Glossary- J
A Data Communication Historical Series
By Bob Pollard

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The continuous flow of garbage from a failed terminal, resulting in a lockup of a LAN, which locks out other users or resulting in a line made unavailable to others.

In IEEE 802.3, a data packet whose length exceeds that prescribed in the standard.


Hardware devices on which the permanent wiring of telecommunications circuits or apparatus is terminated to provide a physical access point by the insertion of a plug. See Technical Control (TC).


Causing a disturbance or interference to open air radio transmission in order to deliberately prevent clear communications


Joint Army, Navy, and Air Force Publication


Joint Academic Network: X.25 WAN connecting university and research institutions in the United Kingdom.


Java is a network programming language invented by Sun Microsystems. Java is often used to build large, complex systems that involve several different computers interacting across networks, such as transaction processing systems. A very common use of Java is to create programs that can be safely downloaded to your computer through the Internet and immediately run without fear of viruses or other harm to your computer or files. Using small Java programs (Applets), Web pages can include functions such as animation’s or calculators, and other fancy features.


  A programming language: Mostly used in the construction of web pages and provides features that make the web page more interactive. When Java Script is included in an HTML (Hypertext Markup Language) file it relies on the browser to interpret the Java Script. When Java Script is combined with Cascading Style Sheets (CSS) and later versions of HTML (4.0 and later) the result is often called DHTML (Dynamic Hypertext Markup Language).

  JavaScript is a scripting language that can run wherever there is a suitable script interpreter such as Web browsers, Web servers, or the Windows Scripting Host. The scripting environment used to run JavaScript greatly affects the security of the host machine:

  A Web page with JavaScript runs within a Web browser in much the same way as Java applets and does not have access to host machine resources.

  An Active Server Page (ASP) or a Windows Scripting Host (WSH) script containing JavaScript is potentially hazardous since these environments allow scripts unrestricted access to machine resources (file system, registry, etc.) and application objects.


Just a Bunch of Disks: A group of hard disks, usually without intelligence (processors).


Joint Computer Aided Logistics System


Joint Communications Control Center


Java Database Connectivity: Java API that enables Java programs to execute SQL statements. This allows Java programs to interact with any SQL-compliant database. Because nearly all relational database management systems (DBMS) support SQL, and because Java itself runs on most platforms, JDBC makes it possible to write a single database application that can run on different platforms and can interact with different DBMS(s). JDBC is similar to ODBC but is designed specifically for Java programs, whereas ODBC is language-independent. JDBC was developed by Java-Soft, a subsidiary of Sun Microsystems.


Java Development Kit: A software development package from Sun Microsystems that implements the basic set of tools needed to write, test and debug Java applications and applets.


Job Entry Subsystem: Usually refers to an IBM host environment involving the control program and procedures for the host processing of a job or series of jobs and related tasks.


Joint Interface Operating Procedures-Message Text Formats


Refers to a form of line distortion caused when a transmitted signal continuously deviates from its reference timing position, causing errors.

The inter-packet delay variance; that is, the difference between inter-packet arrival and departure. Jitter is an important QoS metric for voice and video applications.


Joint Operation Planning and Execution System (JOPES): Network Operations Control Center


A set of data programs files and instructions, Job Control Language (JCL), IBM terminology.




A system level structure that allows single processes to be grouped together and managed as a single unit.


Usually a harmless program: Cause various illustrations to display on the monitor screen, such as a screen saver.


These are not viruses, but may contain a virus if infected or otherwise altered.


Joint Photographic Experts Group: An ISO (International Standards Organization) generated video compression standard for storage and transmission of still graphic image formats.


Java Telephony Application Programming Interface: A call control model developed by Sun Microsystems.

J2ME (Java 2 Micro Edition):

Java environment optimized to run applications on small devices with limited processing power and memory. See BREW for a similar technology from QUALCOMM.


Refers to search index software that can be applied to an organization's gopher menus; it is similar to Veronica. It supposedly was named for its inventor, Rhett Jones, as Jonzy's Universal Gopher Hierarchy Excavation and Display.


The highest Frequency Division Multiplexing (FDM) carrier system level that contains 3600 voice frequency (VF) or telephone channels in six master groups, also known as hyper group.


The wire/wires used to cross-connect circuits for testing or diagnostic purposes. This may be accomplished on a wiring block or main frame; normally not a patch cord action.

Electrical switch consisting of a number of pins and a connector that can be attached to the pins in a variety of ways; Different circuits are created by attaching the connector to different pins.

JUNCTION:A junction is a point in the telecommunications network that comprises a switching office or facility cross-connect and/or ADM hardware; a point of connectivity where multiple fiber links come together, and/or a source or destination for a wavelength path.


Japan UNIX Network: Nationwide, noncommercial network in Japan, designed to promote communication between Japanese and other researchers.


John von Neumann Computer Network: A regional network owned and operated by Global Enterprise Services, Inc.; composed of T1 and slower serial links that provide midlevel networking services to sites in the Northeastern United States.