Fiber Optics Illustrated Dictionary - Part 55 doc

Java appletAnimportant component ofJava object-oriented programming, an applet is a Java class used to extend Java.. Java Community ProcessJCP.Anopen, internation-ally inclusive means of

Fiber Optics Illustrated Dictionary

JARLSee 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 of

applica-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

relevant to personal communications devices ThePersonalJava 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 of software 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'teasily be pre-dicted in advance will be used The tradeoff is

that the Libraries require a certain amount of space

TheEmbeddedJava application environment is

designed to facilitate development of software for dedicated-function embedded devices which may be stand-alone or embedded Only the class libraries needed to support a prespeci-fied set of tasks are installed onto the EmbeddedJava-enableddevice 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" ofthe 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 appletAnimportant component ofJava object-oriented programming, an applet is a Java 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 A powerful, 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

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 withJDK.,which functions in a

man-ner similar to many common archive utilities See

PKZIP,RAR

Java Community ProcessJCP.Anopen,

internation-ally inclusive means of developing 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 FrameworkJECF A

securable, extensible framework for conducting

elec-tronic commerce, developed by Sun Microsystems

The initial component of JECF is JavaWallet, 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 spaceA means of resolving names in a

software program to Java runtime classes In general,

the system applies to classes, packages, and class

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 namesjavaandsunare reserved by Sun Micro-systems

There was some support for this concept and also some controversy.Ingeneral, 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 InterfaceJNI A Java 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

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 of computer 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 of operation 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

of interest 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

JTAPI 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

on the central processing unit and its support systems

Ifyou 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 TheNM enables Java portability across many different systems See Java

Java XML, JXMLAnarea of development and a mailing list devoted to Java and XML, particularly Java Class and Bean metadata expressed as CML documents, conversion ofmetadatatobytecodes, re-versible conversion of Java 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 a helium-neon gas la-ser, the first laser to emit a steady beam of light and the forerunner of electrical 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 JavaScript Across-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 havbe-ing 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-CTI applications that run on SunXTL, Sun's

propri-etary implementation JavaTel operates with the

So-laris operating system and will run on top of Sun's

earlier CTI implementation, the SunXTL system See

CallPatli, Java Telephony API

JBIGJoint 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

JavaWalletA family of products developed in the

Java programming language for enabling secured

electronic commerce transactions JavaWallet

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 JavaWallet may be used in

Java-enabled browsers, as well See Java

JBIG AllianceAnother name for the JPEG and JPEG

committees officially known as the ISOIIEC JTC 1

SC29 Working Group 1, sometimes abbreviated as

ISO SC29/WG1 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

lossless compression ofmonochrome, grayscale, and

color images

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

JBODSee just a bunch of disks

JCLSee Job Control Language

JDBCJava database connectivity This is a product 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 of Design Communication JDS Uniphase CorporationA 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 JECFSee Java Electronic Commerce Framework JECSSee Job-by-Email Control System

JEDECJoint 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/

JEDISee Joint Electronic Document Interchange JEDICJapan Electronic Data Interchange Council, Japan EDI Council.Aninterdisciplinary council of member organizations, including electronics organi-zations, manufacturers, software developers, and trade associations It was formed in recognition ofthe importance of electronic data interchange (EDI) 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/

JEEVESSee Ask Jeeves

JEEVES DNS ResolverA 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 JEIDASee Japan Electronic Industry Development Association

JEMASee Japan Electronic Messaging Association

Fiber Optics Illustrated Dictionary

JEPI See Joint Electronics Payment Initiative

jerkAmeasure of the rate ofchange ofacceleration,

in other words, the first derivative of acceleration,

similar to the relationship between speed and

veloc-ity and velocveloc-ity and acceleration

JET See Just-Enough-Time

JFIFA minimal implementation of the JPEG family

ofimage compression methods This is often the

im-plementation incorporated into Web browsers See

Joint Photographics Experts Group

JHTML 1.Anopen source cross-platform HTML

editor written in Java by Riyad Kalla 2 AMac-based

plugin application for the Jedit text editor that enables

it to generate HTML code 3 See JavaServer Pages

jiffyA unit of time equal to 1/60 ofa second (North

America), or 1/50 of a second elsewhere Since the

proliferation ofcomputers, 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

jiffybox 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

JiniA 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 offluid

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 CommunityJiniCom Acommunity ofJini

