diff --git a/include/config.h b/include/config.h
index b606b5db1..53a3ebd79 100644
--- a/include/config.h
+++ b/include/config.h
@@ -579,5 +579,6 @@ typedef unsigned char uchar;
 #endif
 
 #include "global.h" /* Define everything else according to choices above */
+#include "filesize.h" /* Define file sizes shared between nethack and recover */
 
 #endif /* CONFIG_H */
diff --git a/include/decl.h b/include/decl.h
index 54a58aa03..a666a5db8 100644
--- a/include/decl.h
+++ b/include/decl.h
@@ -7,70 +7,6 @@
 #define DECL_H
 
 #define E extern
-#if !defined(MICRO) && !defined(VMS) && !defined(WIN32)
-#define LOCKNAMESIZE (PL_NSIZ + 14) /* long enough for uid+name+.99 */
-#define LOCKNAMEINIT "1lock"
-#define BONESINIT "bonesnn.xxx.le"
-#define BONESSIZE sizeof(BONESINIT)
-#else
-#if defined(MICRO)
-#define LOCKNAMESIZE FILENAME
-#define LOCKNAMEINIT ""
-#define BONESINIT ""
-#define BONESSIZE FILENAME
-#endif
-#if defined(VMS)
-#define LOCKNAMESIZE (PL_NSIZ + 17) /* long enough for _uid+name+.99;1 */
-#define LOCKNAMEINIT "1lock"
-#define BONESINIT "bonesnn.xxx_le;1"
-#define BONESSIZE sizeof(BONESINIT)
-#endif
-#if defined(WIN32)
-#define LOCKNAMESIZE (PL_NSIZ + 25) /* long enough for username+-+name+.99 */
-#define LOCKNAMEINIT ""
-#define BONESINIT "bonesnn.xxx.le"
-#define BONESSIZE sizeof(BONESINIT)
-#endif
-#endif
-
-#define INDEXT ".xxxxxx"           /* largest indicator suffix */
-#define INDSIZE sizeof(INDEXT)
-
-#if defined(UNIX) || defined(__BEOS__)
-#define SAVEX "save/99999.e"
-#ifndef SAVE_EXTENSION
-#define SAVE_EXTENSION ""
-#endif
-#else /* UNIX || __BEOS__ */
-#ifdef VMS
-#define SAVEX "[.save]nnnnn.e;1"
-#ifndef SAVE_EXTENSION
-#define SAVE_EXTENSION ""
-#endif
-#else /* VMS */
-#if defined(WIN32) || defined(MICRO)
-#define SAVEX ""
-#if !defined(SAVE_EXTENSION)
-#ifdef MICRO
-#define SAVE_EXTENSION ".svh"
-#endif
-#ifdef WIN32
-#define SAVE_EXTENSION ".NetHack-saved-game"
-#endif
-#endif /* !SAVE_EXTENSION */
-#endif /* WIN32 || MICRO */
-#endif /* else !VMS */
-#endif /* else !(UNIX || __BEOS__) */
-
-#ifndef SAVE_EXTENSION
-#define SAVE_EXTENSION ""
-#endif
-
-#ifndef MICRO
-#define SAVESIZE (PL_NSIZ + sizeof(SAVEX) + sizeof(SAVE_EXTENSION) + INDSIZE)
-#else
-#define SAVESIZE FILENAME
-#endif
 
