micros~1 = M = middle-out implementation

middle-endian adj.

Not big-endian or little-endian. Used of perverse byte orders such as 3-4-1-2 or 2-1-4-3, occasionally found in the packed-decimal formats of minicomputer manufacturers who shall remain nameless. See NUXI problem. Non-US hackers use this term to describe the American mm/dd/yy style of writing dates (Europeans write little-endian dd/mm/yy, and Japanese use big-endian yy/mm/dd for Western dates).

--The Jargon File version 4.3.1, ed. ESR, autonoded by rescdsk.