Address Range
  Start     End Description		Versions
  ------ ------ ----------------------- -----------
  000400-000500 BIOS Data Area
  000700-	IBMBIO.COM or IO.SYS
  [000413]	Extended BIOS Data Area
  0C0000-0DFFFF Device ROMs
  0E0000-0EFFFF Expanded System ROM	(AT, PS/2)
  0E0000-0EFFFF Standard Cartridges	(PCJr)
  0F0000-0FFFFF System ROM
  FF0000-FFFFFF System ROM (AT, PS/2)

see also:

• DOS\MemMap
• CMOS Memory