 /* max size of a windowtype option */
 #define WINTYPELEN 16
@@ -945,6 +881,7 @@ struct instance_globals {
     boolean chosen_symset_start;
     boolean chosen_symset_end;
     int symset_which_set;
+    /* SAVESIZE, BONESSIZE, LOCKNAMESIZE are defined in "filesize.h" */
     char SAVEF[SAVESIZE]; /* holds relative path of save file from playground */
 #ifdef MICRO
     char SAVEP[SAVESIZE]; /* holds path of directory for save file */
diff --git a/include/filesize.h b/include/filesize.h
new file mode 100644
index 000000000..5ec05904e
--- /dev/null
+++ b/include/filesize.h
@@ -0,0 +1,79 @@
+/* NetHack 3.7	filesize.h	$NHDT-Date: 1575245033 2019/12/02 00:03:53 $  $NHDT-Branch: NetHack-3.6 $:$NHDT-Revision: 1.126 $ */
+/*-Copyright (c) Michael Allison, 2020. */
+/* NetHack may be freely redistributed.  See license for details. */
+
+#ifndef FILESIZE_H 
+#define FILESIZE_H
+
+/*
+ *  Declarations for some file sizes, some of which need to be shared
+ *  between NetHack and recover. By placing them in here, there is less
+ *  chance of deviation between the two.
+ */
+
+#if !defined(MICRO) && !defined(VMS) && !defined(WIN32)
+#define LOCKNAMESIZE (PL_NSIZ + 14) /* long enough for uid+name+.99 */
+#define LOCKNAMEINIT "1lock"
+#define BONESINIT "bonesnn.xxx.le"
+#define BONESSIZE sizeof(BONESINIT)
+#else
+#if defined(MICRO)
+#define LOCKNAMESIZE FILENAME
+#define LOCKNAMEINIT ""
+#define BONESINIT ""
+#define BONESSIZE FILENAME
+#endif
+#if defined(VMS)
+#define LOCKNAMESIZE (PL_NSIZ + 17) /* long enough for _uid+name+.99;1 */
+#define LOCKNAMEINIT "1lock"
+#define BONESINIT "bonesnn.xxx_le;1"
+#define BONESSIZE sizeof(BONESINIT)
+#endif
+#if defined(WIN32)
+#define LOCKNAMESIZE (PL_NSIZ + 25) /* long enough for username+-+name+.99 */
+#define LOCKNAMEINIT ""
+#define BONESINIT "bonesnn.xxx.le"
+#define BONESSIZE sizeof(BONESINIT)
+#endif
+#endif
+
+#define INDEXT ".xxxxxx"           /* largest indicator suffix */
+#define INDSIZE sizeof(INDEXT)
+
+#if defined(UNIX) || defined(__BEOS__)
+#define SAVEX "save/99999.e"
+#ifndef SAVE_EXTENSION
+#define SAVE_EXTENSION ""
+#endif
+#else /* UNIX || __BEOS__ */
+#ifdef VMS
+#define SAVEX "[.save]nnnnn.e;1"
+#ifndef SAVE_EXTENSION
+#define SAVE_EXTENSION ""
+#endif
+#else /* VMS */
+#if defined(WIN32) || defined(MICRO)
+#define SAVEX ""
+#if !defined(SAVE_EXTENSION)
+#ifdef MICRO
+#define SAVE_EXTENSION ".svh"
+#endif
+#ifdef WIN32
+#define SAVE_EXTENSION ".NetHack-saved-game"
+#endif
+#endif /* !SAVE_EXTENSION */
+#endif /* WIN32 || MICRO */
+#endif /* else !VMS */
+#endif /* else !(UNIX || __BEOS__) */
+
+#ifndef SAVE_EXTENSION
+#define SAVE_EXTENSION ""
+#endif
+
+#ifndef MICRO
+#define SAVESIZE (PL_NSIZ + sizeof(SAVEX) + sizeof(SAVE_EXTENSION) + INDSIZE)
+#else
+#define SAVESIZE FILENAME
+#endif
+
+#endif /* FILESIZE_H */
diff --git a/sys/msdos/Makefile.GCC b/sys/msdos/Makefile.GCC
index 1b0521b7c..16ecd8ec0 100644
--- a/sys/msdos/Makefile.GCC
+++ b/sys/msdos/Makefile.GCC
@@ -424,8 +424,8 @@ YOU_H	   = $(MONST_H)		$(YOUPROP_H)	    $(INCL)/align.h   \
 DISPLAY_H  = $(MONDATA_H)	$(INCL)/vision.h    $(INCL)/display.h
 PCCONF_H   = $(INCL)/micro.h	$(INCL)/system.h    $(INCL)/pcconf.h \
 	    $(MSYS)/pcvideo.h
-CONFIG_H   = $(GLOBAL_H)	$(INCL)/tradstdc.h  $(INCL)/config1.h \
-	    $(INCL)/config.h
+CONFIG_H   = $(GLOBAL_H)	$(INCL)/filesize.h  $(INCL)/tradstdc.h \
+	     $(INCL)/config1.h $(INCL)/config.h
 DECL_H	   = $(YOU_H)		$(INCL)/spell.h	    $(INCL)/color.h   \
 	     $(INCL)/obj.h	$(INCL)/onames.h    $(INCL)/pm.h      \
 	      $(INCL)/decl.h
diff --git a/sys/unix/Makefile.src b/sys/unix/Makefile.src
index 7af0bba60..06002056c 100644
--- a/sys/unix/Makefile.src
+++ b/sys/unix/Makefile.src
@@ -729,11 +729,12 @@ depend: ../sys/unix/depend.awk \
 
