diff --git a/src/ikarus.boot b/src/ikarus.boot
index 099e54f..9db05c8 100644
Binary files a/src/ikarus.boot and b/src/ikarus.boot differ
diff --git a/src/ikarus.posix.ss b/src/ikarus.posix.ss
new file mode 100644
index 0000000..85d3ba2
--- /dev/null
+++ b/src/ikarus.posix.ss
@@ -0,0 +1,114 @@
+
+(library (ikarus posix)
+  (export posix-fork fork waitpid system file-exists? delete-file
+          env environ)
+  (import 
+    (except (ikarus)
+       posix-fork fork waitpid system file-exists? delete-file
+       env environ))
+
+  (define posix-fork
+    (lambda ()
+      (foreign-call "ikrt_fork")))
+
+  (define fork
+    (lambda (parent-proc child-proc)
+      (let ([pid (posix-fork)])
+        (cond
+          [(fx= pid 0) (child-proc)]
+          [(fx= pid -1) 
+           (error 'fork "failed")]
+          [else (parent-proc pid)]))))
+
+  (define waitpid
+    (lambda (pid)
+      (unless (fixnum? pid)
+        (error 'waitpid "~s is not a fixnum" pid))
+      (foreign-call "ikrt_waitpid" pid)))
+
+  (define system
+    (lambda (x)
+      (unless (string? x)
+        (error 'system "~s is not a string" x))
+      (let ([rv (foreign-call "ik_system" x)])
+        (if (fx= rv -1)
+            (error 'system "failed")
+            rv))))
+
+  (define file-exists?
+    (lambda (x)
+      (unless (string? x)
+        (error 'file-exists? "filename ~s is not a string" x))
+      (let ([v (foreign-call "ikrt_file_exists" x)])
+        (cond
+          [(boolean? v) v]
+          [else
+           (error 'file-exists?
+                  (case v
+                    [(1) "the path ~s contains a non-directory"]
+                    [(2) "the path ~s is too long"]
+                    [(3) "the path ~s is not accessible"]
+                    [(4) "the path ~s contains too many symbolic links"]
+                    [(5) "internal access error while accessing ~s"]
+                    [(6) "IO error encountered while accessing ~s"]
+                    [else "Unknown error in ~s"])
+                  x)]))))
+
+  (define delete-file
+    (lambda (x)
+      (unless (string? x)
+        (error 'delete-file "filename ~s is not a string" x))
+      (let ([v (foreign-call "ikrt_delete_file" x)])
+        (case v
+          [(0) (void)]
+          [else
+           (error 'delete-file
+                  (case v
+                    [(1) "the path ~s contains a non-directory"]
+                    [(2) "the path ~s is too long"]
+                    [(3) "the file ~s does not exist"]
+                    [(4) "the path ~s is not accessible"]
+                    [(5) "the path ~s contains too many symbolic links"]
+                    [(6) "you do not have permissions to delete ~s"]
+                    [(7) "device ~s is busy"]
+                    [(8) "IO error encountered while deleting ~s"]
+                    [(9) "~s is in a read-only file system"]
+                    [(10) "internal access error while deleting ~s"]
+                    [else "Unknown error while deleting ~s"])
+                  x)]))))
+
+  (define env
+    (let ()
+      (define env
+        (case-lambda
+          [(key) 
+           (if (string? key)
+               (foreign-call "ikrt_getenv" key)
+               (error 'env "the key: ~s is not a string" key))]
+          [(key val) (env key val #t)]
+          [(key val overwrite?)
+           (if (string? key)
+               (if (string? val)
+                   (unless (foreign-call "ikrt_setenv" key val overwrite?)
