What is a Low-Level Programming Language?
There is some disagreement regarding the exact definition of a low-level programming language, but all definitions share some things in common regarding the characteristics of such a computer language. Those characteristics include: similarity to binary code, required knowledge of the role of the central processing unit (CPU) and the ability of the programmer to control hardware via the language. Some people consider any computer language a low-level one if it is not similar to a language that people speak. Others consider any language that requires the programmer to understand the intricate and very complex workings of the CPU a low-level one. It should be remembered that a truly low-level programming language generally fits all of these descriptions.
Binary code, also called machine code, is the only language that the CPU, or the "brain" of a computer, understands and "speaks." Machine code, if viewed by a person, looks like many sequences of the numerals 1 and 0; they represent a state of being on or being off, much like a light that is either turned on or turned off. Code of a high-level programming language would look very different from machine code in that it contains symbols and actual words that are used in a language, usually English, that people speak. This does not mean, however, that someone who is not a computer programmer would understand the code in a high-level language any more than they would a low-level one.
Among the greatest advantages of a low-level programming language is the ability and freedom to exercise precise control over things such as memory usage and processing time. This means that programs written in a low-level language should make very efficient use of system resources, which can be highly desired when coding for systems with very limited resources. Such an advantage does not come without a price. Developers and engineers who code in a low-level programming language must have a sound understanding of the functions of the CPU in order to write instructions that affect memory and processing time.
Coding in a low-level programming language is extremely time consuming and tedious. This understandably increases the cost involved with having a program developed in such a language, because the equivalent of as little as two lines of code in a high-level language can require as many as 20 lines in a low-level programming language. Such slow development makes low-level languages primarily suited for very small programs. They are hardly ever used for the development of larger programs.
@Mammmood - I agree. C is not a low level programming language; it just gives you comparable speed to one. However nowadays this is all a moot point. Nobody needs that kind of power anymore because computers have increased their processing speed.
We even have languages like C# which are compiled down to an intermediate interpreter, yet C# seems to be all the rage. Everyone is using it instead of C++ and Java in my opinion. The low level stuff is reserved for people working on portable devices and firmware.
@NathanG - A question that came in forums in those days was, did anyone consider C programming to be a low level language?
I stumbled upon this question when I was learning C, and there those programmers who saw it as their aim to try to separate the men from the boys in the programming world.
They said C should be considered as much a low level language as any of the assembly languages.
I tended to disagree however. C was much more human readable than either assembly or machine language, and apart from its use of pointers, was closer even to BASIC in terms of its constructs and so forth.
@hamje32 - Yes, I remember those days. I had a TRS-80 model III and while I would normally program in BASIC, sometimes I would find a low level programming language example from a book or hobbyist computer magazine and try to enter it directly into the computer.
There wasn’t much room for error. One wrong word or hexadecimal character and your program would crash. But as you said, in those days, when hardware was at a minimum and memory was at a premium, that was the only way that you could achieve any real speed.
I remember the early space invaders and other graphics types programs – some of them were not that sophisticated in terms of visuals, but what they lacked in visuals they made up for in thoughtfulness. They were written in machine language and I would load them from a cassette player, since I didn’t have a floppy disk.
I remember when computers first came out in the early 1980s. At that time machine level language and assembly language were two of the earlier low-level programming languages.
As a matter of fact, short of coding in complete binary – which was impossible for any programmer – these two low-level computer languages were as close as you were going to get to actually communicating with the computer’s memory.
Assembly was a little easier. I tried both. Machine language was made up of hexadecimal commands sent to the register, whereas assembly language had English commands like “Mov,” “Push” and “Pop” that did the same things.
In those days, if you wanted speed you had to go low-level. I couldn’t tolerate it myself because of how tedious it was, so I stuck with BASIC programming, which didn’t give me speed, but it sure was easy.
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