A compiler is a specialized computer program that converts source code written in one programming language into another language, usually machine language (also called machine code) so that it can be understood by processors (i.e., logic chips).
Source code is the version of software (usually an application program or an operating system) as it is originally written (i.e., typed into a computer) by a human in plain text (i.e., human readable alphanumeric characters). Source code can be written in any of numerous programming languages, some of the most popular of which are C, C++, Java, Perl, PHP, Python and Tcl/Tk. The output of a compiler is referred to as object code.
The FORTRAN team led by John Backus at IBM is generally credited as having introduced the first complete compiler, in 1957.
The first compiler for pascal was written on paper by Wirth, who then ran it by hand on itself, and then manually entered the resulting machine code. By dint of attention to detail, he then had a working pascal compiler.
The A-0 system, written by Grace Hopper in 1951 and 1952 for the UNIVAC I, was the first compiler ever developed for an electronic computer. The A-0 functioned more as a loader or linker than the modern notion of a compiler. A program was specified as a sequence of subroutines and arguments. The subroutines were identified by a numeric code and the arguments to the subroutines were written directly after each subroutine code. The A-0 system converted the specification into machine code that could be fed into the computer a second time to execute the program.
Source: Wikipedia , few of the IT enlightened Friends …
