Altair 8800b microcomputer, c 1975.

UNITED KINGDOM - DECEMBER 07: In 1975 MITS, New Mexico, manufactured a computer based on the Intel 8080 microprocessor. Selling the computer in kit form enabled the company to keep costs low, making it affordable to home users and marking the beginning of the personal computer age. The Altair did not resemble the computers of today. It had no keyboard, visual display, disk drive or storage unit, only a panel covered with lights and switches. This was of little consequence to buyers at the time who, for 397 dollars, were able to purchase their own functioning computer system. Users entered programming instructions using the switches on the front panel and, when the program was loaded, red lights on the panel indicated the results. (Photo by SSPL/Getty Images)