Fiber Optics Illustrated Dictionary JARL See Japan Amateur Radio League, Inc. JAS-lb Japan's second amateur radio satellite, launched in 1990, 4 years after its first satellite was put into orbit. Six years later, in 1996, this was fol- lowed by JAS-2. See JAS-2. JAS-2 Japan's third amateur radio satellite, launched in 1996 using an H-ll launch vehicle. JATE See Japan Approvals Institute for Telecommu- nications Equipment. Java An object-oriented, platform-independent, threaded programming language that came into be- ing largely because its two earliest contributors were not satisfied with C and C++, and wanted a way to develop programs with less effort and code. Thus, Bill Joy proposed an object environment based on C++ to Sun Microsystems engineers, and James Gosling, author of EMACS, developed a language called Oak. Communications between Patrick Naughton of Sun, Mike Sheridan, James Gosling, and Bill Joy resulted in the Green Project and collaborative work began. Eventually, in 1995, Java was introduced by Sun Microsystems. Java requires significantly less code than C for many types of applications, is generally easier to learn, works well in conjunction with the Web, and has a good chance of becoming a wide- spread language of choice for software development. On the Web it is frequently used to supplement HTML as a means to interact with and convey information to Web users. HTML is a markup language, a type of language where a user can learn a few commands and install a basic Web page without too much technical knowledge. However, Web users with more sophis- ticated needs or the desire to interact with users in a more fluid and interactive manner than is possible with HTML generally select Perl and/or Java for implementing calculations, specialized interfaces, and more complex programming structures than are possible with HTML. At first, Web users were slow to adopt Java. Those who were familiar with C and other powerful, fast development languages were uncomfortable with Java's limits and slow running times. However, Java has continued to evolve, the Web has continued to evolve (and now is accessed on faster systems and Internet links), and developers have begun to realize that there is an enormous middle ground ofapplica- tions that don't have to run as fast as C to be useful and that can be implemented far faster and more readily with Java. Examples include basic menu se- lections, games based on strategy rather than speed, interactive database interfaces, more sophisticated interactive forms than are possible with HTML, sta- tistical charts and graphs, and much more. Java support from Sun includes the Java Develop- ment Kit (JDK), available for various Sun platfonns, Windows NT, and Windows 95 Intel. Independent ports exist for other operating systems, including Linux, NeXTStep, and Amiga. Macintosh support is provided by Apple Computer's Macintosh Runtime for Java (MRJ), and Windows 3.1 support is provided byffiM. Two applications environments are particularly 532 relevant to personal communications devices. The PersonalJava application environment is designed to facili tate development ofsoftware for private network or Web-connected con- sumer devices that may be executing applets. This requires that a core set ofsoftware librar- ies be installed on the PersonalJava-enabled device. The PersonalJava AE comprises the Java Virtual Machine (JVM) and an optimized version of the Java class library. This environ- ment is useful in situations where generalized applications or those that can't easily be pre- dicted in advance will be used. The tradeoff is that the Libraries require a certain amount of space. The EmbeddedJava application environment is designed to facilitate development ofsoftware for dedicated-function embedded devices which may be stand-alone or embedded. Only the class libraries needed to support aprespeci- fied set of tasks are installed onto the EmbeddedJava-enabled device. This is useful in very specific dedicated applications where the purpose of the device is well defined and not likely to change in the near future. Space is saved and the resource "footprint" of the de- vice is smaller (which often lowers the cost). The tradeoff is that future needs may not al- ways be anticipated or met without changing the core set of library routines. Java can be used in conjunction with the HotJava Web browser to allow Java programs to run on a desktop computer. Java infonnation and specifications are available through the Javasoft Web si teo See J2ME, Java APIs, Java applet, Java Archive, JDBC, JOLT Project, JStamp. http://www.javasoft.com/ There is a good Java Frequently Asked Questions (FAQ) listing by Elliotte Rusty Harold on the Web. http://sunsite.unc.edu/javafaq/javafaq.htrnl Java APIs A number of important applications pro- gramming interfaces associated with Sun Microsys- tems' Java provide specifications and procedures for applications development. Java applet An important component of Java object- oriented programming, an applet is aJava class used to extend Java. Applets can intercommunicate within the same virtual machine environment. Applets are run within the circumscribed context of a Web browser, applet viewer, or other application that supports applets. This provides a measure of ex- tensibility along with a certain amount of security, since the applet can normally only read and write files on the host machine through the application through which it is running. See Java. Java Application Environment JAE. See Java. Java Archive JAR. Apowerful, Java open standard, platfonn-independent, compression file fonnat for images and sound that brings together a set of files into one. In this way, Java applets and their associ- ated components can be bundled and downloaded as © 2003 by CRC Press LLC a single file; however, it can also be used as ageneral- purpose compression/archiving tool, similar to ZIP. JAR files are very small, even smaller than PKZIP files, in many cases. JAR has some support for data security. Individual portions ofa JAR can be digitally signed and authen- ticated. JAR archives can be created with the JAR utility included with JDK., which functions in a man- ner similar to many common archive utilities. See PKZIP,RAR. JavaCommunity Process JCP. An open, internation- ally inclusive means ofdeveloping and revising Sun Microsystems' Java technology specifications and related support resource. More than 300 companies and individual participants are involved in this effort. Almost 100 Java technology specifications are being developed through the JCP, which was initiated in 1995. See Java. Java Electronic Commerce Framework JECF. A securable, extensible framework for conducting elec- tronic commerce, developed by Sun Microsystems. The initial component of JECF is Java Wallet, a cli- ent-side application distributed as part of the Java Commerce toolkit as a core component of the Java environment. Java CommerceAPIs are used to imple- ment basic services within the Java Commerce Cli- ent that can be used to develop online shopping malls and banking applications. See Java, JavaWallet. Java name space A means of resolving names in a software program to Java runtime classes. In general, the system applies to classes, packages, and class members. Classes can be moved or removed from specified name spaces, which can be useful for secu- rity implementations. Classes themselves are part of a package. By handling things this way, rather than with global variables, name space conflicts are avoided in environments