diff --git Makefile Makefile
index 16df332d5..1b1bc7484 100644
--- Makefile
+++ Makefile
@@ -54,7 +54,7 @@ else ifeq ($(OSTYPE),mingw)
     LDFLAGS += -static-libgcc -static-libstdc++ -static
   endif
   LDFLAGS   += -pthread -Wl,--large-address-aware
-  SOURCES   += simsys_w32_png.cc
+  SOURCES   += sys/simsys_w32_png.cc
   CFLAGS    += -Wno-deprecated-copy -Wno-c++11-narrowing -DNOMINMAX -DWIN32_LEAN_AND_MEAN -DWINVER=0x0501 -D_WIN32_IE=0x0500
   LIBS      += -lmingw32 -lgdi32 -lwinmm -lws2_32 -limm32
 
@@ -71,11 +71,11 @@ else ifeq ($(OSTYPE),mingw)
 endif
 
 ifeq ($(BACKEND),sdl2)
-  SOURCES += clipboard_s2.cc
+  SOURCES += sys/clipboard_s2.cc
 else ifeq ($(OSTYPE),mingw)
-  SOURCES += clipboard_w32.cc
+  SOURCES += sys/clipboard_w32.cc
 else
-  SOURCES += clipboard_internal.cc
+  SOURCES += sys/clipboard_internal.cc
 endif
 
 LIBS += -lbz2 -lz
@@ -491,7 +491,6 @@ SOURCES += simobj.cc
 SOURCES += simplan.cc
 SOURCES += simskin.cc
 SOURCES += simsound.cc
-SOURCES += simsys.cc
 SOURCES += simticker.cc
 SOURCES += simtool.cc
 SOURCES += simware.cc
@@ -517,6 +516,7 @@ SOURCES += squirrel/squirrel/sqobject.cc
 SOURCES += squirrel/squirrel/sqstate.cc
 SOURCES += squirrel/squirrel/sqtable.cc
 SOURCES += squirrel/squirrel/sqvm.cc
+SOURCES += sys/simsys.cc
 SOURCES += unicode.cc
 SOURCES += utils/cbuffer_t.cc
 SOURCES += utils/csv.cc
@@ -532,7 +532,7 @@ SOURCES += vehicle/simroadtraffic.cc
 SOURCES += vehicle/simvehicle.cc
 
 ifeq ($(BACKEND),allegro)
-  SOURCES += simsys_d.cc
+  SOURCES += sys/simsys_d.cc
   SOURCES += sound/allegro_sound.cc
   SOURCES += music/allegro_midi.cc
   ifeq ($(ALLEGRO_CONFIG),)
@@ -547,13 +547,13 @@ ifeq ($(BACKEND),allegro)
 endif
 
 ifeq ($(BACKEND),gdi)
-  SOURCES += simsys_w.cc
+  SOURCES += sys/simsys_w.cc
   SOURCES += music/w32_midi.cc
   SOURCES += sound/win32_sound.cc
 endif
 
 ifeq ($(BACKEND),sdl)
-  SOURCES += simsys_s.cc
+  SOURCES += sys/simsys_s.cc
   ifeq ($(OSTYPE),mac)
     ifeq ($(shell expr $(AV_FOUNDATION) \>= 1), 1)
       # Core Audio (AVFoundation) base sound system routines
@@ -596,7 +596,7 @@ ifeq ($(BACKEND),sdl)
 endif
 
 ifeq ($(BACKEND),sdl2)
-  SOURCES += simsys_s2.cc
+  SOURCES += sys/simsys_s2.cc
   ifeq ($(OSTYPE),mac)
     ifeq ($(shell expr $(AV_FOUNDATION) \>= 1), 1)
       # Core Audio (AVFoundation) base sound system routines
@@ -639,7 +639,7 @@ ifeq ($(BACKEND),sdl2)
 endif
 
 ifeq ($(BACKEND),mixer_sdl2)
-  SOURCES += simsys_s2.cc
+  SOURCES += sys/simsys_s2.cc
   ifeq ($(SDL2_CONFIG),)
     ifeq ($(OSTYPE),mac)
       SDL_CFLAGS  := -F /Library/Frameworks -I/Library/Frameworks/SDL2.framework/Headers
@@ -663,7 +663,7 @@ ifeq ($(BACKEND),mixer_sdl2)
 endif
 
 ifeq ($(BACKEND),mixer_sdl)
-  SOURCES += simsys_s.cc
+  SOURCES += sys/simsys_s.cc
   SOURCES += sound/sdl_mixer_sound.cc
   SOURCES += music/sdl_midi.cc
   ifeq ($(SDL_CONFIG),)
@@ -678,7 +678,7 @@ ifeq ($(BACKEND),mixer_sdl)
 endif
 
