diff --git a/archiver.go b/archiver.go
index 8632b82fd..ca8542b65 100644
--- a/archiver.go
+++ b/archiver.go
@@ -20,14 +20,14 @@ import (
 )
 
 const (
-	maxConcurrentBlobs    = 32
-	maxConcurrency        = 10
-	maxConcurrencyPreload = 20
+	maxConcurrentBlobs = 32
+	maxConcurrency     = 10
 )
 
 var archiverAbortOnAllErrors = func(str string, fi os.FileInfo, err error) error { return err }
 var archiverAllowAllFiles = func(string, os.FileInfo) bool { return true }
 
+// Archiver is used to backup a set of directories.
 type Archiver struct {
 	s *server.Server
 
@@ -37,6 +37,7 @@ type Archiver struct {
 	Filter func(item string, fi os.FileInfo) bool
 }
 
+// NewArchiver returns a new archiver.
 func NewArchiver(s *server.Server) *Archiver {
 	arch := &Archiver{
 		s:         s,
@@ -53,6 +54,7 @@ func NewArchiver(s *server.Server) *Archiver {
 	return arch
 }
 
+// Save stores a blob read from rd in the server.
 func (arch *Archiver) Save(t pack.BlobType, id backend.ID, length uint, rd io.Reader) error {
 	debug.Log("Archiver.Save", "Save(%v, %v)\n", t, id.Str())
 
@@ -73,6 +75,7 @@ func (arch *Archiver) Save(t pack.BlobType, id backend.ID, length uint, rd io.Re
 	return nil
 }
 
+// SaveTreeJSON stores a tree in the server.
 func (arch *Archiver) SaveTreeJSON(item interface{}) (backend.ID, error) {
 	data, err := json.Marshal(item)
 	if err != nil {
@@ -209,99 +212,6 @@ func (arch *Archiver) SaveFile(p *Progress, node *Node) error {
 	return err
 }
 
-func (arch *Archiver) saveTree(p *Progress, t *Tree) (backend.ID, error) {
-	debug.Log("Archiver.saveTree", "saveTree(%v)\n", t)
-	var wg sync.WaitGroup
-
-	// TODO: do all this in parallel
-	for _, node := range t.Nodes {
-		if node.tree != nil {
-			id, err := arch.saveTree(p, node.tree)
-			if err != nil {
-				return nil, err
-			}
-			node.Subtree = id
-			p.Report(Stat{Dirs: 1})
-		} else if node.Type == "file" {
-			if len(node.Content) > 0 {
-				removeContent := false
-
-				// check content
-				for _, id := range node.Content {
-					packID, _, _, _, err := arch.s.Index().Lookup(id)
-					if err != nil {
-						debug.Log("Archiver.saveTree", "unable to find storage id for data blob %v: %v", id.Str(), err)
-						arch.Error(node.path, nil, fmt.Errorf("unable to find storage id for data blob %v: %v", id.Str(), err))
-						removeContent = true
-						continue
-					}
-
-					if ok, err := arch.s.Test(backend.Data, packID.String()); !ok || err != nil {
-						debug.Log("Archiver.saveTree", "pack %v of blob %v not in repository (error is %v)", packID, id, err)
-						arch.Error(node.path, nil, fmt.Errorf("pack %v of blob %v not in repository (error is %v)", packID, id, err))
-						removeContent = true
-					}
-				}
-
-				if removeContent {
-					debug.Log("Archiver.saveTree", "removing content for %s", node.path)
-					node.Content = node.Content[:0]
-				}
-			}
-
-			if len(node.Content) == 0 {
-				// start goroutine
-				wg.Add(1)
-				go func(n *Node) {
-					defer wg.Done()
-
-					n.err = arch.SaveFile(p, n)
-					p.Report(Stat{Files: 1})
-				}(node)
-			}
-		}
-	}
-
-	wg.Wait()
-
-	usedIDs := backend.NewIDSet()
-
-	// check for invalid file nodes
-	for _, node := range t.Nodes {
-		if node.Type == "file" && node.Content == nil && node.err == nil {
-			return nil, fmt.Errorf("node %v has empty content", node.Name)
-		}
-
-		// remember used hashes
-		if node.Type == "file" && node.Content != nil {
-			for _, id := range node.Content {
-				usedIDs.Insert(id)
-			}
-		}
-
-		if node.Type == "dir" && node.Subtree != nil {
-			usedIDs.Insert(node.Subtree)
-		}
-
-		if node.err != nil {
-			err := arch.Error(node.path, nil, node.err)
-			if err != nil {
-				return nil, err
-			}
-
-			// save error message in node
-			node.Error = node.err.Error()
-		}
-	}
-
-	id, err := arch.SaveTreeJSON(t)
-	if err != nil {
-		return nil, err
-	}
-
-	return id, nil
-}
-
 func (arch *Archiver) fileWorker(wg *sync.WaitGroup, p *Progress, done <-chan struct{}, entCh <-chan pipe.Entry) {
 	defer func() {
 		debug.Log("Archiver.fileWorker", "done")
@@ -459,36 +369,36 @@ func (arch *Archiver) dirWorker(wg *sync.WaitGroup, p *Progress, done <-chan str
 	}
 }
 
