The first hardware product was the Z-80 SoftCard which enabled the Apple II to run the CP/M operating system, at the time an industry-standard operating system for running business software and many compilers and interpreters for several high-level languages on microcomputers. The SoftCard was first demonstrated publicly at the West Coast Computer Faire in March 1980. It was an immediate success; 5,000 cards, a large number given the microcomputer market at the time, were purchased in the initial three months at $349 each and it was Microsoft's number one revenue source in 1980.