32-bit
The number of bits that can be processed or transmitted in parallel, or the number of bits used for single element in a data format. Although this term is used throughout computing and data processing (as are 8-bit, 16-bit, and similar formulations), in VB terms, this means the number of bits used to represent memory addresses. The break between 16-bit and 32-bit processing happened with the introduction of VB5 and OCX technology.

A  Index

Access Protocol
The software and API that allows applications and databases to communicate information. Examples include ODBC - Open DataBase Connectivity, an early protocol that is often used in conjuction with others and ADO - ActiveX Data Objects, Microsoft's latest protocol for accessing all kinds of information, including databases.

ActiveX
is Microsoft's specification for reusable software components. ActiveX is based on COM, the Component Object Model. The basic idea is to define exactly how software components interact and interoperate so developers can create components that work together using the definition. ActiveX components were originally called OLE Servers and ActiveX Servers and this renaming (actually for marketing rather than technical reasons) has created a lot of confusion about what they are. A lot of languages and applications support ActiveX in some way or another and Visual Basic supports it very strongly since it's one of the cornerstones of the Win32 environment.

Note: Dan Appleman, in his book on VB.NET, has this to say about ActiveX, "(Some) products come out of the marketing department. ... What was ActiveX? It was OLE2 -- with a new name."

API
is a TLA (Three Letter Acronym) for Application Program Interface. An API consists of the routines, protocols and tools that programmers must use to ensure that their programs are compatible with the software that the API is defined for. A well defined API helps applications work together by providing the same basic tools for all programmers to use. A wide variety of software from operating systems to individual components are said to have an API.

B  Index

C  Index

Cache
A cache is a temporary information store used in both hardware (a processor chip typically includes a hardware memory cache) and software. In web programming, a cache stores the most recent web pages visited. When the 'Back' button (or other methods) are used to revisit a web page, the browser will check the cache to see if the page is stored there and will retrieve it from the cache to save time and processing. Programmers should remember that program clients might not always retrieve a page directly from the server. This sometimes results in very subtle program bugs.

CGI
is Common Gateway Interface. This is an early standard used to transfer information between a web server and a client over a network. For example, a form in a "shopping cart" application might contain information about a request to purchase a particular item. The information could be passed to a web server using CGI. CGI is still used a great deal, ASP is a complete alternative that works better with Visual Basic.

Client/Server
A computing model that divides processing between two (or more) processes. A 'client' makes requests that are carried out by the 'server'. It's important to understand that the processes could be running on the same computer but they normally run over a network. For example, when developing ASP applications, programmers often use PWS, a 'server' that runs on the same computer with a browser 'client' such as IE. When the same application goes into production, it normally runs over the Internet. In advanced business applications, multiple layers of clients and servers are used. This model now dominates computing and replaced the model of mainframes and 'dumb terminals' which were really only display monitors attached directly to a large mainframe computer.

COM
is Component Object Model. Although often associated with Microsoft, COM is an open standard that specifies how components work together and interoperate. Microsoft used COM as the basis for ActiveX and OLE. The use of the COM API ensures that a software object can be launched within your application using a wide variety of programming languages including Visual Basic. Components save a programmer from having to re-write code. A component can be large or small and can perform any kind of processing, but it must be re-usable and it must conform to set standards to for interoperability.

Control
In Visual Basic, the tool you use to create objects on a Visual Basic form. Controls are selected from the Toolbox and then used to draw objects on the form with the mouse pointer. It's key to realize that the control is just the tool used to create GUI objects, not the object itself.

Cookie
A small packet of information that is originally sent from a web server to your browser and stored on your computer. When your computer consults the originating web server again, the cookie is sent back to the server, allowing it to respond to you using information from the previous interaction. Cookies are usually used to provide customized web pages using a profile of your interests that were provided the first time you access the web server. In other words, the web server will appear to "know" you and provide what you want. Some people feel that allowing cookies is a security problem and disable them using an option provided by the browser software. As a programmer, you can't depend on the ability to use cookies all the time.

D  Index

DLL
is Dynamic Link Library, a set of functions that can be executed, or data that can be used by a Windows application. DLL is also the file type for DLL files. For example, 'crypt32.dll' is the Crypto API32 DLL used for cryptography on Microsoft operating systems. There are hundreds and possibly thousands installed on your computer. Some DLLs are used only by a specific application, while others, such as crypt32.dll, are used by a wide variety of applications. The name refers to the fact that DLL's contain a library of functions that can be accessed (linked) on demand (dynamically) by other software.

E  Index

Event Procedure
A block of code that is called when an object is manipulated in a Visual Basic program. The manipulation can be done by a user of the program through the GUI, by the program, or through some other process such as the expiration of a time interval. For example, most Form object have a Click event. The Click Event Procedure for the form Form1 would be identified by the name Form1_Click().

F  Index

File Extension / File Type
In Windows, DOS and some other operating systems, one or several letters at the end of a filename. Filename extensions follow a period (dot) and indicate the type of file. For example, 'this.txt' is a plain text file, 'that.htm' or 'that.html' indicates that the file is a web page. The Windows operating system stores this association information in the Windows Registry and it can be changed using the 'File Types' dialog window provided by Windows Explorer.

Frames
A format for web documents that divides the screen into areas that can be formatted and controlled independently. Often, one frame is used to select a category while another frame shows the contents of that category.

