hi there... im relatively new to the world of unix and to the Dani Web community too...

I am interested in the memory management techniques followed in the UNIX OS.

when i read thru a document related to that i came upon a paragraph, which im not able to decipher... this is regarding the concept of Virtual Memory.... the following is the subject...

"We saw that some virtual memory sections aren't mapped to physical memory. While some of them were simply paged out, others were never allocated by the process. When a process runs, its virtual memory table is small. As it allocates more memory pages, the table grows. However, if the process tries to access a virtual memory address of a section it hasn't allocated yet, the operating system has no where to bring this page from. The designers of the Unix system decided that this situation indicates a program bug, and thus instead of making an automatic allocation of a memory page in such a case, they chose to send a signal to the process. This signal is a SEGV signal (or SIGSEGV), and its default signal handler prints out a "Segmentation violation - core dumped" message, and dumps the memory image of the process into a file named 'core' in the process's current directory."

It will be easier if this is explained with some real time scenarion...
I need some light thrown upon this subject.. So any person who is ready to help me is invited... I wud also request upon some authoritative sources from where i can gain knowledge on this subject....

Eagerly awaitin a reply for the same....