such as the Internet where the loading of dynamic, modular applications is prevalent. A naming scheme was proposed, based upon Inter- net domain naming conventions, to provide unique package naming that included the name of the orga- nization developing or providing the package. Thus, a unique package name might be: com.companyname.jdbc.coolapp or, as some developers have chosen: companyname.javascript.coolObject The names java and sun are reserved by Sun Micro- systems. There was some support for this concept and also some controversy. In general, developers have been following the guidelines for Java name space, but in some instances, the Java community has expressed a preference that core applications be placed within name space conventions with shorter, more generic names rather than the longer, company-linked names. See Java, Java telephony API. Java Native Interface JNI. AJava native program- ming interface that ensures portability of Java appli- cations across different platforms supporting Java. It is available with the standard Sun Microsystems Java Development Kit (JDK). Since there always seem to Sampling of Java Applications Programming Interfaces Java DPI Description Java Media API Java media applications programming interface. Java Security API The Java applications programming interface (API) for building authentication through digital signatures and other low- and high-level security features into Java programs. Support is provided for key and certificate management, and access control data. This provides a means for Java applets to be "signed" to ensure authenticity. Java Speech API JSAPI. The Java object-oriented open API for speech. Specifications for the development of speech recognition and synthesis applications. JSAPI supports speech dictation systems, employing very large vocabularies and grammar- based speech interactive dialog systems (command-and-control). The API provides three basic types of support: resource management, a set of classes and interfaces for a speech recognition system, and a set of classes and interfaces for speech synthesis. Related functions, speech coding and compression, are handled by the Java Media Framework and Codec support. Java Telephony API JTAPI. The Java telephone API designed to provide portability of telephony applications across applications and across different hardware platfonns. JTAPI is a sanctioned specification extension to Java that is used in conjunction with toolkits (such as Lucent's Passageways and Sun's JavaTel), to serve as a guide for the creation of applications. JTAPI was jointly developed by Sun Microsystems, IBM, Intel Corporation, Lucent Technologies, Novell Corporation, and Nortel Corporation. 533 © 2003 by CRC Press LLC Fiber Optics Illustrated Dictionary be a few platform-specific functions that people like to use, the JNI is intended to take advantage offunc- tionality on a specific platform that is not within the Java Virtual Machine (JVM) environment. It enables native code (e.g., C++) to be integrated into Java ap- plications. See Java, Java Virtual Machine. Java telephony API JTAP!. Applications develop- ment tools based on the Sun Microsystems Java pro- gramming language that enable portable Java appli- cations to set up, manage, redirect, and otherwise ad- minister telephone calls handled through digital data networks. JTAPI was developed by illM, Intel, Lu- cent, Nortel, Novell, and Sun Microsystems. JTAPI implementations provide the interface between Java telephony applications and hardware or software telephony services. JTAPI provides a means to ac- cess telephony Call Control, Physical Device Con- trol, Media Services, and Administrative Services. JTAPI is an extensible, scalable specification appro- priate for communications in first-party call control in consumer devices to third-party call control in dis- tributed call centers. JTAPI development was begun in the mid-1990s by a consortium ofcomputer and telecommunications companies who desired a por- table, object-oriented means to integrate computers and telephony call control. JTAPI version 1.0 was released in October 1997 and version 1.3 was en- dorsed by the Enterprise Computer Telephony Forum in July 1999. JTAPI is a java extension package comprising the classes, interfaces, and principles ofoperation in the javax.* name space (e.g., javax.swing). JTAPI makes it possible to create applications that interact with and control telephone services. This is ofinterest to many developers, consumers, and busi- ness users of telephone services. The more obvious applications include call management, logging, dial- ing, and tracking software. Automated voicemail, facsimiles, and document distribution programs are also of interest. But there are also likely to be new and novel Internet telephony and personal digital as- sistant programs developed and designed to interface computer ,and telephone technologies in ways not previously possible. Since JTAPI does not encompass every signaling pro- tocol and since there is no way to anticipate every possible JTAPI application, some of the more inno- vative applications will require interfaces to extend and supplement the JTAPI specification. JT API can run on top ofexisting telephony standards, including TAPI, TSAPI, Callpath (IBM), and SunXTL. JavaTel is Sun Microsystems' JTAPI runtime envi- ronment for the Sun platform. See Java, JavaTel, javax name space, Telephony Application Program- ming Interface. Java Virtual Machine NM. Software routines for interpreting Java bytecodes into machine code. This interpretation/conversion process makes it possible to run Java applications on many different platforms. Each computer hardware architecture has a different way ofinterpreting programming instructions, based 534 on the central processing unit and its support systems. If you have a software program running indirectly within a virtual environment instead of directly on the host platform, a way to convert the program in- structions to those expected by the host processor is needed. The NM enables Java portability across many different systems. See Java. Java XML, JXML An area of development and a mailing list devoted to Java and XML, particularly Java Class and Bean metadata expressed as CML documents, conversion of meta data to bytecodes, re- versible conversion ofJava Object Streams to XML documents, and other related issues. JavaBeans A Sun Microsystems Java language ob- ject-oriented, platform-independent security model included in JDK. See Java. Javan, Ali (1928- ) An Iranian physicist of Azerbaijani descent, Javan has lived in the U.S. since 1949. In 1960, Javan invented ahelium-neon gas la- ser, the first laser to emit a steady beam of light and the forerunner ofelectrical discharge pumped gas la- sers. He was awarded The Franklin Institute's Ballantine Medal in 1962 for his achievement. In 1975, Javan received the Fredric Ives Medal from the Optical Society of America. Javan founded La- ser Science, Inc. in 1981, to develop and construct laser-based systems such as atomic clocks and opti- cal communications systems for government agen- cies. The company was merged into Thermo Electron's Photonics Division in 1997. See Dicke, Robert; laser history; Patel, C; Townes, Charles. JavaScriptAcross-platform, scripted, open standard programming language familiar to most through the implementation incorporated into Netscape Web browsers. It is only superficially similar to Java, be- ing slower and having a simpler syntax and limited functionality. JavaServer Pages