Observer effect (information technology)
Encyclopedia
In information technology
, the observer effect is the potential impact of the act of observing a process output while the process is running. For example: if a process uses a log file to record its progress, the process could slow. Furthermore, the act of viewing the file while the process is running could cause an I/O error in the process, which could, in turn, cause it to stop.
Another example would be observing the performance of a CPU by running both the observed and observing programs on the same CPU, which will lead to inaccurate results because the observer program itself affects the CPU performance (modern, heavily cached and pipelined CPUs are particularly affected by this kind of observation).
Observing (or rather, debugging
) a running program by modifying its source code (such as adding extra output or generating log files) or by running it in a debugger
may sometimes cause certain bug
s to diminish or change their behavior, creating extra difficulty for the person trying to isolate the bug (see Heisenbug).
Information technology
Information technology is the acquisition, processing, storage and dissemination of vocal, pictorial, textual and numerical information by a microelectronics-based combination of computing and telecommunications...
, the observer effect is the potential impact of the act of observing a process output while the process is running. For example: if a process uses a log file to record its progress, the process could slow. Furthermore, the act of viewing the file while the process is running could cause an I/O error in the process, which could, in turn, cause it to stop.
Another example would be observing the performance of a CPU by running both the observed and observing programs on the same CPU, which will lead to inaccurate results because the observer program itself affects the CPU performance (modern, heavily cached and pipelined CPUs are particularly affected by this kind of observation).
Observing (or rather, debugging
Debugging
Debugging is a methodical process of finding and reducing the number of bugs, or defects, in a computer program or a piece of electronic hardware, thus making it behave as expected. Debugging tends to be harder when various subsystems are tightly coupled, as changes in one may cause bugs to emerge...
) a running program by modifying its source code (such as adding extra output or generating log files) or by running it in a debugger
Debugger
A debugger or debugging tool is a computer program that is used to test and debug other programs . The code to be examined might alternatively be running on an instruction set simulator , a technique that allows great power in its ability to halt when specific conditions are encountered but which...
may sometimes cause certain bug
Software bug
A software bug is the common term used to describe an error, flaw, mistake, failure, or fault in a computer program or system that produces an incorrect or unexpected result, or causes it to behave in unintended ways. Most bugs arise from mistakes and errors made by people in either a program's...
s to diminish or change their behavior, creating extra difficulty for the person trying to isolate the bug (see Heisenbug).