Siemens SIMATIC S5 Series - Memory Distribution

3
3-3
Working with S5-DOS/ST
C79000-G8576-C760-03
3.1 Memory Distribution
Extended Memory
HMA 64 Kbyte
ROM-BIOS
SETUP
ARCNET
VGA-BIOS
Video-RAM
Video-RAM
DOS Data Area
BIOS Data Area
Int. Vector
High Memory
Area
1 Mbyte
Hardware
expansions,
area available
for programs
by using
EMM386.EXE
UMBs
Video area
UMBs
Video area
640 Kbytes
Extended
memory
High memory
area
Upper memory
Area
Conventional user memory
EMM386.EXE
HIMEM.SYS
EMM386.EXE
Example
User Memory Management