 ifeq ($(BACKEND),posix)
-  SOURCES += simsys_posix.cc
+  SOURCES += sys/simsys_posix.cc
   SOURCES += music/no_midi.cc
   SOURCES += sound/no_sound.cc
 endif
diff --git Simutrans-GDI.vcxproj Simutrans-GDI.vcxproj
index 7be419f6e..f084c0dcd 100644
--- Simutrans-GDI.vcxproj
+++ Simutrans-GDI.vcxproj
@@ -124,14 +124,14 @@
     </Link>
   </ItemDefinitionGroup>
   <ItemGroup>
-    <ClCompile Include="clipboard_w32.cc" />
-    <ClCompile Include="simsys_w.cc" />
-    <ClCompile Include="simsys_w32_png.cc" />
     <ClCompile Include="music\w32_midi.cc" />
     <ClCompile Include="sound\win32_sound.cc" />
+    <ClCompile Include="sys\clipboard_w32.cc" />
+    <ClCompile Include="sys\simsys_w.cc" />
+    <ClCompile Include="sys\simsys_w32_png.cc" />
   </ItemGroup>
   <ItemGroup>
-    <ClInclude Include="simsys_w32_png.h" />
+    <ClInclude Include="sys\simsys_w32_png.h" />
   </ItemGroup>
   <Import Project="$(VCTargetsPath)\Microsoft.Cpp.targets" />
   <ImportGroup Label="ExtensionTargets">
diff --git Simutrans-Main.vcxitems Simutrans-Main.vcxitems
index c28ef9f01..8380be1aa 100644
--- Simutrans-Main.vcxitems
+++ Simutrans-Main.vcxitems
@@ -38,7 +38,6 @@
     <ClCompile Include="$(MSBuildThisFileDirectory)simplan.cc" />
     <ClCompile Include="$(MSBuildThisFileDirectory)simskin.cc" />
     <ClCompile Include="$(MSBuildThisFileDirectory)simsound.cc" />
-    <ClCompile Include="$(MSBuildThisFileDirectory)simsys.cc" />
     <ClCompile Include="$(MSBuildThisFileDirectory)simticker.cc" />
     <ClCompile Include="$(MSBuildThisFileDirectory)simtool.cc" />
     <ClCompile Include="$(MSBuildThisFileDirectory)simware.cc" />
@@ -318,6 +317,7 @@
     <ClCompile Include="$(MSBuildThisFileDirectory)squirrel\squirrel\sqstate.cc" />
     <ClCompile Include="$(MSBuildThisFileDirectory)squirrel\squirrel\sqtable.cc" />
     <ClCompile Include="$(MSBuildThisFileDirectory)squirrel\squirrel\sqvm.cc" />
+    <ClCompile Include="$(MSBuildThisFileDirectory)sys\simsys.cc" />
     <ClCompile Include="$(MSBuildThisFileDirectory)utils\cbuffer_t.cc" />
     <ClCompile Include="$(MSBuildThisFileDirectory)utils\csv.cc" />
     <ClCompile Include="$(MSBuildThisFileDirectory)utils\log.cc" />
@@ -357,7 +357,6 @@
     <ClInclude Include="$(MSBuildThisFileDirectory)simplan.h" />
     <ClInclude Include="$(MSBuildThisFileDirectory)simskin.h" />
     <ClInclude Include="$(MSBuildThisFileDirectory)simsound.h" />
-    <ClInclude Include="$(MSBuildThisFileDirectory)simsys.h" />
     <ClInclude Include="$(MSBuildThisFileDirectory)simticker.h" />
     <ClInclude Include="$(MSBuildThisFileDirectory)simtool.h" />
     <ClInclude Include="$(MSBuildThisFileDirectory)simtool-dialogs.h" />
@@ -663,6 +662,7 @@
     <ClInclude Include="$(MSBuildThisFileDirectory)squirrel\squirrel\squserdata.h" />
     <ClInclude Include="$(MSBuildThisFileDirectory)squirrel\squirrel\squtils.h" />
     <ClInclude Include="$(MSBuildThisFileDirectory)squirrel\squirrel\sqvm.h" />
+    <ClInclude Include="$(MSBuildThisFileDirectory)sys\simsys.h" />
     <ClInclude Include="$(MSBuildThisFileDirectory)tpl\array_tpl.h" />
     <ClInclude Include="$(MSBuildThisFileDirectory)tpl\array2d_tpl.h" />
     <ClInclude Include="$(MSBuildThisFileDirectory)tpl\binary_heap_tpl.h" />
diff --git Simutrans-SDL2.vcxproj Simutrans-SDL2.vcxproj
index cceef28c5..b7ee145cc 100644
--- Simutrans-SDL2.vcxproj
+++ Simutrans-SDL2.vcxproj
@@ -124,14 +124,14 @@
     </Link>
   </ItemDefinitionGroup>
   <ItemGroup>
-    <ClCompile Include="clipboard_s2.cc" />
-    <ClCompile Include="simsys_s2.cc" />
-    <ClCompile Include="simsys_w32_png.cc" />
     <ClCompile Include="music\w32_midi.cc" />
     <ClCompile Include="sound\sdl2_sound.cc" />
+    <ClCompile Include="sys\clipboard_s2.cc" />
+    <ClCompile Include="sys\simsys_s2.cc" />
+    <ClCompile Include="sys\simsys_w32_png.cc" />
   </ItemGroup>
   <ItemGroup>
-    <ClInclude Include="simsys_w32_png.h" />
+    <ClInclude Include="sys\simsys_w32_png.h" />
   </ItemGroup>
   <Import Project="$(VCTargetsPath)\Microsoft.Cpp.targets" />
   <ImportGroup Label="ExtensionTargets">
diff --git Simutrans-Server.vcxproj Simutrans-Server.vcxproj
index a79521489..d51246178 100644
--- Simutrans-Server.vcxproj
+++ Simutrans-Server.vcxproj
@@ -123,10 +123,10 @@
     </Link>
   </ItemDefinitionGroup>
   <ItemGroup>
-    <ClCompile Include="clipboard_internal.cc" />
-    <ClCompile Include="simsys_posix.cc" />
     <ClCompile Include="music\no_midi.cc" />
     <ClCompile Include="sound\no_sound.cc" />
+    <ClCompile Include="sys\clipboard_internal.cc" />
+    <ClCompile Include="sys\simsys_posix.cc" />
   </ItemGroup>
   <Import Project="$(VCTargetsPath)\Microsoft.Cpp.targets" />
   <ImportGroup Label="ExtensionTargets">
diff --git bauer/wegbauer.cc bauer/wegbauer.cc
index 88bb313db..5f78af5c1 100644
--- bauer/wegbauer.cc
+++ bauer/wegbauer.cc
@@ -64,7 +64,7 @@
 #include "../gui/messagebox.h"
 
