diff --git a/CHANGELOG b/CHANGELOG
index eeddffb..e17fedf 100644
--- a/CHANGELOG
+++ b/CHANGELOG
@@ -2,6 +2,9 @@ Maui 3.3.1
   - Fixed issue where hostlist was being overwritten resulting in broken $PBS_NODEFILE. (Alexis Cousein)
   - Fixed issue where users could set system priority on their own jobs. (Bas van der Vlies)
   - Made showgrid's, and other's, arguments case-insensitive. (David Chin)
+  - Added build system changes to support Cygwin (Yauheni Charniauski, UIIP Minsk)
+  - Added the --with-cygrunsrv configure option for start maui as Windows service (doesn't use a background daemon).
+    Cygwin utility cygrunsrv.exe goes it into background independently (Igor Ilyenko, UIIP Minsk)
 
 Maui 3.3
   - Fixed configure script. Was putting RMCFG[name] TYPE=PBS@RMNMHOST@.
diff --git a/Makefile.in b/Makefile.in
index 7fa2b97..376f9e8 100644
--- a/Makefile.in
+++ b/Makefile.in
@@ -6,6 +6,7 @@
 BUILDROOT=
 export MSCHED_HOME=${BUILDROOT}@SPOOLDIR@
 export INST_DIR=${BUILDROOT}@prefix@
+export DAEMONDEF=@DAEMONDEF@
 export OPSYS=@OPSYS@
 export OS=@OS@
 export CC=@CC@
diff --git a/configure b/configure
index 73bbcff..b613991 100755
--- a/configure
+++ b/configure
@@ -311,7 +311,7 @@ ac_includes_default="\
 # include <unistd.h>
 #endif"
 
-ac_subst_vars='SHELL PATH_SEPARATOR PACKAGE_NAME PACKAGE_TARNAME PACKAGE_VERSION PACKAGE_STRING PACKAGE_BUGREPORT exec_prefix prefix program_transform_name bindir sbindir libexecdir datadir sysconfdir sharedstatedir localstatedir libdir includedir oldincludedir infodir mandir build_alias host_alias target_alias DEFS ECHO_C ECHO_N ECHO_T LIBS CC CFLAGS LDFLAGS CPPFLAGS ac_ct_CC EXEEXT OBJEXT LN_S SPOOLDIR MACHINE SEED OPSYS OS HOSTNAME USER BUILDDATE BUILDDIR RMTYPE LLDIR LLDEF PBSTARGETDIR SGEBUILDDIR SGEOSDIR LSFDIR LSFLIBS LSFDEFS PBSCFLAGS PBSLDFLAGS RMPORT RMHOST RMSOCKETPROTOCOL RMWIREPROTOCOL RMVERSION RMNMPORT RMNMHOST AMTYPE AMHOST AMPORT AMSOCKETPROTOCOL AMWIREPROTOCOL AMOTHER PCREDIR CPP EGREP LIBOBJS POW_LIB LTLIBOBJS'
+ac_subst_vars='SHELL PATH_SEPARATOR PACKAGE_NAME PACKAGE_TARNAME PACKAGE_VERSION PACKAGE_STRING PACKAGE_BUGREPORT exec_prefix prefix program_transform_name bindir sbindir libexecdir datadir sysconfdir sharedstatedir localstatedir libdir includedir oldincludedir infodir mandir build_alias host_alias target_alias DEFS ECHO_C ECHO_N ECHO_T LIBS CC CFLAGS LDFLAGS CPPFLAGS ac_ct_CC EXEEXT OBJEXT LN_S SPOOLDIR MACHINE SEED DAEMONDEF OPSYS OS HOSTNAME USER BUILDDATE BUILDDIR RMTYPE LLDIR LLDEF PBSTARGETDIR SGEBUILDDIR SGEOSDIR LSFDIR LSFLIBS LSFDEFS PBSCFLAGS PBSLDFLAGS RMPORT RMHOST RMSOCKETPROTOCOL RMWIREPROTOCOL RMVERSION RMNMPORT RMNMHOST AMTYPE AMHOST AMPORT AMSOCKETPROTOCOL AMWIREPROTOCOL AMOTHER PCREDIR CPP EGREP LIBOBJS POW_LIB LTLIBOBJS'
 ac_subst_files='rm_config ll_definitions sdr_definitions pbs_definitions sge_definitions lsf_definitions mx_definitions pcre_definitions'
 
 # Initialize some variables set by options.
@@ -862,6 +862,7 @@ Optional Packages:
   --with-sss-am[=PORT]    use SSS Allocation Manager (default port [8865])
   --with-mx               use MX
   --with-pcre[=DIR]       use PCRE (pcre dir (location of PCRE include and lib directories) [/path/to/pcre]
+  --with-cygrunsrv        run as Windows service for Cygwin (do not use a background daemon)
 
