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Data logging

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Data logging is the practice of recording sequential data, often chronologically.

1 Etymology
2 Computer data logging
3 Automotive data logging
4 See also
5 References
6 Sources
7 External links

Etymology

To log is a verbed derivative of the noun logbook; the verb form means to record in a logbook, and may have been coined in the 1820s. The term logbook itself stems from the practice of floating a stationary "log" (actually a wooden block attached to a reel via rope) to provide a fixed point of reference for the purpose of measuring a ship's speed (see Knot (speed)). Computer scientists adopted the verb to log circa 1963 to describe the systematic recording of specific types of data processing events.

Computer data logging

Main article: Computer data logging

In computerized data logging, a computer program may automatically record events in a certain scope in order to provide an audit trail that can be used to diagnose problems. Examples of physical systems which have logging subsystems include process control systems, and the black box recorders installed in aircraft. Many operating systems and multitudinous computer programs include some form of logging subsystem. Some operating systems provide a syslog service (described in RFC 3164), which allows the filtering and recording of log messages to be performed by a separate dedicated subsystem, rather than placing the onus on each application to provide its own ad hoc logging system. In many cases, the logs are not esoteric and hard to understand; they need to be subjected to log analysis in order to make sense of them. It can be useful to combine log file entries from multiple sources. This approach, in combination with statistical analysis, may yield correlations between seemingly-unrelated events on different servers. Other solutions employ network-wide querying and reporting.

Automotive data logging

The performance characteristics of a car can be monitored through its diagnostic port. There are several ways to do this; one way is by using a hand-held device with software already installed and the appropriate cable to hook into the diagnostic port. Another method is to use a PDA loaded with specialized software and employ a special cable that plugs into the diagnostic port. Finally, a PC can be used, laptops generally work best, using specialized software and connecting it to the car with a specially-made cable. Data logging a car allows one to observe how well the car is running. A data logger can be used to help tune the car, especially if modifications have been made to the vehicle. The reason it helps is that it logs various parameters in the engine such as ignition timing, injector pulse, RPM, knock/detonation, barometer pressure, temperature, oxygen sensors, and various other sensor data. Using the information that is provided (and either some sort of piggy-back or standalone system), a user can change the injector pulse width so that the engine is fed more or less fuel, increase or decrease ignition timing, and other changes. Such changes are made to make the car run more reliably or achieve higher performance.