This publication provides readers with introduction to computer data storage and data storage device. An overview of major types of computer data storage devices is outlined. An overview of aperture computer memory, page address register, static random access memory (SRAM), dynamic random access memory (DRAM), mass storage and stable storage is provided. Special focus lies on computer memory management, allocation and protection storage. Focus lies on secondary, tertiary and off-line computer storage. CONTENTS: Introduction to Computer Data Storage and Data Storage Device; Major Types of Computer Data Storage Devices: An Overview; Focus on Primary Computer Data Storage: An Overview; Focus on Computer Memory Management, Allocation and Protection Storage: An Overview; Focus on Secondary, Tertiary and Off-Line Computer Storage: An Overview.