diff --git a/extra/unix/bsd/bsd.factor b/extra/unix/bsd/bsd.factor
index e652f1b9f9..cb7b347c20 100755
--- a/extra/unix/bsd/bsd.factor
+++ b/extra/unix/bsd/bsd.factor
@@ -1,7 +1,7 @@
 ! Copyright (C) 2005, 2006 Slava Pestov.
 ! See http://factorcode.org/license.txt for BSD license.
+USING: alien.syntax combinators system vocabs.loader ;
 IN: unix
-USING: alien.syntax ;
 
 ! FreeBSD
 
@@ -15,8 +15,6 @@ USING: alien.syntax ;
 : O_TRUNC   HEX: 0400 ; inline
 : O_EXCL    HEX: 0800 ; inline
 
-: FD_SETSIZE 1024 ; inline
-
 : SOL_SOCKET HEX: ffff ; inline
 : SO_REUSEADDR HEX: 4 ; inline
 : SO_OOBINLINE HEX: 100 ; inline
@@ -83,3 +81,10 @@ C-STRUCT: sockaddr-un
 : SEEK_SET 0 ; inline
 : SEEK_CUR 1 ; inline
 : SEEK_END 2 ; inline
+
+os {
+    { "macosx"  [ "unix.bsd.macosx"  require ] }
+    { "freebsd" [ "unix.bsd.freebsd" require ] }
+    { "openbsd" [ "unix.bsd.openbsd" require ] }
+    { "netbsd"  [ "unix.bsd.netbsd"  require ] }
+} case
diff --git a/extra/unix/bsd/freebsd/freebsd.factor b/extra/unix/bsd/freebsd/freebsd.factor
new file mode 100644
index 0000000000..94bb708527
--- /dev/null
+++ b/extra/unix/bsd/freebsd/freebsd.factor
@@ -0,0 +1,3 @@
+IN: unix
+
+: FD_SETSIZE 1024 ;
diff --git a/extra/unix/bsd/macosx/macosx.factor b/extra/unix/bsd/macosx/macosx.factor
new file mode 100644
index 0000000000..3c0617ad17
--- /dev/null
+++ b/extra/unix/bsd/macosx/macosx.factor
@@ -0,0 +1,3 @@
+IN: unix
+
+: FD_SETSIZE 1024 ; inline
diff --git a/extra/unix/bsd/netbsd/netbsd.factor b/extra/unix/bsd/netbsd/netbsd.factor
new file mode 100644
index 0000000000..ac18749830
--- /dev/null
+++ b/extra/unix/bsd/netbsd/netbsd.factor
@@ -0,0 +1,3 @@
+IN: unix
+
+: FD_SETSIZE 256 ; inline
diff --git a/extra/unix/bsd/openbsd/openbsd.factor b/extra/unix/bsd/openbsd/openbsd.factor
new file mode 100644
index 0000000000..3c0617ad17
--- /dev/null
+++ b/extra/unix/bsd/openbsd/openbsd.factor
@@ -0,0 +1,3 @@
+IN: unix
+
+: FD_SETSIZE 1024 ; inline
diff --git a/extra/unix/stat/netbsd/32/32.factor b/extra/unix/stat/netbsd/32/32.factor
new file mode 100644
index 0000000000..bb2df6d6d3
--- /dev/null
+++ b/extra/unix/stat/netbsd/32/32.factor
@@ -0,0 +1,26 @@
+USING: kernel alien.syntax math ;
+IN: unix.stat
+
+! NetBSD 4.0
+
+C-STRUCT: stat
+    { "dev_t" "st_dev" }
+    { "mode_t" "st_mode" }
+    { "ino_t" "st_ino" }
+    { "nlink_t" "st_nlink" }
+    { "uid_t" "st_uid" }
+    { "gid_t" "st_gid" }
+    { "dev_t" "st_rdev" }
+    { "timespec" "st_atim" }
+    { "timespec" "st_mtim" }
+    { "timespec" "st_ctim" }
+    { "timespec" "st_birthtim" }
+    { "off_t" "st_size" }
+    { "blkcnt_t" "st_blocks" }
+    { "blksize_t" "st_blksize" }
+    { "uint32_t" "st_flags" }
+    { "uint32_t" "st_gen" }
+    { { "uint32_t" 2 } "st_qspare" } ;
+
+FUNCTION: int stat  ( char* pathname, stat* buf ) ;
+FUNCTION: int lstat ( char* pathname, stat* buf ) ;
diff --git a/extra/unix/stat/netbsd/64/64.factor b/extra/unix/stat/netbsd/64/64.factor
new file mode 100644
index 0000000000..f1f6f93dbd
--- /dev/null
+++ b/extra/unix/stat/netbsd/64/64.factor
@@ -0,0 +1,27 @@
+USING: kernel alien.syntax math ;
+IN: unix.stat
+
+! NetBSD 4.0
+
+C-STRUCT: stat
+    { "dev_t" "st_dev" }
+    { "ino_t" "st_ino" }
+    { "mode_t" "st_mode" }
+    { "nlink_t" "st_nlink" }
+    { "uid_t" "st_uid" }
+    { "gid_t" "st_gid" }
+    { "dev_t" "st_rdev" }
+    { "timespec" "st_atim" }
+    { "timespec" "st_mtim" }
+    { "timespec" "st_ctim" }
+    { "off_t" "st_size" }
+    { "blkcnt_t" "st_blocks" }
+    { "blksize_t" "st_blksize" }
+    { "uint32_t" "st_flags" }
+    { "uint32_t" "st_gen" }
+    { "uint32_t" "st_spare0" }
+    { "timespec" "st_birthtim" }
+    { "int" "__pad5" } ;
+
+FUNCTION: int stat  ( char* pathname, stat* buf ) ;
+FUNCTION: int lstat ( char* pathname, stat* buf ) ;
diff --git a/extra/unix/stat/netbsd/netbsd.factor b/extra/unix/stat/netbsd/netbsd.factor
index bb2df6d6d3..8057e5939b 100644
--- a/extra/unix/stat/netbsd/netbsd.factor
+++ b/extra/unix/stat/netbsd/netbsd.factor
@@ -1,26 +1,7 @@
-USING: kernel alien.syntax math ;
+USING: layouts combinators vocabs.loader ;
 IN: unix.stat
 