JSP. An industry collaboration project lead by Sun Microsystems to enable Web de- velopers to develop and maintain dynamic Web pages for integration with existing business systems. JSP enables the development of platform-independent Web-based applications. It separates the user inter- face from the content generation so that changes in layout don't change the underlying content. JSP uses XML-style tags and scripts written in Java. Format- ting tags (HTML or XML) are passed back to the re- sponse page. JSP is an extension of the Java Servlet technology, platform-independent Java server-side modules that fit into a Web server framework to ex- tend the capabilities of the server with minimal over- head. JSP specifications are freely available to the development community so that Web servers and applications servers can be JSP-enabled. See Java. JavaTel Aplatform-independent, scalable telephony applications toolkit based on the Java Telephony API, introduced by Sun Microsystems in 1997. JavaTel was designed to support computer telephony integra- tion (CTn by enabling the development ofJava-based call center, voice response, Internet phone, and man- agement applications. Thus, Java-based computer telephony applications can run on any Java- © 2003 by CRC Press LLC enabled device, rather than being constrained to CTI applications that run on SunXTL, Sun's propri- etary implementation. JavaTel operates with the So- laris operating system and will run on top ofSun's earlier CTI implementation, the SunXTL system. See CallPatli, Java Telephony API. JBIG Joint Bi-Levellmage Experts Group. A group formed after the JPEG group to concentrate on the task of lossless compression of bilevel, one-bit, monochrome images such as those commonly gen- erated by printers, fax machines, etc. It is officially the ISO/IEC JTCI SC29 Working Group 1 and is re- sponsible for both JPEG and JBIG standards. The JBIG format incorporates discrete levels of de- tail by successively doubling resolution. The image is divided into strips for processing, each with a hori- zontal bar and a specified height, with each strip coded and transmitted separately. The order and char- acteristics ofindividual strips can be specified by the user. The image can then be progressively decoded, one strip at a time, as received. Once an image has been segmented according to strips and specified parameters, the resulting bilevel bitmaps are compressed with a Q-coder. Two contexts are defined by JBIG, the base layer, which is the low- est resolution, and the remaining differential layers. These provide contexts for optimization of the com- pression. The JBIG fonnat works well with the many common bilevel images that include text and line art. It is an accepted standard as ITU-T T.82. The JIBG2 stan- dard, which represents work since the original JBIG specification, has been released as an International Standard (IS 14492). See JBIG, color; JPEG; MPEG. JavaWallet A family ofproducts developed in the Java programming language for enabling secured electronic commerce transactions. Java Wallet incor- porates the Java Commerce Client, Commerce Java- Beans components, the Gateway Security Model, and Java Commerce Messages, which may be used inde- pendently of one another and may be bundled with other applications. Java Wallet may be used in Java- enabled browsers, as well. See Java. JBIGAlliance Another name for the JPEG and JPEG committees officially known as the ISOIIEC JTC 1 SC29 Working Group 1, sometimes abbreviated as ISO SC29/WG 1. See JBIG. JBIG, color; COLOR-JBIGAproject to develop a JBIG-based, lossless, decompression system for document image processing for a variety of types of documents including bitonal, grayscale, and color. This is an interesting direction, since the original JBIG concept was to create, in a sense, a lossless, monochrome version of the JPEG file format. How- ever, it is clear that a lossless color format has many applications (including commercial graphics, medi- cal images, business documents, etc.). What remains to be seen is how a new format can improve upon the sophisticated and well-supported Tag Image File Format (TIFF) file format, which already supports loss less compression of monochrome, grayscale, and color images. Since JBIG is an ISO standard, a color version of JBIG is of interest to the European community. Pre- sumably the developers feel that there are capabili- ties and aspects of JBIG not already supported by TIFF. See JBIG, Tag Image File Format. JBOD See just a bunch of disks. JCL See Job Control Language. JDBC Java database connectivity. This is aproduct from Sun Microsystems that facilitates the linking of Java programs to tabular databases. It provides con- nectivity to a number of standard database formats, including SQL, common spreadsheet fonnats, and flat files. See Java. IDC 1. Japan Digital Cellular. See Personal Digital Cellular. 2. Java Developer Connection. The Sun Microsystems support forum and interactive message board for registered Java developers. (Nonregistered developers can read message, but not post to the mes- sage board.). 3. Journal ofDesign Communication. JDS Uniphase Corporation A public company formed by the merging of IDS Fitel and pniphase, IDS is a significant distributor of wavelength divi- sion multiplexing modules, monitors, and connectors for fiber optic cables. In June 2002, the company announced a smaller semi- conductor optical amplifier (SOA) for fiber-based communications links operating in optical C-band frequencies. The component has a unique integrated polarization-independent optical isolator meeting Multi-Source Agreement (MSA) standards. JECF See Java Electronic Commerce Framework. JECS See Job-by-Email Control System. JEDEC Joint Electron Device Engineering Council. JEDEC was originally formed as the Joint Electron Tube Engineering Council (JETEC) in 1944. JEDEC is a standards-developing body of more than 300 member companies representing the electronics in- dustry as part of the Electronic Industries Alliance (EIA). http://www.eia.org/jedec/ JEDI See Joint Electronic Document Interchange. JEDIC Japan Electronic Data Interchange Council, Japan EDI Council. An interdisciplinary council of member organizations, including electronics organi- zations, manufacturers, software developers, and trade associations. It was formed in recognition of the importance ofelectronic data interchange (ED I) to Japan's consumer and industrial infrastructure and to encourage a common awareness and purpose simi- lar to that fostered by the open EDI environments in Europe and North America. The JEDIC fosters edu- cational, internationalization, and standardization efforts. http://www.ecom.jp/jedic/ JEEVES See Ask Jeeves. JEEVES DNS Resolver A significant pioneer net- work domain name resolver (DNS) developed by Paul Mockapetris which was the precursor to the widely used Berkeley Internet Name Domain (BIND). See Berkeley Internet Name Domain; CHIVES DNS Resolver; Mockapetris, Paul. JEIDA See Japan Electronic Industry Development Association. JEMA See Japan Electronic Messaging Association. 535 © 2003 by CRC Press LLC Fiber Optics Illustrated Dictionary JEPI See Joint Electronics Payment Initiative. jerk A measure of the rate of change of acceleration, in other words, the first derivative of acceleration, similar to the relationship between speed and veloc- ity and velocity and acceleration. JET See Just-Enough-Time. JFIFA minimal implementation of the JPEG family of image compression methods. This is often the im- plementation incorporated into Web browsers. See Joint Photographics Experts Group. JHTML 1. An open source cross-platform HTML editor written in Java by Riyad Kalla. 