In the last several years, Visual Basic has evolved rapidly. Until recently, Visual Basic was a proprietary language used only by Microsoft products. Microsoft now licenses Visual Basic for Applications to those software developers who want to add programmability to their applications. This will increase Visual Basic prevalence. ...
Interpreted or Compiled Languages
Computer languages can be interpreted or compiled. An interpreter executes a program, while a compiled language uses a compiler to translate the high-level language into machine language. Visual Basic is now both an interpreted language and a compiled language. The developer has a choice when creating a Visual Basic executable whether...
Low-Visual and High-Visual Languages
Computer languages can be described as having a low-visual or a high-visual orientation. Prior to 1990, most languages were low-visual languages, so programmers had considerable difficulty designing the computer forms and reports, data entry screens, and navigation tools...
Procedure-Oriented and Event-Oriented Languages
Besides low-level and high-level languages, computer languages can be classified as procedure-oriented or event-oriented. Procedure-oriented languages tend to run without human interference or the taking of some action by the user: A computer program is executed by a simple run instruction, and usually runs from top to bottom, with all the code...
Learning How VB Differs from other Languages
Of the 1,000 or so computer languages that have been developed, each language can be categorized based upon the following criteria:
Low-level or High-level
Procedure-oriented or Event-oriented
High-visual or Low-visual
Interpreted or compiled
Imagine 1,000 or so languages! Where does Visual Basic fit? This section...
Running a Visual Basic Program
Welcome to the world of Visual Basic. Released by Microsoft in 1991, Visual Basic was designed to be a visually oriented programming language in contrast to the popular languages of that time (Pascal, C, COBOL, and FORTRAN). Although Visual Basic is similar to QBasic – the procedural languages supplied with every version of MS-DOS beginning...
Introduction
Visual Basic is the most popular programming language for the world’s most popular operating system. By encapsulating the complexities of the windows application program interface (API) into easily manipulated objects, Visual Basic is the first language people consider when they want rapid application development for the Windows environment. ...
Data Processing Concepts
Computer processing involves manipulating the symbols that represent things. It is the fastest and most accurate way of performing human tasks. The word ‘data’ is the plural of ‘datum’ means fact. It has three basic activities:
a) Capture Input data through input devices.
b) Manipulate by:
organizing similar...
Concept of File
The data needed to develop a file are gathered from different sources. These facts are then logically organized and stored in storage media to create a file records. The objectives of file organization are: (1) To provide a means for locating, processing, select...
Softwares
Softwares are Programs. A program is a set of instruction to the computer to make it do things. Computers are just an inert mass of electronic gadgetry. It comes to life only when a program is fed into it. these programs can be bought or tailor made. There are three types of softwares - System, Utility and Application...
Output devices
Instruments for interpretation and communication between human and computers are output devices. These devices take machine coded output results from the processor and convert them for human reading. Display screens and printers are output devices.
Visual Display Units (VDU): It...
Input Devices
Devices used for data entry purposes are called Input Devices. Key Board, Mouse, Input Pen, Track Ball, Joystick, Microphones, Touch screen, Input Tablet are all Input Devices, but Key board remains most common. It is very similar to a typewriter key board. However, it has additional numeric key pads, functions keys etc.
Magnetic Ink Character...
Secondary Storage Devices
Secondary or Auxiliary storage are used to supplement the limited storage capacity of the primary storage section. these devices are On-line to the Processor. They accept data and programs from the processor, retain them and write them back as required. Both floppy disks and rigid disks are secondary storage for PCs. The rigid disks are generally...
Primary Storage
A computer's memory stores data and program that controls the processing. They are stored in cells at one byte per cell. This storage is called memory, main memory, primary memory, main storage, primary storage, random access memory etc. The processor has access to each cell,...
Computer Hardware
Functional Diagram of Computer:
Source: www.wikipedia.org
Buses: Circuits that are provided between two or more devices like CPU (Central Processing Unit) and Peripherals for communication are called Buses. these are parallel electrical lines. All 8 bit PCs...
Character Coding
Most computers use a coded version of true binary to represent characters. Many coding schemes have been developed over the years. The most popular is Binary Coded Decimal (BCD). In this a set of 4 to 6 bits is encoded. The most common method is to encode a pack of 2 numeric digits in an 8 bit byte called Packed Decimal. In another form straight...
How Computers Remember
Every piece of information that is entered into a computer's memory is encoded as some unique combination of the digits 0 and 1. These 0 and 1s are called Bits. A bit is an electronic device that is either On or Off, representing the 0 or 1.
Byte: A byte is the amount of computer memory that can store one character of data. A character is...
Classification of Computers
Computers are classified into 3 categories; Digital, Analog and Hybrid.
Digital: It is a counting device. The data are coded into Binary digits i.e. 0s and 1s. It manipulates the data that are given to it. These are further classified on the basis of use and size.
Analog: It works by measuring voltage by the supply of continuous electrical...
Computer Generations
Computer Generation: The ENIAC (Electronic Numeric Integrater and Calculater), EDSAC (Electronic Delay Storage Automatic Calculator), UNIVAC-I (Universal Automatic Computer) were known as First Generation computers. They were slow, used Vacuum Tubes and high power, large space to house and had limited programming capability.
The second generation...
History of Computers
Development of Computers: From Abacuss used in BC 3000 for counting to micro-computers of today, have undergone tremendous changes. Logarithm for mathematical calculations was invented in 1614 by John Napier followed by William Oughtred's Slide Rule, a calculating device in...
Computer Fundamentals
Definition to a Computer: Computer is a electric machine. It can store, retrieve, manipulate and transmit data (information). It carries out instructions to solve problems quickly and accurately. The name "Computer" means to reckon or "to compute" has derived from the Latin...
