diff --git a/platforms/dos/.gitignore b/platforms/dos/.gitignore
new file mode 100644
index 0000000..8368546
--- /dev/null
+++ b/platforms/dos/.gitignore
@@ -0,0 +1,2 @@
+y*
+src/
\ No newline at end of file
diff --git a/platforms/dos/Makefile.mk b/platforms/dos/Makefile.mk
new file mode 100644
index 0000000..7879900
--- /dev/null
+++ b/platforms/dos/Makefile.mk
@@ -0,0 +1,38 @@
+# run with wmake from OpenWatcomC
+
+coreObjFiles   = PFCOMPIL.OBJ PF_CGLUE.OBJ PF_CLIB.OBJ PF_CORE.OBJ PF_INNER.OBJ PF_IO.OBJ PF_MAIN.OBJ PF_MEM.OBJ PF_SAVE.OBJ PF_TEXT.OBJ PF_WORDS.OBJ
+ioObjFiles     =
+customObjFiles = PFCUSTOM.OBJ 
+allObjFiles    = $(coreObjFiles) $(ioObjFiles) $(customObjFiles) missing.obj
+
+.c.obj
+	wcc386 -fp3 -fpi87 -I. -DPF_SUPPORT_FP $<
+	
+pforth.dic: pforth.exe
+	cd ..\fth
+	..\csrc\pforth -i system.fth
+	cd ..\csrc
+	move ..\fth\pforth.dic .
+
+pforth.exe: $(allObjFiles)
+	%write pforth.lnk NAME   $@
+	%write pforth.lnk SYSTEM DOS4G
+	%write pforth.lnk FILE   {$(allObjFiles)}
+	wlink  @pforth.lnk
+
+clean:  .symbolic
+	del *.dic *.exe *.lnk *.obj *.err
+
+test: pforth.dic .symbolic
+    copy pforth.dic ..\fth\
+	cd ..\fth
+	..\csrc\pforth -q t_corex.fth
+	..\csrc\pforth -q tstrings.fth
+	..\csrc\pforth -q t_locals.fth
+	..\csrc\pforth -q t_alloc.fth
+	..\csrc\pforth -q t_floats.fth
+# this will not succeed:	..\csrc\pforth -q t_file.fth
+	del pforth.dic
+	cd ..\csrc\
+	echo
+	echo "all tests PASSED"
diff --git a/platforms/dos/README b/platforms/dos/README
new file mode 100644
index 0000000..2da4a04
--- /dev/null
+++ b/platforms/dos/README
@@ -0,0 +1,47 @@
+Build environment
+-----------------
+PForth has been build (and run) under both FreeDos and DosBox.
+Others (DR-DOS, MS-DOS...) might work as well.
+
+
+Preparation steps
+-----------------
+DOS limits file names to 8+3 characters.
+Currently 19 relevant files in the PForth source tree violate this rule (see rename.txt for details).
+It is recommended to perform the following steps on a POSIX system (tested under MSYS2/Cygwin):
+  1) run ./step-1-prepare-sourceTree.sh to rename all files to 8+3 characters convention.
+     It will check that no new files violate the convention and abort if so.
+	 In that case extend rename.txt.
+  2) Select OS-specific routine and run appropriate script, e.g.:
+     ./step-2a-select-stdio.sh
+	 For now only stdio is tested.
+  3) Create an archive and transfer it to the build environment.
+     Both FreeDos and Linux-hosts for DosBox provide tar, so you can:
+     tar cf pf-dos.tar src/	 
+     FreeDos also provides unzip.exe if you want to create a ZIP file instead.
+
+
+Compiler
+--------
+FreeDos developers seem to prefer OpenWatcomC (install it via fdimples on FreeDos).
+It has been used to compile PForth successfully under both FreeDos and DosBox.
+(The latter does not provide a "move" command, so the build needs a bit of help at 1 point after pforth.dic has been created).
+This build targets 386 hardware and and a DOS extender (DOS4GW) since the standard 16-bit build (via owcc) failed.