2. A Mac-based plugin application for the Jedit text editor that enables it to generate HTML code. 3. See JavaServer Pages. jiffy A unit of time equal to 1/60 ofa second (North America), or 1/50 ofa second elsewhere. Since the proliferation of computers, other definitions ofajiffy have been used, such as 1/100 second or a clock tick in the CPU. The term is most widely used in the film and video editing industries for editing timing pur- poses. See SMPTE Time Code. jiffy box A box enclosure for mounting electronics for easy access. Ajiffy box can be "opened in ajiffy" ( quickly) because it generally slides or snaps openor is open-ended rather than being secured with screws. This is useful for prototype electronics that may change frequently or components that must be at- tached to others. The box may have ridges or bays for quick mounting of circuit boards. Jini A Sun Microsystems network technology for providing a simple modular infrastructure for deliv- ering platform-independent network services and for facilitating spontaneous interactions among programs using these services. Jini architecture, released in the late 1990s, typically consists of servers and clients registered with a lookup service. Upon registration, a client can specify the needed servers. Some interesting applications have been developed with Jini technology, which can be adapted to appli- cations that are computationally intensive and require the resources of a network of computers. For ex- ample, researchers in the Computer Graphics and Scientific Visualization Group in Italy used Jini to evaluate a novel distributed computing environment for scientific visualization (e.g., the modeling of fluid motion over wing structures). In July 2001, GroupServe announced a Developer Web Site with expanded services for Jini technology, augmenting those offered by Sun. These include Jini- based email, database, and transaction interfaces. The services are accessed by proxies downloaded by the Jini Access Module (JAM). They run locally, re- motely, or as shared resources. See Java, Jini Com- munity. Jini Community JiniCom. A community of Jini net- work services human and technical resources, JiniCom aids members in Jini development and hosts numerous community projects. It distributes the Jini Technology Core Platform Compatibility Kit (TCK) for testing Jini services for compliance to the Jini specification. To date, Jini standards distributed through the Community include the following, and 536 more are in the draft standard stage (e.g., Internet Protocol interconnect standards): Technology Core Platform Specification - Speci- fications for discovery and join protocols and formats, entry methods and templates, distrib- uted leasing and events, transactions, and lookup services. Helper Utilities and Services - Specifications for a set of standard helper utilities and services which extend the Jini Technology Core Plat- form. They encapsulate desirable behaviors in the form of reusable components to simplify the server/client development process. JavaSpaces Service Specification - A distributed persistence and object exchange mechanism for code written in Java. See Java, Jini. http://www.jini.orgl JIOA See Japan Institute of Office Automation. JIPS JANET Internet Protocol (IP) Service. See JANET. JIROA development architecture for resource man- agement distributed by Sun Microsystems as an ex- tension to the Java platform. It provides an open, dy- namic, extensible, scalable, network-centric manage- ment framework that can be integrated as a platform- independent system. It allows complex distributed environments, such as storage area networks (SANs), to be interconnected and managed. It does this through a standard management domain, including management services for logging, lookup, schedul- ing, events, security, and transactions through a stan- dardized interface. The system locates and commu- nicates with the services as FederatedBeans compo- nents (a cooperative concept based on the JavaBeans idea). See Java, Just-Enough- Time. JIT See Just-In-Time. JITT Just-In- Time-Training. A laptop-based intelli- gent feedback training project for astronauts and flight operators. The program was established in the mid-1990s by the NASA/Johnson Space Center. jitter 1. Random or periodic signal amplitude or phase instability or degradation of relatively short duration. Jitter arises from various causes, including poor connections, overly long cables, incompatibili- ties between software and hardware, or weather. See wander. 2. Random or periodic temporal variations of short duration in a data stream. This is essentially a timing problem with relation to a clock source. With increased demand for wideband data services such as full broadcast video, reference clocks and related transmission signals become important aspects of data communications but can also provide one more source of signal interference. When expressed dia- grammatically, jitter can be visualized as small tim- ing differences between a reference clock represent- ing the ideal signal and the jittered signal. At first glance, the two timing diagrams may look the same, but closer inspection reveals small deviations from the ideal clock backwards or forwards in time. On an oscilloscope, the jitter signal will be just slightly out of phase with the image and position of an ideal, © 2003 by CRC Press LLC expected signal. Networks may be tuned to tolerate a certain amount of low-level jitter, but persistent or high amplitude jitter should be investigated or cor- rected. See jitter, network; wander. 3. Unstable or er- ratic display on a television or computer monitor where the image deviates slightly but noticeably from the expected pattern in small jerky or wavy motions. jitter tolerance Since jitter is apersistentpossibility in high-performance network systems, especially those running through a number ofinterface devices from different vendors, many systems will specify a certain tolerance for jitter and will correct for jitter within certain parameters, when possible. The terms of the jitter tolerance depend upon the type of sys- tem, but may be specified in lost bits, timing dispari- ties, or other characteristics. Since jitter can be trans- ferred to an adjacent connecting device and thus can increase from one component to the next, the sum total of the jitter effects must also be below that which the system can tolerate. jitter, network In networks, jitter refers to a number of problems arising from demultiplexing, incorrect physical connectors or regenerators, and latency times between consecutive transmission packets. When data are serially transmitted, as is common in data networks, timing is a means to synchronize the data stream so the receiver can interpret, convert, or otheIWise process the incoming information to make sense of the data and recover them for use on the lo- cal system or for conversion or fOlWarding to another system. The success or failure of this timing synchro- nization is partly dependent upon knowing the jitter characteristics of the transmission from previous ex- perience or by dynamically analyzing the jitter in the incoming data stream and extracting useful informa- tion. This may be direct information such as the ref- erence level and frequency of the signal or may be calculated to derive other information such as wave- form characteristics and