 #ifdef DEBUG_ROUTES
-#include "../simsys.h"
+#include "../sys/simsys.h"
 #endif
 
 // built bridges automatically
diff --git dataobj/height_map_loader.cc dataobj/height_map_loader.cc
index 33074170e..1cd3fecd6 100644
--- dataobj/height_map_loader.cc
+++ dataobj/height_map_loader.cc
@@ -12,7 +12,7 @@
 #include "environment.h"
 #include "height_map_loader.h"
 #include "../simio.h"
-#include "../simsys.h"
+#include "../sys/simsys.h"
 
 
 height_map_loader_t::height_map_loader_t(bool new_format):
diff --git dataobj/loadsave.cc dataobj/loadsave.cc
index 0eb29331a..c9592b010 100644
--- dataobj/loadsave.cc
+++ dataobj/loadsave.cc
@@ -10,7 +10,7 @@
 #include <assert.h>
 #include <errno.h>
 
-#include "../simsys.h"
+#include "../sys/simsys.h"
 #include "../simtypes.h"
 #include "../macros.h"
 #include "../simversion.h"
diff --git dataobj/route.cc dataobj/route.cc
index b096c1215..ed25c9e49 100644
--- dataobj/route.cc
+++ dataobj/route.cc
@@ -32,7 +32,7 @@
 
 
 #ifdef DEBUG_ROUTES
-#include "../simsys.h"
+#include "../sys/simsys.h"
 #endif
 
 
diff --git dataobj/scenario.cc dataobj/scenario.cc
index 4bf3b2658..1a813226a 100644
--- dataobj/scenario.cc
+++ dataobj/scenario.cc
@@ -3,7 +3,7 @@
  * (see LICENSE.txt)
  */
 
-#include "../simsys.h"
+#include "../sys/simsys.h"
 #include "../simconst.h"
 #include "../simtypes.h"
 #include "../simdebug.h"
diff --git dataobj/tabfile.cc dataobj/tabfile.cc
index c5f52191e..63244d55f 100644
--- dataobj/tabfile.cc
+++ dataobj/tabfile.cc
@@ -12,7 +12,7 @@
 #define dr_fopen fopen
 #endif
 
-#include "../simsys.h"
+#include "../sys/simsys.h"
 #include "../simdebug.h"
 #include "../descriptor/image.h"
 #include "koord.h"
diff --git dataobj/translator.cc dataobj/translator.cc
index 0a2349de3..e0243ca5c 100644
--- dataobj/translator.cc
+++ dataobj/translator.cc
@@ -10,7 +10,7 @@
 
 #include "../macros.h"
 #include "../simdebug.h"
-#include "../simsys.h"
+#include "../sys/simsys.h"
 #include "../simtypes.h"
 #include "../display/simgraph.h" // for unicode stuff
 #include "translator.h"
diff --git descriptor/reader/obj_reader.cc descriptor/reader/obj_reader.cc
index cdf9e4a57..1f90820ce 100644
--- descriptor/reader/obj_reader.cc
+++ descriptor/reader/obj_reader.cc
@@ -9,9 +9,9 @@
 // for the progress bar
 #include "../../simcolor.h"
 #include "../../display/simimg.h"
-#include "../../simsys.h"
 #include "../../simtypes.h"
 #include "../../simloadingscreen.h"
+#include "../../sys/simsys.h"
 
 #include "../skin_desc.h"	// just for the logo
 #include "../ground_desc.h"	// for the error message!
diff --git display/font.cc display/font.cc
index 948ad0b3a..b3b9c4d28 100644
--- display/font.cc
+++ display/font.cc
@@ -6,7 +6,7 @@
 #include <stdlib.h>
 #include <stdio.h>
 #include <string.h>
-#include "../simsys.h"
+#include "../sys/simsys.h"
 #include "../simtypes.h"
 #include "../simmem.h"
 #include "../simdebug.h"
diff --git display/simgraph0.cc display/simgraph0.cc
index bb42cd364..1380aeab4 100644
--- display/simgraph0.cc
+++ display/simgraph0.cc
@@ -4,7 +4,7 @@
  */
 
 #include "../simconst.h"
-#include "../simsys.h"
+#include "../sys/simsys.h"
 #include "../descriptor/image.h"
 
 #include "simgraph.h"
diff --git display/simgraph16.cc display/simgraph16.cc
index 3ba42193e..5c189308b 100644
--- display/simgraph16.cc
+++ display/simgraph16.cc
@@ -14,7 +14,7 @@
 #include "font.h"
 #include "../pathes.h"
 #include "../simconst.h"
-#include "../simsys.h"
+#include "../sys/simsys.h"
 #include "../simmem.h"
 #include "../simdebug.h"
 #include "../descriptor/image.h"
diff --git gui/ai_selector.cc gui/ai_selector.cc
index f1872718f..e0c220ae4 100644
--- gui/ai_selector.cc
+++ gui/ai_selector.cc
@@ -4,7 +4,7 @@
  */
 
