Wednesday, December 29, 2010

Computer science

Computer science or computing science (sometimes abbreviated CS) is the study of the theoretical foundations of information and computation and of practical techniques for their implementation and application in computer systems. It is frequently described as the systematic study of algorithmicprocesses that create, describe, and transform information (Dell XPS M1210 Battery) http://www.hdd-shop.co.uk .

Computer science has many sub-fields; some, such as computer graphics, emphasize the computation of specific results, while others, such as computational complexity theory, study the properties of computational problems. Still others focus on the challenges in implementing computations (Dell Studio XPS 1340 Battery) .

For example, programming language theory studies approaches to describe computations, while computer programming applies specific programming languages to solve specific computational problems, and human-computer interaction focuses on the challenges in making computers and computations useful, usable, and universally accessible to people (Dell Studio XPS 1640 Battery) .

The general public sometimes confuses computer science with careers that deal with computers (such as information technology), or think that it relates to their own experience of computers, which typically involves activities such as gaming, web-browsing, and word-processing (Dell Vostro 1710 Battery) .

However, the focus of computer science is more on understanding the properties of the programs used to implement software such as games and web-browsers, and using that understanding to create new programs or improve existing ones (Dell KM958 battery) .

History

The early foundations of what would become computer science predate the invention of the modern digital computer. Machines for calculating fixed numerical tasks, such as the abacus, have existed since antiquity (Sony VGP-BPS13 battery) .

Wilhelm Schickard designed the first mechanical calculator in 1623, but did not complete its construction. Blaise Pascal designed and constructed the first working mechanical calculator, the Pascaline, in 1642. Charles Babbage designed adifference engine in Victorian times helped by Ada Lovelace (Sony VGP-BPS13/B battery) .

Around 1900, punch-card machines were introduced. However, all of these machines were constrained to perform a single task, or at best some subset of all possible tasks.

During the 1940s, as newer and more powerful computing machines were developed, the term computer came to refer to the machines rather than their human predecessors (Sony VGP-BPS13/S battery) .

As it became clear that computers could be used for more than just mathematical calculations, the field of computer science broadened to study computation in general. Computer science began to be established as a distinct academic discipline in the 1950s and early 1960s (Sony VGP-BPS13A/B battery) .

The first computer science degree program in the United States was formed at Purdue University in 1962. Since practical computers became available, many applications of computing have become distinct areas of study in their own right (Sony VGP-BPS13B/B battery) .

Although many initially believed it was impossible that computers themselves could actually be a scientific field of study, in the late fifties it gradually became accepted among the greater academic population. It is the now well-known IBM brand that formed part of the computer science revolution during this time (Sony VGP-BPL9 battery) .

IBM (short for International Business Machines) released the IBM 704 and later the IBM 709 computers, which were widely used during the exploration period of such devices. "Still, working with the IBM [computer] was frustrating...if you had misplaced as much as one letter in one instruction, the program would crash, and you would have to start the whole process over again" (Sony VGP-BPS13B/B battery) .

During the late 1950s, the computer science discipline was very much in its developmental stages, and such issues were commonplace.

Time has seen significant improvements in the usability and effectiveness of computer science technology (Sony VGP-BPL15 battery) .

Modern society has seen a significant shift from computers being used solely by experts or professionals to a more widespread user base. Initially, computers were quite costly, and for their most-effective use, some degree of human aid was needed, in part by professional computer operators (Dell Inspiron E1505 battery) .

However, as computers became widespread and far more affordable, less human assistance was needed, although residues of the original assistance still remained.

Major achievements

The German military used the Enigma machine (shown here) during World War IIfor communication they thought to be secret (Dell Latitude E6400 battery) .

The large-scale decryption of Enigma traffic at Bletchley Park was an important factor that contributed to Allied victory in WWII.

Despite its short history as a formal academic discipline, computer science has made a number of fundamental contributions to science and society (HP Pavilion dv6000 Battery) .

These include:

  • The start of the "digital revolution," which includes the current Information Age and the Internet.
  • A formal definition of computation and computability, and proof that there are computationally unsolvable and intractable problems (SONY VAIO VGN-FZ Battery) .
  • The concept of a programming language, a tool for the precise expression of methodological information at various levels of abstraction (SONY VAIO VGN-FZ18 Battery) .
  • In cryptography, breaking the Enigma machine was an important factor contributing to the Allied victory in World War II.
  • Scientific computing enabled practical evaluation of processes and situations of great complexity, as well as experimentation entirely by software (SONY VAIO VGN-FZ180E Battery) .
  • It also enabled advanced study of the mind, and mapping of the human genome became possible with the Human Genome Project. Distributed computingprojects such as Folding@home explore protein folding (SONY VAIO VGN-FZ220E Battery) .
  • Algorithmic trading has increased the efficiency and liquidity of financial markets by using artificial intelligence, machine learning, and other statistical andnumerical techniques on a large scale.
  • Image synthesis, including video by computing individual video frames (SONY VAIO VGN-FZ340E Battery) .
  • Human language processing, including practical speech-to-text conversion and automated translation of languages
  • Simulation of various processes, including computational fluid dynamics, physical, electrical, and electronic systems and circuits, as well as societies and social situations (notably war games) along with their habitats, among many others (SONY VAIO VGN-FZ430E Battery) .
  • Modern computers enable optimization of such designs as complete aircraft. Notable in electrical and electronic circuit design are SPICE as well as software for physical realization of new (or modified) designs. The latter includes essential design software for integrated circuits (SONY VAIO VGN-FZ460E Battery) .

Areas of computer science

As a discipline, computer science spans a range of topics from theoretical studies of algorithms and the limits of computation to the practical issues of implementing computing systems in hardware and software (SONY VAIO VGN-FZ480E Battery) .

CSAB, formerly called Computing Sciences Accreditation Board – which is made up of representatives of the Association for Computing Machinery (ACM), and the IEEE Computer Society (IEEE-CS) – identifies four areas that it considers crucial to the discipline of computer science:theory of computation, algorithms and data structures, programming methodology and languages, and computer elements and architecture (SONY VAIO VGN-FZ4000 Battery) .

In addition to these four areas, CSAB also identifies fields such as software engineering, artificial intelligence, computer networking and communication, database systems, parallel computation, distributed computation, computer-human interaction, computer graphics, operating systems, and numerical and symbolic computation as being important areas of computer science (SONY VAIO VGN-FZ31E Battery) .

Theoretical computer science

The broader field of theoretical computer science encompasses both the classical theory of computation and a wide range of other topics that focus on the more abstract, logical, and mathematical aspects of computing (SONY VAIO VGN-FZ31B Battery) .

Theory of computation

According to Peter J. Denning, the fundamental question underlying computer science is, "What can be (efficiently) automated?" The study of the theory of computation is focused on answering fundamental questions about what can be computed and what amount of resources are required to perform those computations (SONY VAIO VGN-FZ31J Battery) .

In an effort to answer the first question, computability theory examines which computational problems are solvable on various theoretical models of computation. The second question is addressed by computational complexity theory, which studies the time and space costs associated with different approaches to solving a computational problem (SONY VAIO VGN-FZ31M Battery) .

The famous "P=NP?" problem, one of the Millennium Prize Problems, is an open problem in the theory of computation.

Multiprocessing

Multiprocessing is running a system with more than one processor (SONY VAIO VGN-FZ31Z Battery) .

The theory is of course that you can double performance by using two processors instead of one. And the reality of course is that it doesn't work this well, although multiprocessing can result in improved performance under certain conditions. In order to employ multiprocessing effectively, the computer system must have all of the following in place (SONY VAIO VGN-FZ38M Battery) :

Motherboard Support

A motherboard capable of handling multiple processors. This means additional sockets or slots for the extra chips, and a chipset capable of handling the multiprocessing arrangement SONY VGP-BPS8 Battery .

Processor Support

Processors that are capable of being used in a multiprocessing system. Not all are, and in fact some versions of the same processor are while others are not SONY VGP-BPS13 Battery .

Operating System Support

An operating system that supports multiprocessing, such as Windows NT or one of the various flavors of UNIX SONY VGP-BPS13/S Battery .

Computational science

Computational science (or scientific computing) is the field of study concerned with constructing mathematical models and quantitative analysis techniques and using computers to analyse and solvescientific problems SONY VGP-BPS13A/B Battery .