clock periods. In SONET and other high-speed networks, timing is quite important and lack of synchronization can cause fluctuations in the data packets with respect to the reference clock cycle. This type of phase variation can be filtered with adjustment mechanisms. Jitter specifications for SONET network interfaces are de- scribed in ANSI TI.I05.03-1994, and for computer networks in general in ANSI TI.I 02-1993. See jitter. JitterTrack of Time Interval Error JTIE. A testing and diagnostic tool for measuring clock characteris- tics against a reference value with respect to short duration signal phase instabilities Gitter). The refer- ence is measured over a specified time interval and evaluated for phase characteristics and anomalies. In networks, the TIE is typically measured in nanosec- onds. See jitter, network. JNT See Joint Network Team. job In computer operations, a process submitted for later execution. The term was borrowed from factory terminology in the days when computers were large, slow, and very expensive to operate and maintain. Thus, demands for computing time exceeded re- sources, and it could take days or weeks for a job (a computer program) to be processed, executed, and returned to the person who submitted the job (usu- ally on punch cards or paper tape). In those days, jobs were commonly processed in queues, sometimes ac- cording to various priorities, and eventually returned to the user. Since paper media were frequently used to store the results, the finished jobs, along with the original program, were often sorted into cubbyholes in the same manner as postal mail. Computing has changed. Systems are now fast and numerous and employ multitasking architectures. The term job is now mostly associated with background tasks and low-priority processes, or batch files that run in the background while the user continues to use the machine for other applications. Specialized ap- plications and intensive scientific applications are still processed as jobs in the sense that they are submit- ted to an organizing authority (e.g., a server) and may take a long time to process, so the term is not out- :~i:~;[~~~~;!1!~:!~~~~~~p~~;(. operating system, usually in the format of an inter- preted scripting language. Although the phrase is now used generically, it was originally developed as a con- trollanguage by ffiM for the control of programs on older ffiM batch-based computing systems. Job-by-Email Control System JECS. A software application to facilitate communication between a remote computer (server) and a home or office com- puter. In other words, it enables a task to be em ailed from one location to another, processed, and emailed back, rather than having it run realtime over a long- distance link. This is similar to batch processing in the days of timeshare systems, except on a larger scale over the Internet. It is an important concept and many jobs may be handled this way over large distributed networks in the future. Jobs, Steven P. (1955- )An early entrant to the mi- crocomputer industry, Steven Jobs began as an em- ployee of Atari at the age of 17, hired to do video games development. Through the Home Brew Com- puter Club, he met Stephen Wozniak, an electronic hardware enthusiast, who was working as an engi- neer for Hewlett-Packard. Wozniak was designing telephone access devices and homebrew computer projects, and Jobs became interested in the business potential of these designs. By 1976 Jobs had left Atari, and he and Wozniak to- gether created a new company called Apple Com- puter. They were planning to sell a microcomputer in kit form, a project probably inspired by the Altair, a humble little history-making microcomputer first re- leased as a kit in 1974. Both Jobs and Wozniak had a strong orientation and commitment to educational markets. Despite his youth, Jobs displayed a futurist orienta- tion, charismatic personality, and marketing flair. These traits have continued to keep him in the head- lines for more than 20 years. Apple gained a foothold in the industry, and John Sculley was recruited to head the corporation. Under Sculley's leadership, Apple 537 © 2003 by CRC Press LLC Fiber Optics Illustrated Dictionary became a billion dollar company and, as it grew, the two Steves receded into the background due to com- pany growing pains, personal interests, and differ- ences of opinion with the corporation, although not before becoming millionaires while in their twenties. Jobs left Apple Computer and founded NeXT, Inc. in 1985. This company designed some of the best computing hardware and software available in the 1980s. The elegantly simple hardware, robust oper- ating system, stunning graphical user interface, straightforward built-in networking capabilities, Unix underpinnings, and various software utilities were as good as or better than many systems being sold a de- cade later. The NeXT hardware and operating sys- tem was aesthetic, well conceived, and reliable; busi- ness owners, frustrated with the limitations of cur- rent business computers, watched with a keen eye when the NeXT computer was released in 1987. Un- fortunately, by not cultivating the early interest from the business community and targeting education al- most exclusively, Jobs may have made one of his big- gest mistakes. The NeXT corporation was acquired by Apple Com- puter in 1996-1997. Interest in the NeXT in 1997 was due at least in part to its very good graphical user in- terface and integration with Internet services, which were now becoming important to consumers. By the mid-1990s, 8 years after its introduction, the con- sumer learning curve had improved and users began to appreciate the NeXT design and concept. Jobs' brash assertion in the 1980s that the NeXT was the computer for the '90s turned out to be more truth than bluster. Much of the NeXT philosophy is now incor- porated into Apple computers. Ayear before the NeXT was released, in 1986, Jobs purchased the computer division of Lucas film, Ltd., and incorporated it as an independent company called Pixar, cofounded with Edwin E. Catrnull as vice presi- dent and CTO. Jobs has long been chairman and CEO ofPixar, a creative software, multimedia, motion pic- ture company which made history with the Academy Award-winning "Toy Story," a computer-generated full-length motion picture distributed in 1995 by Walt Disney Pictures. After a few years of quiet creative work, Steve Jobs' name again splashed across headlines in 1997 when Apple bought NeXT. Jobs was back as an executive at Apple, acting in an interim capacity, and specula- tion about whether he would again head Apple kept reporters on their toes. The management change and publicity created a flurry of activity at Apple, and stocks reacted accordingly. Jobs' return to the lime- light showed that public interest in his activities hadn't declined after more than two decades. The re- vival of Apple Computer, at a time when analysts were predicting its demise, is in no small part due to Jobs' presence and creative inspiration. Steven Jobs has aphilosophical bent, as can be seen from his keynote speeches and interviews with ma- jor computing magazines, and it seems clear that his commitment to education and to harnessing the cre- ative potential of computers for improving human 538 lives is sincere. It is likely that he will never be far from the creative computing activities that will oc- cur in the future, and will probably, in fact, be the in- spirational force for many innovations yet to come. See Apple computer; Wozniak, Stephen. JOFX