 #include "../simdebug.h"
-#include "../simsys.h"
+#include "../sys/simsys.h"
 
 #include "ai_selector.h"
 #include "messagebox.h"
diff --git gui/banner.cc gui/banner.cc
index 25b8c1879..4a54ec019 100644
--- gui/banner.cc
+++ gui/banner.cc
@@ -8,7 +8,7 @@
 #include "../display/simimg.h"
 #include "../simworld.h"
 #include "../simskin.h"
-#include "../simsys.h"
+#include "../sys/simsys.h"
 #include "../simversion.h"
 #include "../display/simgraph.h"
 #include "../macros.h"
diff --git gui/components/gui_textinput.cc gui/components/gui_textinput.cc
index d7547876d..6d7d967a8 100644
--- gui/components/gui_textinput.cc
+++ gui/components/gui_textinput.cc
@@ -8,9 +8,10 @@
 #include "../gui_frame.h"
 #include "gui_textinput.h"
 #include "../simwin.h"
-#include "../../simsys.h"
 #include "../../dataobj/translator.h"
 #include "../../utils/simstring.h"
+#include "../../sys/simsys.h"
+
 
 gui_textinput_t::gui_textinput_t() :
 	gui_component_t(true),
diff --git gui/gui_theme.cc gui/gui_theme.cc
index bb96147f8..259c96e67 100644
--- gui/gui_theme.cc
+++ gui/gui_theme.cc
@@ -10,7 +10,7 @@
 #include "../simworld.h"
 #include "../simskin.h"
 #include "../simmenu.h"
-#include "../simsys.h"
+#include "../sys/simsys.h"
 #include "../dataobj/environment.h"
 #include "../dataobj/tabfile.h"
 #include "components/gui_button.h"
diff --git gui/help_frame.cc gui/help_frame.cc
index 10dc65b31..a7b020b60 100644
--- gui/help_frame.cc
+++ gui/help_frame.cc
@@ -8,7 +8,7 @@
 #include "../simmem.h"
 #include "simwin.h"
 #include "../simmenu.h"
-#include "../simsys.h"
+#include "../sys/simsys.h"
 #include "../simworld.h"
 #include "../simticker.h" // TICKER_HEIGHT
 
diff --git gui/loadfont_frame.cc gui/loadfont_frame.cc
index ab6f37479..6f06878ad 100644
--- gui/loadfont_frame.cc
+++ gui/loadfont_frame.cc
@@ -11,7 +11,7 @@
 
 #include "loadfont_frame.h"
 
-#include "../simsys.h"
+#include "../sys/simsys.h"
 #include "../simworld.h"
 #include "../simversion.h"
 #include "../pathes.h"
diff --git gui/loadfont_frame.h gui/loadfont_frame.h
index cdf1a1587..49183e3ab 100644
--- gui/loadfont_frame.h
+++ gui/loadfont_frame.h
@@ -9,7 +9,7 @@
 
 #ifdef USE_FREETYPE
 #include "gui_theme.h"
-#include "../simsys.h"
+#include "../sys/simsys.h"
 
 #include <ft2build.h>
 #include FT_FREETYPE_H
diff --git gui/loadsave_frame.cc gui/loadsave_frame.cc
index a18bec06a..a1904ab79 100644
--- gui/loadsave_frame.cc
+++ gui/loadsave_frame.cc
@@ -9,7 +9,7 @@
 
 #include "loadsave_frame.h"
 
-#include "../simsys.h"
+#include "../sys/simsys.h"
 #include "../simworld.h"
 #include "../simversion.h"
 #include "../pathes.h"
diff --git gui/map_frame.cc gui/map_frame.cc
index e9f020488..ac0cd3788 100644
--- gui/map_frame.cc
+++ gui/map_frame.cc
@@ -11,7 +11,7 @@
 #include "map_frame.h"
 
 #include "simwin.h"
-#include "../simsys.h"
+#include "../sys/simsys.h"
 
 #include "../simworld.h"
 #include "../display/simgraph.h"
diff --git gui/message_frame_t.cc gui/message_frame_t.cc
index f81b1599f..5c664b8bd 100644
--- gui/message_frame_t.cc
+++ gui/message_frame_t.cc
@@ -11,7 +11,7 @@
 #include "../simworld.h"
 #include "../simmenu.h"
 #include "../simmesg.h"
-#include "../simsys.h"
+#include "../sys/simsys.h"
 
 #include "../dataobj/scenario.h"
 #include "../dataobj/translator.h"
diff --git gui/pakselector.cc gui/pakselector.cc
index 2ce4bb1e9..e002944f5 100644
--- gui/pakselector.cc
+++ gui/pakselector.cc
@@ -8,7 +8,7 @@
 #include "pakselector.h"
 #include "../dataobj/translator.h"
 #include "../dataobj/environment.h"
-#include "../simsys.h"
+#include "../sys/simsys.h"
 
 pakselector_t::pakselector_t() :
 	savegame_frame_t( NULL, true, env_t::program_dir, true ),
diff --git gui/savegame_frame.cc gui/savegame_frame.cc
index 7ab8f9e4f..190d1ec80 100644
--- gui/savegame_frame.cc
+++ gui/savegame_frame.cc
@@ -9,7 +9,7 @@
 
