatively static scientific visualization tasks. There is no support for system wide synchronization nor for real-time user-drived reactive services such as required for advanced simulation tasks of the virtual reality type. Also, while parallel (e.g. HPF) modules can be included in the AVS network, there is no support for parallel I/O or/and parallel dataflow between individual HPF tasks, i.e. all communication must be mediated by the corresponding host programs which causes substantial bottleneck. We are currently developing at NPAC a set of tools which will allow to extend AVS functionality is the areas discussed above and to provide support for virtual reality simulations as well as for televirtuality service engineering. The underlying software model is provided by the MOVIE (Multitasking Object-oriented Visual Interactive Environment) model at NPAC. MOVIE system is a network of MOVIE servers -- interpreters of a high-level object-oriented programming language, MovieScript. MovieScript extends PostScript in areas such as GUI prototyping, Fortran90--like matrix algebra and operating support for the real-time pre-emptive multithreading. A specific design of a MOVIE network can be adapted to a particular computational domain. In particular, all dynamic features of the AVS model in the heterogenous distributed mode can be reproduced in terms of MOVIE tasks or threads, but the model also offers support for multitasking data parallel processing and reactive real-time programming. For example, we constructed recently the HPF interpreter in terms of a mesh of MOVIE servers, operating simultaneously in the data parallel (HPF) mode and the asynchronous mode driven by interactive user queries. In the early development stage is the next level tool in this category, HPCGS (High Performance Coarse Grain Support for HPDC) which will allow for concurrent execution of and parallel dataflow between several HPF modules. AVS-like visual network editor will be also provided to facilitate application editing tasks. Finally, we also plan to provide support for the World Wide Web services in terms of the CGI (Common Gateway Interface) scripts. Such scripts, passed from the Web browser to the Web server to the MOVIE host server of the HPCGS system will allow for remote interactive control of high performance simulations, running on NPAC systems. The architecture of HPCGS will also play a role of the first prototype towards televirtuality (TVR) services at NPAC. Current hypermedia browsers such as NCSA Mosaic are not adequate to support two-way interactivity of the TVR model but there are ongoing VR-oriented activities in the WWW community and several new consumer level VR products will offer soon "by wire" support as well. We are also addressing the issue of possible integration of MOVIE with Mosaic which would offer real-time interactive scriptable control and graphics/GUI at the browser/user side as well.