dd(1) and JCL

The dd(1) command is very common utility in Unix systems, used to write images, files and so on.

But where does the name dd comes from?
I thought it came from something like data dumper or something like that. I was wrong!
I discovered the name comes from the worst language ever implemented: JCL or Job Control Language.

JCL, in fact, includes a directive to define a source for data named DD, that in turn is a directive for a dataset, a fancy name for a file.
Last, dd copies its name from the DD directive, and also jokes on that! As usual, Unix is more than operating system, it’s a culture!