diff --git a/path.go b/path.go
index e5b5f41..331ce00 100644
--- a/path.go
+++ b/path.go
@@ -1,190 +1,32 @@
 package nasin
 
-import "io"
 import "os"
-import "io/fs"
-import "strings"
 import "path/filepath"
 
-// FS is Tomo's implementation of fs.FS. It provides access to a specific part
-// of the filesystem.
-type FS struct {
-	path string
+// ApplicationUserDataDir returns the directory path where an application can
+// store its user data files. If the directory does not exist, it will be
+// created.
+func ApplicationUserDataDir (app ApplicationDescription) (string, error) {
+	return userMkdirAll(app.ID, userDataDir)
 }
 
-// FileWriter is a writable version of fs.File.
-type FileWriter interface {
-	fs.File
-	io.Writer
+// ApplicationUserConfigDir returns the directory path where an application can
+// store its user configuration files.
+func ApplicationUserConfigDir (app ApplicationDescription) (string, error) {
+	return userMkdirAll(app.ID, userConfigDir)
 }
 
-// ApplicationUserDataFS returns an FS that an application can use to store user
-// data files.
-func ApplicationUserDataFS (app ApplicationDescription) (*FS, error) {
-	dataDir, err := userDataDir()
-	if err != nil { return nil, err }
-	return appFs(dataDir, app)
+// ApplicationUserCacheDir returns the directory path where an application can
+// store its user cache files.
+func ApplicationUserCacheDir (app ApplicationDescription) (string, error) {
+	return userMkdirAll(app.ID, userCacheDir)
 }
 
-// ApplicationUserConfigFS returns an FS that an application can use to store
-// user configuration files.
-func ApplicationUserConfigFS (app ApplicationDescription) (*FS, error) {
-	configDir, err := userConfigDir()
-	if err != nil { return nil, err }
-	return appFs(configDir, app)
-}
-
-// ApplicationUserCacheFS returns an FS that an application can use to store
-// user cache files.
-func ApplicationUserCacheFS (app ApplicationDescription) (*FS, error) {
-	cacheDir, err := userCacheDir()
-	if err != nil { return nil, err }
-	return appFs(cacheDir, app)
-}
-
-func pathErr (op, path string, err error) error {
-	return &fs.PathError {
-		Op:   op,
-		Path: path,
-		Err:  err,
-	}
-}
-
-func appFs (root string, app ApplicationDescription) (*FS, error) {
-	// remove slashes
-	appid := app.ID
-	appid = strings.ReplaceAll(appid, "/", "-")
-	appid = strings.ReplaceAll(appid, "\\", "-")
-
-	path := filepath.Join(root, appid)
-
-	// ensure the directory actually exists
-	err := os.MkdirAll(path, 700)
-	if err != nil { return nil, err }
-
-	return &FS { path: path }, nil
-}
-
-func (this FS) subPath (name string) (string, error) {
-	if !fs.ValidPath(name)         { return "", fs.ErrInvalid }
-	if strings.Contains(name, "/") { return "", fs.ErrInvalid }
-	return filepath.Join(this.path, name), nil
-}
-
-// Open opens the named file.
-func (this FS) Open (name string) (fs.File, error) {
-	path, err := this.subPath(name)
-	if err != nil {
-		return nil, pathErr("open", name, err)
-	}
-
-	return os.Open(path)
-}
-
-// Create creates or truncates the named file.
-func (this FS) Create (name string) (FileWriter, error) {
-	path, err := this.subPath(name)
-	if err != nil {
-		return nil, pathErr("create", name, err)
-	}
-
-	return os.Create(path)
-}
-
-// OpenFile is the generalized open call; most users will use Open or Create
-// instead.
-func (this FS) OpenFile (
-	name string,
-	flag int,
-	perm os.FileMode,
-) (
-	FileWriter,
-	error,
-) {
-	path, err := this.subPath(name)
-	if err != nil {
-		return nil, pathErr("open", name, err)
-	}
-
-	return os.OpenFile(path, flag, perm)
-}
-
-// ReadDir reads the named directory and returns a list of directory entries
-// sorted by filename.
-func (this FS) ReadDir (name string) ([]fs.DirEntry, error) {
-	path, err := this.subPath(name)
-	if err != nil {
-		return nil, pathErr("readdir", name, err)
-	}
-
-	return os.ReadDir(path)
-}
-
-// ReadFile reads the named file and returns its contents.
-// A successful call returns a nil error, not io.EOF.
-// (Because ReadFile reads the whole file, the expected EOF
-// from the final Read is not treated as an error to be reported.)
-//
-// The caller is permitted to modify the returned byte slice.
-func (this FS) ReadFile (name string) ([]byte, error) {
-	path, err := this.subPath(name)
-	if err != nil {
-		return nil, pathErr("readfile", name, err)
-	}
-
-	return os.ReadFile(path)
-}
-
-// WriteFile writes data to the named file, creating it if necessary.
-func (this FS) WriteFile (name string, data []byte, perm os.FileMode) error {
-	path, err := this.subPath(name)
-	if err != nil {
-		return pathErr("writefile", name, err)
-	}
-
-	return os.WriteFile(path, data, perm)
-}
-
-// Stat returns a FileInfo describing the file.
-func (this FS) Stat (name string) (fs.FileInfo, error) {
-	path, err := this.subPath(name)
-	if err != nil {
-		return nil, pathErr("stat", name, err)
-	}
-
-	return os.Stat(path)
-}
-
-// Remove removes the named file or (empty) directory.
-func (this FS) Remove (name string) error {
-	path, err := this.subPath(name)
-	if err != nil {
-		return pathErr("remove", name, err)
-	}
-
-	return os.Remove(path)
-}
-
-// RemoveAll removes name and any children it contains.
-func (this FS) RemoveAll (name string) error {
-	path, err := this.subPath(name)
-	if err != nil {
-		return pathErr("removeall", name, err)
-	}
-
-	return os.RemoveAll(path)
-}
-
-// Rename renames (moves) oldname to newname.
-func (this FS) Rename (oldname, newname string) error {
-	oldpath, err := this.subPath(oldname)
-	if err != nil {
-		return pathErr("rename", oldname, err)
-	}
-	newpath, err := this.subPath(newname)
-	if err != nil {
-		return pathErr("rename", newname, err)
-	}
-
-	return os.Rename(oldpath, newpath)
+func userMkdirAll (sub string, getter func () (string, error)) (string, error) {
+	path, err := getter()
+	if err != nil { return "", err }
+	path = filepath.Join(path, sub)
+	err = os.MkdirAll(path, 0700)
+	if err != nil { return "", err }
+	return path, nil
 }