-type ArchivePipe struct {
+type archivePipe struct {
 	Old <-chan WalkTreeJob
 	New <-chan pipe.Job
 }
 
 func copyJobs(done <-chan struct{}, in <-chan pipe.Job, out chan<- pipe.Job) {
-	i := in
-	o := out
-
-	o = nil
-
 	var (
-		j  pipe.Job
-		ok bool
+		// disable sending on the outCh until we received a job
+		outCh chan<- pipe.Job
+		// enable receiving from in
+		inCh = in
+		job  pipe.Job
+		ok   bool
 	)
+
 	for {
 		select {
 		case <-done:
 			return
-		case j, ok = <-i:
+		case job, ok = <-inCh:
 			if !ok {
-				// in ch closed, we're done
-				debug.Log("copyJobs", "in channel closed, we're done")
+				// input channel closed, we're done
+				debug.Log("copyJobs", "input channel closed, we're done")
 				return
 			}
-			i = nil
-			o = out
-		case o <- j:
-			o = nil
-			i = in
+			inCh = nil
+			outCh = out
+		case outCh <- job:
+			outCh = nil
+			inCh = in
 		}
 	}
 }
@@ -499,7 +409,7 @@ type archiveJob struct {
 	new    pipe.Job
 }
 
-func (a *ArchivePipe) compare(done <-chan struct{}, out chan<- pipe.Job) {
+func (a *archivePipe) compare(done <-chan struct{}, out chan<- pipe.Job) {
 	defer func() {
 		close(out)
 		debug.Log("ArchivePipe.compare", "done")
@@ -619,7 +529,10 @@ func (j archiveJob) Copy() pipe.Job {
 	return j.new
 }
 
-func (arch *Archiver) Snapshot(p *Progress, paths []string, pid backend.ID) (*Snapshot, backend.ID, error) {
+// Snapshot creates a snapshot of the given paths. If parentID is set, this is
+// used to compare the files to the ones archived at the time this snapshot was
+// taken.
+func (arch *Archiver) Snapshot(p *Progress, paths []string, parentID backend.ID) (*Snapshot, backend.ID, error) {
 	debug.Log("Archiver.Snapshot", "start for %v", paths)
 
 	debug.Break("Archiver.Snapshot")
@@ -638,14 +551,14 @@ func (arch *Archiver) Snapshot(p *Progress, paths []string, pid backend.ID) (*Sn
 		return nil, nil, err
 	}
 
-	jobs := ArchivePipe{}
+	jobs := archivePipe{}
 
 	// use parent snapshot (if some was given)
-	if pid != nil {
-		sn.Parent = pid
+	if parentID != nil {
+		sn.Parent = parentID
 