Function
In Visual Basic, a type of subroutine that can accept an argument and returns a value assigned to the function as though it was a variable. You can code your own functions or use builtin functions provided by Visual Basic. For example, in this example, both Now and MsgBox are functions. Now returns the system time.
MsgBox(Now)

G  Index

H  Index

Host
A Computer or a process on a computer that provides a service to another computer or process. For example, VBScript can be 'hosted' by the web browser program, Internet Explorer.

I  Index

ISAPI
is the Internet Server Application Program Interface. Usually, any term that ends in the characters 'API' is an Application Program Interface. This is the API used by Microsoft's Internet Information Server (IIS) web server. Web applications that use ISAPI run considerably faster than those that use CGI, since they share the 'process' (programming memory space) used by the IIS web server and therefore avoid the time consuming program load and unload process that CGI requires. A similar API used by Netscape is called NSAPI.

K  Index

K  Index

L  Index

M  Index

Method
A way to identify a software function that performs an action or a service for a particular object. For example, the Hide() method for form Form1 removes the form from the program display but doesn't unload it from memory. It would be coded:
Form1.Hide

N  Index

Newsgroup
A discussion group operated through the Internet. Newsgroups (also known as Usenet) are accessed and viewed on the web. Outlook Express (distributed by Microsoft as part of IE) supports newsgroup viewing. Newsgroups tend to be popular, fun, and alternative. See Usenet.

O  Index

OCX
The file extension (and generic name) for OLE Custom control (the X must have been added because it looked cool to Microsoft Marketing types). OCX modules are independent program modules that can be accessed by other programs in a Windows environment. OCX controls replaced VBX controls written in Visual Basic. OCX, both as a marketing term and a technology, was replaced by ActiveX controls. ActiveX is backward compatible with OCX controls because ActiveX containers, such as Microsoft's Internet Explorer, can execute OCX components. OCX controls can be either 16-bit or 32-bit.

P  Index

Perl
is an acronym that actually expands to 'Practical Extraction and Report Language' but this doesn't do much to help you understand what it is. Although it was created for text processing, Perl has become the most popular language for writing CGI programs and was the original language of the web. People who have a lot of experience with Perl love it and swear by it. New programmers, however, tend to swear at it instead because it has a reputation for not being easy to learn. VBScript and Javascript are replacing Perl for web programming today. Perl is also used a great deal by Unix and Linux administrators for automating their maintenance work.

Process
refers to a program that is currently executing, or "running" on a computer.

Property
In Visual Basic, a named attribute of an object. For example, every Toolbox object has a Name property. Properties can be set by changing them in the Properties window at design time or by program statements at run time. For example, I might change the Name property of a form Form1 with the statement:
Form1.Name = "MyFormName"

VB 6 uses Property Get, Property Set and Property Let statements to manipulate properties of objects. This syntax has been completely overhauled in VB.NET. The Get and Set syntax isn't necessary and Let isn't supported at all.

Q  Index

R  Index

S  Index

Scope
The part of a program where a variable can be recognized and used in statements. For example, if a variable is declared (DIM statement) in the Declarations section of a form, then the variable can be used in any procedure in that form (such as the Click event for a button on the form).

T  Index

U  Index

URL
Uniform Resource Locator - This is the unique address of any a document on the Internet. The different parts of a URL have specific meaning.

The Parts of a URL

Protocol	Domain Name	Path	File Name
http://	visualbasic.about.com/	library/	blglossa.htm

'Protocol', for example, could be FTP:// or MailTo:// among other things.

Usenet
Usenet is a world-wide distributed discussion system. It consists of a set of 'newsgroups' with names that are classified hierarchically by subject. 'Articles' or 'messages' are posted to these newsgroups by people on computers with the appropriate software. These articles are then broadcast to other interconnected computer systems via a wide variety of networks. Visual Basic is discussed in a number of different newsgroups such as Microsoft.public.vb.general.discussion.

V  Index

VBX
The file extension (and generic name) of components used by 16-bit versions of Visual Basic (VB1 through VB4). Now obsolete, VBXs do not have two of the properties (inheritance and polymorphism) many believe are required by true object-oriented systems. Starting with VB5, OCX and then ActiveX controls became current.

Virtual Machine
A term used to describe a platform, that is, the software and operating environment, for which you are writing code. This is a key concept in VB.NET because the virtual machine that the VB 6 programmer writes to is radically different than the one the VB.NET program uses. As a starting point (but there is much more), VB.NET's virtual machine requires the presence of the CLR (Common Language Runtime). To illustrate the concept of a virtual machine platform in actual use, VB.NET provides for alternates in the Build menu Configuration Manager:

W  Index

Win32
the Windows API for Microsoft Windows 9X, NT, and 2000.

X  Index

XML
The Extensible Markup Language allows designers to create their own customized 'markup tags' for information. This makes it possible to define, transmit, validate, and interpret information between applications with greater flexibility and accuracy. The XML specification was developed by the W3C (the World Wide Web consortium - an association whose members are international corporations) but XML is used for applications far beyond the web. (Many definitions you can find on the web state that it's used only for the web, but this is a common misunderstanding. XHTML is a specific set of markup tags that are based on HTML 4.01 as well as XML that is exclusively for web pages.) VB.NET and all Microsoft .NET technologies use XML extensively.

Y

Z