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.
Types of Peripheral Devices. Peripheral devices can be external or internal. 1  Examples of external peripherals include mouse, keyboard, printer, monitor, external Zip drive or scanner.  Examples of internal peripherals include CD-ROM drive, CD-R drive or internal modem.