From 0 to O style nimbus:
* The Indian scholar Pingala
(circa 5th-2nd century BC) used binary numbers in the form of short and long syllables.
* In 498 AD, Indian mathematician and astronomer Aryabhata
stated that "from place to place each is ten times the preceding" which is the origin of the modern decimal-based place value notation.
* The rules governing the use of zero appeared for the first time in Brahmagupta's
book Brahmasputha Siddhanta
(The Opening of the Universe), written in 628 AD.
documented the binary numeral system (base 2). In 1679, while mulling over his binary arithmetic, Leibniz imagined a machine in which binary numbers were represented by marbles, governed by a rudimentary sort of punched cards.
* In 1847 Boole
published the pamphlet Mathematical Analysis of Logic
* The "Turing" machine was described in 1936 by Turing
who called it an "a-machine" (automatic machine).
* While consulting for the Moore School of Electrical Engineering, von Neumann
described a computer architecture in which the data and the program are both stored in the computer's memory in the same address space.
submitted a proposal to his superiors at IBM to develop a more practical alternative to assembly language for programming their IBM 704 mainframe computer. The first manual for FORTRAN appeared in October 1956, with the first FORTRAN compiler delivered in April 1957.
* Dijkstra's algorithm, conceived by Dutch computer scientist Dijkstra
, is a graph search algorithm that solves the single-source shortest path problem for a graph with nonnegative edge path costs, producing a shortest path tree.
created the C programming language and, with long-time colleague Ken Thompson, the Unix operating system.
* In 1970, Kay
joined Xerox Corporation's Palo Alto Research Center, PARC. In the 1970s he was one of the key members there to develop prototypes of networked workstations using the programming language Smalltalk.
pioneered the concept of copyleft, and he is the main author of several copyleft licenses including the GNU General Public License, the most widely used free software license.
* +Linus Torvalds
was the principal force behind the development of the Linux kernel. He also created the revision control system Git.
* +Andy Hertzfeld
was a designer for the Macintosh system software. In 2002, he helped Mitch Kapor promote open source software with the Open Source Applications Foundation. Hertzfeld joined Google in 2005, and in 2011 was the key designer of the Circles user interface in Google+.