 #include "savegame_frame.h"
 #include "../pathes.h"
-#include "../simsys.h"
+#include "../sys/simsys.h"
 #include "../simdebug.h"
 #include "simwin.h"
 #include "../utils/simstring.h"
diff --git gui/scenario_frame.cc gui/scenario_frame.cc
index 5718296b5..b13ccbfbd 100644
--- gui/scenario_frame.cc
+++ gui/scenario_frame.cc
@@ -4,7 +4,7 @@
  */
 
 #include "../simdebug.h"
-#include "../simsys.h"
+#include "../sys/simsys.h"
 
 #include "scenario_frame.h"
 #include "scenario_info.h"
diff --git gui/settings_frame.cc gui/settings_frame.cc
index 36c8a52c8..7834a93c8 100644
--- gui/settings_frame.cc
+++ gui/settings_frame.cc
@@ -5,7 +5,7 @@
 
 #include <string>
 #include "../simcity.h"
-#include "../simsys.h"
+#include "../sys/simsys.h"
 #include "simwin.h"
 
 #include "../dataobj/environment.h"
diff --git gui/simwin.cc gui/simwin.cc
index 52ed99a5a..21f8dddb3 100644
--- gui/simwin.cc
+++ gui/simwin.cc
@@ -13,7 +13,7 @@
 #include "../display/viewport.h"
 #include "../simmenu.h"
 #include "../simskin.h"
-#include "../simsys.h"
+#include "../sys/simsys.h"
 #include "../simticker.h"
 #include "simwin.h"
 #include "../simintr.h"
diff --git gui/sprachen.cc gui/sprachen.cc
index fa06b22d5..2546f2ef6 100644
--- gui/sprachen.cc
+++ gui/sprachen.cc
@@ -18,7 +18,7 @@
 
 #include "../dataobj/environment.h"
 #include "../dataobj/translator.h"
-#include "../simsys.h"
+#include "../sys/simsys.h"
 #include "../utils/simstring.h"
 
 
diff --git gui/themeselector.cc gui/themeselector.cc
index fe7a67e23..983d88829 100644
--- gui/themeselector.cc
+++ gui/themeselector.cc
@@ -7,7 +7,7 @@
 
 #include "themeselector.h"
 #include "simwin.h"
-#include "../simsys.h"
+#include "../sys/simsys.h"
 #include "../simevent.h"
 #include "gui_theme.h"
 #include "../utils/simstring.h"
diff --git gui/welt.cc gui/welt.cc
index 63766dd8e..ff2228928 100644
--- gui/welt.cc
+++ gui/welt.cc
@@ -37,7 +37,7 @@
 
 #include "../display/simgraph.h"
 
-#include "../simsys.h"
+#include "../sys/simsys.h"
 #include "../utils/simstring.h"
 #include "../utils/simrandom.h"
 
diff --git makeobj/Makeobj.vcxproj makeobj/Makeobj.vcxproj
index d14f654b6..b0b699ea9 100644
--- makeobj/Makeobj.vcxproj
+++ makeobj/Makeobj.vcxproj
@@ -124,7 +124,6 @@
     <ClInclude Include="..\simconst.h" />
     <ClInclude Include="..\simdebug.h" />
     <ClInclude Include="..\simmem.h" />
-    <ClInclude Include="..\simsys.h" />
     <ClInclude Include="..\simtypes.h" />
     <ClInclude Include="..\simunits.h" />
     <ClInclude Include="..\simversion.h" />
@@ -188,6 +187,7 @@
     <ClInclude Include="..\display\simgraph.h" />
     <ClInclude Include="..\display\simimg.h" />
     <ClInclude Include="..\network\checksum.h" />
+    <ClInclude Include="..\sys\simsys.h" />
     <ClInclude Include="..\tpl\hashtable_tpl.h" />
     <ClInclude Include="..\tpl\inthashtable_tpl.h" />
     <ClInclude Include="..\tpl\stringhashtable_tpl.h" />
diff --git nettools/Nettool.vcxproj nettools/Nettool.vcxproj
index affdff51b..439f289d1 100644
--- nettools/Nettool.vcxproj
+++ nettools/Nettool.vcxproj
@@ -107,7 +107,6 @@
     <ClInclude Include="..\simmem.h" />
     <ClInclude Include="..\simobj.h" />
     <ClInclude Include="..\simplan.h" />
-    <ClInclude Include="..\simsys.h" />
     <ClInclude Include="..\simtypes.h" />
     <ClInclude Include="..\simunits.h" />
     <ClInclude Include="..\simversion.h" />
@@ -149,6 +148,7 @@
     <ClInclude Include="..\network\network_socket_list.h" />
     <ClInclude Include="..\network\pakset_info.h" />
     <ClInclude Include="..\network\pwd_hash.h" />
+    <ClInclude Include="..\sys\simsys.h" />
     <ClInclude Include="..\tpl\hashtable_tpl.h" />
     <ClInclude Include="..\tpl\quickstone_tpl.h" />
     <ClInclude Include="..\tpl\slist_tpl.h" />
diff --git network/network_cmd_ingame.cc network/network_cmd_ingame.cc
index 81dab1288..04cfe8468 100644
--- network/network_cmd_ingame.cc
+++ network/network_cmd_ingame.cc
@@ -18,7 +18,7 @@
 #include "../simversion.h"
 #include "../gui/simwin.h"
 #include "../simmesg.h"
-#include "../simsys.h"
+#include "../sys/simsys.h"
 #include "../dataobj/environment.h"
 #include "../player/simplay.h"
 #include "../gui/player_frame_t.h"
diff --git network/network_file_transfer.cc network/network_file_transfer.cc
index eee5fafda..8ad69f778 100644
--- network/network_file_transfer.cc
+++ network/network_file_transfer.cc
@@ -6,7 +6,7 @@
 #include "network_file_transfer.h"
 #include "../simdebug.h"
 #include "../simloadingscreen.h"
-#include "../simsys.h"
+#include "../sys/simsys.h"
 
