diff --git a/src/kernel/apps/rld/rldelf.c b/src/kernel/apps/rld/rldelf.c
index 43f04d2b9f..2c4904ca28 100644
--- a/src/kernel/apps/rld/rldelf.c
+++ b/src/kernel/apps/rld/rldelf.c
@@ -7,6 +7,7 @@
 #include <string.h>
 #include <stdio.h>
 #include <Errors.h>
+#include <kerrors.h>
 #include <elf32.h>
 #include <user_runtime.h>
 #include <syscalls.h>
diff --git a/src/kernel/core/arch/x86/arch_cpu.c b/src/kernel/core/arch/x86/arch_cpu.c
index 089b2bab33..9ad5a359aa 100755
--- a/src/kernel/core/arch/x86/arch_cpu.c
+++ b/src/kernel/core/arch/x86/arch_cpu.c
@@ -9,6 +9,7 @@
 #include <debug.h>
 #include <smp.h>
 #include <Errors.h>
+#include <kerrors.h>
 
 #include <stage2.h>
 
diff --git a/src/kernel/core/arch/x86/arch_int.c b/src/kernel/core/arch/x86/arch_int.c
index b6b268dce8..d1ba319fee 100755
--- a/src/kernel/core/arch/x86/arch_int.c
+++ b/src/kernel/core/arch/x86/arch_int.c
@@ -11,6 +11,7 @@
 #include <smp.h>
 #include <syscalls.h>
 #include <Errors.h>
+#include <kerrors.h>
 #include <vm_priv.h>
 #include <ksyscalls.h>
 
diff --git a/src/kernel/core/arch/x86/arch_vm.c b/src/kernel/core/arch/x86/arch_vm.c
index 29e384e767..deaf004f91 100755
--- a/src/kernel/core/arch/x86/arch_vm.c
+++ b/src/kernel/core/arch/x86/arch_vm.c
@@ -9,6 +9,7 @@
 #include <vm_priv.h>
 #include <debug.h>
 #include <Errors.h>
+#include <kerrors.h>
 
 #include <arch/vm.h>
 #include <arch/int.h>
diff --git a/src/kernel/core/arch/x86/arch_vm_translation_map.c b/src/kernel/core/arch/x86/arch_vm_translation_map.c
index 52a35e49ee..f1f917d26b 100755
--- a/src/kernel/core/arch/x86/arch_vm_translation_map.c
+++ b/src/kernel/core/arch/x86/arch_vm_translation_map.c
@@ -16,6 +16,7 @@
 #include <string.h>
 #include <stage2.h>
 #include <Errors.h>
+#include <kerrors.h>
 
 #include <arch/cpu.h>
 #include <arch/vm_translation_map.h>
diff --git a/src/kernel/core/cbuf.c b/src/kernel/core/cbuf.c
index 0abaac033f..61606972e8 100644
--- a/src/kernel/core/cbuf.c
+++ b/src/kernel/core/cbuf.c
@@ -9,6 +9,7 @@
 #include <arch/debug.h>
 #include <cbuf.h>
 #include <arch/cpu.h>
+#include <kerrors.h>
 #include <Errors.h>
 #include <debug.h>
 #include <int.h>
diff --git a/src/kernel/core/elf.c b/src/kernel/core/elf.c
index 6bfec1a312..78357decd9 100644
--- a/src/kernel/core/elf.c
+++ b/src/kernel/core/elf.c
@@ -7,6 +7,7 @@
 
 #include <kernel.h>
 #include <Errors.h>
+#include <kerrors.h>
 #include <elf.h>
 #include <vfs.h>
 #include <vm.h>
diff --git a/src/kernel/core/fd.c b/src/kernel/core/fd.c
index 17e07f40ba..1c259ad31a 100644
--- a/src/kernel/core/fd.c
+++ b/src/kernel/core/fd.c
@@ -61,7 +61,7 @@ new_fd(struct io_context *ioctx, struct file_descriptor *f)
 		}
 	}
 	if (fd < 0) {
-		fd = ERR_NO_MORE_HANDLES;
+		fd = EMFILE;
 		goto err;
 	}
 
diff --git a/src/kernel/core/fs/bootfs.c b/src/kernel/core/fs/bootfs.c
index 19a21d973b..23d26a4943 100755
--- a/src/kernel/core/fs/bootfs.c
+++ b/src/kernel/core/fs/bootfs.c
@@ -11,6 +11,7 @@
 #include <lock.h>
 #include <vm.h>
 #include <Errors.h>
+#include <kerrors.h>
 #include <arch/cpu.h>
 #include <sys/stat.h>
 