Java Open Financial Exchange. AJava-based toolkit from Xenosys Corporation for developing Open Financial Exchange (OFX) applications and applets. JOFX is part of the LiveBusiness Founda- tion Classes for Java (LBFC), a set of Java frame- works, libraries, etc. for e-commerce. See Open Fi- nancial Exchange. JOHNNIAC A historic large-scale computer built by Willis Ware, the JOHNNIAC was unveiled in 1954 by the Rand Corporation. Significantly, the first op- erator of the JOHNNIAC was Keith Uncapher, who became the first chair of the IEEE Computer Group, now the renowned IEEE Computer Society. See ILLIAC, MANIAC. Johnson, John (ca. 1910s- )An American member of the U.S. Army who made significant contributions to the understanding of night vision image intensify- ing technology in the 1950s. Johnson's findings came to be called the Johnson Criteria and guided future developments in night vision for a variety of appli- cations. Johnson was also a pioneer in fiber optics, working in the Army Corps labs under Robert Wiseman who realized the potential of the technology for length- ening Iightguides after hearing a lecture on the sub- ject. Johnson approached American Optical, one of the leading lens firms at the time, about optical fi- bers, but was referred to W. Hicks, who had left the firm to form his own company. Johnson's concept and Hicks inventive skills turned out to be a good match, resulting in the development of fiber pulling, fiber- based vacuum assemblies, and fiber array faceplates. See Hicks, W. Johnson, John Bertrand (1887-1970) A Swedish- born American physicist, Johnson developed the first sealed-cathode commercial cathode-ray tube (CRT) in 1922. He made important observations ofthermal noise while working at Bell Laboratories in 1927 and described his observations in PhysicalReview (July 1928). The phenomenon came to be known as Johnson noise. Johnson was selected to receive the IEEE David Sarnoff award in 1970 for his contribu- tions to electronics and communications. See Johnson noise. Johnson, Reynold B. (ca. 1906-1998) An American research scientist and founding manager (1952) of the IBM Almaden Research Center. He later became president of Education Engineering Associates, Johnson pioneered the development of magnetic disk technology and computerized educational systems. A prolific inventor, Johnson received more than 90 patents in a range ofcommunications systems, edu- cational technologies, and magnetic storage devices. Johnson was elected to the National Academy of En- gineering in 1981 for his contributions in engineer- ing itU1ovatiol1 and educational leadership. In 1986 he received the National Medal of Technology, © 2003 by CRC Press LLC followed two years later by the IEEE Computer Pio- neer Award. The Reynold B. Johnson Information Storage Award was established in his honor in 1992. SeeRAMAC. Johnson noise In electronics, heat-based agitation of electrons in conductors creates low frequency noise in the circuit. In communications circuits, the amount of noise is related to the receiver bandwidth and source temperature. Johnson noise is sometimes also called thermal noise and is characteristically emitted by all objects with temperatures above absolute zero. An understanding of Johnson noise is important to the design and production of antennas and to noise processing and filtering techniques in communica- tions. See Johnson, John B. joining In computing, the process of combining data files or streams. In the context of packet communi- cations, the reassembly of packets that have been re- ceived disassembled. The term also refers to joining a conference, chat, or network community. Joining is one of the most important and ubiquitous functions used in data transmissions. It is very com- mon for data to be chopped up into pieces as it is routed, especially if there is a limit to file sizes in the sending or receiving systems. Join utilities are also used in connection with large files stored across more than one floppy or more than one hard drive parti- tion, or computer. What is split apart usually needs to be rejoined when the data are accessed or moved later on. In packet communications, individual packets from a larger data file are not necessarily transmitted through the same route in a distributed network. The concept of splitting the packets and sending them through many routes arose in the days when the u.S. military was looking for a means to safeguard data transmissions in the event of an offensive strike. It was proposed that if the data were traveling through different routes, it was less likely that the entire con- tent would be lost. In subsequent computing appli- cations, this was found to be a good model for many aspects of communications, including email, file transfer protocols, and much more, so joining the separate pieces of the communication at the destina- tion became an important function ofa system. In file management, individual parts ofa file are of- ten stored where there is sufficient room and are not necessarily contiguous. Pointers are used as a virtual joining mechanism to tell the file retrieval algorithms where to look for the next "chunk" of data. Thus, the joining ofa block of data that has been stored in sepa- rate sections often happens when an application is run and the program requires the entire contents of a graphics or text file. In telephony and online communications, joining re- fers to entering a live communications venue such as a conference call, an Internet Relay Chat (IRC) talk session, or other community communication. Specific steps or commands for joining usually must be ad- hered to, especially in public discussions where stan- dardized commands make it easier for people to join or leave. Joining is an important function in computer work- groups. When users on several different computers are sharing or updating the same database, for ex- ample, it is important for the applications and oper- ating system to keep track of who is joined into the workgroup application so that searching, retrieval, updating, and other common functions are handled so that one user doesn't wipe out the corrections or additions of another user. In client/server applications, certain protocols and procedures can be put in place for a client to join a network system or specific process. This is a resource management tool to allocate resources on a more ef- ficient or as-needed basis to conserve computing re- sources. Thus, many Internet Service Providers (ISPs) that provide 24-hour connections to the Internet, for example, may actually time out a user when a sys- tem is idle in order to allocate that user's Internet Pro- tocol (IP) number to another user. When activity is detected from the first user, the system must again m;Bi, join the network and a new IP number will be dynami- ;':f.~ cally allocated to allow the user to rejoin the Inter- net. This process is typically transparent to the user. joint 1. Connection between two or more conductors. This may be a chemical bond, solder joint, or wires touching, clamped, or wound together. 2. Ajoining part, or space, between two sections, nodes, or articu- lations. 