diff --git a/scheme/ikarus.boot.4.prebuilt b/scheme/ikarus.boot.4.prebuilt
index d269109..a534189 100644
Binary files a/scheme/ikarus.boot.4.prebuilt and b/scheme/ikarus.boot.4.prebuilt differ
diff --git a/scheme/ikarus.boot.8.prebuilt b/scheme/ikarus.boot.8.prebuilt
index 052eead..1477441 100644
Binary files a/scheme/ikarus.boot.8.prebuilt and b/scheme/ikarus.boot.8.prebuilt differ
diff --git a/scheme/ikarus.load.ss b/scheme/ikarus.load.ss
index 673f760..2c8ca1b 100644
--- a/scheme/ikarus.load.ss
+++ b/scheme/ikarus.load.ss
@@ -30,11 +30,10 @@
   (define fasl-extension ".ikarus-fasl")
 
   (define (load-serialized-library filename sk)
-    ;;; TODO: check file last-modified date
     (let ([ikfasl (string-append filename fasl-extension)])
       (cond
         [(not (file-exists? ikfasl)) #f]
-        [(<= (file-ctime ikfasl) (file-ctime filename))
+        [(< (file-mtime ikfasl) (file-mtime filename))
          (fprintf (current-error-port)
             "WARNING: not using fasl file ~s because it is older \
              than the source file ~s\n" 
diff --git a/scheme/ikarus.posix.ss b/scheme/ikarus.posix.ss
index a912292..cc66747 100644
--- a/scheme/ikarus.posix.ss
+++ b/scheme/ikarus.posix.ss
@@ -16,7 +16,8 @@
 
 (library (ikarus.posix)
   (export posix-fork fork waitpid system file-exists? delete-file
-          nanosleep getenv env environ file-ctime current-directory
+          nanosleep getenv env environ file-ctime file-mtime
+          current-directory
           file-regular? file-directory? file-symbolic-link? make-symbolic-link
           directory-list make-directory delete-directory change-mode
           kill strerror 
@@ -26,7 +27,8 @@
     (except (ikarus)
        nanosleep
        posix-fork fork waitpid system file-exists? delete-file
-       getenv env environ file-ctime current-directory
+       getenv env environ file-ctime file-mtime 
+       current-directory
        file-regular? file-directory? file-symbolic-link? make-symbolic-link
        directory-list make-directory delete-directory change-mode
        kill strerror
@@ -237,16 +239,22 @@
         (unless (eq? r #t)
           (raise/strerror who r path)))))
 
-  (define (file-ctime x)
-    (define who 'file-ctime)
+  (define ($file-time x who proc)
     (unless (string? x) 
       (die who "not a string" x))
     (let ([p (cons #f #f)])
-      (let ([v (foreign-call "ikrt_file_ctime" (string->utf8 x) p)])
+      (let ([v (proc (string->utf8 x) p)])
         (case v
           [(0) (+ (* (car p) #e1e9) (cdr p))]
           [else (raise/strerror who v x)]))))
 
+  (define (file-ctime x)
+    ($file-time x 'file-ctime 
+      (lambda (u p) (foreign-call "ikrt_file_ctime" u p))))
+
+  (define (file-mtime x)
+    ($file-time x 'file-mtime 
+      (lambda (u p) (foreign-call "ikrt_file_mtime" u p))))
 
   (define ($getenv-bv key)
     (foreign-call "ikrt_getenv" key))
diff --git a/scheme/last-revision b/scheme/last-revision
index af2b5c5..047d57f 100644
--- a/scheme/last-revision
+++ b/scheme/last-revision
@@ -1 +1 @@
-1657
+1658
diff --git a/scheme/makefile.ss b/scheme/makefile.ss
index 0c5f00f..23a9a01 100755
--- a/scheme/makefile.ss
+++ b/scheme/makefile.ss
@@ -1256,6 +1256,7 @@
     [change-mode                                 i]
     [make-symbolic-link                          i]
     [file-ctime                                  i]
+    [file-mtime                                  i]
     [fork                                        i]
     [define-record-type                          i r rs]
     [fields                                      i r rs]
diff --git a/src/ikarus-io.c b/src/ikarus-io.c
index dfe238c..e8c2ccd 100644
--- a/src/ikarus-io.c
+++ b/src/ikarus-io.c
@@ -298,6 +298,19 @@ ikrt_file_ctime(ikptr filename, ikptr res){
   return fix(0);
 }
 
+ikptr
+ikrt_file_mtime(ikptr filename, ikptr res){
+  struct stat s;
+  int err = stat((char*)(filename + off_bytevector_data), &s);
+  if(err) {
+    return ik_errno_to_code();
+  }
+  
+  ref(res, off_car) = fix(s.st_mtime);
+  ref(res, off_cdr) = 0;
+  return fix(0);
+}
+
 
 
 
diff --git a/src/ikarus-runtime.c b/src/ikarus-runtime.c
index e5b9bf2..75a0032 100644
--- a/src/ikarus-runtime.c
+++ b/src/ikarus-runtime.c
@@ -246,13 +246,13 @@ ik_munmap(ikptr mem, unsigned long int size){
   assert(((-pagesize) & (int)mem) == (int)mem);
   total_allocated_pages -= pages;
 #ifndef __CYGWIN__
-  int err = munmap((char*)(long)mem, mapsize);
+  int err = munmap((char*)mem, mapsize);
   if(err != 0){
     fprintf(stderr, "ik_munmap failed: %s\n", strerror(errno));
     exit(-1);
   }
 #else 
-  win_munmap(mem, mapsize);
+  win_munmap((char*)mem, mapsize);
 #endif
 #ifndef NDEBUG
   fprintf(stderr, "UNMAP 0x%08x .. 0x%08x\n", (int)mem,