TURN ON ANNOTATIONS. There are important updates. Lesson 1 of my series of tutorials on learning the BASIC programming language. Lesson 2 will be uploaded in a few days Please check out my website. A PLC (Programmable Logic Controllers) is an industrial computer used to monitor inputs, and depending upon their state make decisions based on its program or logic, to control (turn on/off) its outputs to automate a machine or a process. NEMA defines a PROGRAMMABLE LOGIC CONTROLLER as.

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As with any modern programming language, Visual Basic supports many common programming constructs and language elements. This guide describes all the major elements of programming with Visual Basic.

In This Section

Program Structure and Code Conventions
Contains documentation on the basic structure and code conventions of Visual Basic, such as naming conventions, comments in code, and limitations within Visual Basic.

Visual Basic Language Features
Provides links to topics that introduce and discuss important features of Visual Basic, including LINQ and XML literals.

COM Interop
Explains the interoperability issues associated with creating and using component object model (COM) objects with Visual Basic.

Related Sections

Visual Basic Language Reference
Provides reference information about various aspects of Visual Basic programming.

Visual Basic Command-Line Compiler
Offers information on using the Visual Basic command-line compiler, the compiler options, and the Keyword Upgrade tool.

BASIC
Designed by
Paradigm	Non-structured, later procedural, later object-oriented
First appeared	May 1, 1964; 55 years ago
Major implementations
Influenced by
Influenced
BASIC Programming at Wikibooks

BASIC (Beginner's All-purpose Symbolic Instruction Code)^[1] is a family of general-purpose, high-level programming languages whose design philosophy emphasizes ease of use. In 1964, John G. Kemeny and Thomas E. Kurtz designed the original BASIC language at Dartmouth College. They wanted to enable students in fields other than science and mathematics to use computers. At the time, nearly all use of computers required writing custom software, which was something only scientists and mathematicians tended to learn.

In addition to the language itself, Kemeny and Kurtz developed the Dartmouth Time Sharing System (DTSS), which allowed multiple users to edit and run BASIC programs at the same time. This general model became very popular on minicomputer systems like the PDP-11 and Data General Nova in the late 1960s and early 1970s. Hewlett-Packard produced an entire computer line for this method of operation, introducing the HP2000 series in the late 1960s and continuing sales into the 1980s. Many early video games trace their history to one of these versions of BASIC.

The emergence of early microcomputers in the mid-1970s led to the development of the original Microsoft BASIC in 1975. Due to the tiny main memory available on these machines, often 4 kB, a variety of Tiny BASIC dialects were also created. BASIC was available for almost any system of the era, and naturally became the de facto programming language for the home computer systems that emerged in the late 1970s. These machines almost always had a BASIC installed by default, often in the machine's firmware or sometimes on a ROM cartridge.

BASIC fell from use during the later 1980s as newer machines with far greater capabilities came to market and other programming languages (such as Pascal and C) became tenable. In 1991, Microsoft released Visual Basic, combining a greatly updated version of BASIC with a visual forms builder. This reignited use of the language and 'VB' remains a major programming language in the form of VB.NET.

11Syntax
- 11.3Examples
15References

Origin[edit]

John G. Kemeny was the math department chairman at Dartmouth College, and largely on his reputation as an innovator in math teaching, in 1959 the school won an Alfred P. Sloan Foundation award for $500,000 to build a new department building.^[2]Thomas E. Kurtz had joined the department in 1956, and from the 1960s they agreed on the need for programming literacy among students outside the traditional STEM fields. Kemeny later noted that “Our vision was that every student on campus should have access to a computer, and any faculty member should be able to use a computer in the classroom whenever appropriate. It was as simple as that.'^[3]

Kemeny and Kurtz had made two previous experiments with simplified languages, DARSIMCO (Dartmouth Simplified Code) and DOPE (Dartmouth Oversimplified Programming Experiment). These did not progress past a single freshman class. New experiments using Fortran and ALGOL followed, but Kurtz concluded these languages were too tricky for what they desired. As Kurtz noted, Fortran had numerous oddly-formed commands, notably an 'almost impossible-to-memorize convention for specifying a loop: 'DO 100, I = 1, 10, 2'. Is it '1, 10, 2' or '1, 2, 10', and is the comma after the line number required or not?'^[3]

Moreover, the lack of any sort of immediate feedback was a key problem; the machines of the era used batch processing and took long times to complete a run of a program. Kurtz suggested that time-sharing offered a solution; a single machine could divide up its processing time among many users, giving them the illusion of having a slow computer to themselves. Small programs would return results in a few seconds. This led to increasing interest in a system using time-sharing and a new language specifically for use by non-STEM students.^[3]

Kemeny wrote the first version of BASIC. The acronymBASIC comes from the name of an unpublished paper by Thomas Kurtz.^[4] The new language was heavily patterned on FORTRAN II; statements were one-to-a-line, numbers were used to indicate the target of loops and branches, and many of the commands were similar or identical. However, the syntax was changed wherever it could be improved. For instance, the difficult to remember DO loop was replaced by the much easier to remember FOR I = 1 TO 10 STEP 2, and the line number used in the DO was instead indicated by the NEXT I.^[a] Likewise, the cryptic IF statement of Fortran, whose syntax matched a particular instruction of the machine on which it was originally written, became the simpler IF I=5 THEN GOTO 100. These changes made the language much less idiosyncratic while still having an overall structure and feel similar to the original FORTRAN.^[3]

The project received a $300,000 grant from the National Science Foundation, which was used to purchase a GE-225 computer for processing, and a Datanet-30 realtime processor to handle the Teletype Model 33teleprinters used for input and output. A team of a dozen undergraduates worked on the project for about a year, writing both the DTSS system and the BASIC compiler.^[3] The main CPU was later replaced by a GE-235,^[3] and still later by a GE-635

The first version BASIC language was released on 1 May 1964.^[5]^[6]

One of the graduate students on the implementation team was Mary Kenneth Keller, one of the first people in the United States to earn a Ph.D. in computer science and the first woman to do so.^[7]

Initially, BASIC concentrated on supporting straightforward mathematical work, with matrix arithmetic support from its initial implementation as a batch language, and character string functionality being added by 1965.Wanting use of the language to become widespread, its designers made the compiler available free of charge. (In the 1960s, software became a chargeable commodity; until then, it was provided without charge as a service with the very expensive computers, usually available only to lease.) They also made it available to high schools in the Hanover, New Hampshire area and put considerable effort into promoting the language. In the following years, as other dialects of BASIC appeared, Kemeny and Kurtz's original BASIC dialect became known as Dartmouth BASIC.

New Hampshire recognized the accomplishment in 2019 when it erected a highway historical marker recognizing the creation of BASIC.^[8]

In This Section

Related Sections

Origin[edit]

Spread on minicomputers

Basic Programming Manual