Winn L. Rosch Hardware Bible, Sixth Edition

Logical Organization

Some people fall into the egregious habit of thinking all memory is alike. Nefarious computer vendors are particular culprits. They are likely to lump together anything inside a computer involving memory chips as memory, implying that you can use it for running your programs. To them memory is memory, and that's that. But all memory is not the same. The random access memory used for running software gets divvied up among multiple functions inside your computer, putting it off-limits to your applications. You often end up with less usable memory than you might think you have inside your computer.

Some of your computer's RAM is compartmentalized for special functions. Computers with Intel microprocessors reserve a megabyte ...