 #include <string.h>
 #include <errno.h>
@@ -99,7 +99,7 @@ char const* network_receive_file( SOCKET const s, char const* const save_as, sin
 #include "../simworld.h"
 #include "../utils/simstring.h"
 
-#include "../simsys.h"
+#include "../sys/simsys.h"
 
 
 // connect to address (cp), receive gameinfo, close
diff --git script/api_function.cc script/api_function.cc
index 943c57a3f..755ed426c 100644
--- script/api_function.cc
+++ script/api_function.cc
@@ -6,7 +6,7 @@
 #include "api_function.h"
 #include <stdio.h>
 
-#include "../simsys.h"
+#include "../sys/simsys.h"
 
 #include "../dataobj/environment.h"
 
diff --git script/dynamic_string.cc script/dynamic_string.cc
index e96f8f57f..a5847c26e 100644
--- script/dynamic_string.cc
+++ script/dynamic_string.cc
@@ -6,7 +6,7 @@
 #include "dynamic_string.h"
 #include "script.h"
 
-#include "../simsys.h"
+#include "../sys/simsys.h"
 #include "../simworld.h"
 #include "../network/network.h"
 #include "../network/network_cmd_scenario.h"
diff --git simevent.cc simevent.cc
index 172c30de3..4c729be3e 100644
--- simevent.cc
+++ simevent.cc
@@ -4,7 +4,7 @@
  */
 
 #include "simevent.h"
-#include "simsys.h"
+#include "sys/simsys.h"
 #include "tpl/slist_tpl.h"
 
 // system-independent event handling routines
diff --git siminteraction.cc siminteraction.cc
index 69794aa3a..deed53bee 100644
--- siminteraction.cc
+++ siminteraction.cc
@@ -16,7 +16,7 @@
 #include "simmenu.h"
 #include "player/simplay.h"
 #include "simsound.h"
-#include "simsys.h"
+#include "sys/simsys.h"
 #include "simticker.h"
 #include "gui/simwin.h"
 #include "simworld.h"
diff --git simintr.cc simintr.cc
index 852c851eb..c426c4647 100644
--- simintr.cc
+++ simintr.cc
@@ -7,7 +7,7 @@
 #include <string.h>
 
 #include "simdebug.h"
-#include "simsys.h"
+#include "sys/simsys.h"
 #include "simintr.h"
 #include "gui/simwin.h"
 #include "player/simplay.h"
diff --git simloadingscreen.cc simloadingscreen.cc
index 32a6bf320..521e012d0 100644
--- simloadingscreen.cc
+++ simloadingscreen.cc
@@ -5,7 +5,7 @@
 
 #include "simloadingscreen.h"
 
-#include "simsys.h"
+#include "sys/simsys.h"
 #include "descriptor/image.h"
 #include "descriptor/skin_desc.h"
 #include "simskin.h"
diff --git simmain.cc simmain.cc
index efe945c0a..d422debf9 100644
--- simmain.cc
+++ simmain.cc
@@ -39,7 +39,7 @@
 #include "simmenu.h"
 #include "siminteraction.h"
 
-#include "simsys.h"
+#include "sys/simsys.h"
 #include "display/simgraph.h"
 #include "simevent.h"
 
diff --git simsound.cc simsound.cc
index 764a5f4ce..99a86ee03 100644
--- simsound.cc
+++ simsound.cc
@@ -10,7 +10,7 @@
 #include "descriptor/sound_desc.h"
 #include "sound/sound.h"
 #include "simsound.h"
-#include "simsys.h"
+#include "sys/simsys.h"
 #include "simio.h"
 #include "simdebug.h"
 
diff --git simworld.cc simworld.cc
index b4fbf606d..61de9e3ae 100644
--- simworld.cc
+++ simworld.cc
@@ -31,7 +31,6 @@
 #include "simmesg.h"
 #include "simskin.h"
 #include "simsound.h"
-#include "simsys.h"
 #include "simticker.h"
 #include "simunits.h"
 #include "simversion.h"
@@ -39,6 +38,7 @@
 #include "simtool.h"
 #include "gui/simwin.h"
 #include "simworld.h"
+#include "sys/simsys.h"
 
 #include "tpl/vector_tpl.h"
 #include "tpl/binary_heap_tpl.h"
diff --git sound/win32_sound.cc sound/win32_sound.cc
index 36674feb6..e8919ac47 100644
--- sound/win32_sound.cc
+++ sound/win32_sound.cc
@@ -9,7 +9,7 @@
 #include <mmsystem.h>
 
 #include "sound.h"
-#include "../simsys.h"
+#include "../sys/simsys.h"
 