 		// load parent snapshot
-		parent, err := LoadSnapshot(arch.s, pid)
+		parent, err := LoadSnapshot(arch.s, parentID)
 		if err != nil {
 			return nil, nil, err
 		}
@@ -745,6 +658,8 @@ func isFile(fi os.FileInfo) bool {
 	return fi.Mode()&(os.ModeType|os.ModeCharDevice) == 0
 }
 
+// Scan traverses the dirs to collect Stat information while emitting progress
+// information with p.
 func Scan(dirs []string, p *Progress) (Stat, error) {
 	p.Start()
 	defer p.Done()
diff --git a/archiver_int_test.go b/archiver_int_test.go
index 948d44ba6..d26a9ce53 100644
--- a/archiver_int_test.go
+++ b/archiver_int_test.go
@@ -115,7 +115,7 @@ func TestArchivePipe(t *testing.T) {
 	go testTreeWalker(done, treeCh)
 	go testPipeWalker(done, pipeCh)
 
-	p := ArchivePipe{Old: treeCh, New: pipeCh}
+	p := archivePipe{Old: treeCh, New: pipeCh}
 
 	ch := make(chan pipe.Job)
 
diff --git a/backend/generic.go b/backend/generic.go
index 0244cdab1..c7d569972 100644
--- a/backend/generic.go
+++ b/backend/generic.go
@@ -100,7 +100,7 @@ outer:
 
 // wrap around io.LimitedReader that implements io.ReadCloser
 type blobReader struct {
-	f      io.Closer
+	cl     io.Closer
 	rd     io.Reader
 	closed bool
 }
@@ -120,7 +120,7 @@ func (l *blobReader) Close() error {
 	}
 
 	if !l.closed {
-		err := l.f.Close()
+		err := l.cl.Close()
 		l.closed = true
 		return err
 	}
@@ -128,6 +128,8 @@ func (l *blobReader) Close() error {
 	return nil
 }
 
-func LimitReader(f io.ReadCloser, n int64) *blobReader {
-	return &blobReader{f: f, rd: io.LimitReader(f, n)}
+// LimitReadCloser returns a new reader wraps r in an io.LimitReader, but also
+// implements the Close() method.
+func LimitReadCloser(r io.ReadCloser, n int64) *blobReader {
+	return &blobReader{cl: r, rd: io.LimitReader(r, n)}
 }
diff --git a/backend/id.go b/backend/id.go
index 261f4802d..e960b8eaf 100644
--- a/backend/id.go
+++ b/backend/id.go
@@ -10,7 +10,7 @@ import (
 // IDSize contains the size of an ID, in bytes.
 const IDSize = hashSize
 
-// References content within a repository.
+// ID references content within a repository.
 type ID []byte
 
 // ParseID converts the given string to an ID.
diff --git a/backend/local/local.go b/backend/local/local.go
index 0fbd5fcf7..a50d2ef31 100644
--- a/backend/local/local.go
+++ b/backend/local/local.go
@@ -312,7 +312,7 @@ func (b *Local) GetReader(t backend.Type, name string, offset, length uint) (io.
 		return f, nil
 	}
 
-	return backend.LimitReader(f, int64(length)), nil
+	return backend.LimitReadCloser(f, int64(length)), nil
 }
 
 // Test returns true if a blob of the given type and name exists in the backend.
diff --git a/backend/sftp/sftp.go b/backend/sftp/sftp.go
index 09dad6242..5c850ce77 100644
--- a/backend/sftp/sftp.go
+++ b/backend/sftp/sftp.go
@@ -446,7 +446,7 @@ func (r *SFTP) GetReader(t backend.Type, name string, offset, length uint) (io.R
 		return f, nil
 	}
 
-	return backend.LimitReader(f, int64(length)), nil
+	return backend.LimitReadCloser(f, int64(length)), nil
 }
 
 // Test returns true if a blob of the given type and name exists in the backend.
diff --git a/cache.go b/cache.go
index 53e14873e..24f7a17fd 100644
--- a/cache.go
+++ b/cache.go
@@ -13,6 +13,7 @@ import (
 	"github.com/restic/restic/server"
 )
 
