J
 
 JAD
 
      Joint Application Design; techniques developed by IBM that make
      systems development a joint effort between the information
      systemsdepartment and the departments for which the system is
      intended.
 
 JBIG
 
      Joint Bi-level Image experts Group. A proposed standard for the
      compression of grayscale images. Uses the same arithmetic
      estimation algorthms (called the QM Coder) as JPEG.
 
 JCL
 
      1. Job Control Language. (IBM) 2. Job Command Language.
 
 JIS
 
      Japanese Industrial Standard.
 
 JITC
 
      Joint Interoperability Test Center; maintains publiclyavailable
      product registers of GOSIP conformance and interoperability.
 
 jitter
 
      Type of line distortion caused by the variation of a signal from
      its reference timing positions that can cause data transmission
      errors and loss of synchronization in high-speed synchronous
      communications.
 
 join
 
      In relational database management, to match one file against
      another based on some condition creating a third file with data
      from the matching files.
 
 joins
 
      In OCR, characters that touch, or otherwise do not have white
      boundaries around all their edges.
 
 journal drive
 
      An optical disk drive that records all database activity as as it
      happens.
 
 journal printer
 
      Special-purpose printer which provides hard-copy output for audit
      trail and demand printing functions.
 
 JOVIAL
 
      Jules Own Version of the International Algebraic Language
      (programming language).
 
 JPEG
 
      Joint Photographic Experts Group. An ISO/ITU-TSS standard for still
      color image compression.
 
 JPEG++
 
      Storm Technology's proprietary extension to JPEG.
 
 JTM
 
      Job Transfer and Manipulation, defined in IS 8831.
 
 jukebox
 
      Storage device for multiple sets of CD-ROMs, tape cartridges or
      disk modules. Using carousels, robot arms and other methods, a
      jukebox physically moves the storage medium from its assigned
      location to an optical or magnetic station for reading and writing.
 
 jumper
 
      A wire used to link equipment and cable on a distributing frame.
 
 junctor
 
      An internal switching system connection between lines and trunks.