@@ -138,7 +139,7 @@ bootfs_delete_vnode(struct bootfs *fs, struct bootfs_vnode *v, bool force_delete
 	// cant delete it if it's in a directory or is a directory
 	// and has children
 	if(!force_delete && ((v->stream.type == STREAM_TYPE_DIR && v->stream.u.dir.dir_head != NULL) || v->dir_next != NULL)) {
-		return ERR_NOT_ALLOWED;
+		return EPERM;
 	}
 
 	// remove it from the global hash table
@@ -218,7 +219,7 @@ static int
 bootfs_insert_in_dir(struct bootfs_vnode *dir, struct bootfs_vnode *v)
 {
 	if(dir->stream.type != STREAM_TYPE_DIR)
-		return ERR_INVALID_ARGS;
+		return EINVAL;
 
 	v->dir_next = dir->stream.u.dir.dir_head;
 	dir->stream.u.dir.dir_head = v;
@@ -355,7 +356,7 @@ bootfs_create_vnode_tree(struct bootfs *fs, struct bootfs_vnode *root)
 
 			new_vnode = bootfs_create_vnode(fs, leaf);
 			if(new_vnode == NULL)
-				return ERR_NO_MEMORY;
+				return ENOMEM;
 
 			// set up the new node
 			new_vnode->stream.type = STREAM_TYPE_FILE;
@@ -390,7 +391,7 @@ bootfs_mount(fs_cookie *_fs, fs_id id, const char *device, void *args, vnode_id
 
 	fs = kmalloc(sizeof(struct bootfs));
 	if(fs == NULL) {
-		err = ERR_NO_MEMORY;
+		err = ENOMEM;
 		goto err;
 	}
 
@@ -405,14 +406,14 @@ bootfs_mount(fs_cookie *_fs, fs_id id, const char *device, void *args, vnode_id
 	fs->vnode_list_hash = hash_init(BOOTFS_HASH_SIZE, (addr)&v->all_next - (addr)v,
 		&bootfs_vnode_compare_func, &bootfs_vnode_hash_func);
 	if(fs->vnode_list_hash == NULL) {
-		err = ERR_NO_MEMORY;
+		err = ENOMEM;
 		goto err2;
 	}
 
 	// create a vnode
 	v = bootfs_create_vnode(fs, "");
 	if(v == NULL) {
-		err = ERR_NO_MEMORY;
+		err = ENOMEM;
 		goto err3;
 	}
 
@@ -494,7 +495,7 @@ bootfs_lookup(fs_cookie _fs, fs_vnode _dir, const char *name, vnode_id *id)
 	TRACE(("bootfs_lookup: entry dir 0x%x, name '%s'\n", dir, name));
 
 	if (dir->stream.type != STREAM_TYPE_DIR)
-		return ERR_VFS_NOT_DIR;
+		return ENOTDIR;
 
 	mutex_lock(&fs->lock);
 
@@ -605,7 +606,7 @@ bootfs_open(fs_cookie _fs, fs_vnode _v, file_cookie *_cookie, stream_type st, in
 
 	cookie = kmalloc(sizeof(struct bootfs_cookie));
 	if (cookie == NULL) {
-		err = ERR_NO_MEMORY;
+		err = ENOMEM;
 		goto err;
 	}
 
@@ -783,12 +784,12 @@ bootfs_seek(fs_cookie _fs, fs_vnode _v, file_cookie _cookie, off_t pos, int st)
 						cookie->u.file.pos = pos + cookie->s->u.file.len;
 					break;
 				default:
-					err = ERR_INVALID_ARGS;
+					err = EINVAL;
 
 			}
 			break;
 		default:
-			err = ERR_INVALID_ARGS;
+			err = EINVAL;
 	}
 
 	mutex_unlock(&fs->lock);
@@ -819,7 +820,7 @@ bootfs_read_dir(fs_cookie _fs, fs_vnode _vnode, file_cookie _cookie, struct dire
 	dirent->d_reclen = strlen(cookie->u.dir.ptr->name);
 
 	if (sizeof(struct dirent) + dirent->d_reclen + 1 > bufferSize) {
-		status = ERR_VFS_INSUFFICIENT_BUF;
+		status = ENOBUFS;
 		goto err;
 	}
 
@@ -912,28 +913,28 @@ bootfs_writepage(fs_cookie _fs, fs_vnode _v, iovecs *vecs, off_t pos)
 
 	TRACE(("bootfs_writepage: vnode 0x%x, vecs 0x%x, pos 0x%x 0x%x\n", v, vecs, pos));
 
-	return ERR_NOT_ALLOWED;
+	return EPERM;
 }
 
 
 static int
 bootfs_create(fs_cookie _fs, fs_vnode _dir, const char *name, stream_type st, void *create_args, vnode_id *new_vnid)
 {
-	return ERR_VFS_READONLY_FS;
+	return EROFS;
 }
 
 
 static int
 bootfs_unlink(fs_cookie _fs, fs_vnode _dir, const char *name)
 {
-	return ERR_VFS_READONLY_FS;
+	return EROFS;
 }
 
 
 static int
 bootfs_rename(fs_cookie _fs, fs_vnode _olddir, const char *oldname, fs_vnode _newdir, const char *newname)
 {
-	return ERR_VFS_READONLY_FS;
+	return EROFS;
 }
 
 
@@ -985,7 +986,7 @@ bootfs_wstat(fs_cookie _fs, fs_vnode _v, struct stat *stat, int stat_mask)
 	TRACE(("bootfs_wstat: vnode 0x%x (0x%x 0x%x), stat 0x%x\n", v, v->id, stat));
 
 	// cannot change anything
-	return ERR_VFS_READONLY_FS;
+	return EROFS;
 }
 
 
diff --git a/src/kernel/core/fs/devfs.c b/src/kernel/core/fs/devfs.c
index 7c58ebb69c..16fdd4719f 100755
--- a/src/kernel/core/fs/devfs.c
+++ b/src/kernel/core/fs/devfs.c
@@ -13,6 +13,7 @@
 #include <lock.h>
 #include <vm.h>
 #include <Errors.h>
+#include <kerrors.h>
 #include <drivers.h>
 #include <sys/stat.h>
 
diff --git a/src/kernel/core/fs/rootfs.c b/src/kernel/core/fs/rootfs.c
index 6bd6505bbd..ca6c42f789 100755
--- a/src/kernel/core/fs/rootfs.c
+++ b/src/kernel/core/fs/rootfs.c
@@ -11,6 +11,7 @@
 #include <lock.h>
 #include <vm.h>
 #include <Errors.h>
+#include <kerrors.h>
 #include <sys/stat.h>
 
 #include <rootfs.h>
diff --git a/src/kernel/core/fs/vfs.c b/src/kernel/core/fs/vfs.c
index 2d211d1cfb..ff393c9340 100755
--- a/src/kernel/core/fs/vfs.c
+++ b/src/kernel/core/fs/vfs.c
@@ -21,6 +21,7 @@
 #include <bootfs.h>
 #include <devfs.h>
 #include <Errors.h>
+#include <kerrors.h>
 #include <atomic.h>
 #include <OS.h>
 #include <fd.h>
diff --git a/src/kernel/core/khash.c b/src/kernel/core/khash.c
index 61028e0e58..48a2e02451 100644
--- a/src/kernel/core/khash.c
+++ b/src/kernel/core/khash.c
@@ -106,7 +106,7 @@ int hash_remove(void *_hash_table, void *e)
 		}
 	}
 