+// Cache is used to locally cache items from a server.
 type Cache struct {
 	base string
 }
@@ -29,6 +30,7 @@ func NewCache(be backend.Identifier) (*Cache, error) {
 	return &Cache{base: basedir}, nil
 }
 
+// Has checks if the local cache has the id.
 func (c *Cache) Has(t backend.Type, subtype string, id backend.ID) (bool, error) {
 	filename, err := c.filename(t, subtype, id)
 	if err != nil {
@@ -51,6 +53,9 @@ func (c *Cache) Has(t backend.Type, subtype string, id backend.ID) (bool, error)
 	return true, nil
 }
 
+// Store returns an io.WriteCloser that is used to save new information to the
+// cache. The returned io.WriteCloser must be closed by the caller after all
+// data has been written.
 func (c *Cache) Store(t backend.Type, subtype string, id backend.ID) (io.WriteCloser, error) {
 	filename, err := c.filename(t, subtype, id)
 	if err != nil {
@@ -73,6 +78,8 @@ func (c *Cache) Store(t backend.Type, subtype string, id backend.ID) (io.WriteCl
 	return file, nil
 }
 
+// Load returns information from the cache. The returned io.ReadCloser must be
+// closed by the caller.
 func (c *Cache) Load(t backend.Type, subtype string, id backend.ID) (io.ReadCloser, error) {
 	filename, err := c.filename(t, subtype, id)
 	if err != nil {
@@ -98,8 +105,9 @@ func (c *Cache) purge(t backend.Type, subtype string, id backend.ID) error {
 	return err
 }
 
+// Clear removes information from the cache that isn't present in the server any more.
 func (c *Cache) Clear(s *server.Server) error {
-	list, err := c.List(backend.Snapshot)
+	list, err := c.list(backend.Snapshot)
 	if err != nil {
 		return err
 	}
@@ -120,19 +128,19 @@ func (c *Cache) Clear(s *server.Server) error {
 	return nil
 }
 
-type CacheEntry struct {
+type cacheEntry struct {
 	ID      backend.ID
 	Subtype string
 }
 
-func (c CacheEntry) String() string {
+func (c cacheEntry) String() string {
 	if c.Subtype != "" {
 		return c.ID.Str() + "." + c.Subtype
 	}
 	return c.ID.Str()
 }
 
-func (c *Cache) List(t backend.Type) ([]CacheEntry, error) {
+func (c *Cache) list(t backend.Type) ([]cacheEntry, error) {
 	var dir string
 
 	switch t {
@@ -145,7 +153,7 @@ func (c *Cache) List(t backend.Type) ([]CacheEntry, error) {
 	fd, err := os.Open(dir)
 	if err != nil {
 		if os.IsNotExist(err) {
-			return []CacheEntry{}, nil
+			return []cacheEntry{}, nil
 		}
 		return nil, err
 	}
@@ -156,7 +164,7 @@ func (c *Cache) List(t backend.Type) ([]CacheEntry, error) {
 		return nil, err
 	}
 
-	entries := make([]CacheEntry, 0, len(fis))
+	entries := make([]cacheEntry, 0, len(fis))
 
 	for _, fi := range fis {
 		parts := strings.SplitN(fi.Name(), ".", 2)
@@ -168,7 +176,7 @@ func (c *Cache) List(t backend.Type) ([]CacheEntry, error) {
 			continue
 		}
 
-		e := CacheEntry{ID: id}
+		e := cacheEntry{ID: id}
 
 		if len(parts) == 2 {
 			e.Subtype = parts[1]
diff --git a/chunker/chunker.go b/chunker/chunker.go
index eb92a50c7..9e016e4dd 100644
--- a/chunker/chunker.go
+++ b/chunker/chunker.go
@@ -12,16 +12,17 @@ const (
 	MiB = 1024 * KiB
 