+                     (error 'env "failed to set ~s to ~s" key val))
+                   (error 'env "the value: ~s is not a string" val))
+               (error 'env "the key: ~s is not a string" key))]))
+      env))
+
+  (define environ
+    (lambda ()
+      (map 
+        (lambda (s)
+          (define (loc= s i n)
+            (cond
+              [(fx= i n) i]
+              [(char=? (string-ref s i) #\=) i]
+              [else (loc= s (fx+ i 1) n)]))
+          (let ([n (string-length s)])
+            (let ([i (loc= s 0 n)])
+              (cons (substring s 0 i)
+                    (if (fx< (fxadd1 i) n)
+                        (substring s (fxadd1 i) n)
+                        "")))))
+        (foreign-call "ikrt_environ"))))
+  )
diff --git a/src/libposix.ss b/src/libposix.ss
deleted file mode 100644
index 4a52fa3..0000000
--- a/src/libposix.ss
+++ /dev/null
@@ -1,112 +0,0 @@
-
-(library (ikarus posix)
-  (export)
-  (import (scheme))
-
-(define ikarus-posix-fork
-  (lambda ()
-    (foreign-call "ikrt_fork")))
-
-(primitive-set! 'posix-fork ikarus-posix-fork)
-
-(primitive-set! 'fork
-  (lambda (parent-proc child-proc)
-    (let ([pid (ikarus-posix-fork)])
-      (cond
-        [(fx= pid 0) (child-proc)]
-        [(fx= pid -1) 
-         (error 'fork "failed")]
-        [else (parent-proc pid)]))))
-
-(primitive-set! 'waitpid
-  (lambda (pid)
-    (unless (fixnum? pid)
-      (error 'waitpid "~s is not a fixnum" pid))
-    (foreign-call "ikrt_waitpid" pid)))
-
-(primitive-set! 'system
-  (lambda (x)
-    (unless (string? x)
-      (error 'system "~s is not a string" x))
-    (let ([rv (foreign-call "ik_system" x)])
-      (if (fx= rv -1)
-          (error 'system "failed")
-          rv))))
-
-(primitive-set! 'file-exists?
-  (lambda (x)
-    (unless (string? x)
-      (error 'file-exists? "filename ~s is not a string" x))
-    (let ([v (foreign-call "ikrt_file_exists" x)])
-      (cond
-        [(boolean? v) v]
-        [else
-         (error 'file-exists?
-                (case v
-                  [(1) "the path ~s contains a non-directory"]
-                  [(2) "the path ~s is too long"]
-                  [(3) "the path ~s is not accessible"]
-                  [(4) "the path ~s contains too many symbolic links"]
-                  [(5) "internal access error while accessing ~s"]
-                  [(6) "IO error encountered while accessing ~s"]
-                  [else "Unknown error in ~s"])
-                x)]))))
-
-(primitive-set! 'delete-file
-  (lambda (x)
-    (unless (string? x)
-      (error 'delete-file "filename ~s is not a string" x))
-    (let ([v (foreign-call "ikrt_delete_file" x)])
-      (case v
-        [(0) (void)]
-        [else
-         (error 'delete-file
-                (case v
-                  [(1) "the path ~s contains a non-directory"]
-                  [(2) "the path ~s is too long"]
-                  [(3) "the file ~s does not exist"]
-                  [(4) "the path ~s is not accessible"]
-                  [(5) "the path ~s contains too many symbolic links"]
-                  [(6) "you do not have permissions to delete ~s"]
-                  [(7) "device ~s is busy"]
-                  [(8) "IO error encountered while deleting ~s"]
-                  [(9) "~s is in a read-only file system"]
-                  [(10) "internal access error while deleting ~s"]
-                  [else "Unknown error while deleting ~s"])
-                x)]))))
-
-(primitive-set! 'env
-  (let ()
-    (define env
-      (case-lambda
-        [(key) 
-         (if (string? key)
-             (foreign-call "ikrt_getenv" key)
-             (error 'env "the key: ~s is not a string" key))]
-        [(key val) (env key val #t)]
-        [(key val overwrite?)
-         (if (string? key)
-             (if (string? val)
-                 (unless (foreign-call "ikrt_setenv" key val overwrite?)
-                   (error 'env "failed to set ~s to ~s" key val))
-                 (error 'env "the value: ~s is not a string" val))
-             (error 'env "the key: ~s is not a string" key))]))
-    env))
-
-(primitive-set! 'environ
-  (lambda ()
-    (map 
-      (lambda (s)
-        (define (loc= s i n)
-          (cond
-            [(fx= i n) i]
-            [(char=? (string-ref s i) #\=) i]
-            [else (loc= s (fx+ i 1) n)]))
-        (let ([n (string-length s)])
-          (let ([i (loc= s 0 n)])
-            (cons (substring s 0 i)
-                  (if (fx< (fxadd1 i) n)
-                      (substring s (fxadd1 i) n)
-                      "")))))
-      (foreign-call "ikrt_environ"))))
-)
diff --git a/src/makefile.ss b/src/makefile.ss
index 2e279cb..2d29477 100755
--- a/src/makefile.ss
+++ b/src/makefile.ss
@@ -57,7 +57,7 @@
       "ikarus.syntax.ss"
       "ikarus.pretty-print.ss"
       "ikarus.cafe.ss"
-      "libposix.ss"
+      "ikarus.posix.ss"
       "libtimers.ss"
       "library-manager.ss"
       "libtoplevel.ss"))