Red Hat Summit2.2. How programs are made
Methods of conversion from human-readable source code to machine code (instructions that the computer follows to execute the program) include the following:
- The program is natively compiled.
- The program is interpreted by raw interpreting.
- The program is interpreted by byte compiling.
2.2.1. Natively Compiled Code
Natively compiled software is software written in a programming language that compiles to machine code with a resulting binary executable file. Such software can be run stand-alone.
RPM packages built this way are architecture-specific.
If you compile such software on a computer that uses a 64-bit (x86_64) AMD or Intel processor, it does not execute on a 32-bit (x86) AMD or Intel processor. The resulting package has architecture specified in its name.
2.2.2. Interpreted Code
Some programming languages, such as bash or Python, do not compile to machine code. Instead, their programs' source code is executed step by step, without prior transformations, by a Language Interpreter or a Language Virtual Machine.
Software written entirely in interpreted programming languages is not architecture-specific. Hence, the resulting RPM Package has the noarch string in its name.
Interpreted languages are either Raw-interpreted programs or Byte-compiled programs. These two types differ in program build process and in packaging procedure.
2.2.2.1. Raw-interpreted programs
Raw-interpreted language programs do not need to be compiled and are directly executed by the interpreter.
2.2.2.2. Byte-compiled programs
Byte-compiled languages need to be compiled into byte code, which is then executed by the language virtual machine.
Some languages offer a choice: they can be raw-interpreted or byte-compiled.
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