Chapter 7

Secondary storage characteristics Primary storage Volatile storage Temporary storage Random Access Memory (RAM) Secondary storage Nonvolatile storage Permanent storage Secondary storage characteristics Media Capacity Storage devices Access speed Secondary storage permanently saves information for future use; to share information with others; to modify at later date Secondary storage is nonvolatile – stores programs and data as opposed to temporary storage (RAM) Characteristics include: Media or medium – actual physical materials that holds the data and programs Capacity – measures how much a particular storage medium can hold Storage devices – hardware that reads data and programs from storage media (most also write to storage media) Access speed or access time – measures the amount of time required by the storage device to retrieve data and programs Writing– process of saving information to the secondary storage device Reading – process of accessing information from secondary storage

Store and organize files using tracks, sectors, and cylinders Use rigid, metallic platters that are stacked one on top of one another Store and organize files using tracks, sectors, and cylinders Large capacity (terabytes) Two types of hard disks: Internal Hard Disk: Located inside system unit and often designated as the C: drive External Hard Disks Performance enhancements Composed of metallic rather than plastic disks Platters – rigid metallic, stacked one on top of another Track-rings of concentric circles Each track is divided into wedge-shaped sections called sectors A cylinder (Key Term) runs through each track of a stack of platters Fast information storage and retrieval

Hold over 100 gigabytes (GB) of data Three types Compact Disc (CD) Digital Versatile Disc (DVD) Blu-Ray (Hi-Def) Disc Use laser technology. CD (Key Term) and DVD (Key Term) are optical disk formats. Compact, high capacity form of permanent storage (up to 50 gigabytes of data) Optical discs are read by an optical disc drive Laser beam writes by creating a pattern of pits (holes) and lands (flat areas) to encode data bits Laser beams reflect off the pits and lands to read the data Rotational speed determines how fast data can be transferred from the CD Optical disks come in many different sizes Most common is 4 ¾ inches Stored in a protective case called jewel boxes

Large amounts of secondary storage called mass storage that support enterprise storage systems Devices include: File servers: – dedicated computer with very large storage capacities RAID systems: specialized devices that enhance organizational security by constantly making backup copies of files Organizational cloud storage:– high speed internet connection to a dedicated remote organizational cloud storage server. Mass storage devices that support enterprise storage systems are File servers (Key Term) – dedicated computer with very large storage capacities that provide user access to fast storage and retrieval of data Network attached storage (NAS) – similar to a files server except less expensive RAID systems (Key Term) – larger versions of the specialized devices discussed earlier in this chapter that enhance organizational security by constantly making backup copies of files moving across the organization’s networks Tape library (Key Term) – device that provides automatic access to data archived on a large collection or library of tapes Organizational cloud storage – high speed internet connection to a dedicated remote organizational cloud storage server.