Digital Equipment Corporation

Mark E Arsenault

Karen Lee Noel

Michael Seward Harvey

Thomas R Benson

Ronald F Brender

Kenneth W Cowan

Leonard S Szubowicz

Richard E Peterson

Mark W Davis

Gary M Barton

Cheryl D Stocks

A method executed in a computer system for detecting and handling an invalid use of a data structure is described. The method includes the steps of providing a data structure associated with a first computing environment. The data structure includes a field having a value stored therein identifying an inaccessible address in a second computing environment. This field is used in detecting an invalid use of the data structure in the second computing environment by a computer program attempting to access memory using said inaccessible address indicated by said value contained in the first field. Additionally a preferred data structure is described as are alternative embodiments of detecting an invalid use of a data structure.

Method and apparatus for handling and detecting an invalid use of a data

A correlation system communicates with preprocessors and a debugger in a translation system to correlate symbols and code segments of an input user program with symbols and code segments of an output executable version of the program. The correlation system stores information relating to changes to symbols and code segments made by each preprocessor in input correlation tables associated with input files and output correlation tables associated with output files of each preprocessor. The information includes pointers that depict the translations of the symbols and code segments, and information which characterizes the translations as exact, inexact or name change correlations. When the user identifies a symbol or a code segment in an output file, the debugger extracts the symbol name and code segment information from the output correlation table to identify the corresponding symbol or code segment in the input file.

Correlation system

A memory analysis system analyzes memory 'events,' i.e., the allocation or deallocation of memory locations, associated with the execution of an application program and produces a graphic display associating dynamically allocated memory segments with various program sub-routines. The system communicates with a debugger to trace the memory allocation routines back through the source code version of the application program and produce a call-stack, which lists the various source code sub-routines associated with the allocation of the segment and makes available the applicable lines of the source code. The system assigns to each of these locations a segment type, which relates to a program sub-routine that calls for it. The system includes a kernel processor that replaces calls to memory allocation and deallocation routines in the program with substitute routines that include instructions to notify the kernel processor each time a memory event occurs. The kernel processor monitors the response from the operating system and sends to a main processor included in the system a message that indicates the type event, identifies the memory locations involved and includes related information from the debugger tables which identifies the associated source code sub-routines. The main processor then controls the graphic display of the information. The kernel and the main processors communicate through a section of global memory that is set up as one or more circular queues. The kernel processor suspends the execution of the application program whenever the memory event queue is full, to maintain the application program and the display in relative synchronism.

Memory analysis system for dynamically displaying memory allocation and

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Mason, NH, United States of America

Mark E Arsenault