Computer Science is the study of computers and their usage for computation, systems control, data processing, and information retrieval. It deals with the design and analysis of algorithms, software development, hardware design, database management systems, artificial intelligence (AI), networking, and parallel computing. Computer science also encompasses other fields such as programming languages, computer graphics, human-computer interaction (HCI), cryptography, and digital forensics.
The history of computer science can be traced back to early pre-historic times when people started using counting rods and pebbles for simple arithmetic computations. The first known mechanical calculator was invented by Blaise Pascal in the 17th century. In the 19th century, Charles Babbage designed a programmable mechanical computer called the Analytical Engine but it was never completed due to lack of funds. In 1937, John Atanasoff and Clifford Berry developed the first electronic computer called the Atanasoff–Berry Computer (ABC). However, this machine was not actually built until 1973. In 1941–1942 Konrad Zuse designed and built the first fully functional programmable Turing complete calculator called the Z3 which used Boolean logic instead of binary numbers like previous machines. Turing complete means that a machine can perform any calculation that could be done by hand if given enough time and memory space.
During World War II many advances were made in digital computing due to war needs such as code breaking and ballistics trajectory calculations. Alan Turing played a pivotal role in Crackin codes at Bletchley Park using an electromechanical device called The Bombe which helped decipher German messages encrypted with Enigma machines. Colossus was another machine used at Bletchley Park for codebreaking; it could read 5500 characters per second from paper tape allowing operators to look for patterns manually. At Harvard University in 1944 Howard Aiken built Mark I which was a large scale electro-mechanical computer 7 feet tall weighing 5 tons consisting of 500 miles of wire! This machine could perform 3 operations per second on 20 digit numbers however it was not very versatile since each problem required special wiring configuration changes before being run on Mark I
In 1945 John von Neumann wrote a report detailing his ideas for an electronic stored program digital computer which became blueprint for modern computers known as Von Neumann architecture or EDVAC (Electronic Discrete Variable Automatic Computer). This new type of computer could store both instructions AND data in its memory thereby greatly reducing reloading time between successive calculations compared to earlier machines like Mark I where instructions had to be fed into separate storage units located outside main memory unit holding only data.. This breakthrough allowed much more complex programs to be written since now loops & subroutines could easily be implemented leading way towards development high level programming languages like FORTRAN & COBOL during 1950s