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JBOD See Just a Bunch Of Disks.

Joint Photographic Experts Group (JPEG) JPEG is a group of experts which was formed to produce a standard for compressing images, (ISO/IEC JTC1 SC29). JPEG is also a lossy compression technique that reduces the size of the image data file. However the cost of this is the loss of some information. JPEG is never used for text compression (http://www.jpeg.org/). See Lossy compression.

JND See Just Noticeable Difference.

JPEG See Joint Photographic Experts Group.

Jukebox An archiving jukebox can contain one of many types of media (CD-ROM, tape or disks). The jukebox moves the media from its location by means of a robot or carousel to a reading /writing area. The time for this movement of disk to read is usually 10 - 20 seconds. See Advanced Intelligent Tape (AIT), Digital Linear Tape (DLT), Magneto Optical Disk (MOD), Linear Tape Open (LTO), Digital Audio Tape (DAT) and Digital Versatile Disk (DVD).

Just a Bunch Of Disks (JBOD) A disk based archiving system, analogous to a large disk in a PC, which contains no fault tolerance management of the data. See Redundant Array of Inexpensive Disks (RAID).

Just Noticeable Difference (JND) This is the smallest amount of difference in brightness between two adjacent points on a display that can be perceived by an observer. See Brightness.