Evolution of Programming Languages - PowerPoint Presentation

I will examine the different generations of programming languages and discuss basic facts about each. I will also discuss the Fifth Generation Language, which some individuals may or may not agree exists.

Computers can understand only ones and zeros, or binary language. Basically ones and zeros represent on or off signals to the computer, and are known as bits. The first-generation programming instructions were entered through the front panel switches of the computer system. On the earliest computers this was completed by changing the wires, dials and switches. Later the bits could be entered using paper tapes that looked like ticker tape from a telegraph, or punch cards. With these tapes and or cards the machine was told what, how and when to do something.

To have a flawless program a programmer needed to have a very detailed knowledge of the computer where he or she worked on. A small mistake could cause the computer to crash. Originally, no translator was used to compile or assemble the first-generation language. The main benefit of programming in a first-generation programming language is that the code a user writes can run very fast and efficiently, since it is directly executed by the CPU.

Each CPU manufacturer has its own machine language. This means that programs that are written for one type of CPU will not work on any other type of CPU. PC's, Apple's, and even different generation Pentium processors all have their own machine language with are not compatible between each other.

Because the first generation languages were regarded as very user unfriendly people set out to look for something faster and easier to understand. The result was the birth of the second generation languages (2GL) at the mid of the 1950's. These generation made use of symbols and are called assemblers. An assembler is a program that translates symbolic instructions to processor instructions.

A programmer no longer had to work with one's and zero's when using an assembly language; he or she can use symbols instead. These symbols are called mnemonics (STO = store or MOV = move) and are used in conjunction with different numeral systems like hexadecimal to give the computer instructions. Assembler language still works on a very low level with the computer with the language specific to and dependent on a particular processor family and environment.

Second-generation languages are sometimes used in kernels and device drivers, but more often find use in extremely intensive processing such as games, video editing, graphic manipulation/rendering, emulation/virtualization, simulation, encryption and compression.

In the late 50's Dr. Grace Murray Hooper developed the idea of writing programs using English instructions called source code. A computer program, called a compiler, would then convert this source code into a form that the computer could understand. With a 3GL there was no longer a need to work with symbolic commands. Instead a programmer could use a programming language what resembles a natural language. A fragment might be: let b = c + 2 * dThe oldest 3GL is FORTRAN (Formula Translation) which was developed around 1953 by IBM. This is a language primarily intended for technical and scientific purposes. Standardization of FORTRAN started 10 years later, and a recommendation was finally published by the International Standardization Organization (ISO) in 1968. COBOL (Common Business Oriented Language) was developed around 1959 and is like its name says primarily used, up till now, in the business world.

4GL programming language is a programming environment designed with a specific purpose in mind, such as the development of commercial business software. In the evolution of computing, the 4GL followed the 3GL in an upward trend toward higher abstraction and statement power. The primary feature is that you do not indicate HOW a computer must perform a task but WHAT it must do. In other words the assignments can be given on a higher functional level such as: SELECT * FROM STUDENT.

A few instructions in a 4GL will do the same as hundreds of instructions in a lower generation language like COBOL or BASIC. Applications of 4GL's are concentrating on the daily performed tasks such like screen forms, requests for data, change data, and making hard copies. In most of these cases 4GL deals with structured query language (SQL) or Data Base Management Systems (DBMS).

Part of the 4GL deals with markup languages. This is a sequence of characters or symbols, called tags, which determine how a document should look. Hypertext markup language (HTML) is a specific markup language that gives formatting instructions that determine how a Web browser will display the contents of a document.

Some say that 5GL is a programming language based around solving problems using constraints given to the program, rather than using an algorithm written by a programmer. While fourth-generation programming languages are designed to build specific programs, fifth-generation languages are designed to make the computer solve the problem for you. Fifth-generation languages are used mainly in artificial intelligence research. Prolog, OPS5, and Mercury are the best known fifth-generation languages.

Another group looks at 5GL as programming that uses a visual or graphical development interface to create source language that is usually compiled with a 3GL or 4GL language compiler. Others say that there is no fifth generation language.

The idea of generational languages is that each is an abstraction of the former, so we had machine code; assembler; third generation languages such as COBOL, FORTRAN and so forth; and finally 4GLs. You can't get a further level of abstraction than a 4GL so there can't be such a thing as a 5GL.

Reference:•Robat, C (2007). Introduction into software history. Retrieved February 8,2008, from The History of Computing Project Web Site: http://www.thocp.net/software/software_reference/introduction_to_software_history2.htm#sofwaregenerations•Malaga, R (2005). Information systems technology. New Jersey: PearsonEducation, Inc•Wikipedia, (2007). Fifth-generation programming language.

Retrieved February 10, 2008, from Wikipedia Web site: http://en.wikipedia.org/wiki/5GL