The native language of the computer. In order for a program to run, it must be presented to the computer as binary-coded machine instructions that are specific to that CPU model or family. Although programmers are sometimes able to modify machine language in order to fix a running program, they do not create it. Machine language is created by programs called "assemblers," "compilers" and "interpreters," which convert the lines of programming code a human writes into the machine language the computer understands.|
Machine languages differ substantially. What may take one instruction in one machine can take 10 instructions in another. See RISC.
What and Where
Machine language tells the computer what to do and where to do it. When a programmer writes TOTAL = TOTAL + SUBTOTAL, that statement is converted into a machine instruction that tells the computer to add the contents of the two areas of memory where TOTAL and SUBTOTAL are stored and put the result in TOTAL.
Logical Vs. Physical
A programmer deals with data logically, "add this, subtract that," but the computer must be told precisely where this and that are located. See hardware platforms, assembly language, interpreter and RISC.