In practical use, it is typically the application of computer simulation and other forms of computation to problems in various scientific disciplines SONY VGP-BPS13B/B Battery .

Artificial Intelligence

This branch of computer science aims to create synthetic systems which solve computational problems, reason and/or communicate like animals and humans do SONY VGP-BPS13A/S Battery .

This theoretical and applied subfield requires a very rigorous and integrated expertise in multiple subject areas such as applied mathematics, logic, semiotics, electrical engineering, philosophy of mind, neurophysiology, and social intelligence which can be used to advance the field of intelligence research or be applied to other subject areas which require computational understanding and modelling such as in finance or thephysical sciences SONY VGP-BPS13AS Battery .

This field started in full earnest when Alan Turing, the pioneer of computer science and artificial intelligence, proposed the Turing Test for the purpose of answering the ultimate question... "Can computers think ?" (Dell Inspiron 1320n Battery) .

Software Systems

The field of software systems encompasses a wide range of sub-fields, which involve principled design and analysis of various kinds of software based systems (Dell Inspiron 1464 Battery) .

These fields use concepts and techniques from theoretical computer science, artificial intelligence, mathematics, electrical engineering, and so on to build software systems for various real world tasks (Dell Inspiron 1564 Battery) .

Paradigms

Following Peter Wegner, Amnon H. Eden proposes that there are three paradigms at work in various areas of computer science:

  • a "rationalist paradigm", which treats computer science as branch of mathematics, which is prevalent in theoretical computer science, and mainly employs deductive reasoning (Dell Inspiron 1764 Battery) ,
  • a "technocratic paradigm", readily identifiable with engineering approaches, most prominent in software engineering, and
  • a "scientific paradigm", which approaches computer-related artifacts from the empirical perspective of natural sciences, and identifiable in some branches of artificial intelligence (the study of artificial life for instance) (Dell Studio 1450 Battery) .

Relationship with other fields

Despite its name, a significant amount of computer science does not involve the study of computers themselves. Because of this, several alternative names have been proposed. Certain departments of major universities prefer the term computing science, to emphasize precisely that difference (Dell Studio 1457 Battery) .

Danish scientist Peter Naur suggested the term datalogy, to reflect the fact that the scientific discipline revolves around data and data treatment, while not necessarily involving computers. The first scientific institution to use the term was the Department of Datalogy at the University of Copenhagen, founded in 1969, with Peter Naur being the first professor in datalogy (Dell Latitude D610 Battery) .

The term is used mainly in the Scandinavian countries. Also, in the early days of computing, a number of terms for the practitioners of the field of computing were suggested in the Communications of the ACMturingineer, turologist, flow-charts-man, applied meta-mathematician, and applied epistemologist (Toshiba NB100 Battery) .

Three months later in the same journal, comptologist was suggested, followed next year by hypologist. The term computics has also been suggested. In continental Europe, names such asinformatique (French), Informatik (German) or informatica (Dutch), derived from information and possibly mathematics or automatic, are more common than names derived from computer/computation (Toshiba Satellite M65 battery) .

The renowned computer scientist Edsger Dijkstra stated, "Computer science is no more about computers than astronomy is about telescopes." The design and deployment of computers and computer systems is generally considered the province of disciplines other than computer science (Toshiba Satellite M60 battery) .

For example, the study of computer hardware is usually considered part of computer engineering, while the study of commercial computer systems and their deployment is often called information technology or information systems. However, there has been much cross-fertilization of ideas between the various computer-related disciplines (Dell Latitude D830 Battery) .

Computer science research has also often crossed into other disciplines, such as philosophy, cognitive science, linguistics,

mathematics, physics, statistics, andeconomics.Computer science is considered by some to have a much closer relationship with mathematics than many scientific disciplines, with some observers saying that computing is a mathematical science (Dell Latitude D620 Battery) .

Early computer science was strongly influenced by the work of mathematicians such as Kurt Gödel and Alan Turing, and there continues to be a useful interchange of ideas between the two fields in areas such as mathematical logic, category theory, domain theory, and algebra (Dell Inspiron Mini 10 Battery) .

The relationship between computer science and software engineering is a contentious issue, which is further muddied by disputes over what the term "software engineering" means, and how computer science is defined. David Parnas, taking a cue from the relationship between other engineering and science disciplines (Sony VGN-FW11S Battery) ,

has claimed that the principal focus of computer science is studying the properties of computation in general, while the principal focus of software engineering is the design of specific computations to achieve practical goals, making the two separate but complementary disciplines (Sony VGN-FW11M Battery) .

The academic, political, and funding aspects of computer science tend to depend on whether a department formed with a mathematical emphasis or with an engineering emphasis. Computer science departments with a mathematics emphasis and with a numerical orientation consider alignment with computational science (Sony VGN-FW139E/H battery) .

Both types of departments tend to make efforts to bridge the field educationally if not across all research.

Computer science education

Some universities teach computer science as a theoretical study of computation and algorithmic reasoning (Dell Latitude E5400 Battery) .

These programs often feature the theory of computation, analysis of algorithms, formal methods, concurrency theory, databases, computer graphics, and systems analysis, among others. They typically also teach computer programming, but treat it as a vessel for the support of other fields of computer science rather than a central focus of high-level study (Dell Latitude E4200 Battery) .

Other colleges and universities, as well as secondary schools and vocational programs that teach computer science, emphasize the practice of advanced programming rather than the theory of algorithms and computation in their computer science curricula. Such curricula tend to focus on those skills that are important to workers entering the software industry (Dell Vostro A840 Battery) .

The practical aspects of computer programming are often referred to as software engineering. However, there is a lot of disagreement over the meaning of the term, and whether or not it is the same thing as programming (Dell Inspiron 300M Battery) .

A computer scientist is a scientist who has acquired knowledge of computer science, the study of the theoretical foundations of information and computation and their application in computersystems (Dell Studio 1737 battery) .

Computer scientists typically work on the theoretical side of computer systems, as opposed to the hardware side that computer engineers mainly focus on (although there is overlap). Although computer scientists can also focus their work and research on specific areas (such as algorithm development and design (Dell Inspiron E1505 battery) ,

software engineering, information theory, database theory, computational complexity theory, human-computer interaction, computer programming, programming language theory, computer graphics, and computer vision), their foundation is the theoretical study of computing from which these other fields derive (Dell RM791 battery) .

Computer scientists typically have some kind of degree in computer science.

As its name implies, computer science is a pure science, not an applied science or applied business field. As an analogy to the medical field, a computer scientist is like the cancer researcher who might study molecular biology or biochemistry in-depth (Dell XPS M1530 battery) ,

while an information technology specialist is like the physician who studies those fields at a higher level and focuses on their application to patient care.

Computer scientists can follow more practical applications of their knowledge, doing things such as software development, web development, and database programming (Dell XPS M2010 battery) .

Computer scientists can also be found in the field of information technology consulting. Computer scientists can also be seen as a type of mathematician, seeing as how much of the field is dependent on mathematics itself (Acer Aspire One battery) .

Informatics is the science of information, the practice of information processing, and the engineering of information systems. Informatics studies the structure, algorithms, behavior, and interactions of natural and artificial systems that store, process, access and communicate information (Toshiba Satellite P10 Battery) .

It also develops its own conceptual and theoretical foundations and utilizes foundations developed in other fields. Since the advent of computers, individuals and organizations increasingly process information digitally. This has led to the study of informatics that has computational, cognitive and social aspects, including study of the social impact of information technologies (SONY VGN-FZ210CE Battery) .

Etymology

In 1957 the German computer scientist Karl Steinbuch coined the word Informatik by publishing a paper called Informatik: Automatische Informationsverarbeitung ("Informatics: Automatic Information Processing") (Dell Precision M70 Battery) .

The English term Informatics is sometimes understood as meaning the same as computer science. However, the German word Informatik is the correct translation of English computer science

The French term informatique was coined in 1962 by Philippe Dreyfus together with various translations—informatics (English) (Toshiba Satellite L305 Battery) ,

also proposed independently and simultaneously by Walter F. Bauerand associates who co-founded Informatics Inc., and informatica (Italian, Spanish, Romanian, Portuguese, Dutch), referring to the application of computers to store and process information (Toshiba Satellite T4900 Battery) .

