diff --git a/hdr/lol.h b/hdr/lol.h
index 721bb1b..5cacf31 100644
--- a/hdr/lol.h
+++ b/hdr/lol.h
@@ -73,12 +73,19 @@ struct lol {
   unsigned short min_pars;     /* 64 minimum para req by program execed   */
   unsigned short uppermem_root;/* 66 Start of umb chain (usually 9fff)    */
   unsigned short last_para;    /* 68 para: start scanning during memalloc */
+  /* ANY ITEM BELOW THIS POINT MAY CHANGE */
   /* FreeDOS specific entries */
   unsigned char os_setver_minor;/*6a settable minor DOS version           */
   unsigned char os_setver_major;/*6b settable major DOS version           */
   unsigned char os_minor;      /* 6c minor DOS version                    */
   unsigned char os_major;      /* 6d major DOS version                    */
-  unsigned char rev_number;    /* 6e minor DOS version                    */
+  unsigned char rev_number;    /* 6e DOS revision#, only 3 bits           */
   unsigned char version_flags; /* 6f DOS version flags                    */
   char *os_release;            /* 70 near pointer to os_release string    */
+#ifdef WIN31SUPPORT
+  unsigned short winInstanced; /* WinInit called                          */
+  unsigned long  winStartupInfo[4];
+  unsigned short instanceTable[5];
+#endif
 };
+
diff --git a/hdr/win.h b/hdr/win.h
new file mode 100644
index 0000000..fdf8483
--- /dev/null
+++ b/hdr/win.h
@@ -0,0 +1,39 @@
+#ifndef __WINSUPPORT_H
+#define __WINSUPPORT_H
+#ifdef    WIN31SUPPORT  /* defined to enable kernel hooks for win3.x compatibility */
+
+
+extern UWORD winInstanced; /* internal flag marking if Windows is active */
+
+/* contains information about data that must be kept for each active DOS
+   instance, ie data that can NOT be shared between multiple VMs.
+ */
+struct WinStartupInfo
+{
+  UWORD winver;  /* this structure version, matches Windows version */
+  ULONG next;    /* far pointer to next WinStartupInfo structure or NULL */
+  ULONG vddName; /* far pointer to ASCIIZ pathname of virtual device driver */
+  ULONG vddInfo; /* far pointer to vdd reference data or NULL if vddName=NULL */
+  ULONG instanceTable;    /* far pointer to array of instance data */
+  ULONG optInstanceTable; /* used only if winver set to 0x400 (w95)*/
+};
+extern struct WinStartupInfo winStartupInfo;
+
+/* contains a list of offsets relative to DOS data segment of
+   various internal variables.
+ */
+struct WinPatchTable
+{
+  UWORD dosver;
+  UWORD OffTempDS;
+  UWORD OffTempBX;
+  UWORD OffInDOS;
+  UWORD OffMachineID;
+  UWORD OffCritSectPatches;
+  UWORD OffLastMCBSeg;  /* used by Win 3.1 if DOS version 5 or higher */
+};
+extern struct WinPatchTable winPatchTable;
+
+
+#endif /* WIN31SUPPORT   */
+#endif /* __WINSUPPORT_H */