bytes) of memory. IBM reserved the upper 384 KB for hardware-specific tasks (BIOS, video memory, and expansion cards), leaving 640 KB for the operating system and applications. As software grew in complexity, enthusiasts sought ways to reclaim reserved address space for system RAM. 2. Technical Methodology
Breaking the 640K Barrier: The Legacy of 896K.txt and Early PC Memory Expansion 896K.txt
The 896K.txt methodology relies on the fact that while the memory segments A000hcap A 000 h FFFFhcap F cap F cap F cap F h bytes) of memory
If a user lacked a high-resolution video card or specific expansion ROMs, segments B and E could sometimes be populated with RAM. and expansion cards)
Achieving 896K required more aggressive "filling" of the upper memory area (UMA). This involved: