Environmental Protection. Didymo (Didymosphenia geminata), also known as rock snot, is a non-native invasive microscopic algae (diatom) that can produce large amounts of stalk material to form thick brown mats on stream bottoms. Didymo threatens aquatic habitat, biodiversity and recreational opportunities.
peripheral device - (computer science) electronic equipment connected by cable to the CPU of a computer; disk drives and printers are important peripherals.
A printer is known as a peripheral device. A computer peripheral is a device that is connected to a computer but is not part of the core computer architecture. The core elements of a computer are the central processing unit, power supply, motherboard and the computer case that contains those three components.