Quick Question(DLL's and Kernals)

[LevyDee]

So I guess I'm curious, what are DLL's(Dynamically linked libraries right?), and what are they used for and why? And what exactly is a kernal? Its a program that communicates between software and hardware right, and would a regular programmer ever right a kernal program?? I'm just looking for a nutshell description to these questions. Thanks!

[Ancient Dragon]

>>what are DLL's
Libraries of functions that are shared among all processes and threads which greatly reduces the amount of memory that program consume. If it were not for DLLs every program on your computer would be at least tripple its current size.

>>what exactly is a kernal
The operating system.

>>would a regular programmer ever right a kernal program
They could, but not very many do. I have programmed since 1985 and not once did I write a kernel program or extension. If you want to write a device driver for a specific piece of hardware then you will need to write a kernel extension for it. There are, of course, other reasons to do it, but that one is probably the most common one.

[LevyDee]

Ok, so say I should want to get into the software industry, which I am going to school for it, should I bother right now to learn more about how kernals work and how to maybe write drivers? I think that would actually be kind of fun to learn regardless. Also, could you give me an example of a real world use of a DLL? Thanks

[Ancient Dragon]

Real-world use of DLLs??? Every function in the win32 api are contained in DLLs. Just look in your compiler's install directory and you will find lots of DLLs. Same in c:\windows directory.

How to write a DLL of your own is another matter, and a subject for larger discussion. There is lots of information out there, but most of them use very old comilers such as vc++ 6.0. Here is one that uses current vc++ compiler.

[LevyDee]

I see. So after looking through the link you sent, a DLL is really nothing more then a library of functions. It used to be scary like it was some crazy thing(not to say it cant be!), but now that I understand the concept its pretty cool.

[Ancient Dragon]

DLLs can be scarry, and even down right dangerous. Its called "DLL Hell" because installing a DLL on a computer can often cause other programs to crash or not work right. Installation prograsms have to compare version information in DLLs before upgrading to a different one.