The analytical engine, an important step in the history of computers, was the design of a mechanical general- purpose computer by the British mathematician Charles Babbage. It was first described in 1837. Because of financial, political, and legal issues, the engine was never built. In its logical design the machine was essentially modern, anticipating the first completed general-purpose computers by about 100 years. The input (programs and data) was to be provided to the machine via punched cards, a method being used at the time to direct mechanical looms such as the Jacquard loom. For output, the machine would have a printer, a curve plotter and a bell. The machine would also be able to punch numbers onto cards to be read in later. It employed ordinary base-10 fixed-point arithmetic. There was to be a store (i.e., a memory) capable of holding 1,000 numbers of 50 decimal digits each (ca. 20.7kB). An arithmetical unit (the “mill") would be able to perform all four arithmetic operations, plus comparisons and optionally square roots. Like the central processing unit (CPU) in a modern computer, the mill would rely upon its own internal procedures, to be stored in the form of pegs inserted into rotating drums called “barrels," in order to carry out some of the more complex instructions the user's program might specify. The programming language to be employed by users was akin to modern day assembly languages. Loops and conditional branching were possible and so the language as conceived would have been Turing-complete long before Alan Turing's concept. Three different types of punch cards were used: one for arithmetical operations, one for numerical constants, and one for load and store operations, transferring numbers from the store to the arithmetical unit or back. There were three separate readers for the three types of cards.
Early computer era
Plankalkl is a computer language developed for engineering purposes by Konrad Zuse. It was the _rst high- level non-von Neumann programming language to be designed for a computer and was designed between 1943 and 1945. Also, notes survive with scribblings about such a plan calculation dating back to 1941. Plankalkl was not published at that time owing to a combination of factors such as conditions in wartime and postwar Nazi Germany. By 1946, Zuse had written a book on the subject but this remained unpublished. In 1948 Zuse published a paper about the Plankalkl in the “Archiv der Mathematik" but still did not attract much feedback - for a long time to come programming a computer would only be thought of as programming with machine code. The Plankalkl was eventually more comprehensively published in 1972 and the first compiler for it was implemented in 1998. Another independent implementation followed in the year 2000 by the Free University of Berlin. Plankalkl drew comparisons to APL and relational algebra. It includes assignment statements, subroutines, conditional statements, iteration, floating point arithmetic, arrays, hierarchical record structures, assertions, exception handling, and other advanced features such as goal-directed execution. Thus, this language included many of the syntactical elements of structured programming languages that would be invented later, but it failed to be recognized widely.
Short Code was one of the first higher-level languages ever developed for an electronic computer. Unlike machine code, Short Code statements represented mathematic expressions rather than a machine instruction. Short Code was proposed by John Mauchly in 1949 and originally known as Brief Code. William Schmitt implemented a version of Brief Code in 1949 for the BINAC computer, though it was never debugged and tested. The following year Schmitt implemented a new version of Brief Code for the UNIVAC I where it was now known as Short Code. While Short Code represented...