Stac Electronics was an engineering company founed in 1983 by seven friends at Caltech. Originally headquartered in Pasadena, California and later in Carlsbad, California, the company developed interesting hardware and software technology, but struggled financially, until the release of Stacker disk compression software in 1990. This product was a runaway hit in the days when disk drives had relatively small capacities (20 to 80 megabytes) and were very expensive. Stacker doubled disk capacity (on average), and usually increased disk performance by reducing the amount of data that had to be read or written. Stac sold several million units of Stacker over the product's lifetime.