Key Terms (applications generation)

Key Terms (applications generation)

1. Translator

   • Interpreter
     • Line by line translation of code, checking for errors. Although this is a good way to identify bugs in the source code, it is a very slow process
   • Compiler
     • Translates code as a whole program into object code. This creates a much more efficent program than an interpreter would, as the compiler steps add a bit more to the code.
   • Assembler
     • Translates assembly language into object code

2. Compilation steps

   • Lexical analysis
     • Identifies keywords(operations, variables) and translates them into tokens. The first step of compiling
   • Syntax analysis
     • The compiler uses this to check that the code written uses valid syntax for it's language. Without this the code will have little meaning.
   • Code generation
     • Converts the source code(after is has been anaylised into object code(a series of instructions for the processor) before the library code is also added.
     • Object code is the code after the source code has been compiled, it is ready for the processor to read it and library code to be added.
   • Optimisation
     • The process of making sure the code runs as quickly as it can using as little memory as possible. Lines of code that have no effect on the outcome of the program can be deleted, more efficent lines of code can also be substituted in.

3. Libraries, Linkers and Loaders

   • Libraries are used to store tasks that have already been coded, to prevent having to code them again.
   • A linkers job is to provide the contents of a library and compiled files together. So they can be exicuted together
     • Static linker
       • This add whatever library code is needed directly into the program that has been compiled, making one large program.
     • Dynamic linker
       • A dynamic linker links the programs together through the OS's loader. This was the library code is only used when the program is run, rather than having one large file.
   • Loaders are a part of the OS that is tasked with loading programs to and from the memory