3. Ajunction where two or more structural members are combined. Joint Bi-Level Image Experts Group See JBIG. joint cache A shorter-term storage cache shared by a larger base of users or networks. Some significant j oint cache proposals have been based on newly de- veloped models for distributed network systems. Based on the premise that the Internet is a system as a whole accessed by joint users, ajoint cache on the Internet is a mechanism for handling Internet traffic caching based on virtual rather than machine-specific or local-network-specific models. As an example, a dynamic joint cache system was de- scribed by Dolgikh and Sikhov at the TERENA Net- working Conference 2001, based on Zipf-like distri- bution. The model was based on research at the Sa- mara Region Network for Science and Education. The authors proposed and tested an analytical model ofa cache system that can be used to determine the scope, frequency of requests, and maximum effi- ciency levels for the most requested document in a cache system. While a simple example, this is an im- portant basic concept that can be generalized to many Internet resources, including popular, high-traffic Web pages. This and similar efforts to conceive top- down structures based on the Internet as a whole, rather than bottom-up services based on individual networks or computers, are an important trend in the Internet development community, where the sum of the parts is seen as a larger resource that should be accessible to the greater Internet community. If the trend continues, computing applications that were impossible on smaller systems may emerge as possi- bilities on a global distributed network. joint circuit Shared communication link. 539 © 2003 by CRC Press LLC Fiber Optics Illustrated Dictionary Joint Electronic Document Interchange, UCL- JEDI JED!. A project to survey, identify, and test a number of formats for electronic document inter- change with an eye to standardizing the research com- munity and facilitating the process therein. The project was initiated as the result of a call for pro- posals announced by UKERNA in 1994. The partici- pants are studying popular interchange formats for word processing in academic and commercial envi- ronments. The project aims to identify format con- version methods and the relationships between de facto and internationally recognized standards. JointElectronics PaymentInitiative JEPI. An idea initiated by CommerceNet and W3C in 1995, JEPI was aimed at developing and demonstrating payment- selection, negotiation, and purchasing electronic commerce scenarios in order to build a commerce mechanism practical for use in real world applications and which could be published as an open standard. The initial inspiration for the technology came from Eastlake's Universal Payment Preamble and the W3C's PEP technology for HTTP transmissions pay- ments. The Open Software Foundation and the Finan- cial Service Technology Consortium were also in- volved in the early stages. The project was organized into four main groups including Browser Technology, Server Technology, Payments Systems, and Merchant Systems. Companies joining the effort were expected to commit to implementing the negotiation protocol in a product for testing. By August 1996, the project had progressed to where Internet Draft documents were distributed in RFC format, in view of an eventual release of an IETF specification of the Universal Payment Preamble (UPP) and the development of an HTTP Extension Protocol (PEP) in the HTTP Working Group. By August 2001, the W3C working group was specify- ing and recommending the syntax and processing parameters for XML signatures. The project is on- going. See e-commerce. Joint Intelligence Virtual Network JIYN. A U.S. Government network for providing round-the-clock TS-SCI multimedia communications, including se- cured videoconferencing. This is one of the multime- dia services supported on the Joint Worldwide Intel- ligence Communications System. JointNetwork Team JNT. An organization founded in March 1979 in the U.K. by recommendations of the Computer Board and Science Research Council (SRC) to study the networking requirements of the academic community and make proposals. The role was transferred to UKERNAAprill, 1994. Joint Photographic Experts Group JPEG (pron. jay-peg). The Joint Photographic Experts Group was founded in 1986 to develop a standard for the com- pression of still, continuous-tone images. Soon after its formation, its goals were adopted jointly by the International Organization for Standardization (ISO) and the International Telegraph and Telephone Con- sultative Committee (CCITT), now the lTU-T. Re- search proposals for such an image compression scheme were solicited internationally, with a dead- 540 line of March 1987. By January 1988, the evaluators had narrowed down the suggestions and selected an Adaptive Discrete Cosine Transform method, culmi- nating in a new standard described in ISO 10918-1 Recommendation T.8. Following the publication of the draft standard, work began on improving com- pression ratios further, and providing scalability. See JPEG file format. jointpole,jointutilitypoleA shared telephone pole resource established in the early telegraphy and tele- phone days. When there were many small switch- boards, rather than one large telephone provider, wires were everywhere, along with many poles to support them. It was not uncommon for individual wires to be running to each business and even to each neighboring business. Utility companies and sub- scribers and those with private lines quickly realized that the sharing ofa telegraph/telephone pole had ad- vantages, including cost, ease of maintenance, and aesthetics. Thus joint poles were designated for car- rying transmission lines belonging to more than one entity. However, coordination ofshared resources became an issue, so joint pole agreements and joint pole committees were established throughout the country in the early 1900s to manage joint poles. As electrical power superseded candles and oil lamps, electrical wires were also slung along telegraph poles, which came to be known as utility poles. Utility poles are still with us and the demand for places to string communications lines has increased dramatically since the mid-1990s. Cable TV and fi- ber optic Internet access cables now share space with the telephone and electrical lines on utility poles. Deregulation has also complicated the administration of poles as to who is responsible for their installa- tion, maintenance, and use. Joint pole committees are still important, perhaps more than ever. New com- munications companies, seeking to establish services at reasonable costs, have a vested interest injoint pole agreements and have shown interest in being involved in joint pole committees in their distribution areas. Some relatively standard configurations for joint poles have developed over the years. In general, the poles are strung in a hierarchical arrangement from top to bottom, based upon the the electrical charac- teristics of the lines strung and the frequency with which they may need to be changed or serviced. Since ground wires aid in deflecting energy discharges from lightning and rarely need to be serviced, they are placed at the top. Moving down the pole, various pri- mary and secondary transmission wires are con- nected. The more recent cable TV or fiber optics bundles running between poles are usually fat, well- shielded cables attached near the bottom, often run- ning in bundles held together with short straps. On poles with. several types of transmission lines, certain distances are maintained between different types of wires to reduce electromagnetic interference. With fiber optic cables, which use light rather than electricity to transmit information, electrical interfer- ence isn't a problem except at points where the fibers are connected through electrical amplifiers