 # config.h timestamp
 $(CONFIG_H): ../include/config.h ../include/config1.h ../include/tradstdc.h \
-		../include/global.h ../include/coord.h ../include/vmsconf.h \
-		../include/system.h ../include/nhlua.h ../include/unixconf.h \
-		../include/os2conf.h ../include/micro.h ../include/pcconf.h \
-		../include/tosconf.h ../include/amiconf.h ../include/macconf.h \
-		../include/beconf.h ../include/wceconf.h ../include/ntconf.h
+		../include/global.h ../include/filesize.h ../include/coord.h \
+		../include/vmsconf.h ../include/system.h ../include/nhlua.h \
+		../include/unixconf.h ../include/os2conf.h ../include/micro.h \
+		../include/pcconf.h ../include/tosconf.h ../include/amiconf.h \
+		../include/macconf.h ../include/beconf.h ../include/wceconf.h \
+		../include/ntconf.h
 	touch $(CONFIG_H)
 # hack.h timestamp
 $(HACK_H): ../include/hack.h $(CONFIG_H) ../include/lint.h ../include/align.h \
diff --git a/sys/winnt/Makefile.gcc b/sys/winnt/Makefile.gcc
index 92828aea3..d835bab80 100644
--- a/sys/winnt/Makefile.gcc
+++ b/sys/winnt/Makefile.gcc
@@ -469,11 +469,11 @@ endif
 #==========================================
 
 CONFIG_H = $(INCL)/config.h $(INCL)/config1.h $(INCL)/tradstdc.h \
-	       $(INCL)/global.h $(INCL)/coord.h $(INCL)/vmsconf.h \
-	       $(INCL)/system.h $(INCL)/unixconf.h $(INCL)/os2conf.h \
-	       $(INCL)/micro.h $(INCL)/pcconf.h $(INCL)/tosconf.h \
-	       $(INCL)/amiconf.h $(INCL)/macconf.h $(INCL)/beconf.h \
-	       $(INCL)/ntconf.h
+		$(INCL)/global.h $(INCL)/filesize.h $(INCL)/coord.h \
+		$(INCL)/vmsconf.h $(INCL)/system.h $(INCL)/unixconf.h \
+		$(INCL)/os2conf.h $(INCL)/micro.h $(INCL)/pcconf.h \
+		$(INCL)/tosconf.h $(INCL)/amiconf.h $(INCL)/macconf.h \
+		$(INCL)/beconf.h $(INCL)/ntconf.h
 
 HACK_H = $(INCL)/hack.h $(CONFIG_H) $(INCL)/align.h $(INCL)/context.h \
 	       $(INCL)/dungeon.h $(INCL)/monsym.h $(INCL)/mkroom.h \
diff --git a/sys/winnt/Makefile.msc b/sys/winnt/Makefile.msc
index 11bbbadb2..0ea5deffb 100644
--- a/sys/winnt/Makefile.msc
+++ b/sys/winnt/Makefile.msc
@@ -485,11 +485,12 @@ PDCLIB =
 #==========================================
 
 CONFIG_H = $(INCL)\config.h $(INCL)\config1.h $(INCL)\tradstdc.h \
-		$(INCL)\global.h $(INCL)\coord.h $(INCL)\vmsconf.h \
-		$(INCL)\system.h $(INCL)\nhlua.h $(INCL)\unixconf.h \
-		$(INCL)\os2conf.h $(INCL)\micro.h $(INCL)\pcconf.h \
-		$(INCL)\tosconf.h $(INCL)\amiconf.h $(INCL)\macconf.h \
-		$(INCL)\beconf.h $(INCL)\wceconf.h $(INCL)\ntconf.h
+		$(INCL)\global.h $(INCL)\filesize.h $(INCL)\coord.h \
+		$(INCL)\vmsconf.h $(INCL)\system.h $(INCL)\nhlua.h \
+		$(INCL)\unixconf.h $(INCL)\os2conf.h $(INCL)\micro.h \
+		$(INCL)\pcconf.h $(INCL)\tosconf.h $(INCL)\amiconf.h \
+		$(INCL)\macconf.h $(INCL)\beconf.h $(INCL)\wceconf.h \
+		$(INCL)\ntconf.h
 