-! NetBSD 4.0
-
-C-STRUCT: stat
-    { "dev_t" "st_dev" }
-    { "mode_t" "st_mode" }
-    { "ino_t" "st_ino" }
-    { "nlink_t" "st_nlink" }
-    { "uid_t" "st_uid" }
-    { "gid_t" "st_gid" }
-    { "dev_t" "st_rdev" }
-    { "timespec" "st_atim" }
-    { "timespec" "st_mtim" }
-    { "timespec" "st_ctim" }
-    { "timespec" "st_birthtim" }
-    { "off_t" "st_size" }
-    { "blkcnt_t" "st_blocks" }
-    { "blksize_t" "st_blksize" }
-    { "uint32_t" "st_flags" }
-    { "uint32_t" "st_gen" }
-    { { "uint32_t" 2 } "st_qspare" } ;
-
-FUNCTION: int stat  ( char* pathname, stat* buf ) ;
-FUNCTION: int lstat ( char* pathname, stat* buf ) ;
+cell-bits {
+    { 32 [ "unix.stat.netbsd.32" require ] }
+    { 64 [ "unix.stat.netbsd.64" require ] }
+} case
diff --git a/extra/unix/types/netbsd/netbsd.factor b/extra/unix/types/netbsd/netbsd.factor
index 77636a6d6d..6d33547627 100755
--- a/extra/unix/types/netbsd/netbsd.factor
+++ b/extra/unix/types/netbsd/netbsd.factor
@@ -18,7 +18,7 @@ TYPEDEF: ulonglong      u_int64_t
 
 TYPEDEF: __uint32_t     __dev_t
 TYPEDEF: __uint32_t     dev_t
-TYPEDEF: __uint64_t     ino_t
+TYPEDEF: __uint32_t     ino_t
 TYPEDEF: __uint32_t     mode_t
 TYPEDEF: __uint32_t     nlink_t
 TYPEDEF: __uint32_t     uid_t
@@ -26,7 +26,6 @@ TYPEDEF: __uint32_t     gid_t
 TYPEDEF: __int64_t      off_t
 TYPEDEF: __int64_t      blkcnt_t
 TYPEDEF: __uint32_t     blksize_t
-TYPEDEF: __uint32_t     fflags_t
-TYPEDEF: int            ssize_t
+TYPEDEF: longlong       ssize_t
 TYPEDEF: int            pid_t
 TYPEDEF: int            time_t
diff --git a/extra/unix/unix.factor b/extra/unix/unix.factor
index 09d77fee11..d02e180cff 100755
--- a/extra/unix/unix.factor
+++ b/extra/unix/unix.factor
@@ -149,6 +149,5 @@ FUNCTION: ssize_t write ( int fd, void* buf, size_t nbytes ) ;
     { [ linux? ] [ "unix.linux" require ] }
     { [ bsd? ] [ "unix.bsd" require ] }
     { [ solaris? ] [ "unix.solaris" require ] }
-    { [ t ] [ ] }
 } cond