or © 2003 by CRC Press LLC where the signal is converted to run on wires. How- ever, optical fibers are dependent upon carefully de- signed splices and joints and, when bundled, don't have the same bend tolerances as small wires, so these factors need to be taken into consideration for fiber more than for wire. The design of insulators and con- necting mechanisms on joint poles is also dependent upon the types of cables and power distribution lev- els carried on the pole. See joint trench, Joint User Service. See the joint pole illustrations and more de- tailed explanation on the following pages. Joint Procurement Consortium JPC. A Bell con- sortium composed ofa number of regional Bell hold- ing companies including Ameritech, BellSouth, Pa- cific Bell, and SBC Communications, which reviews telecommunications product offerings and makes rec- ommendations. In 1996, the JPC signed contracts with Alcatel for ADSL equipment for use over twisted copper pair networks as an alternative to fiber. Joint Technical Committee JTC. The JTC is now called JTC 1. It is an International Standards Organisation/International Electrotechnical Commis- sion (ISO/IEC) information technology standards body concerned with the specification, design, pro- motion, and development of systems used for the cap- ture, representation, and processing of information. http://www.jtc I.org/ joint trenchA means of aggregating cable installa- tions so more than one department or company can share space within a single conduit or other wiring distribution system to save money and to limit the number of individual conduits installed in public ar- eas. For utility services, guidelines and regulations require that other companies using a joint conduit must be contacted before any street upheaval or dig- ging is undertaken. This is important in order to limit the disruption that inevitably occurs when major line changes or installations are made under or near pub- lic streets. See joint pole. Joint User ServiceA tariffed, Federal Communica- tions Commission (FCC) system for buying or oth- erwise sharing telecommunications services by mu- tual agreement. Local public utility service regula- tions have restrictions on how certain services may be shared and may require that all associated users be identified. See joint pole,joint trench. Joint Worldwide Intelligence Communications System JWICS. A U.S secured global multimedia intelligence communications system. The system re- places the Defense Data Network's (DDN's) DSNET3 as the Sensitive Compartmented Informa- tion (SCI) portion of the Defense Infonnation Sys- tem Network (DISN) and is intended to facilitate the rapid exchange of audio/visual data. Data includes videoconferencing, graphics and scanned document files, Defense Intelligence Network (DIN) broad- casts, etc. JWICS was initially set up on a switched TI backbone with TI and, in some cases, slower con- nections, with a plan to transition to faster T3. Much of the communication is relayed via satellites. The system is designed to be installed at all major com- mand sites in addition to the availability of portable versions such as the Mobile Integrated Communica- tions System, which uses a self-contained JWICS system packaged into a set oftransit cases. The lead contractor for the system is the Defense Intelligence Agency (DIA). The goal ofa secure system is not easily realized. In 1999 there were concerns about monitoring indi- vidual user activity on INTELINK as accessed through JWICS. It was realized that there were cir- cumstances where unaudited use could be carried out if local access control (LAC) was not carefully imple- mented and contained. Until the configuration prob- lems could be solved, it was recommended that gov- ernment contractor access be limited to authorized individuals accessing the system through sites where U.S. Government or military personnel were avail- able to oversee. See Joint Intelligence Virtual Net- work. JOLT Project Java Open Language Toolkit Project. A collaborative effort to produce a freely distribut- able "clean-room" clone of Sun Microsystems' Java sufficiently compatible to pass Sun's Java validation suite. The participants instituted a plan to develop a development-quality Java compiler, an embeddable Java interpreter with a full class library, and docu- mentation for all the JOLT components. The initial implementation was targeted for Linux/i386. It was also planned to embed JOLT into a freely distribut- able, full-featured Web browser. See Java. Jones plugAmulticontact polarized receptacle con- nector. Josephson effectA quantum effect, which is not easy to explain, but as an example, imagine a nonsuper- conducting material, such as a semiconductor or non- conductor, sandwiched between layers of supercon- ducting material, so that the supercurrent tunnels through the nonsuperconductor and can variously be affected by magnetic fields. See Josephsonjunction. Josephson junction A fast data technology some- times used in place ofsilicon that provides a means to do very fast circuit switching. Josephsonjunctions can be connected together in series, provided their oscillating properties are matched. This is difficult, but has been achieved in devices called Josephson arrays. Josephson junctions have practical applica- tions in many areas, but are ofparticular interest to researchers and engineers working with precision voltage metering, microwave electronics, and high- temperature superconductors. Named after British researcher Brian Josephson. See Josephson effect. Josephson, Brian (1940- ) A Welsh-born British physicist who received a Nobel Prize for physics in 1973 for his discovery of the Josephson effect. See Josephson effect, Josephsonjunction. Joshi effect 1. In electronics, when alternating cur- rent is passed through a gas dielectric condenser and the gas is continuously irradiated with certain wave- lengths of light, the associated fall or rise in the cur- rent is called the Joshi effect. 2. Similar to a theoreti- cal model called the Prisoner's Dilemma (known to game theorists), Joshi is named for a Reed student from India who proposed a model for behavior on the 541 © 2003 by CRC Press LLC . It does this through a standard management domain, including management services for logging, lookup, schedul- ing, events, security, and transactions through a stan- dardized interface. The system locates and commu- nicates with the services as FederatedBeans compo- nents (a cooperative concept based on the JavaBeans idea). See Java, Just-Enough- Time. JIT See Just-In-Time. JITT Just-In- Time-Training. A laptop-based intelli- gent feedback training project for astronauts and flight operators. The program was established in the mid-1990s by the NASA/Johnson Space Center. jitter 1. Random or periodic. extension to Java that is used in conjunction with toolkits (such as Lucent's Passageways and Sun's JavaTel), to serve as a guide for the creation of applications. JTAPI was jointly developed by Sun Microsystems, IBM, Intel Corporation, Lucent Technologies, Novell Corporation, and Nortel Corporation. 533 © 2003 by CRC Press LLC Fiber Optics Illustrated Dictionary be a few platform-specific functions that people like to use, the JNI is intended to take advantage offunc- tionality on a specific. specification appro- priate for communications in first-party call control in consumer devices to third-party call control in dis- tributed call centers. JTAPI development was begun in the mid-1990s by a consortium ofcomputer and telecommunications