List and Explain the Characteristics of an Operating System

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A compiler is a computer program that implements a programming language specification to "translate" programs, usually as a set of files which constitute the source code written in source language, into their equivalent machine readable instructions (the target language, often having a binary form known as object code). This translation process is called compilation. We compile the source program to create the compiled program. The compiled program can then be run (or executed) to do what was specified in the original source program. The source language is always a higher-level language in comparison to machine code, written using some mixture of English words and mathematical notation, assembly language being the lowest compilable language (an assembler being a special case of a compiler that translates assembly language into machine code). Higher-level languages are the most complex to support in a compiler/interpreter, not only because they increase the level of abstraction between the source code and the resulting machine code, but because increased complexity is required to formalize those abstract structures. The target language is normally a low-level language such as assembly, written with somewhat cryptic abbreviations for machine instructions, in this cases it will also run an assembler to generate the final machine code. But some compilers can directly generate machine code for some actual or virtual computer e.g. byte-code for the Java Virtual Machine. Another common approach to the resulting compilation effort is to target a virtual machine. That will do just-in-time compilation and byte-code interpretation and blur the traditional categorizations of compilers and interpreters. For example, C and C++ will generally be compiled for a target `architecture'. The draw-back is that because there are many types of processor there will need to be as many distinct compilations. In contrast Java will target a Java Virtual Machine, which is an...
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