Bill Gates and Paul Allen form Traf-O-Data in 1971 to sell their computer traffic-analysis systems. 1972: Gary Kildall writes PL/M, the first high-level programming language for the Intel microprocessor. Steve Jobs and Steve Wozniak are building and selling "blue boxes" in Southern California in 1971. April 1972: Intel introduces the 8008, the first 8-bit microprocessor. Jonathan A. Titus designs the Mark-8, "Your Personal Minicomputer," according to the July, 1974 cover of Radio-Electronics. Popular Electronics features the MITS Altair 8800 on its cover, January 1975. It is hailed as the first "personal" computer. Thousands of orders for the 8800 rescue MITS from bankruptcy. Pictured below: The Homebrew Computer Club in 1975. Paul Allen and Bill Gates develop BASIC for the Altair 8800. Microsoft is born. 1977: Apple is selling its Apple II for $1,195, including 16K of RAM but no monitor. Software Arts develops the first spreadsheet program, Visicalc, by the spring of 1979. It is released in October and is an immediate success. Copies shipped per month rise from 500 to 12,000 between 1979 and 1981. By 1980 Apple has captured 50% of the personal computer market. In 1980 Microsoft is approached by IBM to develop BASIC for its personal computer project. The IBM PC is released in August, 1981. The Apple Macintosh debuts in 1984. It features a simple, graphical interface, uses the 8-MHz, 32-bit Motorola 68000 CPU, and has a built-in 9-inch B/W screen. Microsoft Windows 1.0 ships in November, 1985. Motorola announces the 68040, a 32-bit 25MHz microprocessor. Microsoft's sales for 1989 reach $1 billion, the first year to do so.