 Some influential environment variables:
   CC          C compiler command
@@ -2234,6 +2235,8 @@ echo "$as_me: WARNING: Unexpected OS release 'AIX4$RELEASE', attempting build wi
     { echo "$as_me:$LINENO: WARNING: Unexpected AIX level: $OSLEVEL, attempting build with OPSYS=$OPSYS" >&5
 echo "$as_me: WARNING: Unexpected AIX level: $OSLEVEL, attempting build with OPSYS=$OPSYS" >&2;}
   fi
+elif echo "$OS" | grep -q "CYGWIN"; then
+  OPSYS="__CYGWIN"
 elif test "$OS" = "Linux"; then
   OPSYS="__LINUX"
 elif test "$OS" = "HP-UX"; then
@@ -2743,6 +2746,17 @@ if test "$PCREDIR" != 'FALSE'; then
 	pcre_definitions=include/Makefile.inc.pcre
 fi
 
+# CYGRUNSRV
+
+# Check whether --with-cygrunsrv or --without-cygrunsrv was given.
+if test "${with_cygrunsrv+set}" = set; then
+  withval="$with_cygrunsrv"
+  DAEMONDEF="-D__CYGRUNSRV"
+else
+  DAEMONDEF=""
+fi;
+
+
 # Make sure one RM was specified
 if test "$RMTYPE" = ''; then
   { { echo "$as_me:$LINENO: error: At least one Resource Manager must be specified" >&5
@@ -7201,6 +7215,7 @@ s,@LN_S@,$LN_S,;t t
 s,@SPOOLDIR@,$SPOOLDIR,;t t
 s,@MACHINE@,$MACHINE,;t t
 s,@SEED@,$SEED,;t t
+s,@DAEMONDEF@,$DAEMONDEF,;t t
 s,@OPSYS@,$OPSYS,;t t
 s,@OS@,$OS,;t t
 s,@HOSTNAME@,$HOSTNAME,;t t
diff --git a/configure.ac b/configure.ac
index 2f7d30d..da7930c 100644
--- a/configure.ac
+++ b/configure.ac
@@ -53,6 +53,8 @@ if test "$OS" = "AIX"; then
     OSLEVEL=`oslevel`
     AC_MSG_WARN([Unexpected AIX level: $OSLEVEL, attempting build with OPSYS=$OPSYS])
   fi
+elif echo "$OS" | grep -q "CYGWIN"; then
+  OPSYS="__CYGWIN"
 elif test "$OS" = "Linux"; then
   OPSYS="__LINUX"
 elif test "$OS" = "HP-UX"; then
@@ -466,6 +468,15 @@ if test "$PCREDIR" != 'FALSE'; then
 	pcre_definitions=include/Makefile.inc.pcre
 fi
 
+
+# CYGRUNSRV
+AC_ARG_WITH(cygrunsrv,
+	[  --with-cygrunsrv        run as Windows service for Cygwin (do not use a background daemon)],
+	[DAEMONDEF="-D__CYGRUNSRV"],
+	[DAEMONDEF=""])
+AC_SUBST(DAEMONDEF)
+
+
 # Make sure one RM was specified
 if test "$RMTYPE" = ''; then
   AC_MSG_ERROR([At least one Resource Manager must be specified])
diff --git a/src/mcom/Makefile b/src/mcom/Makefile
index b8b0000..006e90f 100644
--- a/src/mcom/Makefile
+++ b/src/mcom/Makefile
@@ -13,7 +13,7 @@ SHELL  =/bin/sh
   LP   =-L$(LIB) $(SCHEDLP) $(MXLP) $(REGEXLP)
   IP   =$(SCHEDIP) $(REGEXIP) $(MXIP)
   INCS =$(INC)moab.h $(INC)moab-proto.h 
-  DEFS =-D$(OPSYS) $(OSDEF) $(MXDEF) $(REGEXDEF) $(SECDEF)
+  DEFS =-D$(OPSYS) $(OSDEF) $(MXDEF) $(REGEXDEF) $(SECDEF) $(DAEMONDEF)
 
 LIBMCOM  =libmcom.a
 LOBJECTS =MSU.o MSec.o MS3I.o MXML.o MConst.o MTComm.o MComm.o
diff --git a/src/moab/MFile.c b/src/moab/MFile.c
index 993e81b..f631b5c 100644
--- a/src/moab/MFile.c
+++ b/src/moab/MFile.c
@@ -1184,7 +1184,7 @@ int MFULock(
   char *LockFile)   /* I */
 
   {
-#if !defined(__LINUX) && !defined(__HPUX) && !defined(__NT)
+#if !defined(__LINUX) && !defined(__CYGWIN) && !defined(__HPUX) && !defined(__NT)
   int          fd;
   struct flock lock;
   char         Name[MAX_MLINE];
@@ -1197,7 +1197,7 @@ int MFULock(
     Directory,
     LockFile);
 