-	return ERR_GENERAL;
+	return B_ERROR;
 }
 
 void *hash_find(void *_hash_table, void *e)
diff --git a/src/kernel/core/lock.c b/src/kernel/core/lock.c
index 698a513b37..6c20be3733 100644
--- a/src/kernel/core/lock.c
+++ b/src/kernel/core/lock.c
@@ -26,7 +26,7 @@ int recursive_lock_get_recursion(recursive_lock *lock)
 int recursive_lock_create(recursive_lock *lock)
 {
 	if(lock == NULL)
-		return ERR_INVALID_ARGS;
+		return EINVAL;
 	lock->holder = -1;
 	lock->recursion = 0;
 	lock->sem = create_sem(1, "recursive_lock_sem");
@@ -80,7 +80,7 @@ int mutex_init(mutex *m, const char *in_name)
 	const char *name;
 
 	if(m == NULL)
-		return ERR_INVALID_ARGS;
+		return EINVAL;
 
 	if(in_name == NULL)
 		name = "mutex_sem";
diff --git a/src/kernel/core/module.c b/src/kernel/core/module.c
index f58d358a70..10e0869961 100644
--- a/src/kernel/core/module.c
+++ b/src/kernel/core/module.c
@@ -5,10 +5,6 @@
 ** Distributed under the terms of the NewOS License.
 */
 
-// TODO:
-// - "offsetof" macro is missing
-//   -> move it to a public place
-
 #include <kernel.h>
 #include <module.h>
 #include <lock.h>
@@ -533,21 +529,21 @@ static inline int init_module(module *module)
 		
 		case MOD_INIT:
 			SHOW_ERROR( 0, "circular reference to %s\n", module->name );
-			res = ERR_GENERAL;
+			res = B_ERROR;
 			break;
 		
 		case MOD_UNINIT:
 			SHOW_ERROR( 0, "tried to load module %s which is currently unloading\n", module->name );
-			res = ERR_GENERAL;
+			res = B_ERROR;
 			break;
 
 		case MOD_ERROR:
 			SHOW_INFO( 0, "cannot load module %s because its earlier unloading failed\n", module->name );
-			res = ERR_GENERAL;
+			res = B_ERROR;
 			break;
 		
 		default:
-			res = ERR_GENERAL;
+			res = B_ERROR;
 	}
 	
 	return res;
@@ -563,11 +559,11 @@ static inline int uninit_module(module *module)
 		case MOD_INIT:
 			panic( "Trying to unload module %s which is initializing\n", 
 				module->name );
-			return ERR_GENERAL;
+			return B_ERROR;
 
 		case MOD_UNINIT:
 			panic( "Trying to unload module %s which is un-initializing\n", module->name );
-			return ERR_GENERAL;
+			return B_ERROR;
 		
 		case MOD_RDY:
 			{
@@ -592,7 +588,7 @@ static inline int uninit_module(module *module)
 			
 		// fall through
 		default:	
-			return ERR_GENERAL;		
+			return B_ERROR;		
 	}
 }
 
@@ -640,12 +636,12 @@ static inline int module_create_dir_iterator( module_iterator *iter, int file, c
 	
 	dir = (struct module_dir_iterator *)kmalloc( sizeof( *dir ));
 	if (dir == NULL )
-		return ERR_NO_MEMORY;
+		return ENOMEM;
 		
 	dir->name = (char *)kstrdup( name );
 	if (dir->name == NULL ) {
 		kfree( dir );
-		return ERR_NO_MEMORY;
+		return ENOMEM;
 	}
 
 	dir->file = file;
@@ -830,7 +826,7 @@ static inline int module_enter_base_path(module_iterator *iter)
 
 	if (iter->base_path_id >= (int)num_module_paths ) {
 		SHOW_FLOW0( 3, "no locations left\n" );
-		return ERR_NOT_FOUND;
+		return ENOENT;
 	}
 
 	SHOW_FLOW(3, "trying base path (%s)\n", module_paths[iter->base_path_id]);
diff --git a/src/kernel/core/port.c b/src/kernel/core/port.c
index d005095abd..7fcc28c4ba 100644
--- a/src/kernel/core/port.c
+++ b/src/kernel/core/port.c
@@ -13,7 +13,7 @@
 #include <cbuf.h>
 #include <Errors.h>
 #include <int.h>
-
+#include <kerrors.h>
 #include <string.h>
 #include <stdlib.h>
 
diff --git a/src/kernel/core/sem.c b/src/kernel/core/sem.c
index f5326595a7..b03362716a 100644
--- a/src/kernel/core/sem.c
+++ b/src/kernel/core/sem.c
@@ -15,6 +15,7 @@
 #include <memheap.h>
 #include <thread.h>
 #include <Errors.h>
+#include <kerrors.h>
 
