9 - Programming Languages

Abstract

This chapter focuses on the differences among machine, assembly, and high-level programming languages. The chapter reviews the operation of program translators such as assemblers, compilers, and interpreters. Each computer can understand only its own machine language. Machine language instructs a computer to perform its most fundamental operations, machine language consists of strings of numbers—reduced to 1s and 0s—that cause the computer to perform various operations, and machine languages are said to be machine dependent—they are closely related to the structure of a particular computer. However, programmers rarely write in machine language. Today assembly languages or high-level languages are used. A program of instructions written in assembly language is called a source program—an assembler program translates it into a machine language program also called an object program. Programs can be written faster in assembly language, but they must be translated into machine language before execution. Machine dependent assembly language programs are not portable.