+OpenWatcomC does not implement two required functions for floating point operation, missing.c fixes that.
+The test suite runs fine except for unimplemtented stuff in t_file.fth.
+
+Potentially you could build pforth using DJGPP (gcc and gnu-make).
+Unfortunately I found it unusable (it crashed way too often).
+
+PForth assumes 32bit several times in the source code. 
+Thus not 16 bit compilers (like Turbo C) were tried.
+
+
+where / how to build?
+---------------------
+Extract the prepared sources to a drive with sufficient free space and execute:
+cd .\src\csrc
+wmake
+
+If that worked fine, try this next:
+wmake test
diff --git a/platforms/dos/missing.c b/platforms/dos/missing.c
new file mode 100644
index 0000000..5fc4ba7
--- /dev/null
+++ b/platforms/dos/missing.c
@@ -0,0 +1,23 @@
+ #include "missing.h"
+ 
+double round(double x)  {
+  double i, s;
+  if( x>=0 ) {
+    i = floor(x);
+    s = 1.0;
+  } else {
+    i = ceil(x);
+    s = -1.0;
+  }
+  if( fabs(x - i) < 0.5 )
+    return i;      /* round down */
+  else
+    return i + s;  /* round up   */
+}
+
+double log1p(double x)  {
+  if( -1.0 < x  &&  x <= 1.0 )
+    return x - 0.5*x*x + 1.0/3.0*x*x*x - 0.25*x*x*x*x + 0.20*x*x*x*x*x;
+  else
+    return log( 1.0 + x );
+}
diff --git a/platforms/dos/missing.h b/platforms/dos/missing.h
new file mode 100644
index 0000000..b382c46
--- /dev/null
+++ b/platforms/dos/missing.h
@@ -0,0 +1,10 @@
+/* include this in pf_inner.c !! */
+
+#ifndef PF_MISSING_H
+#define PF_MISSING_H
+
+#include <math.h> 
+double round(double x);
+double log1p(double x);
+
+#endif /* PF_MISSING_H */
diff --git a/platforms/dos/rename.txt b/platforms/dos/rename.txt
new file mode 100644
index 0000000..2893426
--- /dev/null
+++ b/platforms/dos/rename.txt
@@ -0,0 +1,19 @@
+src/csrc/pf_io_none.c                   src/csrc/ionone.c
+src/csrc/posix/pf_io_posix.c            src/csrc/posix/ioposix.c
+src/csrc/stdio/pf_fileio_stdio.c        src/csrc/stdio/fiostdio.c
+src/csrc/stdio/pf_io_stdio.c            src/csrc/stdio/iostdio.c
+src/csrc/win32/pf_io_win32.c            src/csrc/win32/iowin32.c
+src/csrc/win32csl/pf_io_win32_console.c src/csrc/win32csl/iowin32c.c
+src/fth/save-input.fth                  src/fth/savinput.fth
+src/fth/structure.fth                   src/fth/structur.fth
+src/fth/t_include.fth                   src/fth/tinclude.fth
+src/fth/t_load_defer.fth                src/fth/tlddefer.fth
+src/fth/t_load_pairs.fth                src/fth/tldpairs.fth
+src/fth/t_load_semi.fth                 src/fth/tldsemi.fth
+src/fth/t_load_undef.fth                src/fth/tldundef.fth
+src/fth/t_required_helper1.fth          src/fth/treqhlp1.fth
+src/fth/t_required_helper2.fth          src/fth/treqhlp2.fth
+src/fth/t_strings.fth                   src/fth/tstrings.fth
+src/fth/utils/dump_struct.fth           src/fth/utils/dumpstru.fth
+src/fth/utils/load_file.fth             src/fth/utils/loadfile.fth
+src/fth/utils/make_all256.fth           src/fth/utils/make_all.fth
diff --git a/platforms/dos/step-1-prepare-sourceTree.sh b/platforms/dos/step-1-prepare-sourceTree.sh
new file mode 100644
index 0000000..853a7cd
--- /dev/null
+++ b/platforms/dos/step-1-prepare-sourceTree.sh
@@ -0,0 +1,62 @@
+#!/bin/sh
+
+echo
+echo "0) clean previous build folder"
+echo "------------------------------"
+rm -rf ./src/
+
+echo
+echo "1) copy sources here"
+echo "--------------------"
+mkdir src
+mkdir src/csrc
+mkdir src/fth
+cp -r ../../csrc/ ./src/
+cp -r ../../fth/  ./src/
+cp    missing.*   ./src/csrc/
+cp    Makefile.mk ./src/csrc/
+find . | grep -i cmake | xargs rm  # Nobody likes CMake!!!