The term was coined as a combination of "information" and "automatic" to describe the science of automating information interactions. The morphology—informat-ion + -ics—uses "the accepted form for names of sciences, as conics, linguistics, optics, or matters of practice, as economics (Toshiba PA3399U-2BRS battery) ,

politics, tactics", and so, linguistically, the meaning extends easily to encompass both the science of information and the practice of information processing.

The naming for computer science is derived from the concept of computation which may or may not involve the existence of information (Toshiba Satellite A200 Battery) .

For example, quantum computation and digital logic do not involve information.

History

This new term was adopted across Western Europe, and, except in English, developed a meaning roughly translated by the English ‘computer science’, or ‘computing science’ (Toshiba Satellite 1200 Battery) .

Mikhailov et al. advocated the Russian term informatika (1966), and the English informatics (1967), as names for the theory of scientific information, and argued for a broader meaning, including study of the use of information technology in various communities (for example, scientific) and of the interaction of technology and human organizational structures (Toshiba Satellite M300 Battery) .

Informatics is the discipline of science which investigates the structure and properties (not specific content) of scientific information, as well as the regularities of scientific information activity, its theory, history, methodology and organization.

Usage has since modified this definition in three ways (Sony Vaio PCG-5G2L Battery) .

First, the restriction to scientific information is removed, as in business informatics or legal informatics. Second, since most information is now digitally stored, computation is now central to informatics. Third, the representation, processing and communication of information are added as objects of investigation Sony Vaio PCG-5G3L Battery ,

since they have been recognized as fundamental to any scientific account of information. Taking information as the central focus of study, then, distinguishes informatics, which includes study of biological and social mechanisms of information processing, from computer science, where digital computation plays a distinguished central role Sony Vaio PCG-5J1L Battery .

Similarly, in the study of representation and communication, informatics is indifferent to the substrate that carries information. For example, it encompasses the study of communication using gesture, speech and language, as well as digital communications and networking Sony Vaio PCG-5K2L Battery .

The first example of a degree level qualification in Informatics occurred in 1982 when Plymouth Polytechnic (now the University of Plymouth) offered a four year BSc(Honours) degree in Computing and Informatics – with an initial intake of only 35 students. The course still runs today making it the longest available qualification in the subject Sony Vaio PCG-5J2L Battery .

A broad interpretation of informatics, as "the study of the structure, algorithms, behaviour, and interactions of natural and artificial computational systems," was introduced by the University of Edinburghin 1994 when it formed the grouping that is now its School of Informatics. This meaning is now (2006) increasingly used in the United Kingdom Sony Vaio PCG-5K1L Battery .

Informatics encompasses the study of systems that represent, process, and communicate information. However, the theory of computation in the specific discipline of theoretical computer sciencewhich evolved from Alan Turing studies the notion of a complex system regardless if information actually exists Sony Vaio PCG-5L1L Battery .

Since both fields process information, there is some disagreement among scientists as to field hierarchy; for example Arizona State University attempted to adopt a broader definition of informatics to even encompass cognitive science at the launch of its School of Computing and Informatics in September 2006 Sony Vaio PCG-6S2L Battery .

The confusion arises since information can be easily stored on a computer and hence informatics could be considered the parent of computer science. However, the original notion of a computer was the name given to the action of computation regardless of the existence of information or the existence of a von neumann architecture Sony Vaio PCG-6S3L Battery .

Humans are examples of computational systems and not information systems. Many fields such as quantum computing theory are studied in theoretical computer science but not related to informatics.

The 2008 Research Assessment Exercise, of the UK Funding Councils, includes a new, Computer Science and Informatics, unit of assessment (UoA), whose scope is described as follows Sony Vaio PCG-6V1L Battery :

The UoA includes the study of methods for acquiring, storing, processing, communicating and reasoning about information, and the role of interactivity in natural and artificial systems, through the implementation, organisation and use of computer hardware, software and other resources Sony Vaio PCG-6W1L Battery .

The subjects are characterised by the rigorous application of analysis, experimentation and design.

At the Indiana University School of Informatics (Bloomington, Indianapolis and Southeast), informatics is defined as "the art, science and human dimensions of information technology" and "the study, application, and social consequences of technology Sony Vaio PCG-6W2L Battery .

" It is also defined in Informatics I101, Introduction to Informatics as "the application of information technology to the arts, sciences, and professions." These definitions are widely accepted in the United States, and differ from British usage in omitting the study of natural computation Sony Vaio PCG-6W3L Battery .

At the University of California, Irvine Department of Informatics, informatics is defined as "the interdisciplinary study of the design, application, use and impact of information technology. The discipline of informatics is based on the recognition that the design of this technology is not solely a technical matter Sony Vaio PCG-7111L Battery ,

but must focus on the relationship between the technology and its use in real-world settings. That is, informatics designs solutions in context, and takes into account the social, cultural and organizational settings in which computing and information technology will be used Sony Vaio PCG-7112L Battery ."

At the University of Michigan, Ann Arbor Informatics interdisciplinary major, informatics is defined as "the study of information and the ways information is used by and affects human beings and social systems. Key to this growing field is that it applies both technological and social perspectives to the study of information Sony Vaio PCG-7113L Battery .

Michigan's interdisciplinary approach to teaching Informatics gives you a solid grounding in contemporary computer programming, mathematics, and statistics, combined with study of the ethical and social science aspects of complex information systems. Experts in the field help design new information technology tools for specific scientific, business, and cultural needs Sony Vaio PCG-7133L Battery ."

In the English-speaking world the term informatics was first widely used in the compound, ‘medical informatics’, taken to include "the cognitive, information processing, and communication tasks of medical practice, education, and research, including information science and the technology to support these tasks" Sony Vaio PCG-7Z1L Battery .

Many such compounds are now in use; they can be viewed as different areas of applied informatics.

One of the most significant areas of applied informatics is that of organisational informatics Sony Vaio PCG-7Z2L Battery .

Organisational informatics is fundamentally interested in the application of information, information systems and ICT within organisations of various forms including private sector, public sector and voluntary sector organisations. As such, organisational informatics can be seen to be sub-category of social informatics and a super-category of business informatics Sony Vaio PCG-8Y1L Battery .

A practitioner of informatics may be called an informatician or an informaticist.

In 1989, the first International Olympiad in Informatics (IOI) was held in Bulgaria. The olympiad involves two days of intense competition for five hours each day Sony Vaio PCG-8Y2L Battery .

Four students are selected from each participating country to attend and compete for Gold, Silver and Bronze medals. The 2008 IOI was held in Cairo, Egypt.

Information science is an interdisciplinary science primarily concerned with the analysis, collection, classification, manipulation, storage, retrieval and dissemination of information Sony Vaio PCG-8Z1L Battery .

Practitioners within the field study the application and usage of knowledge in organizations, along with the interaction between people, organizations and any existing information systems, with the aim of creating, replacing, improving or understanding information systems Sony Vaio PCG-8Z2L Battery .

Information science is often (mistakenly) considered a branch of computer science. However, it is actually a broad, interdisciplinary field, incorporating not only aspects of computer science, but often diverse fields such as archival science, cognitive science, commerce, communications, law, library science,museology, management, mathematics, philosophy, public policy, and the social sciences Sony VAIO PCG-5G2L Battery .

Information science focuses on understanding problems from the perspective of the stakeholders involved and then applying information and other technologies as needed. In other words, it tackles systemic problems first rather than individual pieces of technology within that system Sony VAIO PCG-5G3L Battery .

In this respect, information science can be seen as a response to technological determinism, the belief that technology "develops by its own laws, that it realizes its own potential, limited only by the material resources available, and must therefore be regarded as an autonomous system controlling and ultimately permeating all other subsystems of society Sony VAIO PCG-5J1L Battery .

" Within information science, attention has been given in recent years to human–computer interaction,groupware, the semantic web, value sensitive design, iterative design processes and to the ways people generate, use and find information. Today this field is called the Field of Information, and there are a growing number of Schools and Colleges of Information Sony VAIO PCG-5K2L Battery .

Information science should not be confused with information theory, the study of a particular mathematical concept of information, or with library science, a field related to libraries which uses some of the principles of information science Sony VAIO PCG-5J2L Battery .

