diff --git a/bitcask_test.go b/bitcask_test.go
index 167d0b5..1fec386 100644
--- a/bitcask_test.go
+++ b/bitcask_test.go
@@ -1196,10 +1196,10 @@ func BenchmarkPut(b *testing.B) {
 	}
 
 	variants := map[string][]Option{
-		"NoSync": []Option{
+		"NoSync": {
 			WithSync(false),
 		},
-		"Sync": []Option{
+		"Sync": {
 			WithSync(true),
 		},
 	}
diff --git a/internal/data/datafile.go b/internal/data/datafile.go
index 50a7acb..c9c20e9 100644
--- a/internal/data/datafile.go
+++ b/internal/data/datafile.go
@@ -13,16 +13,17 @@ import (
 )
 
 const (
-	DefaultDatafileFilename = "%09d.data"
+	defaultDatafileFilename = "%09d.data"
 )
 
 var (
-	ErrReadonly  = errors.New("error: read only datafile")
-	ErrReadError = errors.New("error: read error")
+	errReadonly  = errors.New("error: read only datafile")
+	errReadError = errors.New("error: read error")
 
 	mxMemPool sync.RWMutex
 )
 
+// Datafile is an interface  that represents a readable and writeable datafile
 type Datafile interface {
 	FileID() int
 	Name() string
@@ -57,7 +58,7 @@ func NewDatafile(path string, id int, readonly bool, maxKeySize uint32, maxValue
 		err error
 	)
 
-	fn := filepath.Join(path, fmt.Sprintf(DefaultDatafileFilename, id))
+	fn := filepath.Join(path, fmt.Sprintf(defaultDatafileFilename, id))
 
 	if !readonly {
 		w, err = os.OpenFile(fn, os.O_WRONLY|os.O_APPEND|os.O_CREATE, 0640)
@@ -165,7 +166,7 @@ func (df *datafile) ReadAt(index, size int64) (e internal.Entry, err error) {
 		return
 	}
 	if int64(n) != size {
-		err = ErrReadError
+		err = errReadError
 		return
 	}
 
@@ -176,7 +177,7 @@ func (df *datafile) ReadAt(index, size int64) (e internal.Entry, err error) {
 
 func (df *datafile) Write(e internal.Entry) (int64, int64, error) {
 	if df.w == nil {
-		return -1, 0, ErrReadonly
+		return -1, 0, errReadonly
 	}
 
 	df.Lock()
diff --git a/internal/entry.go b/internal/entry.go
index 4f776dd..a1272f5 100644
--- a/internal/entry.go
+++ b/internal/entry.go
@@ -12,6 +12,7 @@ type Entry struct {
 	Value    []byte
 }
 
+// NewEntry creates a new `Entry` with the given `key` and `value`
 func NewEntry(key, value []byte) Entry {
 	checksum := crc32.ChecksumIEEE(value)
 
diff --git a/internal/index/index.go b/internal/index/index.go
index a48143c..d8d2d28 100644
--- a/internal/index/index.go
+++ b/internal/index/index.go
@@ -7,11 +7,14 @@ import (
 	"github.com/prologic/bitcask/internal"
 )
 
+// Indexer is an interface for loading and saving the index (an Adaptive Radix Tree)
 type Indexer interface {
 	Load(path string, maxkeySize uint32) (art.Tree, bool, error)
 	Save(t art.Tree, path string) error
 }
 
+// NewIndexer returns an instance of the default `Indexer` implemtnation
+// which perists the index (an Adaptive Radix Tree) as a binary blob on file
 func NewIndexer() Indexer {
 	return &indexer{}
 }
diff --git a/internal/item.go b/internal/item.go
index 61bbabf..6d245de 100644
--- a/internal/item.go
+++ b/internal/item.go
@@ -1,5 +1,8 @@
 package internal
 
+// Item represents the location of the value on disk. This is used by the
+// internal Adaptive Radix Tree to hold an in-memory structure mapping keys to
+// locations on disk of where the value(s) can be read from.
 type Item struct {
 	FileID int   `json:"fileid"`
 	Offset int64 `json:"offset"`
diff --git a/internal/utils.go b/internal/utils.go
index 158c0d1..a10f402 100644
--- a/internal/utils.go
+++ b/internal/utils.go
@@ -9,11 +9,14 @@ import (
 	"strings"
 )
 
+// Exists returns `true` if the given `path` on the current file system exists
 func Exists(path string) bool {
 	_, err := os.Stat(path)
 	return err == nil
 }
 
+// DirSize returns the space occupied by the given `path` on disk on the current
+// file system.
 func DirSize(path string) (int64, error) {
 	var size int64
 	err := filepath.Walk(path, func(_ string, info os.FileInfo, err error) error {
@@ -28,6 +31,9 @@ func DirSize(path string) (int64, error) {
 	return size, err
 }
 
+// GetDatafiles returns a list of all data files stored in the database path
+// given by `path`. All datafiles are identified by the the glob `*.data` and
+// the basename is represented by an monotomic increasing integer.
 func GetDatafiles(path string) ([]string, error) {
 	fns, err := filepath.Glob(fmt.Sprintf("%s/*.data", path))
 	if err != nil {
@@ -37,6 +43,8 @@ func GetDatafiles(path string) ([]string, error) {
 	return fns, nil
 }
 
+// ParseIds will parse a list of datafiles as returned by `GetDatafiles` and
+// extract the id part and return a slice of ints.
 func ParseIds(fns []string) ([]int, error) {
 	var ids []int
 	for _, fn := range fns {