diff --git a/block.go b/block.go
index d6aff93b5..613975fe0 100644
--- a/block.go
+++ b/block.go
@@ -36,7 +36,7 @@ type DiskBlock interface {
 	// Index returns an IndexReader over the block's data.
 	Index() IndexReader
 
-	// Series returns a SeriesReader over the block's data.
+	// Chunks returns a ChunkReader over the block's data.
 	Chunks() ChunkReader
 
 	// Close releases all underlying resources of the block.
diff --git a/chunks.go b/chunks.go
index 7faf5a76a..5863ed4e1 100644
--- a/chunks.go
+++ b/chunks.go
@@ -28,7 +28,7 @@ import (
 )
 
 const (
-	// MagicChunks is 4 bytes at the head of series file.
+	// MagicChunks is 4 bytes at the head of a series file.
 	MagicChunks = 0x85BD40DD
 )
 
@@ -45,10 +45,10 @@ type ChunkMeta struct {
 
 // ChunkWriter serializes a time block of chunked series data.
 type ChunkWriter interface {
-	// WriteChunks writes several chunks. The data field of the ChunkMetas
+	// WriteChunks writes several chunks. The Chunk field of the ChunkMetas
 	// must be populated.
 	// After returning successfully, the Ref fields in the ChunkMetas
-	// is set and can be used to retrieve the chunks from the written data.
+	// are set and can be used to retrieve the chunks from the written data.
 	WriteChunks(chunks ...*ChunkMeta) error
 
 	// Close writes any required finalization and closes the resources
@@ -172,9 +172,9 @@ func (w *chunkWriter) write(wr io.Writer, b []byte) error {
 func (w *chunkWriter) WriteChunks(chks ...*ChunkMeta) error {
 	// Calculate maximum space we need and cut a new segment in case
 	// we don't fit into the current one.
-	maxLen := int64(binary.MaxVarintLen32)
+	maxLen := int64(binary.MaxVarintLen32) // The number of chunks.
 	for _, c := range chks {
-		maxLen += binary.MaxVarintLen32 + 1
+		maxLen += binary.MaxVarintLen32 + 1 // The number of bytes in the chunk and its encoding.
 		maxLen += int64(len(c.Chunk.Bytes()))
 	}
 	newsz := w.n + maxLen
diff --git a/chunks/bstream.go b/chunks/bstream.go
index 739b17605..26213374f 100644
--- a/chunks/bstream.go
+++ b/chunks/bstream.go
@@ -15,7 +15,7 @@ package chunks
 
 import "io"
 
-// bstream is a stream of bits
+// bstream is a stream of bits.
 type bstream struct {
 	stream []byte // the data stream
 	count  uint8  // how many bits are valid in current byte
diff --git a/chunks/chunk.go b/chunks/chunk.go
index 8c4f8d0b3..86f456be8 100644
--- a/chunks/chunk.go
+++ b/chunks/chunk.go
@@ -18,7 +18,7 @@ import (
 	"fmt"
 )
 
-// Encoding is the identifier for a chunk encoding
+// Encoding is the identifier for a chunk encoding.
 type Encoding uint8
 
 func (e Encoding) String() string {
diff --git a/index.go b/index.go
index eeed5ef58..73b65da30 100644
--- a/index.go
+++ b/index.go
@@ -39,10 +39,10 @@ const (
 
 const compactionPageBytes = minSectorSize * 64
 
-// IndexWriter serialized the index for a block of series data.
-// The methods must generally be called in order they are specified.
+// IndexWriter serializes the index for a block of series data.
+// The methods must generally be called in the order they are specified in.
 type IndexWriter interface {
-	// AddSeries populates the index writer witha series and its offsets
+	// AddSeries populates the index writer with a series and its offsets
 	// of chunks that the index can reference.
 	// The reference number is used to resolve a series against the postings
 	// list iterator. It only has to be available during the write processing.
diff --git a/tsdbutil/buffer.go b/tsdbutil/buffer.go
index 9ee772181..d3246fc64 100644
--- a/tsdbutil/buffer.go
+++ b/tsdbutil/buffer.go
@@ -40,7 +40,7 @@ func (b *BufferedSeriesIterator) Seek(t int64) bool {
 	t0 := t - b.buf.delta
 
 	// If the delta would cause us to seek backwards, preserve the buffer
-	// and just continue regular advancment while filling the buffer on the way.
+	// and just continue regular advancement while filling the buffer on the way.
 	if t0 > b.lastTime {
 		b.buf.reset()
 
diff --git a/wal.go b/wal.go
index e6d74dc20..853065f69 100644
--- a/wal.go
+++ b/wal.go
@@ -147,7 +147,7 @@ func (w *WAL) initSegments() error {
 	if len(fns) == 0 {
 		return nil
 	}
-	// We must open all file in read mode as we may have to truncate along
+	// We must open all files in read/write mode as we may have to truncate along
 	// the way and any file may become the tail.
 	for _, fn := range fns {
 		f, err := os.OpenFile(fn, os.O_RDWR, 0666)
@@ -178,10 +178,10 @@ func (w *WAL) initSegments() error {
 	return nil
 }
 
-// cut finishes the currently active segments and open the next one.
+// cut finishes the currently active segments and opens the next one.
 // The encoder is reset to point to the new segment.
 func (w *WAL) cut() error {
-	// Sync current tail to disc and close.
+	// Sync current tail to disk and close.
 	if tf := w.tail(); tf != nil {
 		if err := w.sync(); err != nil {
 			return err
@@ -276,7 +276,7 @@ func (w *WAL) run(interval time.Duration) {
 	}
 }
 
-// Close sync all data and closes the underlying resources.
+// Close syncs all data and closes the underlying resources.
 func (w *WAL) Close() error {
 	close(w.stopc)
 	<-w.donec
@@ -309,9 +309,10 @@ func (w *WAL) entry(et WALEntryType, flag byte, buf []byte) error {
 	w.mtx.Lock()
 	defer w.mtx.Unlock()
 
-	// Cut to the next segment if exceeds the file size unless it would also
+	// Cut to the next segment if the entry exceeds the file size unless it would also
 	// exceed the size of a new segment.
 	var (
+		// 6-byte header + 4-byte CRC32 + buf.
 		sz    = int64(6 + 4 + len(buf))
 		newsz = w.curN + sz
 	)