|Noun||1.||DD - a doctor's degree in religion|
Synonyms: Doctor of Divinity
|1.||(storage)||DD - double density.|
|2.||DD - Data Dictionary.|
|3.||dd - A Unix copy command with special options suitable for
block-oriented devices; it was often used in heavy-handed
system maintenance, as in "Let's "dd" the root partition
onto a tape, then use the boot PROM to load it back on to a
The Unix "dd" was designed with a weird, distinctly non-Unixy keyword option syntax reminiscent of IBM System/360 JCL (which had an elaborate DD "Dataset Definition" specification for I/O devices); though the command filled a need, the interface design was clearly a prank.
The jargon usage is now very rare outside Unix sites and now nearly obsolete even there, as "dd" has been deprecated for a long time (though it has no exact replacement). The term has been displaced by BLT or simple English "copy".