Source code is written by programmers and is essentially a list of instructions to a computer which humans are able to read and write. 源代碼是由程序員編寫的，本質上是一連串的人們能夠閱讀和編寫的計算機指令。
An assembler language programmer writes one mnemonic instruction for each machine-level instruction. 彙編語言程序設計員為每條機器指令寫一條助記符指令。
Because of the one-to-one relationship between the language and the machine, assemblers are machine dependent, and a program written for one type of computer won't run on another. 因為彙編指令和機器指令之間存在一一對應的關係，彙編語言和機器語言都是依賴於機器的，所以為一種型號計算機編寫的程序不能在另一種型號的機器上執行。
