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Accommodating Heterogeneity in a Debugger for Distributed ComputationsIn an ongoing project at NASA Ames Research Center, we are building debugger for distributed computations running on a heterogeneous set of machines. Historically, such debuggers have been built as front-ends to existing source-level debuggers on the target platforms. In effect, these back-end debuggers are providing a collection of debugger services to a client. The major drawback is that because of inconsistencies among the back-end debuggers, the front-end must use a different protocol when talking to each back-end debugger. This can make the front-end quite complex. We have avoided this complexity problem by defining the client-server debugger protocol. While it does require vendors to adapt their existing debugger code to meet the protocol, vendors are generally interested in doing so because the approach has several advantages. In addition to solving the heterogenous platform debugging problem, it will be pos~sible to write interesting debugger user interfaces that can be easily ported across a variety of machines. This will likely encourage investment in application-domain specific debuggers. In fact, the user interface of our debugger will be geared to scientists developing computational fluid dynamics codes. This paper describes some of the problems encountered in developing a portable debugger for heterogenous, distributed computing and how the architecture of our debugger avoids them. It then provides a detailed description of the debugger client-server protocol. Some of the more interesting attributes of the protocol are: (1) It is object-oriented; (2) It uses callback functions to capture the asynchronous nature of debugging in a procedural fashion; (3) It contains abstractions, such as in-line instrumentation, for the debugging of computationally intensive programs; (4) For remote debugging, it has operations that enable the implementor to optimize message passing traffic between client and server. The soundness of the protocol is being tested through the implementation of a prototype client and server pair.
Document ID
20020014606
Acquisition Source
Ames Research Center
Document Type
Conference Paper
Authors
Hood, Robert
(NASA Ames Research Center Moffett Field, CA United States)
Cheng, Doreen
(NASA Ames Research Center Moffett Field, CA United States)
Cooper, D. M.
Date Acquired
August 20, 2013
Publication Date
January 1, 1994
Subject Category
Computer Programming And Software
Meeting Information
Meeting: Hawaii International Conference on Systems Sciences
Location: Maui, HI
Country: United States
Start Date: January 3, 1995
End Date: January 6, 1995
Funding Number(s)
PROJECT: RTOP 536-01-11
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.

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