Stac Electronics, originally incorporated as State of the Art Consulting and later shortened to Stac, Inc., was a technology company founded in 1983. It is known primarily for its Lempel–Ziv–Stac lossless compression algorithm and Stacker disk compression utility for compressing data for storage.
The original founders included five Caltech graduate students in Computer Science (Gary Clow, Doug Whiting, John Tanner, Mike Schuster and William Dally), two engineers from the industry (Scott Karns and Robert Monsour) and two board members from the industry (Robert Johnson of Southern California Ventures and Hugh Ness of Scientific Atlanta). The first employee was Bruce Behymer, a Caltech undergraduate in Engineering and Applied Science.
Originally headquartered in Pasadena, California and later in Carlsbad, California, the company received venture capital funding to pursue a business plan as a fabless chip company selling application-specific standard products to the tape drive industry. The plan was to include expansion into the disk drive market, which was much larger than the tape drive market. Following the success of Cirrus in the disk drive market, this was the real basis for venture capitalists' interest in Stac.
As part of the application engineering to adapt its data compression chips for use in disk drives, the company implemented a DOS driver that transparently compressed data written to a PC hard disk and decompressed the data transparently upon subsequent hard disk reads. In doing so they discovered that given the relative speed difference between the PC processor and the disk drive access times, it was possible to perform the data compression in software, obviating the need for a data compression chip in every disk drive, as they were planning to produce. This DOS driver was written in x86 assembly language under contract by Paul Houle.
In 1990 the company released Stacker, a disk compression utility. The product was highly successful, due to the relatively small capacities (20 to 80 megabytes) and high prices of contemporary hard drives, at a time when larger software packages such as Microsoft's new Windows user interface were becoming popular. On average, Stacker doubled disk capacity, and usually increased disk performance by compressing the data before writing and after reading, compensating for the relative slowness of the drives. Stac sold several million units of Stacker over the product's lifetime.