Bitmaps You've probably heard of binary, the way that computers represent decimal numbers 1,2,3,4 and so on using just the two digits zero and one so the decimal number becomes in binary computer speak. Later still, you decide to program it to store your photo collection.
Electronic data processing[ edit ] Atanasoff—Berry Computer replica at first floor of Durham Center, Iowa State University Purely electronic circuit elements soon replaced their mechanical and electromechanical equivalents, at the same time that digital calculation replaced analog.
As an analog computer does not use discrete values, but rather continuous values, processes cannot be reliably repeated with exact equivalence, as they can with Turing machines. For example, they all need to be able to read the keys pressed down on the keyboard, store things in memory and retrieve them, and display characters or pictures on the screen.
And since these early computers ran on bulky vacuum tubes, scientists hoping to improve processing speeds would either have to find bigger rooms—or come up with an alternative. What parts does the object contain and how do they all connect together?
Computer-aided design solves these problems in a particularly subtle way. Military to do ballistics calculations, the ENIAC weighs 30 tons and fills an entire 1, square foot room. Once a program was written, it had to be mechanically set into the machine with manual resetting of plugs and switches.
Apart from making it easy to swap data, USB also provides power to things like external hard drives.