I am using a VM with Ubuntu and am looking at memory managment and wanted to know why some of the values changed after I opened a few applications like Firefox and LibreOffice Writer so I understand. The ones I need to know about are amount of memory used by buffers in the kernel, size of the page cache (Memory used for holding physical memory page tables), amount of memory containing dirty pages, and the amount of memory being used for page tables, and the number of shared Memory Segments. Also what is the page cache, page tables, resident memory, and what is shared memory and talk about the command used to view shared memory segement information.