Toward the end of the mainframe era, in the early 1970, interactive programming made its appearance. Rather than developing a program on a deck of cards, cathode ray tube terminals were directly connected to the computer. The computer was able to time share by enabling each user to have a small slice of the computer’s processor time.
Thus, if 20 users were connected to a computer, and each user had a time slice of 25 milliseconds, then each user would have two such slices or 50 milliseconds of computer time each second.
In an interactive environment, a
program interacts directly with user at a display console during its execution, by atternately sending output to the display and reciving input from the keyboard or mouse.
Examples include word-processing systems, spreadsheets, video games, database management systems, and computer assisted instruction systems.