Definitions of information science

Information Science consists of having the knowledge and understanding on how to collect, classify, manipulate, store, retrieve and disseminate any type of information Sony VAIO PCG-5K1L Battery .

Some authors treat informatics as a synonym for information science, especially related to the concept developed by A. I. Mikhailov and other Soviet authors in the mid sixties, which suggested that informatics is a discipline related to the study of Scientific Information Sony VAIO PCG-5L1L Battery .

Because of the rapidly evolving, interdisciplinary nature of informatics, a precise meaning of the term "informatics" is presently difficult to pin down.

Regional differences and international terminology complicate the problem Sony VAIO PCG-6S2L Battery .

Some people note that much of what is called "Informatics" today was once called "Information Science" at least in fields such as Medical Informatics. For example, when library scientists began also to use the phrase "Information Science" to refer to their work, the term informatics emerged Sony VAIO PCG-6S3L Battery :

  • in the United States as a response by computer scientists to distinguish their work from that of library science, and
  • in Britain as a term for a science of information that studies natural, as well as artificial or engineered, information-processing systems Sony VAIO PCG-6V1L Battery .

History

Early beginnings

Information science, in studying the collection, classification, manipulation, storage, retrieval and dissemination of information has origins in the common stock of human knowledge Sony VAIO PCG-6W1L Battery .

Information analysis has been carried out by scholars at least as early as the time of the Abyssinian Empire with the emergence of cultural depositories, what is today known as libraries and archives. Institutionally, information science emerged in the 19th century along with many other social science disciplines Sony VAIO PCG-6W2L Battery .

As a science, however, it finds its institutional roots in the history of science, beginning with publication of the first issues of Philosophical Transactions, generally considered the first scientific journal, in 1665 by the Royal Society (London).

The institutionalization of science occurred throughout the 18th Century Sony VAIO PCG-6W3L Battery .

In 1731, Benjamin Franklin established the Library Company of Philadelphia, the first library owned by a group of public citizens, which quickly expanded beyond the realm of books and became a center of scientific experiment, and which hosted public exhibitions of scientific experiments Sony VAIO PCG-7111L Battery .

Benjamin Franklin did invest a town in Massachusetts with a collection of books that the town voted to make available to all free of charge, which formed the first Public Library. Academie de Chirurgia (Paris) published Memoires pour les Chirurgiens, generally considered to be the first medical journal, in 1736 Sony VAIO PCG-7112L Battery .

The American Philosophical Society, patterned on the Royal Society (London), was founded in Philadelphia in 1743. As numerous other scientific journals and societies are founded, Alois Senefelder develops the concept of lithography for use in mass printing work in Germany in 1796 Sony VAIO PCG-7113L Battery .

19th century

By the 19th Century the first signs of information science emerged as separate and distinct from other sciences and social sciences but in conjunction with communication and computation. In 1801, Joseph Marie Jacquard invented a punched card system to control operations of the cloth weaving loom in France Sony VAIO PCG-7133L Battery .

It was the first use of "memory storage of patterns" system.As chemistry journals emerged throughout the 1820s and 1830s, Charles Babbage developed his "difference engine," the first step towards the modern computer, in 1822 and his "analytical engine” by 1834Sony VAIO PCG-7Z1L Battery .

By 1843 Richard Hoe developed the rotary press, and in 1844 Samuel Morse sent the first public telegraph message. By 1848 William F. Poole begins the Index to Periodical Literature, the first general periodical literature index in the US.

In 1854 George Boole published An Investigation into Laws of Thought..., which lays the foundations for Boolean algebra, which is later used in information retrieval Sony VAIO PCG-7Z2L Battery .

In 1860 a congress is held at Karlsruhe Technische Hochschule to discuss the feasibility of establishing a systematic and rational nomenclature for chemistry. The congress does not reach any conclusive results, but several key participants return home with Stanislao Cannizzaro's outline (1858), which ultimately convinces them of the validity of his scheme for calculating atomic weightsSony VAIO PCG-8Y1L Battery .

By 1865 the Smithsonian Institution began a catalog of current scientific papers, which became the International Catalogue of Scientific Papers in 1902. The following year the Royal Society began publication of its Catalogue of Papers in London. In 1868, Christopher Sholes, Carlos Glidden, and S. W Sony VAIO PCG-8Y2L Battery .

Soule produced the first practical typewriter. By 1872 Lord Kelvin devised an analogue computer to predict the tides, and by 1875 Frank Stephen Baldwin was granted the first US patent for a practical calculating machine that performs four arithmetic functions Sony VAIO PCG-8Z1L Battery .

Alexander Graham Bell and Thomas Edison invented the telephone and phonograph in 1876 and 1877 respectively, and the American Library Association was founded in Philadelphia. In 1879 Index Medicus was first issued by the Library of the Surgeon General, U.S Sony VAIO PCG-8Z2L Battery .

Army, with John Shaw Billings as librarian, and later the library issues Index Catalogue, which achieved an international reputation as the most complete catalog of medical literature WD passport essential (500GB/640GB) .

European documentation

The discipline of European Documentation, which marks the earliest theoretical foundations of modern information science, emerged in the late part of the 19th Century together with several more scientific indexes whose purpose was to organize scholarly literature WD passport essential (250GB/320GB) .

Most information science historians cite Paul Otlet and Henri La Fontaine as the fathers of information science with the founding of the International Institute of Bibliography (IIB) in 1895. A second generation of European Documentalists emerged after the Second World War, most notably Suzanne Briet WD passport essential SE (750GB/1TB) .

However, "information science" as a term is not popularly used in academia until sometime in the latter part of the 20th Century.

Documentalists emphasized the utilitarian integration of technology and technique toward specific social goals WD passport elite(250GB/320GB) .

According to Ronald Day, "As an organized system of techniques and technologies, documentation was understood as a player in the historical development of global organization in modernity – indeed, a major player inasmuch as that organization was dependent on the organization and transmission of information WD passport elite(500GB/640GB) ."

Otlet and Lafontaine (who won the Nobel Prize in 1913) not only envisioned later technical innovations but also projected a global vision for information and information technologies that speaks directly to postwar visions of a global "information society WD passport studio for Mac(320GB/500GB) .

" Otlet and Lafontaine established numerous organizations dedicated to standardization, bibliography, international associations, and consequently, international cooperation. These organizations were fundamental for ensuring international production in commerce WD passport studio for Mac(500GB/640GB) ,

information, communication and modern economic development, and they later found their global form in such institutions as the League of Nations and the United Nations. Otlet designed the Universal Decimal Classification, based onMelville Dewey’s decimal classification system WD Elements series(250GB/320GB) .

Although he lived decades before computers and networks emerged, what he discussed prefigured what ultimately became the World Wide Web. His vision of a great network of knowledge focused ondocuments and included the notions of hyperlinks, search engines, remote access, and social networks WD Elements SE(500GB/640GB) .

Otlet not only imagined that all the world's knowledge should be interlinked and made available remotely to anyone, but he also proceeded to build a structured document collection WD Elements SE(750GB/1TB) .

This collection involved standardized paper sheets and cards filed in custom-designed cabinets according to a hierarchical index (which culled information worldwide from diverse sources) and a commercial information retrieval service (which answered written requests by copying relevant information from index cards) WD Elements desktop(500GB/640GB) .

Users of this service were even warned if their query was likely to produce more than 50 results per search. By 1937 documentation had formally been institutionalized, as evidenced by the founding of the American Documentation Institute (ADI), later called the American Society for Information Science and Technology WD Elements desktop(750GB/1TB) .

Transition to modern information science

With the 1950s came increasing awareness of the potential of automatic devices for literature searching and information storage and retrieval. As these concepts grew in magnitude and potential, so did the variety of information science interests WD Elements desktop(1.5 TB/2TB) .

By the 1960s and 70s, there was a move from batch processing to online modes, from mainframe to mini and microcomputers. Additionally, traditional boundaries among disciplines began to fade and many information science scholars joined with library programs WD passport essential SE (750GB/1TB)--USB 3.0) .

