Programming language generations
I
n
the computer industry, these abbreviations are used to represent
main steps or "generations" in the history of programming
languages.
1GL or first-generation language was (and still is) machine language or the level of instructions and data that the processor is actually given to work on (which in computers is a string of 0s and 1s).
2GL or second-generation language is assembler language. An assembler converts the assembler language statements into machine language.
3GL or third-generation language is a "high-level" programming language, such as PL/I, C, or Java.
A compiler converts the statements of a specific high-level programming language into machine language. (In the case of Java, the output is called bytecode, which is converted into appropriate machine language by a Java virtual machine that runs as part of an operating system platform.)
4GL or fourth-generation language is designed to be closer to natural language than a 3GL language. Languages for accessing databases are often described as 4 GLs.
5GL or fifth-generation language is programming that uses a visual or graphical development interface to create source language that is usually compiled with a 3 GL or 4 GL language compiler. Microsoft, Borland, IBM, and other companies make 5GL visual programming products for developing applications in Java, for example. Visual programming allows you to easily envision object-oriented programming class hierarchies and drag icons to assemble program components.
Ex.4 Retell the text “Programming language generations”.
Ex.5 Read and translate into Russian:
An assembler is a program that takes basic computer instructions and converts them into a pattern of binary digit that the computer's processor can use to perform its basic operations.
Today, assembler programming is used only where very efficient control over processor operations is needed. Historically, most programs have been written in "higher-level" languages such as COBOL, FORTRAN, PL/I, and C. These languages are easier to learn and faster to write programs with than assembler language. The program that processes the source code written in these languages is called a compiler. Like the assembler, a compiler takes higher-level language statements and reduces them to machine code.
A
compiler
is a special program that processes statements written in a
particular programming language and turns them into machine
language or "code" that a computer's processor
uses. Typically, a programmer writes language statements in a
language such as Pascal
or C
one line at a time using an editor.
This file contains what is called the source
statements.
The programmer then runs the appropriate language compiler,
specifying the name of the file that contains the source
statements. When
executing (running), the compiler first analyzes all of the
language statements syntactically one after the other and then
builds the output code. Traditionally, the output of the
compilation has been called object
code
or sometimes an object
module.
The object code is machine code that the processor can process or
"execute" one instruction at a time.
Bytecode is computer source code that is processed by a program. The virtual machine converts generalized machine instruction into specific machine instructions (instructions that this computer's processor will understand). Bytecode is the result of compiler source code written in any language that supports this approach (подход). Most computer languages, such as C and C++, require a separate compiler for each computer platform. Windows and the Intel line of microprocessor architectures are one platform; Apple and the PowerPC processors are another. Using a language that comes with a virtual machine for each platform, your source language statements need to be compiled only once and will then run on any platform.
Ex.6 Pick up the international words in ex.5, pay attention to their pronunciation.