The Reserved Memory is the memory area between 640 KB and 1 MB that has been reserved specifically for system applications.
This area iswhere the BIOSROM and the Read Only Memories ( ROM) for other plug-in cards reside. This is address space, and not stored data. For example, the system BIOS ROM has the hexadecimal address F0000 or 960K. When a VGA or EGA video card is used, the Video ROM address is stored at C0000 or 768K.