 HACK_H = $(INCL)\hack.h $(CONFIG_H) $(INCL)\lint.h $(INCL)\align.h \
 		$(INCL)\dungeon.h $(INCL)\monsym.h $(INCL)\mkroom.h \
diff --git a/util/recover.c b/util/recover.c
index a3ed80984..41e3a1399 100644
--- a/util/recover.c
+++ b/util/recover.c
@@ -27,6 +27,7 @@ void FDECL(set_levelfile_name, (int));
 int FDECL(open_levelfile, (int));
 int NDECL(create_savefile);
 void FDECL(copy_bytes, (int, int));
+static void FDECL(store_formatindicator, (int));
 
 #ifndef WIN_CE
 #define Fprintf (void) fprintf
@@ -37,20 +38,6 @@ static void nhce_message(FILE *, const char *, ...);
 
 #define Close (void) close
 
-#ifdef UNIX
-#define SAVESIZE (PL_NSIZ + 13) /* save/99999player.e */
-#else
-#ifdef VMS
-#define SAVESIZE (PL_NSIZ + 22) /* [.save]<uid>player.e;1 */
-#else
-#ifdef WIN32
-#define SAVESIZE (PL_NSIZ + 40) /* username-player.NetHack-saved-game */
-#else
-#define SAVESIZE FILENAME /* from macconf.h or pcconf.h */
-#endif
-#endif
-#endif
-
 #if defined(EXEPATH)
 char *FDECL(exepath, (char *));
 #endif
@@ -58,6 +45,8 @@ char *FDECL(exepath, (char *));
 #if defined(__BORLANDC__) && !defined(_WIN32)
 extern unsigned _stklen = STKSIZ;
 #endif
+
+/* SAVESIZE is defined in "filesize.h" */
 char savename[SAVESIZE]; /* holds relative path of save file from playground */
 
 int
@@ -216,11 +205,11 @@ restore_savefile(basename)
 char *basename;
 {
     int gfd, lfd, sfd;
-    int res = 0, lev, savelev, hpid, pltmpsiz;
+    int res = 0, lev, savelev, hpid, pltmpsiz, filecmc;
     xchar levc;
     struct version_info version_data;
     struct savefile_info sfi;
-    char plbuf[PL_NSIZ];
+    char plbuf[PL_NSIZ], indicator;
 
     /* level 0 file contains:
      *  pid of creating process (ignored here)
@@ -265,6 +254,10 @@ char *basename;
     }
     if ((read(gfd, (genericptr_t) savename, sizeof savename)
          != sizeof savename)
+        || (read(gfd, (genericptr_t) &indicator, sizeof indicator)
+            != sizeof indicator)
+        || (read(gfd, (genericptr_t) &filecmc, sizeof filecmc)
+            != sizeof filecmc)
         || (read(gfd, (genericptr_t) &version_data, sizeof version_data)
             != sizeof version_data)
         || (read(gfd, (genericptr_t) &sfi, sizeof sfi) != sizeof sfi)
@@ -277,6 +270,7 @@ char *basename;
     }
 
     /* save file should contain:
+     *  format indicator and cmc
      *  version info
      *  savefile info
      *  player name
@@ -299,6 +293,7 @@ char *basename;
         return -1;
     }
 
+    store_formatindicator(sfd);
     if (write(sfd, (genericptr_t) &version_data, sizeof version_data)
         != sizeof version_data) {
         Fprintf(stderr, "Error writing %s; recovery failed.\n", savename);
@@ -394,6 +389,19 @@ char *basename;
     return res;
 }
 
+static void
+store_formatindicator(fd)
+int fd;
+{
+    char indicate = 'h';      /* historical */
+    int cmc = 0;
+
+    write(fd, (genericptr_t) &indicate, sizeof indicate);
+    write(fd, (genericptr_t) &cmc, sizeof cmc);
+}
+
+
+
 #ifdef EXEPATH
 #ifdef __DJGPP__
 #define PATH_SEPARATOR '/'