-#if !defined(__LINUX) && !defined(__HPUX) && !defined(__NT)
+#if !defined(__LINUX) && !defined(__CYGWIN) && !defined(__HPUX) && !defined(__NT)
 
   if (!strstr(LockFile,Directory))
     {
diff --git a/src/moab/MLog.c b/src/moab/MLog.c
index 94ae215..c94d0cb 100644
--- a/src/moab/MLog.c
+++ b/src/moab/MLog.c
@@ -82,7 +82,7 @@ int MLogInitialize(
 
   if (SigSet == 0)
     {
-#   if defined(__AIX41) || defined(__AIX42) || defined(__AIX43) || defined(__IRIX) || defined(__LINUX) || defined(__HPUX) || defined(__SOLARIS)
+#   if defined(__AIX41) || defined(__AIX42) || defined(__AIX43) || defined(__IRIX) || defined(__LINUX) || defined(__CYGWIN) || defined(__HPUX) || defined(__SOLARIS)
       signal(SIGUSR1,(void(*)(int))MLogLevelAdjust);
       signal(SIGUSR2,(void(*)(int))MLogLevelAdjust);
 #   else 
@@ -414,7 +414,7 @@ void MLogLevelAdjust(
         mlog.Threshold);
       }
 
-#if defined(__AIX41) || defined(__AIX42) || defined(__AIX43) || defined(__IRIX) || defined(__LINUX) || defined(__HPUX) || defined(__SOLARIS)
+#if defined(__AIX41) || defined(__AIX42) || defined(__AIX43) || defined(__IRIX) || defined(__LINUX) || defined(__CYGWIN) || defined(__HPUX) || defined(__SOLARIS)
 
     signal(SIGUSR1,(void(*)(int))MLogLevelAdjust);
 
@@ -441,7 +441,7 @@ void MLogLevelAdjust(
         mlog.Threshold);
       }
 
-#if defined(__AIX41) || defined(__AIX42) || defined(__AIX43) || defined(__IRIX) || defined(__LINUX) || defined(__HPUX) || defined(__SOLARIS) || defined(__OSF)
+#if defined(__AIX41) || defined(__AIX42) || defined(__AIX43) || defined(__IRIX) || defined(__LINUX) || defined(__CYGWIN) || defined(__HPUX) || defined(__SOLARIS) || defined(__OSF)
 
     signal(SIGUSR2,(void(*)(int))MLogLevelAdjust);
 
diff --git a/src/moab/MPBSI.c b/src/moab/MPBSI.c
index 8a9b35c..0090760 100644
--- a/src/moab/MPBSI.c
+++ b/src/moab/MPBSI.c
@@ -2657,7 +2657,7 @@ int MPBSQueryMOM(
     "arch",               /* the architecture of the machine */
     "physmem",            /* the amount of physical memory */
     "loadave",            /* the current load average */
-#if defined(__AIX43) || defined(__AIX51) || defined(__LINUX) || defined(__IRIX)
+#if defined(__AIX43) || defined(__AIX51) || defined(__LINUX)  || defined(__CYGWIN) || defined(__IRIX)
     "availmem",
     "totmem",
 #endif /* AIX43 || LINUX || IRIX */
diff --git a/src/moab/Makefile b/src/moab/Makefile
index f972d89..a55de22 100644
--- a/src/moab/Makefile
+++ b/src/moab/Makefile
@@ -18,7 +18,7 @@ SHELL  =/bin/sh
   IP   =$(SCHEDIP) $(LLIP) $(REGEXIP) $(MXIP) $(PBSCFLAGS)
   INCS =$(INC)moab.h $(INC)msched.h
   DEFS =-D$(OPSYS) $(LLDEF) $(SDRDEF) $(PBSDEF) $(OSDEF) $(MXDEF) $(REGEXDEF) \
-        $(SECDEF) $(RMSDEF) $(THREADDEF)
+        $(SECDEF) $(RMSDEF) $(THREADDEF) $(DAEMONDEF)
 
 MOAB     =libmoab.a
 LOBJECTS =MFile.o MConfig.o MQOS.o MLog.o MCred.o MSched.o MAM.o MSR.o MRes.o \
diff --git a/src/server/Makefile b/src/server/Makefile
index 5c22df2..61e112e 100644
--- a/src/server/Makefile
+++ b/src/server/Makefile
@@ -18,7 +18,7 @@ SHELL  =/bin/sh
   IP   =$(SCHEDIP) $(LLIP) $(SGEIP) $(REGEXIP) $(MXIP) $(PBSCFLAGS)
   INCS =$(INC)moab.h $(INC)msched-proto.h $(INC)msched-common.h
   DEFS =-D$(OPSYS) $(LLDEF) $(SDRDEF) $(PBSDEF) $(OSDEF) $(MXDEF) \
-        $(REGEXDEF) $(RMSDEF) $(SECDEF) $(THREADDEF)
+        $(REGEXDEF) $(RMSDEF) $(SECDEF) $(THREADDEF) $(DAEMONDEF)
 
