Upper memory area
Physical memory region on IBM PC compatibles / From Wikipedia, the free encyclopedia
Dear Wikiwand AI, let's keep it short by simply answering these key questions:
Can you list the top facts and stats about Upper memory area?
Summarize this article for a 10 year old
In DOS memory management, the upper memory area (UMA) is the memory between the addresses of 640 KB and 1024 KB (0xA0000–0xFFFFF) in an IBM PC or compatible. IBM reserved the uppermost 384 KB of the 8088 CPU's 1024 KB address space for BIOS ROM (or CSM of some UEFI firmware), Video BIOS, Option ROMs, video RAM, memory-mapped I/O, and obsoleted ROM BASIC.[1]
However, even with video RAM, the ROM BIOS, the Video BIOS, the Option ROMs, and I/O ports for peripherals, much of this 384 KB of address space was unused. As the 640 KB memory restriction became ever more of an obstacle, techniques were found to fill the empty areas with RAM. These areas were referred to as upper memory blocks (UMBs).