diff --git a/.github/workflows/release.yml b/.github/workflows/release.yml
new file mode 100644
index 0000000..e69de29
diff --git a/Bitcaspy.go b/Bitcaspy.go
index 4efafa0..8354690 100644
--- a/Bitcaspy.go
+++ b/Bitcaspy.go
@@ -78,6 +78,17 @@ func Init(cfg ...Config) (*BitCaspy, error) {
 		}
 	}
 
+	// If not in readonly mode, generate a lock file to ensure that only one process is allowed to access the active datafile
+	if !opts.readOnly {
+		lockFilePath := filepath.Join(opts.dir, LOCKFILE)
+		if !exists(lockFilePath) {
+			_, err := getFLock(lockFilePath)
+			if err != nil {
+				return nil, err
+			}
+		}
+	}
+
 	// Create a new active datafile
 	df, err := datafile.New(opts.dir, index)
 	if err != nil {
@@ -113,8 +124,99 @@ func Init(cfg ...Config) (*BitCaspy, error) {
 	go BitCaspy.checkFileSize(BitCaspy.opts.checkFileSizeInterval)
 
 	// if BitCaspy.opts.syncInterval != nil{
-	// 	go BitCaspy
+	// 	go BitCaspy.syn
 	// }
 
 	return BitCaspy, nil
 }
+
+func (b *BitCaspy) Close() error {
+	b.Lock()
+	defer b.Unlock()
+
+	// Generate Hint files from the keydir
+	if err := b.genrateHintFiles(); err != nil {
+		fmt.Errorf("Error generating Hint files from keydir: %v", err)
+	}
+
+	// Close the active data file
+	if err := b.df.Close(); err != nil {
+		fmt.Errorf("Error closing active data file: %v", err)
+	}
+
+	// Close all the stale data files
+	for _, df := range b.stale {
+		if err := df.Close(); err != nil {
+			fmt.Errorf("Error closing stale data file: %v", err)
+		}
+	}
+	return nil
+}
+
+// Gets the key from the keydir and then checks for the key in the keydir hashmap
+// Then it goes to the value offset in the data file
+func (b *BitCaspy) Get(key string) ([]byte, error) {
+	record, err := b.get(key)
+	if err != nil {
+		return nil, err
+	}
+	if record.isExpired() {
+		return nil, ErrExpiredKey
+	}
+	if !record.isValidChecksum() {
+		return nil, ErrChecksumMismatch
+	}
+	return record.Value, nil
+}
+
+// puts the key into the active data file and puts the key and inserts in the keyDir hashmap the fileId, vsize and offset at the data file
+func (b *BitCaspy) Put(key string, value []byte) error {
+	if b.opts.readOnly {
+		return ErrReadOnly
+	}
+	//
+	return b.put(b.df, key, value, nil)
+}
+
+func (b *BitCaspy) Delete(key string) error {
+	b.Lock()
+	defer b.Unlock()
+	if b.opts.readOnly {
+		return ErrReadOnly
+	}
+	return b.delete(key)
+}
+
+func (b *BitCaspy) list_keys() []string {
+	b.Lock()
+	defer b.Unlock()
+	key_lists := make([]string, 0, len(b.KeyDir))
+
+	for key := range b.KeyDir {
+		key_lists = append(key_lists, key)
+	}
+	return key_lists
+}
+
+func (b *BitCaspy) Fold(foldingFunc func(key string, value []byte, acc string) error) error {
+	b.Lock()
+	defer b.Unlock()
+
+	for key, _ := range b.KeyDir {
+		value, err := b.Get(key)
+		if err != nil {
+			return err
+		}
+		if err := foldingFunc(key, value, "rohit"); err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
+func (b *BitCaspy) Sync() error {
+	b.Lock()
+	defer b.Unlock()
+
+	return b.df.Sync()
+}
diff --git a/erros.go b/erros.go
new file mode 100644
index 0000000..0f74491
--- /dev/null
+++ b/erros.go
@@ -0,0 +1,17 @@
+package bitcaspy
+
+import "errors"
+
+var (
+	ErrLocked   = errors.New("a lockfile already exists")
+	ErrReadOnly = errors.New("operation not allowed in read only mode")
+
+	ErrChecksumMismatch = errors.New("invalid data: checksum does not match")
+
+	ErrEmptyKey   = errors.New("invalid key: key cannot be empty")
+	ErrExpiredKey = errors.New("invalid key: key is already expired")
+	ErrLargeKey   = errors.New("invalid key: size cannot be more than 4294967296 bytes")
+	ErrNoKey      = errors.New("invalid key: key is either deleted or expired or unset")
+
+	ErrLargeValue = errors.New("invalid value: size cannot be more than 4294967296 bytes")
+)
diff --git a/ops.go b/ops.go
index d18efc2..c39700b 100644
--- a/ops.go
+++ b/ops.go
@@ -12,7 +12,7 @@ import (
 func (b *BitCaspy) get(key string) (Record, error) {
 	meta, ok := b.KeyDir[key]
 	if !ok {
-		return Record{}, nil
+		return Record{}, ErrNoKey
 	}
 
 	var (
@@ -20,6 +20,7 @@ func (b *BitCaspy) get(key string) (Record, error) {
 		reader *datafile.DataFile
 	)
 	reader = b.df
+	// Isnot in Active data file then go to stale data files
 	if meta.id != b.df.ID() {
 		reader, ok = b.stale[meta.id]
 		if !ok {
@@ -29,7 +30,7 @@ func (b *BitCaspy) get(key string) (Record, error) {
 
 	data, err := reader.Read(meta.value_pos, meta.value_sz)
 	if err != nil {
-		return Record{}, fmt.Errorf("Error reading the dat from database file %v", err)
+		return Record{}, fmt.Errorf("Error reading the data from database file %v", err)
 	}
 
 	//Decode the header