Unit 12 Data Processing

Data processing is any computer process that converts data into information or knowledge. The processing is usually assumed to be automated and running on a computer. Because data are most useful when well-presented and actually informative, data-processing systems are often referred to as information systems to emphasize their practi- cality. Nevertheless, both terms are roughly synonymous, performing similar conversions; data-processing systems typically manipulate raw data into information, and likewise information systems typically take raw data as input to produce information as output.

Data are defined as numbers or characters that represent meas- urements from observable phenomena. A single datum is a single measurement from observable phenomena. Measured information is then algorithmically derived and/or logically deduced and/or statisti- cally calculated from multiple data. Information is defined as either a meaningful answer to a query or a meaningful stimulus that can cascade into further queries.

For example gathering seismic data leads to alteration of seismic data to suppress noise, enhance signal and migrate seismic events to the appropriate location in space. Processing steps typically include analysis of velocities and frequencies, static corrections, deconvolu- tion, normal moveout, dip moveout, stacking, and migration, which can be performed before or after stacking. Seismic processing facili- tates better interpretation because subsurface structures and reflection geometries are more apparent.

174

More generally, the term «data processing» can apply to any process that converts data from one format to another, although data conversion would be the more logical and correct term. From this perspective, data processing becomes the process of converting infor- mation into data and also the converting of data back into information. The distinction is that conversion doesn't require a question (query) to be answered. For example, information in the form of a string of characters forming a sentence in English is converted or encoded meaningless hardware-oriented data to evermore-meaningful informa- tion as the processing proceeds toward the human being.

Embedded System

Conversely, that simple example for pedagogical purposes here is usually described as an embedded system (for the software resident in the keyboard itself) or as (operating-systems programming, because the information is derived from a hardware interface and may involve overt control of the hardware through that interface by an operating system. Typically control of hardware by a device driver manipulating ASIC or FPGA registers is not viewed as part of data processing proper or information systems proper, but rather as the domain of embed- ded systems or (operating-)systems programming. Instead, perhaps a more conventional example of the established practice of using the term data processing is that a business has collected numerous data concerning an aspect of its operations and that this multitude of data must be presented in meaningful, easy-to-access presentations for the managers who must then use that information to increase revenue or to decrease cost. That conversion and presentation of data as information is typically performed by a data-processing application.

Data Analysis

When the domain from which the data are harvested is a sci- ence or an engineering, data processing and infonnation systems are considered too broad of terms and the more specialized term data analysis is typically used, focusing on the highly-specialized and highly-accurate algorithmic derivations and statistical calcula- tions that are less often observed in the typical general business environment. In these contexts data analysis packages like DAP, gretl or PSPP are often used. This divergence of culture is exhibited in the typical numerical representations used in data processing

—175-—

versus numerical; data processing's measurements are typically represented by integers or by fixed-point or binary-coded decimal representations of numbers whereas the majority of data analysis's measurements are often represented by floating-point representa- tion of rational numbers.

Processing

Practically all naturally occurring processes can be viewed as examples of data processing systems where «observable» information in the form of pressure, light, etc. are converted by human observ- ers into electrical signals in me nervous system as the senses we recognize as touch, sound, and vision. Even the interaction of non- living systems may be viewed in this way as rudimentary information processing systems. Conventional usage of the terms data processing and information systems restricts their use to refer to the algorithmic derivations, logical deductions, and statistical calculations that recur perennially in general business environments, rather man in the more expansive sense of all conversions of real-world measurements into real-world information in, say, an organic biological system or even a scientific or engineering system.

In data processing or information processing, a data processing system or data processing unit or data processor is a system which processes data which has been captured and encoded in a format recognizable by the data processing system or has been created and stored by another unit of an information processing system.