They further made themselves multidisciplinary by incorporating disciplines in the sciences, humanities and social sciences, as well as other professional programs, such as law and medicine in their curriculum. By the 1980s, large databases, such as Grateful Med at the National Library of Medicine WD passport essential (500GB/640GB) ,

and user-oriented services such as Dialog and Compuserve, were for the first time accessible by individuals from their personal computers. The 1980s also saw the emergence of numerous special interest groups to respond to the changes. By the end of the decade, special interest groups were available involving non-print media WD passport for Mac(320GB/500GB) ,

social sciences, energy and the environment, and community information systems. Today, information science largely examines technical bases, social consequences, and theoretical understanding of online databases, widespread use of databases in government, industry, and education, and the development of the Internet and World Wide Web WD passport for Mac(640GB/1TB) .

Tuesday, December 28, 2010

Why does my computer need a battery?

Most computers have a small battery. In many cases, the battery is soldered directly onto the motherboard, but the battery is usually in some sort of holder so it is easy to replace. Computers are not the only things that have a small battery like this -- camcorders and digital cameras often have them, too (Dell XPS M1210 Battery) http://www.hdd-shop.co.uk .

Just about any gadget that keeps track of the time will have a battery.

How much you know about batteries and what they do? Test your knowledge with our Batteries Quiz (Dell Studio XPS 1340 Battery) !

In your computer (as well as other gadgets), the battery powers a chip called the Real Time Clock (RTC) chip. The RTC is essentially a quartz watch that runs all the time, whether or not the computer has power. The battery powers this clock. When the computer boots up, part of the process is to query the RTC to get the correct time and date (Dell Studio XPS 1640 Battery) .

A little quartz clock like this might run for five to seven years off of a small battery. Then it is time to replace the battery.

This does not explain why your computer would not boot, however. You would expect the computer to boot fine but have an incorrect time and date (Dell Vostro 1710 Battery) .

The reason your computer would not boot is because the RTC chip also contains 64 (or more) bytes of random access memory (RAM). The clock uses 10 bytes of this space, leaving 54 bytes for other purposes. The BIOS stores all sorts of information in the CMOS RAM area, like the number of floppy and hard disk drives, the hard disk drive type, etc (Dell KM958 battery) .

If the CMOS RAM loses power, the computer may not know anything about the hard disk configuration of your machine, and therefore it cannot boot.

Many more modern computers are not quite so dependent on the CMOS RAM (Sony VGP-BPS13 battery) .

They store the settings in non-volatile RAM that works without any power at all. If the battery goes dead, the clock fails but the computer can still boot using the information in the non-volatile RAM area (Sony VGP-BPS13/B battery) .

What is the difference between a normal lead-acid car battery and a deep cycle battery?

People who have recreational vehicles (RVs) and boats are familiar with deep cycle batteries. These batteries are also common in golf carts and large solar power systems (the sun produces power during the day and the batteries store some of the power for use at night) (Sony VGP-BPS13/S battery) .

If you have read the article How Emergency Power Systems Work, then you also know that an alternative to gasoline-powered generators is an inverter powered by one or more deep cycle batteries (Sony VGP-BPS13A/B battery) .

Both car batteries and deep cycle batteries are lead-acid batteries that use exactly the same chemistry for their operation (see How Batteries Work for more information). The difference is in the way that the batteries optimize their design (Sony VGP-BPS13B/B battery) :

A car's battery is designed to provide a very large amount of current for a short period of time. This surge of current is needed to turn the engine over during starting. Once the engine starts, the alternator provides all the power that the car needs, so a car battery may go through its entire life without ever being drained more than 20 percent of its total capacity (Sony VGP-BPL9 battery) .

Used in this way, a car battery can last a number of years. To achieve a large amount of current, a car battery uses thin plates in order to increase its surface area.

A deep cycle battery is designed to provide a steady amount of current over a long period of time (Sony VGP-BPS13B/B battery) .

A deep cycle battery can provide a surge when needed, but nothing like the surge a car battery can. A deep cycle battery is also designed to be deeply discharged over and over again (something that would ruin a car battery very quickly). To accomplish this, a deep cycle battery uses thicker plates (Sony VGP-BPL15 battery) .

A car battery typically has two ratings:

CCA (Cold Cranking Amps) - The number of amps that the battery can produce at 32 degrees F (0 degrees C) for 30 seconds (Dell Inspiron E1505 battery) .

RC (Reserve Capacity) - The number of minutes that the battery can deliver 25 amps while keeping its voltage above 10.5 volts

Typically, a deep cycle battery will have two or three times the RC of a car battery, but will deliver one-half or three-quarters the CCAs (Dell Latitude E6400 battery) .

In addition, a deep cycle battery can withstand several hundred total discharge/recharge cycles, while a car battery is not designed to be totally discharged.

How do the battery testers on battery packages work?

The little disposable battery testers that you see on batteries or battery packages are a great example of combined technologies -- several existing technologies have been combined in a completely new way (HP Pavilion dv6000 Battery) !

Battery testers depend on two special types of ink: thermochromic and conductive inks. Thermochromic ink changes color depending on its temperature. Conductive ink can conduct electricity. By applying layers of these special inks along with a layer of normal ink using a fairly normal printing press (SONY VAIO VGN-FZ Battery) ,

it is possible to create an extremely inexpensive printed design that changes depending on the amount of electricity it receives.

There are two types of thermochromic ink: liquid crystal and leucodye. Liquid crystal based thermochromic ink is sensitive to very small changes in temperature, but it is fairly difficult to manufacture (SONY VAIO VGN-FZ18 Battery) .

This makes it perfect for use in items like thermometers where you need the sensitivity, but troublesome in an item that needs to be inexpensive and in which a large, abrupt change in temperature will occur. Leucodyes are specially formulated substances that change from a specific color (SONY VAIO VGN-FZ180E Battery) ,

like blue, to a clear state when subjected to a temperature change of about 5 degrees F or more. Thermochromic inks can be formulated to change color at specific temperatures. For battery testers, the desired temperature is usually around 100-120 degrees F (SONY VAIO VGN-FZ220E Battery) .

To create a battery tester, you start with a layer of conductive ink that gets progressively narrower as you move across the tester from "good" to "bad." In the picture above the tester has 3 bars. In other testers the ink is wedge-shaped. The narrowest point indicates the weakest charge; the widest area indicates a full charge (SONY VAIO VGN-FZ340E Battery) .

When current passes through the thin layer of conductive ink, resistance in the ink creates heat. A small amount of current can generate enough heat to affect the smallest area of thermochromic ink; but, as the area widens, more current is needed to change colors (SONY VAIO VGN-FZ430E Battery) .

On top of the conductive ink is a layer of normal ink that conveys the design. In most battery testers, this is some type of "fuel gauge" graphic or text that indicates that a battery is good. The design can be anything, since the normal ink layer does not affect the way the conductive and thermochromic layers interact (SONY VAIO VGN-FZ460E Battery) .

Finally, there is the thermochromic layer. In the photo of the battery tester above, the thermochromic layer is black when cool. By touching a battery to the conductive ink on the back of the paper, a connection between the positive and negative terminals is created (SONY VAIO VGN-FZ480E Battery) .

As a current is generated, the thermochromic ink will turn clear. This reveals the design that is printed in normal ink. If there is enough current, most or all of the thermochromic ink will heat to the temperature needed to become translucent.

One question you might have right now is, "Doesn't the battery tester drain some of the battery's energy?" The answer is, "yes, but not enough to matter." If you tested the battery every 5 minutes it might be a problem, but most people don't do that (SONY VAIO VGN-FZ4000 Battery) .

One type of battery tester available now has the tester right on the battery. You press two small dots indicated on the battery to test it. These points complete a circuit between the battery and the tester, and electricity flows through the conductive ink in the same way as in the tester discussed above (SONY VAIO VGN-FZ31E Battery) .

the different ways to store energy besides using rechargeable batteries

Human beings have been looking for a good way to store energy for a long time. One of the major things that has been holding up electric cars is battery technology -- when you compare batteries to gasoline, the differences are huge (SONY VAIO VGN-FZ31B Battery) .

For example, a typical electric car might carry 1,000 pounds (454 kg) of lead-acid batteries. Those batteries take several hours to recharge, and might give the car a 100-mile (160-km) range. Two or 3 gallons of gasoline give the same range, weigh less than 30 pounds (13 kg), and you can pump that much gasoline in about a minute (SONY VAIO VGN-FZ31J Battery) .