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

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 ofreusable 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 JIOASee Japan Institute of Office Automation JIPS JANET Internet Protocol (IP) Service See JANET

JIROAdevelopment 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

JITSee Just-In-Time

JITTJust-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,

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 toleranceSince jitter is a persistent possibility

in high-performance network systems, especially

those running through a number of interface 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 ofthe jitter effects must also be below that which

the system can tolerate

jitter, networkIn 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 ofthis timing

synchro-nization is partly dependent upon knowing the jitter

characteristics ofthe 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 ofsynchronization 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 ErrorJTIE Atesting

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

jobIn 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

returned to the person who submitted the job (usu-ally on punch cards or paper tape).Inthose 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 termjobis 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 apap-plications 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 byffiMfor the control ofprograms on olderffiMbatch-based computing systems

Job-by-Email Control SystemJECS A software application to facilitate communication between a remote computer (server) and a home or office com-puter.Inother words, it enables a task to be emailed 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 oftimeshare 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- )Anearly 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

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 ofhis

big-gest mistakes

The NeXT corporation was acquired by Apple

Com-puterin1996-1997 Interestinthe 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

A year before the NeXT was released, in 1986, Jobs

purchased the computer division of Lucasfilm, 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 a philosophical 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

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 A Java-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 Ahistoric 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- )AnAmerican member

of the U.S Army who made significant contributions

to the understanding ofnight vision image intensify-ing technology in the 1950s Johnson's findintensify-ings 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 inPhysical Review(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 communicacontribu-tions See Johnson noise

Johnson, Reynold B (ca 1906-1998)AnAmerican research scientist and founding manager (1952) of the IBM Almaden Research Center He later became president of Education Engineering Associates, Johnson pioneered the development ofmagnetic disk technology and computerized educational systems

A prolific inventor, Johnson received more than 90 patents in a range of communications 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,

neer Award The Reynold B Johnson Information

Storage Award was established in his honor in 1992

SeeRAMAC

Johnson noiseInelectronics, 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

calledthermal noise and is characteristically emitted

by all objects with temperatures above absolute zero

Anunderstanding 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 ofcombining data

files or streams In the context of packet

communi-cations, the reassembly ofpackets 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 ifthere 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 funcdestina-tion of a system

In file management, individual parts of a 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 ofdata 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

Intelephony 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

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 aresource 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 anew 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 A junction 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 joint 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

of a 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

Fiber Optics Illustrated Dictionary

Joint Electronic Document Interchange,

UCL-JEDIJED! 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

factoand internationally recognized standards

Joint Electronics Payment InitiativeJEPI.Anidea

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 recommendspecify-ing the syntax and processspecify-ing

parameters forXMLsignatures The project is

on-going See e-commerce

Joint Intelligence Virtual NetworkJIYN.AU.S

Government network for providing round-the-clock

TS-SCI multimedia communications, including

se-cured videoconferencing This is one ofthe

multime-dia services supported on the Joint Worldwide

Intel-ligence Communications System

Joint Network TeamJNT.Anorganization 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 GroupJPEG(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-line ofMarch 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

joint pole, joint utility poleAshared 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 of shared 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 interestinjoint 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 cableTV 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 ofwires 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

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 ofinsulators 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 ConsortiumJPC A Bell

con-sortium composed ofa number ofregional Bell

hold-ing companies includhold-ing 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 CommitteeJTC 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 ofsystems 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 restricregula-tions 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

SystemJWICS 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) porInforma-tion of the Defense InfonnaInforma-tion

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

tions System, which uses a self-contained JWICS system packaged into a set of transit cases The lead contractor for the system is the Defense Intelligence Agency (DIA)

The goal ofa secure system is not easily realized In

1999there 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 iflocal 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 ProjectJava 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.Itwas also planned to embed JOLT into a freely distribut-able, full-featured Web browser See Java

Jones plugAmulticontact polarized receptacle con-nector

Josephson effectAquantum 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 junctionA fast data technology some-times used in place of silicon 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 of particular 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 effect1 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 theoreti-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