IPPJ-High and Low Level Programs Lesson

High and Low Level Programs

Programming in its simplest form is the process of creating and modifying a series of 1s and 0s that influences the path of the electrical current, by means of abstraction. A programming language is a set of words, codes, and symbols that allows a programmer to give instructions to the computer. The two different categories of programming languages are low-level and high-level languages.  

 

Low Level Programs

The first is Machine language. It is a first-generation language and consists of 1s and 0s. This is the lowest level of abstraction. Machine Language programmers often handle numbers as hexadecimal digits, meaning groups of sixteen. Hexadecimal is base 16. It uses the numbers 0-9 and A-F to represent 10-15. The binary code is converted to hexadecimal to make it easier to code and read. A program instruction in binary may look like this: 10110000 01100001. This binary code can be made more human-readable by expressing it in hexadecimal B0 61.      

The other low-level language is Assembly language, which has the same instructions and structures as machine language; however, it uses more meaningful names and abbreviations instead of numbers. You might write "add" and "total" instead of "0110101100101000" for an instruction that adds two numbers. It is considered to be a second-generation language. While easier than machine code, assembly languages are still pretty difficult to understand.  

 

High Level Programs

We will be writing in a high-level programming language. In computer science, a high-level programming language is one which has a relatively high level of abstraction. There are several high-level languages, which are considered third-generation languages. They were developed in the late 1950s and have English-like instructions. They are much easier to use than machine language. Some examples of high-level programming languages are Java, C#, and Ruby. The code resembles English words.  

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These high-level programming languages have to be translated into machine language. When you use Java, you will have to run the source code through a compiler, which will check the code for any syntax errors. All syntax errors must be corrected before we can proceed to the next step. Once the code compiles correctly, a new document called Java bytecode is created. Java is a very special language because it is what we call platform independent. Each operating system has its own machine language. Depending on the operating system, the Java bytecode is run through an interpreter which translates the code into something that can be executed by the computer. The Java Virtual Machine translates the bytecode into something that can be run on our machines. This is the reason that Java is so popular. Applications can be posted on the Internet, and then run on any machine that is viewing the page, regardless of the operating system.

The level of abstraction that is needed in order for a language to qualify as a high level programming language does not come without its penalties. Lower level languages are considered to produce more efficient machine readable code because they are conceptually closer to machine code. They are more difficult to program and require a great deal of resources. High level programs are easier to use but lose some functionality due to the abstractions.    

Compare High and Low Programs Activity

Click the learning activity below to Compare High and Low Programs. Drag the statements to either high or low. [CC BY 4.0] UNLESS OTHERWISE NOTED | IMAGES: LICENSED AND USED ACCORDING TO TERMS OF SUBSCRIPTION