 	// WindowSize is the size of the sliding window.
-	WindowSize = 64
+	windowSize = 64
 
 	// aim to create chunks of 20 bits or about 1MiB on average.
-	AverageBits = 20
+	averageBits = 20
 
-	// Chunks should be in the range of 512KiB to 8MiB.
+	// MinSize is the minimal size of a chunk.
 	MinSize = 512 * KiB
+	// MaxSize is the maximal size of a chunk.
 	MaxSize = 8 * MiB
 
-	splitmask = (1 << AverageBits) - 1
+	splitmask = (1 << averageBits) - 1
 )
 
 type tables struct {
@@ -39,7 +40,7 @@ func init() {
 	cache.entries = make(map[Pol]*tables)
 }
 
-// A chunk is one content-dependent chunk of bytes whose end was cut when the
+// Chunk is one content-dependent chunk of bytes whose end was cut when the
 // Rabin Fingerprint had the value stored in Cut.
 type Chunk struct {
 	Start  uint
@@ -52,7 +53,7 @@ func (c Chunk) Reader(r io.ReaderAt) io.Reader {
 	return io.NewSectionReader(r, int64(c.Start), int64(c.Length))
 }
 
-// A chunker internally holds everything needed to split content.
+// Chunker splits content with Rabin Fingerprints.
 type Chunker struct {
 	pol      Pol
 	polShift uint
@@ -61,7 +62,7 @@ type Chunker struct {
 	rd     io.Reader
 	closed bool
 
-	window [WindowSize]byte
+	window [windowSize]byte
 	wpos   int
 
 	buf  []byte
@@ -97,7 +98,7 @@ func (c *Chunker) Reset(rd io.Reader, p Pol) {
 	c.fillTables()
 	c.rd = rd
 
-	for i := 0; i < WindowSize; i++ {
+	for i := 0; i < windowSize; i++ {
 		c.window[i] = 0
 	}
 	c.closed = false
@@ -116,7 +117,7 @@ func (c *Chunker) Reset(rd io.Reader, p Pol) {
 	}
 
 	// do not start a new chunk unless at least MinSize bytes have been read
-	c.pre = MinSize - WindowSize
+	c.pre = MinSize - windowSize
 }
 
 // Calculate out_table and mod_table for optimization. Must be called only
@@ -154,7 +155,7 @@ func (c *Chunker) fillTables() {
 		var h Pol
 
 		h = appendByte(h, byte(b), c.pol)
-		for i := 0; i < WindowSize-1; i++ {
+		for i := 0; i < windowSize-1; i++ {
 			h = appendByte(h, 0, c.pol)
 		}
 		c.tables.out[b] = h
@@ -246,7 +247,7 @@ func (c *Chunker) Next() (*Chunk, error) {
 			out := c.window[c.wpos]
 			c.window[c.wpos] = b
 			c.digest ^= uint64(c.tables.out[out])
-			c.wpos = (c.wpos + 1) % WindowSize
+			c.wpos = (c.wpos + 1) % windowSize
 
 			// c.append(b)
 			index := c.digest >> c.polShift
@@ -284,7 +285,7 @@ func (c *Chunker) Next() (*Chunk, error) {
 				c.Reset(c.rd, c.pol)
 				c.pos = pos
 				c.start = pos
-				c.pre = MinSize - WindowSize
+				c.pre = MinSize - windowSize
 
 				return chunk, nil
 			}
@@ -330,7 +331,7 @@ func (c *Chunker) slide(b byte) {
 	out := c.window[c.wpos]
 	c.window[c.wpos] = b
 	c.digest ^= uint64(c.tables.out[out])
-	c.wpos = (c.wpos + 1) % WindowSize
+	c.wpos = (c.wpos + 1) % windowSize
 
 	c.append(b)
 }
diff --git a/node.go b/node.go
index 39f1da2cb..3060d54fb 100644
--- a/node.go
+++ b/node.go
@@ -17,6 +17,7 @@ import (
 	"github.com/restic/restic/server"
 )
 
