Apple Products Evolution

The Apple II was introduced on April 16, 1977 at the first West Coast Computer Faire. It differed from its major rivals, the TRS-80 and Commodore PET, because it came with character cell based color graphics and an open architecture. While early models used ordinary cassette tapes as storage devices, they were superseded by the introduction of a 5 1/4 inch floppy disk drive and interface, the Disk II.
The Apple II was chosen to be the desktop platform for the first "killer app" of the business world—the VisiCalc spreadsheet program. VisiCalc created a business market for the Apple II, and gave home users an additional reason to buy an Apple II—compatibility with the office. According to Brian Bagnall, Apple exaggerated its sales figures and was a distant third place to Commodore and Tandy until VisiCalc came along.
By the end of the 1970s, Apple had a staff of computer designers and a production line. The company introduced the ill-fated Apple III in May 1980 in an attempt to compete with IBM and Microsoft in the business and corporate computing market.
Jobs and several Apple employees including Jef Raskin visited Xerox PARC in December 1979 to see the Xerox Alto. Xerox granted Apple engineers three days of access to the PARC facilities in return for the option to buy 100,000 shares (800,000 split-adjusted shares) of Apple at the pre-IPO price of $10 a share. Jobs was immediately convinced that all future computers would use a graphical user interface (GUI), and development of a GUI began for the Apple Lisa.