 
 /*
diff --git clipboard_internal.cc sys/clipboard_internal.cc
similarity index 96%
rename from clipboard_internal.cc
rename to sys/clipboard_internal.cc
index f8a43c63b..05e51d1a0 100644
--- clipboard_internal.cc
+++ sys/clipboard_internal.cc
@@ -6,8 +6,8 @@
 #include <string.h>
 
 #include "simsys.h"
-#include "display/simgraph.h"
-#include "simdebug.h"
+#include "../display/simgraph.h"
+#include "../simdebug.h"
 
 
 #define MAX_SIZE (4096)
diff --git clipboard_s2.cc sys/clipboard_s2.cc
similarity index 92%
rename from clipboard_s2.cc
rename to sys/clipboard_s2.cc
index 37bea7708..d9afd25b3 100644
--- clipboard_s2.cc
+++ sys/clipboard_s2.cc
@@ -3,14 +3,17 @@
  * (see LICENSE.txt)
  */
 
+
+#include "simsys.h"
+
+#include "../display/simgraph.h"
+#include "../simdebug.h"
+#include "../dataobj/translator.h"
+
 #include <SDL2/SDL.h>
 
 #include <string.h>
 
-#include "simsys.h"
-#include "display/simgraph.h"
-#include "simdebug.h"
-#include "dataobj/translator.h"
 
 /**
  * Copy text to the clipboard
diff --git clipboard_w32.cc sys/clipboard_w32.cc
similarity index 95%
rename from clipboard_w32.cc
rename to sys/clipboard_w32.cc
index e79e06bb4..7ed1de5ee 100644
--- clipboard_w32.cc
+++ sys/clipboard_w32.cc
@@ -3,14 +3,17 @@
  * (see LICENSE.txt)
  */
 
+
+#include "simsys.h"
+
+#include "../display/simgraph.h"
+#include "../simdebug.h"
+#include "../dataobj/translator.h"
+
 #include <windows.h>
 
 #include <string.h>
 
-#include "simsys.h"
-#include "display/simgraph.h"
-#include "simdebug.h"
-#include "dataobj/translator.h"
 
 /**
  * Copy text to the clipboard
diff --git simsys.cc sys/simsys.cc
similarity index 99%
rename from simsys.cc
rename to sys/simsys.cc
index b5b14c58f..760b768de 100644
--- simsys.cc
+++ sys/simsys.cc
@@ -20,11 +20,11 @@
 #define NO_UINT64_TYPES
 #endif
 
-#include "macros.h"
-#include "simmain.h"
 #include "simsys.h"
-#include "pathes.h"
-#include "simevent.h"
+#include "../macros.h"
+#include "../simmain.h"
+#include "../pathes.h"
+#include "../simevent.h"
 
 
 #ifdef _WIN32
diff --git simsys.h sys/simsys.h
similarity index 98%
rename from simsys.h
rename to sys/simsys.h
index a885aad3d..dba633ea3 100644
--- simsys.h
+++ sys/simsys.h
@@ -3,12 +3,12 @@
  * (see LICENSE.txt)
  */
 
-#ifndef SIMSYS_H
-#define SIMSYS_H
+#ifndef SYS_SIMSYS_H
+#define SYS_SIMSYS_H
 
 
 #include <stddef.h>
-#include "simtypes.h"
+#include "../simtypes.h"
 #include <zlib.h>
 
 // Provide chdir().
diff --git simsys_d.cc sys/simsys_d.cc
similarity index 98%
rename from simsys_d.cc
rename to sys/simsys_d.cc
index 06e885622..139403774 100644
--- simsys_d.cc
+++ sys/simsys_d.cc
@@ -8,12 +8,13 @@
 #include <stdlib.h>
 #include <stdio.h>
 
-#include "macros.h"
 #include "simsys.h"
-#include "simevent.h"
-#include "display/simgraph.h"
 #include "simsys_w32_png.h"
-#include "simversion.h"
+
+#include "../macros.h"
+#include "../simevent.h"
+#include "../display/simgraph.h"
+#include "../simversion.h"
 
 #include <allegro.h>
 
diff --git simsys_posix.cc sys/simsys_posix.cc
similarity index 97%
rename from simsys_posix.cc
rename to sys/simsys_posix.cc
index 780cd8d13..c519fa9e3 100644
--- simsys_posix.cc
+++ sys/simsys_posix.cc
@@ -17,10 +17,10 @@
 
 #include <signal.h>
 
-#include "macros.h"
-#include "simdebug.h"
-#include "simevent.h"
 #include "simsys.h"
+#include "../macros.h"
+#include "../simdebug.h"
+#include "../simevent.h"
 
 
 static bool sigterm_received = false;
diff --git simsys_s.cc sys/simsys_s.cc
similarity index 99%
rename from simsys_s.cc
rename to sys/simsys_s.cc
index 19321491e..38139eaba 100644
--- simsys_s.cc
+++ sys/simsys_s.cc
@@ -11,13 +11,14 @@
 
 #include <stdio.h>
 
-#include "macros.h"
-#include "simsys_w32_png.h"
-#include "simversion.h"
 #include "simsys.h"
-#include "simevent.h"
-#include "display/simgraph.h"
-#include "simdebug.h"
+#include "simsys_w32_png.h"
+
+#include "../macros.h"
+#include "../simversion.h"
+#include "../simevent.h"
+#include "../display/simgraph.h"
+#include "../simdebug.h"
 
 
 static Uint8 hourglass_cursor[] = {
@@ -90,7 +91,7 @@ static SDL_Cursor* hourglass;
 static SDL_Cursor* blank;
 