 #include <stage2.h>
 
diff --git a/src/kernel/core/syscalls.c b/src/kernel/core/syscalls.c
index c71e173411..c53840e7a3 100644
--- a/src/kernel/core/syscalls.c
+++ b/src/kernel/core/syscalls.c
@@ -11,7 +11,6 @@
 #include <debug.h>
 #include <vfs.h>
 #include <thread.h>
-#include <OS.h>
 #include <sem.h>
 #include <port.h>
 #include <cpu.h>
@@ -19,9 +18,10 @@
 #include <resource.h>
 #include <fd.h>
 #include <sysctl.h>
-#include <sys/socket.h>
 #include <ksocket.h>
 #include <sys/ioccom.h>
+#include <sys/socket.h>
+#include <OS.h>
 
 #define INT32TOINT64(x, y) ((int64)(x) | ((int64)(y) << 32))
 
diff --git a/src/kernel/core/sysctl.c b/src/kernel/core/sysctl.c
index eaeb0ecbb5..9eec39d9c6 100644
--- a/src/kernel/core/sysctl.c
+++ b/src/kernel/core/sysctl.c
@@ -5,9 +5,10 @@
 #include <vm.h>
 #include <debug.h>
 #include <memheap.h>
-#include <Errors.h>
 #include <sysctl.h>
 
+#include <Errors.h>
+
 /* Not sure where to put this definition yet (sys/param.h?), 
  * so just add it here 
  * XXX - horrible hack!
diff --git a/src/kernel/core/thread.c b/src/kernel/core/thread.c
index 8f9c1d5d56..a93e935c3f 100644
--- a/src/kernel/core/thread.c
+++ b/src/kernel/core/thread.c
@@ -32,6 +32,7 @@
 #include <stdlib.h>
 #include <resource.h>
 #include <atomic.h>
+#include <kerrors.h>
 
 struct proc_key {
 	proc_id id;
diff --git a/src/kernel/core/vm/vm.c b/src/kernel/core/vm/vm.c
index fa8b79ca19..91298b5406 100755
--- a/src/kernel/core/vm/vm.c
+++ b/src/kernel/core/vm/vm.c
@@ -3,6 +3,7 @@
 ** Distributed under the terms of the NewOS License.
 */
 #include <Errors.h>
+#include <kerrors.h>
 #include <kernel.h>
 #include <vm.h>
 #include <vm_priv.h>
diff --git a/src/kernel/core/vm/vm_store_anonymous_noswap.c b/src/kernel/core/vm/vm_store_anonymous_noswap.c
index eb33076f39..88cc3da61f 100755
--- a/src/kernel/core/vm/vm_store_anonymous_noswap.c
+++ b/src/kernel/core/vm/vm_store_anonymous_noswap.c
@@ -8,6 +8,7 @@
 #include <debug.h>
 #include <vm_store_anonymous_noswap.h>
 #include <Errors.h>
+#include <kerrors.h>
 
 static void anonymous_destroy(struct vm_store *store)
 {
diff --git a/src/kernel/core/vm/vm_store_device.c b/src/kernel/core/vm/vm_store_device.c
index 94f66efc36..9f48ff87ad 100755
--- a/src/kernel/core/vm/vm_store_device.c
+++ b/src/kernel/core/vm/vm_store_device.c
@@ -9,6 +9,7 @@
 #include <lock.h>
 #include <vm_store_device.h>
 #include <Errors.h>
+#include <kerrors.h>
 
 struct device_store_data {
 	addr base_addr;
diff --git a/src/kernel/core/vm/vm_store_null.c b/src/kernel/core/vm/vm_store_null.c
index 61009bfe38..efe9e751f6 100755
--- a/src/kernel/core/vm/vm_store_null.c
+++ b/src/kernel/core/vm/vm_store_null.c
@@ -10,6 +10,7 @@
 #include <vm_store_null.h>
 #include <vfs.h>
 #include <Errors.h>
+#include <kerrors.h>
 
 static void null_destroy(struct vm_store *store)
 {