Extended Frontier
Everything above 1 megabyte — the vast wilderness of extended memory. Accessible only through HIMEM.SYS and the XMS protocol. The frontier is enormous but alien. Programs born in real mode cannot run ...
Conventional Memory — Locations
Zones
The BIOS Vault
The ROM addresses at the top of the first megabyte — 0xF0000 through 0xFFFFF. Firmware. The original instructions burned into silicon at the factory, immutable since the day the motherboard was manufa...
Conventional Block
The first 640 kilobytes — addresses 0x00000 through 0x9FFFF. The old city. Every program starts here; most programs never leave. Conventional memory is crowded, contested, and precious. IRQ conflicts ...
Upper Memory
The 384 kilobytes above conventional memory — addresses 0xA0000 through 0xFFFFF. EMM386.EXE found the gaps and made them habitable. Programs that earn the LOADHIGH privilege are relocated here, freein...
Streets
- IRQ-7 Bus Line
- Port 3F8 Lane
- Segment 0x40 Trace
- COM1 Serial Way
- DEVICEHIGH Avenue
- Page Frame Passage
- UMB Channel
- EMM386 Gate
- A20 Gate Road
- Protected Mode Pipeline
- DPMI Junction
- XMS Boulevard
- POST Corridor
- INT 19h Vector
- ROM Shadow Lane
- CMOS Register Walk
- IRQ-7 Bus Line
- Port 3F8 Lane
- Segment 0x40 Trace
- COM1 Serial Way
- DEVICEHIGH Avenue
- Page Frame Passage
- UMB Channel
- EMM386 Gate
- A20 Gate Road
- Protected Mode Pipeline
- DPMI Junction
- XMS Boulevard
- POST Corridor
- INT 19h Vector
- ROM Shadow Lane
- CMOS Register Walk