+mv ./src/csrc/win32_console/ ./src/csrc/win32csl/
+
+echo
+echo "2a) rename files to 8+3 filename convention"
+echo "-------------------------------------------"
+cat rename.txt | awk '{if( NF==2 ) print "mv " $1 " " $2}' | sh
+echo "2b) verify that 8+3 filename convention is kept."
+echo "-----------------------------------------------"
+find src/ -type f | awk -f too-long-filenames.awk | tee yMissingRenames
+echo "-----------------------------------------------"
+if test -s yMissingRenames
+then
+  echo "ABORT: more files need to be renamed!"
+else # yMissingRenames
+
+  echo
+  echo "3) extract list of filenames to substitute from 'rename.txt'"
+  echo "-------------------------------------------------------------"
+  cat rename.txt | awk '{if( NF==2 ) print "echo s#`basename " $1 "`#`basename " $2 "`#g"  }' | sh | sed -e 's#\.#\\\.#g' > yFileNames
+
+  echo
+  echo "4) patch file contents"
+  echo "----------------------"
+  for curFile in `find src/ -type f`
+  do
+    sed -f yFileNames -i $curFile
+  done
+  rm yFileNames
+
+  echo
+  echo "4) include missing.h in pf_inner.c"
+  echo "----------------------------------"
+  mv ./src/csrc/pf_inner.c tmp.c
+  cat - tmp.c > ./src/csrc/pf_inner.c << EOF
+#include "missing.h"
+EOF
+  rm tmp.c
+
+  echo
+  echo "99) done"
+  echo "--------"
+  rm yMissingRenames
+
+fi   # yMissingRenames
diff --git a/platforms/dos/step-2a-select-stdio.sh b/platforms/dos/step-2a-select-stdio.sh
new file mode 100644
index 0000000..47544fe
--- /dev/null
+++ b/platforms/dos/step-2a-select-stdio.sh
@@ -0,0 +1,19 @@
+#!/bin/sh
+
+ioSources="fiostdio.c iostdio.c"
+
+cd ./src/csrc/
+
+# 1) copy ioSources to parent dir (so all sources are in 1 folder) and patch the include statements accordingly
+for srcFile in $ioSources
+do
+  cat "./stdio/$srcFile" | sed -e 's#\.\./##g' > $srcFile
+done
+
+# 2) include ioSources in Makefile
+objFiles=`echo $ioSources | sed -e 's#\.c#\\\.obj#g'  `
+cat Makefile.mk | sed -e "s/ioObjFiles     =/ioObjFiles     = $objFiles/g" > Makefile
+rm Makefile.mk
+
+cd ../../
+echo "done"
diff --git a/platforms/dos/too-long-filenames.awk b/platforms/dos/too-long-filenames.awk
new file mode 100644
index 0000000..ad81c2e
--- /dev/null
+++ b/platforms/dos/too-long-filenames.awk
@@ -0,0 +1,22 @@
+# call via:
+#   find csrc/ fth/ -type f | awk -f too-long-filenames.awk
+
+
+BEGIN {
+  FS="/"  # separate by directory 
+}
+
+
+{
+  noParts = split( $NF, parts, "." )
+  if ( noParts!=2 )
+  {
+    if ( noParts>2 )
+      print "----> invalid noParts=" noParts " for file='" $0 "'"
+  }
+  else
+  {
+    if( length(parts[1]) > 8  ||  length(parts[2]) > 3 ) 
+      print $0;
+  }
+}