A Type Library is a software file that describes software interfaces in an operating system, typically Windows. A type library file created by Visual Basic will always have a .TLB extension. The .TLB file is required by a client to connect to a server.

A type library can be thought of as a binary version of an IDL (interface Definition Language) file. Visual basic creates a type library when you create a VB server object, thus eliminating the need for an IDL file. A C-like language used to define interfaces and co-classes for COM. Ole View is a COM utility that reverse-engineers a type library into a readable form of IDL. IDL is used to provide language-independence for COM interfaces so that identical interfaces defined in VB, C++, and Java look the same in IDL even though they look different in the language used for implementation.

There is also the type library in the system that is used to display the type or font on the screen and printed document. This type or font library is located in the systems registry. Every time a program calls upon the type library top to display the font, the type library looks up the registry to locate the type that has to be displayed. If the type is not present in the library the page displays the default of the closest matching font for that type.

However the operating system must know where to find such kind of programs so that it can open them whenever called. This information was initially stored in the information folder denoted as INF in earlier versions of Windows primarily 95 and 98 first edition. Microsoft introduced the registry in windows 98 Second Edition to speed things up while loading and locating programs. But eventually the system slowed down due to huge accumulation of files and data into the registry.

The physical files that make up the registry are stored differently depending on your version of Windows; under Windows 95 & 98 it is contained in two hidden files in your Windows directory, called USER.DAT and SYSTEM.DAT, for Windows Me there is an additional CLASSES.DAT file, while under Windows NT/2000 the files are contained separately in the SystemRootSystem32Config directory. You cannot edit these files directly, you must use a tool commonly known as a registry cleaner to make any changes in the Registry. A simple mistake of deletion of these files can crash your system permanently. So it is not at all recommended.

Learn more about your windows registry:
registry cleaner reviews Find out what works and what dont!

This entry was posted on Saturday, May 23rd, 2009 at 9:33 pm and is filed under Operating Systems. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.