+// Node is a file, directory or other item in a backup.
 type Node struct {
 	Name       string       `json:"name"`
 	Type       string       `json:"type"`
@@ -62,6 +63,7 @@ func (node Node) Tree() *Tree {
 	return node.tree
 }
 
+// NodeFromFileInfo returns a new node from the given path and FileInfo.
 func NodeFromFileInfo(path string, fi os.FileInfo) (*Node, error) {
 	node := &Node{
 		path:    path,
@@ -100,6 +102,7 @@ func nodeTypeFromFileInfo(fi os.FileInfo) string {
 	return ""
 }
 
+// CreateAt creates the node at the given path and restores all the meta data.
 func (node *Node) CreateAt(path string, s *server.Server) error {
 	switch node.Type {
 	case "dir":
diff --git a/restorer.go b/restorer.go
index 740677473..cebd9c894 100644
--- a/restorer.go
+++ b/restorer.go
@@ -12,6 +12,7 @@ import (
 	"github.com/juju/errors"
 )
 
+// Restorer is used to restore a snapshot to a directory.
 type Restorer struct {
 	s  *server.Server
 	sn *Snapshot
@@ -103,6 +104,7 @@ func (res *Restorer) RestoreTo(dir string) error {
 	return res.restoreTo(dir, "", res.sn.Tree)
 }
 
+// Snapshot returns the snapshot this restorer is configured to use.
 func (res *Restorer) Snapshot() *Snapshot {
 	return res.sn
 }
diff --git a/server/key.go b/server/key.go
index bcecb7719..68f00c481 100644
--- a/server/key.go
+++ b/server/key.go
@@ -258,13 +258,13 @@ func (k *Key) DecryptFrom(rd io.Reader) (io.ReadCloser, error) {
 	return crypto.DecryptFrom(k.master, rd)
 }
 
-// Master() returns the master keys for this repository. Only included for
+// Master returns the master keys for this repository. Only included for
 // debug purposes.
 func (k *Key) Master() *crypto.Key {
 	return k.master
 }
 
-// User() returns the user keys for this key. Only included for debug purposes.
+// User returns the user keys for this key. Only included for debug purposes.
 func (k *Key) User() *crypto.Key {
 	return k.user
 }
diff --git a/server/server.go b/server/server.go
index da1974a99..e2a84650c 100644
--- a/server/server.go
+++ b/server/server.go
@@ -422,12 +422,10 @@ func (s *Server) Flush() error {
 	return nil
 }
 
-// Returns the backend used for this server.
 func (s *Server) Backend() backend.Backend {
 	return s.be
 }
 
-// Returns the index of this server.
 func (s *Server) Index() *Index {
 	return s.idx
 }
diff --git a/test/helpers.go b/test/helpers.go
index a3e5a743c..b99f56dec 100644
--- a/test/helpers.go
+++ b/test/helpers.go
@@ -21,7 +21,7 @@ func Assert(tb testing.TB, condition bool, msg string, v ...interface{}) {
 	}
 }
 
-// ok fails the test if an err is not nil.
+// OK fails the test if an err is not nil.
 func OK(tb testing.TB, err error) {
 	if err != nil {
 		_, file, line, _ := runtime.Caller(1)
@@ -30,7 +30,7 @@ func OK(tb testing.TB, err error) {
 	}
 }
 
-// equals fails the test if exp is not equal to act.
+// Equals fails the test if exp is not equal to act.
 func Equals(tb testing.TB, exp, act interface{}) {
 	if !reflect.DeepEqual(exp, act) {
 		_, file, line, _ := runtime.Caller(1)
diff --git a/zerrors_linux.go b/zerrors_linux.go
deleted file mode 100644
index c90a86293..000000000
--- a/zerrors_linux.go
+++ /dev/null
@@ -1,5 +0,0 @@
-package restic
-
-// Add constant O_PATH missing from Go1.3, will be added to Go1.4 according to
-// https://code.google.com/p/go/issues/detail?id=7830
-const O_PATH = 010000000