Quiz Corner

How much you know about batteries and what they do? Test your knowledge with our Batteries Quiz!

Here is a list of other technologies that people commonly use to store energy. Some of these work in an electric car, while others are better for stationary applications (SONY VAIO VGN-FZ31M Battery) :

One of the oldest techniques people have used is the falling weight. You lift the weight to store the energy in it and then let the weight fall to extract the energy. Many grandfather clocks and cuckoo clocks use this technique. By running the string attached to the weights through a gear train, you can use a heavy weight and let it fall over a long period of time (SONY VAIO VGN-FZ31Z Battery) .

(See How Pendulum Clocks Work.) This approach doesn't work very well in an electric car, but it has worked well in clocks for hundreds of years (SONY VAIO VGN-FZ38M Battery) .

Many power plants use the "falling weight" approach in the form of water. The water is pumped uphill to a lake at night when the power plant has excess capacity. During high-demand daytime periods, the water runs through a turbine on its way downhill to a lower lake. (See How Hydropower Plants Work SONY VGP-BPS8 Battery .)

Another way to store energy is in some form of repeatable mechanical deformation. This is the idea behind a spring used in a wind-up clock or a rubber band used in a wind-up airplane. You store the energy by bending (deforming) the material in a spring, and the material releases the energy as it returns to its original shape SONY VGP-BPS13 Battery .

At the scale of a car, this technology has problems because of the weight of the spring, but at smaller scales (like a wristwatch) it works great. See also this page for an interesting example.

Nature has been storing energy for a long time, and if you want to think about it in this way, gasoline is really a form of stored energySONY VGP-BPS13/S Battery .

Plants absorb sunlight and turn it into carbohydrates (see How Food Works for a discussion of carbohydrates). Over millions of years, these carbohydrates can turn into oil or coal. On a more human time scale, we burn wood (which is a carbohydrate) to release stored energy, or turn corn into alcohol and burn the alcohol SONY VGP-BPS13A/B Battery .

Another technique that nature uses to store energy is fat, which many of us are familiar with in a personal way. It is interesting to think about a car that somehow eats grass or some other carbohydrate and stores it as fat SONY VGP-BPS13B/B Battery .

You can take energy and split water into its hydrogen and oxygen atoms using electrolysis. By storing the hydrogen and oxygen in tanks, you can later create energy by burning it, or (more efficiently) by running it through a fuel cell (see How Fuel Cells Work) SONY VGP-BPS13A/S Battery .

You can use the energy to spin up a flywheel and then later extract the energy by using the flywheel to run a generator. This patent has lots of information.

You can store heat directly and later convert the heat to another form of energy like electricity SONY VGP-BPS13AS Battery .

This page discusses some of NASA's experiments in this area.

You can use compressed air to store energy. Toys like the Air Hog store energy in this way. Compressing gases like nitrogen enough produces liquid nitrogen, and this page talks about how you can use liquid nitrogen to power a car (Dell Inspiron 1320n Battery) .

One of the new technologies that may become available in the future involves antimatter. When you combine normal matter with antimatter, you get energy. You store the energy by creating the antimatter. This page talks about it a bit.

Right now, none of these techniques can hold a candle (another form of stored energy!) to gasoline in the convenience sense (Dell Inspiron 1464 Battery) .

Fuel cells using methanol look to be the closest competitor right now, and will probably become available to the general public over the next few years.

different ways to store energy besides using rechargeable batteries

Human beings have been looking for a good way to store energy for a long time (Dell Inspiron 1564 Battery) .

One of the major things that has been holding up electric cars is battery technology -- when you compare batteries to gasoline, the differences are huge. For example, a typical electric car might carry 1,000 pounds (454 kg) of lead-acid batteries. Those batteries take several hours to recharge, and might give the car a 100-mile (160-km) range (Dell Inspiron 1764 Battery) .

Two or 3 gallons of gasoline give the same range, weigh less than 30 pounds (13 kg), and you can pump that much gasoline in about a minute.

Quiz Corner

How much you know about batteries and what they do? Test your knowledge with our Batteries Quiz (Dell Studio 1450 Battery) !

Here is a list of other technologies that people commonly use to store energy. Some of these work in an electric car, while others are better for stationary applications:

One of the oldest techniques people have used is the falling weight (Dell Studio 1457 Battery) .

You lift the weight to store the energy in it and then let the weight fall to extract the energy. Many grandfather clocks and cuckoo clocks use this technique. By running the string attached to the weights through a gear train, you can use a heavy weight and let it fall over a long period of time (Dell Latitude D610 Battery) .

(See How Pendulum Clocks Work.) This approach doesn't work very well in an electric car, but it has worked well in clocks for hundreds of years.

Many power plants use the "falling weight" approach in the form of water (Toshiba NB100 Battery) .

The water is pumped uphill to a lake at night when the power plant has excess capacity. During high-demand daytime periods, the water runs through a turbine on its way downhill to a lower lake. (See How Hydropower Plants Work.)

Another way to store energy is in some form of repeatable mechanical deformation (Toshiba Satellite M65 battery) .

This is the idea behind a spring used in a wind-up clock or a rubber band used in a wind-up airplane. You store the energy by bending (deforming) the material in a spring, and the material releases the energy as it returns to its original shape. At the scale of a car, this technology has problems because of the weight of the spring, but at smaller scales (like a wristwatch) it works great (Toshiba Satellite M60 battery) .

See also this page for an interesting example.

Nature has been storing energy for a long time, and if you want to think about it in this way, gasoline is really a form of stored energy. Plants absorb sunlight and turn it into carbohydrates (see How Food Works for a discussion of carbohydrates) (Dell Latitude D830 Battery) .

Over millions of years, these carbohydrates can turn into oil or coal. On a more human time scale, we burn wood (which is a carbohydrate) to release stored energy, or turn corn into alcohol and burn the alcohol.

Another technique that nature uses to store energy is fat, which many of us are familiar with in a personal way (Dell Latitude D620 Battery) .

It is interesting to think about a car that somehow eats grass or some other carbohydrate and stores it as fat!

You can take energy and split water into its hydrogen and oxygen atoms using electrolysis. By storing the hydrogen and oxygen in tanks, you can later create energy by burning it, or (more efficiently) by running it through a fuel cell (see How Fuel Cells Work) (Dell Inspiron Mini 10 Battery) .

You can use the energy to spin up a flywheel and then later extract the energy by using the flywheel to run a generator. This patent has lots of information.

You can store heat directly and later convert the heat to another form of energy like electricity (Sony VGN-FW11S Battery) .

This page discusses some of NASA's experiments in this area.

You can use compressed air to store energy. Toys like the Air Hog store energy in this way. Compressing gases like nitrogen enough produces liquid nitrogen, and this page talks about how you can use liquid nitrogen to power a car (Sony VGN-FW11M Battery) .

One of the new technologies that may become available in the future involves antimatter. When you combine normal matter with antimatter, you get energy. You store the energy by creating the antimatter. This page talks about it a bit.

Right now, none of these techniques can hold a candle (another form of stored energy!) to gasoline in the convenience sense (Sony VGN-FW139E/H battery) .

Fuel cells using methanol look to be the closest competitor right now, and will probably become available to the general public over the next few years.

With the rise in portable devices such as laptops, cell phones, MP3 players and cordless power tools, the need for rechargeable batteries has grown substantially in recent years (Dell Latitude E5400 Battery) .

The concept of the rechargeable battery has been around since 1859, when French physicist Gaston Plante invented the lead acid cell, which would later become the world's first rechargeable battery. That same chemistry is still used in today's car battery (Dell Latitude E4200 Battery) .

The basic idea behind the rechargeable battery is simple: when electrical energy is applied to the battery, the electron flow from negative to positive that occurs during discharge is reversed and power is restored (Dell Vostro A840 Battery) .

This requires an adapter in the case of devices with built-in batteries or for standard nickel-cadmium or nickel-metal hydride batteries, the most common multi-use rechargeable batteries used today in your remote control, flashlight or digital camera (Dell Inspiron 300M Battery) .

