Just discovered a good article on the history of computing devices from notched bones (yes really) onwards. Well worth reading.

See this fantastic article in The Atlantic Monthly that describes how logic was first invented by Aristotle and then driven forward in the late 19th Century and early 20th Century by some major philosophers until it formed the foundation of digital computers. (Though a shortcoming of the article is its failure to adequately ackknowledge Ada Lovelace.)