Today in Tech History – October 21

1879 - Edison Perfects Light Bulb
             Thomas Edison perfect the first commercial practical incandescent light bulb. Using a filament of carbonized cotton thread, his first attempt at the design results in a bulb that lasts about 13.5 hours before burning out. He later extends the life of bulb to 40 hours. Edison's successful design came only after he had tested over 6000 different vegetable fibers during a span of over 18 months running 1200 experiments and is pending $40000.9

1949 - An Wang Filed a Patent For a Magnetic Ferrite core Memory
             An Wang called his patent " pulse transfer controlling devices." computer designers had been looking for a way to record hundred magnetically stored information without mechanical motion, and Wang's concept of magnetic core memory words central to later computer development.2 years later An Wang found Wang laboratories.

1983 - The seventeenth General Conference on Weights and Measure ruled the meter would be defined as the distance light travels in a vacuum in1/299,792,458 of a second. This actually simplified it from the previous definition of 1,650,763.73 wavelengths of the orange-red emission lion in the electromagnetic spectrum of the Krypton-86 atom in a vacuum.

1991 - Apple Introduces PowerBook
             At the COMDEX computer expo in Las Vegas, Apple introduces the first line of PowerBook notebook computers, the PowerBook 100, PowerBook 140, and PowerBook 170. The first truly portable Macintosh, the PowerBook line redefined portable computing and set the bar for future laptop designs. For example, the PowerBooks were the first laptop to have trackball positioned in front of the keyboard. Most existing PC laptops of the time ran DOS and were therefore keyboard oriented, requiring the use of external mice.

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