Car batteries are one of the oldest kinds of rechargeable batteries and in fact, the electric car predates its gas-powered cousin. In a standard car, there is a single lead-acid SLI battery that supplies power to the starter, lights and ignition system. The battery charger in this case is the alternator, a clever device that converts gasoline power to electrical energy and distributes it where needed (Dell Studio 1737 battery) .

In electric and hybrid cars, traction batteries are used to power the vehicle down the road. Traction batteries come in many varieties, from lead acid, to nickel-cadmium, nickel metal hydride and lithium ion.

The recharging rate has improved substantially over the years and is broken down into three categories (Dell Inspiron E1505 battery) :

Slow: 14-16 hours

Quick: 3-6 hours

Fast: Less than one hour

The rate of charge is determined by how much electrical current is allowed into the battery by the charger (Dell RM791 battery) .

Some batteries can handle higher voltage in a shorter amount of time without overheating, while others need a lesser voltage applied over a longer period of time. The quicker the rate of charge, the more chance there is of over charging, which can ruin a battery's chance of holding its charge (Dell XPS M1530 battery) .

The key in avoiding an over charge is the ability to dissipate the charging current once maximum power has been reached. Most chargers have built-in voltage regulators do this, allowing you to safely leave your cell phone or computer plugged in overnight.

The speed and effectiveness of the charge depends largely on the quality of the charger itself (Dell XPS M2010 battery) .

Chargers vary in performance based on the price tag and like most products you get what you pay for. Chargers are generally designed for specific cell chemistries, although newer universal chargers have sensors built in that identify the cell type and react appropriately (Acer Aspire One battery) .

There are also smart chargers that use a microprocessor to monitor temperature, voltage and state of charge, which is the percentage of power available compared to its full capacity.

One common problem in nickel-cadmium rechargeable batteries is something known as the memory effect (Toshiba Satellite P10 Battery) .

This is when the battery is continually recharged before it has discharged more than 50 percent of its power, causing it to essentially forget that it could fully discharge to begin with. Memory effect is caused by the formation of hard-to-dissolve cadmium crystals deep within the battery (SONY VGN-FZ210CE Battery) .

Cadmium crystals are an unavoidable by-product of discharge; the trick is to keep them small enough to be reformed as cadmium during the charging process. When a battery is not fully discharged, the crystals deep within the battery are not affected by the influx of electrical current, so they are not reformed as cadmium and can grow into the troublesome larger cadmium crystals (Dell Precision M70 Battery) .

The battery will still function normally, but is maxed out at 50 percent. The memory effect can be avoided by fully cycling the battery once every two to three weeks by allowing it to discharge completely, and then fully recharge.

It's important to remember that no battery, rechargeable or otherwise, will last forever (Toshiba Satellite L305 Battery) .

All batteries suffer from aging cells and the longer they are used, the less capacity they ultimately will have. Rechargeable batteries are still a great way to save money and reduce waste (Toshiba Satellite T4900 Battery) .

New Battery Technology Helps Stimulate Nerves

ScienceDaily (Oct. 4, 2005) — MADISON -- With the help of new silicon-based compounds, scientists -- and patients -- are getting a significant new charge out of the tiny lithium batteries used in implantable devices to help treat nervous system and other disorders (Toshiba PA3399U-2BRS battery) .

The lithium battery is the workhorse in implantable devices -- stimulators used to jump start the heart and help the central nervous system make critical connections in, for example, Parkinson's and epilepsy patients (Toshiba Satellite A200 Battery) .

Designed to be extraordinarily reliable and work continuously for years, the tiny batteries that power implantables are indispensable in everything from pacemakers to the electronic stimulators that help restore function in the brains of Parkinson's patients (Toshiba Satellite 1200 Battery) .

But lithium batteries don't last forever and new surgery to maintain many devices seeded into the body is required, as it is to replace batteries and devices at the end of their lives (Toshiba Satellite M300 Battery) .

Moreover, a new generation of tiny electrical devices to stimulate the nervous system, treat incontinence and overcome muscular impairment is coming on line as scientists and engineers continue to shrink the components that make up the devices (Sony Vaio PCG-5G2L Battery) .

Central to that ability, according to University of Wisconsin-Madison Professor Emeritus of chemistry Robert West, is new lithium battery technology, technology capable of making batteries smaller, last longer and, soon, accept a charge from outside the body without the need for surgery Sony Vaio PCG-5G3L Battery .

Using organosilicon compounds, West and his UW-Madison colleagues have developed a new generation of rechargeable lithium ion batteries whose lifetimes are more than twice as long as the batteries now used in the tiny medical devices Sony Vaio PCG-5J1L Battery .

"It turns out the organosilicon compounds are really good for improving lithium battery technology," says West, whose new battery technology powers a "microstimulater" not much larger than a pencil lead and that can be injected near target nerves to help overcome the faulty nervous system wiring at the heart of Parkinson's, epilepsy and incontinence Sony Vaio PCG-5K2L Battery .

"The idea is that whenever you have a broken nerve connection, you can supply the electrical impulse to complete the circuit," West explains.

The microstimulator was developed by a consortium including UW-Madison's Organosilicon Research Center, Argonne National Laboratory, Advanced Bionics Corp., the Alfred Mann Foundation and Quallion, LLC Sony Vaio PCG-5J2L Battery .

The device was recognized earlier this year with an "R&D 100 Award" from R&D Magazine.

West's group developed the electrolyte, the electricity-conducting liquid that is the heart of the battery. The new organosilicon compounds developed by the Wisconsin chemists, says West, have numerous advantages over traditional lithium battery chemistry.

"They're very flexible. They don't solidify Sony Vaio PCG-5K1L Battery .

They're stable, nonflammable, non-toxic and they pose no threat to the environment," says West, an international authority on silicon chemistry. Silicon, the stuff computer chips are made of, is one of the Earth's most abundant elements. Organosilicons are compounds composed of silicon and other natural materials Sony Vaio PCG-5L1L Battery .

In the context of the lithium battery, West's group has been making and testing "designer silicons" that are specially formulated to conduct electricity in a very compact environment. In the lithium battery, charge is maintained as lithium ions flow between the battery's positive and negative electrodes Sony Vaio PCG-6S2L Battery .

"The battery requires something the ions can go through easily. We had to tweak the (organosilicon) molecules to get higher conductivity and stability," says West.

A critical advantage of the new battery technology is lifespan Sony Vaio PCG-6S3L Battery :

"If you're going to implant these things, you want a (battery) lifetime of at least 10 years," says West, whose organosilicon batteries are projected to power the tiny implantable devices for more than 12 years.

In addition to implantable devices for medicine, lithium batteries are used in scores of applications, from spacecraft to iPods Sony Vaio PCG-6V1L Battery .

Patented through the Wisconsin Alumni Research Foundation, the new organosilicon compound technology is also being developed through a new start-up company, Polyron, Inc. The work to develop the new organosilicon compounds was funded by the National Institute of Standards and Technology Sony Vaio PCG-6W1L Battery ,

a federal technology agency that works with industry to develop and apply technology, measurements and standards

Battery Reactions and Chemistry

In any battery, an electrochemical reaction occurs like the ones described on the previous page Sony Vaio PCG-6W2L Battery .

This reaction moves electrons from one pole to the other. The actual metals and electrolytes used control the voltage of the battery -- each different reaction has a characteristic voltage. For example, here's what happens in one cell of a car's lead-acid battery Sony Vaio PCG-6W3L Battery :

The cell has one plate made of lead and another plate made of lead dioxide, with a strong sulfuric acid electrolyte in which the plates are immersed.

Lead combines with SO4 (sulfate) to create PbSO4 (lead sulfate), plus one electron Sony Vaio PCG-7111L Battery .

Lead dioxide, hydrogen ions and SO4 ions, plus electrons from the lead plate, create PbSO4 and water on the lead dioxide plate.

As the battery discharges, both plates build up PbSO4 and water builds up in the acid. The characteristic voltage is about 2 volts per cell, so by combining six cells you get a 12-volt battery Sony Vaio PCG-7112L Battery .

A lead-acid battery has a nice feature -- the reaction is completely reversible. If you apply current to the battery at the right voltage, lead and lead dioxide form again on the plates so you can reuse the battery over and over. In a zinc-carbon battery, there is no easy way to reverse the reaction because there is no easy way to get hydrogen gas back into the electrolyte Sony Vaio PCG-7113L Battery .

