Even though none of them can be left aside, some particular fields of computer science have played a more determinant role than others with regard to the evolution of viruses. One of the most influential fields has been the development of programming languages.
These languages are basically a means of communication with computers in order to tell them what to do. Even though each of them has its own specific development and formulation rules, computers in fact understand only one language called "machine code".
Programming languages act as an interpreter between the programmer and the computer. Obviously, the more directly you can communicate with the computer, the better it will understand you, and more complex actions you can ask it to perform.
According to this, programming languages can be divided into "low and high level" languages, depending on whether their syntax is more understandable for programmers or for computers. A "high level" language uses expressions that are easily understandable for most programmers, but not so much for computers. Visual Basic and C are good examples of this type of language.
On the contrary, expressions used by "low level" languages are closer to machine code, but are very difficult to understand for someone who has not been involved in the programming process. One of the most powerful, most widely used examples of this type of language is "assembler".
In order to explain the use of programming languages through virus history, it is necessary to refer to hardware evolution. It is not difficult to understand that an old 8-bit processor does not have the power of modern 64-bit processors, and this of course, has had an impact on the programming languages used.
In this and the next installments of this series, we will look at the different programming languages used by virus creators through computer history:
- Virus antecessors: Core Wars
As was already explained in the first chapter of this series, a group of programs called Core Wars, developed by engineers at an important telecommunications company, are considered the antecessors of current-day viruses. Computer science was still in the early stages and programming languages had hardly developed. For this reason, authors of these proto-viruses used a language that was almost equal to machine code to program them.
Curiously enough, it seems that one of the Core Wars programmers was Robert Thomas Morris, whose son programmed -years later- the "Morris worm". This malicious code became extraordinarily famous since it managed to infect 6,000 computers, an impressive figure for 1988.
- The new gurus of the 8-bits and the assembler language.
The names Altair, IMSAI and Apple in USA and Sinclair, Atari and Commodore in Europe, bring memories of times gone by, when a new generation of computer enthusiasts "fought" to establish their place in the programming world. To be the best, programmers needed to have profound knowledge of machine code and assembler, as interpreters of high-level languages used too much run time. BASIC, for example, was a relatively easy to learn language which allowed users to develop programs simply and quickly. It had however, many limitations.
This caused the appearance of two groups of programmers: those who used assembler and those who turned to high-level languages (BASIC and PASCAL, mainly).
Computer aficionados of the time enjoyed themselves more by programming useful software than malware. However, 1981 saw the birth of what can be considered the first 8-bit virus. Its name was "Elk Cloner", and was programmed in machine code. This virus could infect Apple II systems and displayed a message when it infected a computer.
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