 SERVER   =maui
 SCHEDLIB =moab
diff --git a/src/server/OServer.c b/src/server/OServer.c
index 75c7b36..b7983dc 100644
--- a/src/server/OServer.c
+++ b/src/server/OServer.c
@@ -5,7 +5,7 @@ int ServerSetSignalHandlers()
   {
   /* trap TERM(15) QUIT(3) INT(2) HUP(1) */
  
-#if defined(__AIX41) || defined(__AIX42) || defined(__AIX43) || defined(__AIX51) || defined(__IRIX) || defined(__LINUX) || defined(__HPUX) || defined(__SOLARIS) || defined(__OSF) || defined(__FREEBSD)
+#if defined(__AIX41) || defined(__AIX42) || defined(__AIX43) || defined(__AIX51) || defined(__IRIX) || defined(__LINUX) || defined(__CYGWIN) || defined(__HPUX) || defined(__SOLARIS) || defined(__OSF) || defined(__FREEBSD)
  
   signal(SIGINT,   SIG_IGN);
   signal(SIGTERM,  (void(*)(int))MSysShutdown);
@@ -120,7 +120,7 @@ int ServerSetSignalHandlers()
     }
   }    /* END BLOCK */ 
 
-#elif defined(__LINUX) || defined(__IRIX) || defined(__HPUX) || defined(__SOLARIS) || defined(__OSF)
+#elif defined(__LINUX) || defined(__CYGWIN) || defined(__IRIX) || defined(__HPUX) || defined(__SOLARIS) || defined(__OSF)
 
   ServerLoadSignalConfig();
  
@@ -143,8 +143,9 @@ int ServerSetSignalHandlers()
 
 
 int ServerDemonize()
+{
+#ifndef __CYGRUNSRV
 
-  {
 #ifndef __NT
   int   pid;
 #endif /* __NT */
@@ -235,6 +236,7 @@ int ServerDemonize()
       }
     }    /* END if (MSched.Mode != msmSim) */
 
+#endif /* __CYGRUNSRV */
   return(SUCCESS);
   }  /* END ServerDemonize() */
 
@@ -305,7 +307,7 @@ int CrashMode(
 
   if (signo == SIGSEGV)
     {
-#if defined(__AIX41) || defined(__AIX42) || defined(__AIX43) || defined(__AIX51) || defined(__LINUX) || defined(__HPUX) || defined(__IRIX) || defined(__SOLARIS) || defined(__OSF) || defined(__FREEBSD)
+#if defined(__AIX41) || defined(__AIX42) || defined(__AIX43) || defined(__AIX51) || defined(__LINUX) || defined(__CYGWIN) || defined(__CYGWIN) || defined(__HPUX) || defined(__IRIX) || defined(__SOLARIS) || defined(__OSF) || defined(__FREEBSD)
 
     signal(SIGSEGV,(void(*)(int))CrashMode);
 
@@ -317,7 +319,7 @@ int CrashMode(
     }
   else if (signo == SIGILL)
     {
-#if defined(__AIX41) || defined(__AIX42) || defined(__AIX43) || defined(__AIX51) || defined(__LINUX) || defined(__HPUX) || defined(__IRIX) || defined(__SOLARIS) || defined(__OSF) || defined(__FREEBSD)
+#if defined(__AIX41) || defined(__AIX42) || defined(__AIX43) || defined(__AIX51) || defined(__LINUX) || defined(__CYGWIN) || defined(__HPUX) || defined(__IRIX) || defined(__SOLARIS) || defined(__OSF) || defined(__FREEBSD)
 
     signal(SIGILL,(void(*)(int))CrashMode);
 
@@ -378,7 +380,7 @@ int ReloadConfig(
 
   MSched.Reload = TRUE;
 
-#if defined(__AIX41) || defined(__AIX42) || defined(__AIX43) || defined(__AIX51) || defined(__LINUX) || defined(__HPUX) || defined(__IRIX) || defined(__SOLARIS) || defined(__OSF) || defined(__FREEBSD)
+#if defined(__AIX41) || defined(__AIX42) || defined(__AIX43) || defined(__AIX51) || defined(__LINUX) || defined(__CYGWIN) || defined(__HPUX) || defined(__IRIX) || defined(__SOLARIS) || defined(__OSF) || defined(__FREEBSD)
 
   signal(SIGHUP,(void(*)(int))ReloadConfig);