 #ifdef MULTI_THREAD
-#include "utils/simthread.h"
+#include "../utils/simthread.h"
 
 static simthread_barrier_t redraw_barrier;
 static pthread_mutex_t redraw_mutex = PTHREAD_MUTEX_INITIALIZER;
diff --git simsys_s2.cc sys/simsys_s2.cc
similarity index 98%
rename from simsys_s2.cc
rename to sys/simsys_s2.cc
index 30d1570e3..24bd6929a 100644
--- simsys_s2.cc
+++ sys/simsys_s2.cc
@@ -17,17 +17,19 @@ extern int __argc;
 extern char **__argv;
 #endif
 
-#include "macros.h"
 #include "simsys_w32_png.h"
-#include "simversion.h"
 #include "simsys.h"
-#include "simevent.h"
-#include "display/simgraph.h"
-#include "simdebug.h"
-#include "dataobj/environment.h"
-#include "gui/simwin.h"
-#include "gui/components/gui_component.h"
-#include "gui/components/gui_textinput.h"
+
+#include "../macros.h"
+#include "../simversion.h"
+#include "../simevent.h"
+#include "../display/simgraph.h"
+#include "../simdebug.h"
+#include "../dataobj/environment.h"
+#include "../gui/simwin.h"
+#include "../gui/components/gui_component.h"
+#include "../gui/components/gui_textinput.h"
+
 
 // Maybe Linux is not fine too, had critical bugs...
 #if !defined(__linux__)
diff --git simsys_w.cc sys/simsys_w.cc
similarity index 98%
rename from simsys_w.cc
rename to sys/simsys_w.cc
index 103b9e706..9f71b1b0a 100644
--- simsys_w.cc
+++ sys/simsys_w.cc
@@ -22,14 +22,20 @@ extern int __argc;
 extern char **__argv;
 #endif
 
-#include "simconst.h"
-#include "display/simgraph.h"
-#include "simdebug.h"
-#include "gui/simwin.h"
-#include "gui/gui_frame.h"
-#include "gui/components/gui_component.h"
-#include "gui/components/gui_textinput.h"
+#include "simsys_w32_png.h"
+#include "simsys.h"
 
+#include "../simconst.h"
+#include "../display/simgraph.h"
+#include "../simdebug.h"
+#include "../gui/simwin.h"
+#include "../gui/gui_frame.h"
+#include "../gui/components/gui_component.h"
+#include "../gui/components/gui_textinput.h"
+#include "../simmem.h"
+#include "../simversion.h"
+#include "../simevent.h"
+#include "../macros.h"
 
 // needed for wheel
 #ifndef WM_MOUSEWHEEL
@@ -39,12 +45,7 @@ extern char **__argv;
 #	define GET_WHEEL_DELTA_WPARAM(wparam) ((short)HIWORD(wparam))
 #endif
 
-#include "simmem.h"
-#include "simsys_w32_png.h"
-#include "simversion.h"
-#include "simsys.h"
-#include "simevent.h"
-#include "macros.h"
+
 
 /*
  * The class name used to configure the main window.
diff --git simsys_w32_png.cc sys/simsys_w32_png.cc
similarity index 99%
rename from simsys_w32_png.cc
rename to sys/simsys_w32_png.cc
index ecb3cf50e..1296099e3 100644
--- simsys_w32_png.cc
+++ sys/simsys_w32_png.cc
@@ -3,10 +3,11 @@
  * (see LICENSE.txt)
  */
 
-#include "macros.h"
-#include "simmem.h"
 #include "simsys_w32_png.h"
 
+#include "../macros.h"
+#include "../simmem.h"
+
 #include <stdio.h>
 #include <stdlib.h>
 
diff --git simsys_w32_png.h sys/simsys_w32_png.h
similarity index 82%
rename from simsys_w32_png.h
rename to sys/simsys_w32_png.h
index 52425a3cb..a141c70df 100644
--- simsys_w32_png.h
+++ sys/simsys_w32_png.h
@@ -3,8 +3,8 @@
  * (see LICENSE.txt)
  */
 
-#ifndef SIMSYS_W32_PNG_H
-#define SIMSYS_W32_PNG_H
+#ifndef SYS_SIMSYS_W32_PNG_H
+#define SYS_SIMSYS_W32_PNG_H
 
 
 #ifdef _WIN32
@@ -12,4 +12,5 @@
 bool dr_screenshot_png(char const* filename, int w, int h, int maxwidth, unsigned short* data, int bitdepth);
 #endif
 
+
 #endif
diff --git utils/log.cc utils/log.cc
index 92418378b..adcb5fa0a 100644
--- utils/log.cc
+++ utils/log.cc
@@ -16,7 +16,7 @@
 
 #include "log.h"
 #include "../simdebug.h"
-#include "../simsys.h"
+#include "../sys/simsys.h"
 
 
 #ifdef MAKEOBJ
diff --git utils/simrandom.cc utils/simrandom.cc
index 7a9cfe5bf..7b580868e 100644
--- utils/simrandom.cc
+++ utils/simrandom.cc
@@ -6,7 +6,7 @@
 #include <assert.h>
 #include <math.h>
 #include "simrandom.h"
-#include "../simsys.h"
+#include "../sys/simsys.h"
 
 /* This is the mersenne random generator: More random and faster! */