During the 1950s, computers were primarily viewed as tools for solving complex math problems, and most people saw the computer as a calculator. Marketing was narrowly targeted, particularly because computers were extremely expensive.
Business to business advertising was the main strategy for computer manufacturers with advertisements focused on "speed, efficiency, economy, and reliability."
Engineers were a primary target and so marketing material tended to be both informative and technical. Since the market was small and highly specialized, direct mailing was the most popular method.