The need for large‐volume storage for oceanographic and environmental measurement applications is critical to the success of modern instrument systems. The use of similar media in differing recording applications (ships, buoys, or land stations) strongly enhances ease of analysis. Magnetic media have been used in many forms for years, accompanied by the inherent problems this mediapresents. Recent magnetic disk technology presents unique potential but, for many reasons, is not suitable for field use in applications where extremes of temperature and motion prevail.