Modern Battery Chemistry
Modern batteries use a variety of chemicals to power their reactions. Typical battery chemistries include:

Zinc-carbon battery - Also known as a standard carbon battery, zinc-carbon chemistry is used in all inexpensive AA, C and D dry-cell batteries Sony Vaio PCG-7133L Battery .

The electrodes are zinc and carbon, with an acidic paste between them that serves as the electrolyte.

Alkaline battery - Alkaline chemistry is used in common Duracell and Energizer batteries, the electrodes are zinc and manganese-oxide, with an alkaline electrolyte Sony Vaio PCG-7Z1L Battery .

Lithium-iodide battery - Lithium-iodide chemistry is used in pacemakers and hearing aides because of their long life.

Lead-acid battery - Lead-acid chemistry is used in automobiles, the electrodes are made of lead and lead-oxide with a strong acidic electrolyte (rechargeable) Sony Vaio PCG-7Z2L Battery .

Nickel-cadmium battery - The electrodes are nickel-hydroxide and cadmium, with potassium-hydroxide as the electrolyte (rechargeable).

Nickel-metal hydride battery - This battery is rapidly replacing nickel-cadmium because it does not suffer from the memory effect that nickel-cadmiums do (rechargeable) Sony Vaio PCG-8Y1L Battery .

Lithium-ion battery - With a very good power-to-weight ratio, this is often found in high-end laptop computers and cell phones (rechargeable).

Zinc-air battery - This battery is lightweight and rechargeable Sony Vaio PCG-8Y2L Battery .

Zinc-mercury oxide battery - This is often used in hearing-aids.

Silver-zinc battery - This is used in aeronautical applications because the power-to-weight ratio is good Sony Vaio PCG-8Z1L Battery .

As you can see, several of these batteries are rechargeable. What makes a battery rechargeable? In the next section, we'll check out how rechargeable batteries work.

How to store a laptop battery properly to save it from an early death Sony Vaio PCG-8Z2L Battery

In the last two parts of this series, I covered the factors of temperature and charging. While the high temperatures inside modern laptops are probably the worst enemy of a Li-ion battery, frequent discharge/charge cycles will negatively influence a battery’s life. If your laptop is a desktop replacement, then you probably only need the battery every now and then Sony VAIO PCG-5G2L Battery.

It can be quite frustrating if you want to use your laptop for the first time after a year without AC, only to realize that your batteries are already dead even though you never really used them. However, if you remove the battery from the laptop and store it accurately, there is a good chance that it will be in good condition when you need it next time Sony VAIO PCG-5G3L Battery .

Don’t store a battery that is almost empty. Stored batteries continue losing energy, albeit at a much slower pace. If the stored battery is totally discharged, it could be destroyed Sony VAIO PCG-5J1L Battery .

Don’t store a fully charged battery. Fully charged batteries deteriorate faster than half-charged batteries. Most articles I’ve read recommended storing laptop batteries with a 40–60% charge Sony VAIO PCG-5K2L Battery .

Store the battery at a low temperature. I usually put it in the fridge. It keeps my battery fresh and crisp. Check out this table at Wikipedia. 0°C (32°F) seems to be the best storage temperature. I wouldn’t put the battery in the freezer even though Li-ion batteries only freeze at approximately ?40°C Sony VAIO PCG-5J2L Battery .

Store the battery in a dry place. A moist environment will accelerate discharging the battery Sony VAIO PCG-5K1L Battery

Universal Laptop Battery Buying Tips

Most people own more than one laptop unit and of different brands. Owning a universal laptop battery seems to be the most convenient way to have when you travel as it allows you to use it with any laptop computer unit when your power supply is running out Sony VAIO PCG-5L1L Battery .

It is true that taking care of your laptop battery is a priority as your mobile computer will be useless with a defective battery on it. There is a need to ensure that it works properly in order not to hamper your convenient usage of your notebook. Proper care of your laptop requires its storage in moderate temperature which is neither too cold not too hot Sony VAIO PCG-6S2L Battery .

Your laptop battery will be short of power once it is cold and it will not discharge fast when it is hot. You need to frequently charge your battery to ensure it to be fully functioning well.

Going for a universal battery for laptops allows it to work on different models, brand, and units Sony VAIO PCG-6S3L Battery .

There are varieties of choices available in most computer shops and online stores. But do know what type of universal battery to buy for your laptop?

One issue with laptop batteries is the danger of explosion Sony VAIO PCG-6V1L Battery .

It may rarely happen but it does happen and anyone could be at risk when using poor quality battery for their laptops. Take note that lithium ion laptop batteries, which are commonly used in the market could explode owing to its cobalt oxide content.

Consideration may be directed also by choosing a laptop that is smaller in size such as ultra portable or light weight laptops Sony VAIO PCG-6W1L Battery .

They have smaller LCD and it uses less power. It has a hard drive that runs only about 4200 rpm which uses less power than those than run at 5400 rpm. This makes your laptop battery drain less quickly Sony VAIO PCG-6W2L Battery .

Universal batteries for laptop use are available in different types according to the size of your laptop. A friend bought a nickel metal laptop battery which is suitable for her small size notebook. I want to buy one myself however I was advised it is not suitable for my laptop which is 16 inches Sony VAIO PCG-6W3L Battery .

The most suitable one is the ED369 battery which is best for laptops that are 13 inches or more in size and when one uses a lot of external devices that requires more battery power. This battery provides 2 to 3 hours of power supply in normal conditions. Simply plug it into the AC adapter of the laptop and it is ready to use Sony VAIO PCG-7111L Battery .

When buying a battery for your laptop always consider the size of your computer and the average consumption of power. You can choose from variable output voltage. Voltage of 16 and 19 v DC are enough to supply most laptops Sony VAIO PCG-7112L Battery .

How to Keep Your Laptop Battery in Good Working Condition

Most laptop batteries just don't last as long as they should because the rightful owner doesn't take the necessary steps to keep it operating properly Sony VAIO PCG-7113L Battery .

Just a few normal maintenance of the laptop battery can certainly make a big difference in how long your battery will last both in short term life span and long term as well. Here are a few tips on how to take care of your battery to ensure you get the absolute most out of it Sony VAIO PCG-7133L Battery .

The first point to consider is the fact that you should never use or store your battery in very extreme conditions. For instance, never leave your laptop in the trunk of your car when it is either freezing out or in the middle of a hot summer day. You shouldn't even leave it in your car period Sony VAIO PCG-7Z1L Battery .

Make sure it is only used in room temperature conditions and also away from humid and wet conditions like those that exist in a steamy shower or bathroom.

If you are in the market for a laptop that only has a long lasting battery, consider buying one that is smaller and lighter in weight Sony VAIO PCG-7Z2L Battery .

These ultra thin or compact laptops generally will last longer than their bigger and bulkier counterparts.

Be aware as well that you can always adjust the power settings in your control panel to make the battery last longer Sony VAIO PCG-8Y1L Battery .

You will of course be somewhat limited in the functions that your computer can process and it will also operate at a much lower speed than normal.

There is an easy way to clean your battery so that it doesn't develop any rust or debris Sony VAIO PCG-8Y2L Battery .

Simply take a cotton swab or Q-tip with a dab of rubbing alcohol and gently wipe off all of the connectors. Make sure to completely dry the battery before you ever attempt putting it back in the computer.

Every few weeks you want to make sure to drain your battery completely and then let it charge up all the way Sony VAIO PCG-8Z1L Battery .

This is just a natural process that your battery needs to go through in order to maintain its long battery lifespan.

If all else fails and your laptops battery just isn't lasting as long as it should, it may then be time to think about just buying a new battery Sony VAIO PCG-8Z2L Battery .

I always do a search online to find a suitable battery for my laptop. Ordering from the manufacturer itself will ensure that you do in fact get the right battery that will work properly in your laptop. If you end up getting the wrong battery, it could ultimately damage or completely ruin your laptop WD passport essential (500GB/640GB) .

So always be careful and know what you are buying before you spend any money.

For even more great information about Replacement Laptop Batteries, visit Wade's new Laptop Power Adapters website. Learn about how to find the right batteries and adapters to fit your specific laptop WD passport essential (250GB/320GB) .