core

n. Main storage or RAM. Dates from the days of ferrite-core memory; now
archaic as techspeak most places outside IBM, but also still used in the
Unix community and by old-time hackers or those who would sound like them.
Some derived idioms are quite current; in core , for example, means in
memory (as opposed to on disk ), and both core dump and the core image or
core file produced by one are terms in favor. Some varieties of Commonwealth
hackish prefer store.

