Chapter 7 Secondary Storage

Write-once discs (R for recordable)

Can be written once. After that, the disc can only be read many times but cannot be written on or erased.

Capacity

Capacity is how much data a particular storage medium can hold and is another characteristic of secondary storage.

Track

Closed, concentric ring on a disk on which data is recorded. Each track is divided into sections called sectors.

Mass Storage devices

Devices such as file servers, RAID systems, tape libraries, optical jukeboxes and more.

Hard Disks

Enclosed disk drive containing one or more metallic disks. Hard disks use magnetic charges to record data and have large storage capacities and fast retrieval times.

External Hard Drives

Uses the same technology as an internal hard disk but is used primarily to compliment an internal hard disk by providing additional storage. It is typically connected to USB or Firewire Port on the system unit and it is easily removed.

Enterprise Storage system

Using mass storage devices, a strategy designed for organizations to promote efficient and safe use of data across the networks within their organizations.

Solid State Storage

A secondary storage that has no moving parts. Data is stored and retrieved electronically directly from these devices, much as they would be from conventional computer memory.

Flash memory card

A solid-state storage device widely used in notebook computers. Flash memory also used in a variety of specialized input devices to capture and transfer data to desktop computers.

Blu-Ray discs

A type of high definition disc with a capacity of 25 to 50 gigabytes.

Digital Versatile Discs

A type of optical disc similar to CD-ROMs except that more data can be packed into the same amount of space. Similar to CD-ROMs except that more data can be packed into the same amount of space. DVD drives can store a typical capacity of 4.7 GB on one side.

Cloud Storage

Also known as online storage. An Internet based space for storing data and files.

Storage Area Network (SAN)

An architecture that links remote computer storage devices such as enterprise storage systems to computers so that the devices are available as locally attached drives.

Read only memory disks (ROM)

Are discs that cannot be written or erased by the user.

Rewritable discs (RW for rewritable or RAM for Random Access Memory)

Are similar to write-once discs except that the disc surface is not permanently altered when data is recorded.

Cloud Computing

Data stored at a server on the Internet and available anywhere the Internet can be accessed.

File Server

Dedicated computer with large storage capacity providing users access to shared folders or fast storage and retrieval of information used in that business.

Solid State Drives (SSD)

Designed to be connected inside a microcomputer system the same way an internal hard disk would but contains solid-state memory instead of magnetic disks to store data.

Redundant Array of inexpensive disks (RAID)

Groups of inexpensive hard-disk drives related or grouped together using networks and special software. They improve performance by expanding external storage.

Cylinder

Hard disks store and organize files using tracks, sectors, and ____________. A _________ runs through each track of a stack of platters. Cylinders differentiate files stored on the same track and sector of different platters.

Storage Devices

Hardware that reads data and programs from storage media. Most also write to storage media.

Organizational cloud storage

High-speed Internet connection to a dedicated remote organizational Internet drive site.

Primary Storage

Holds data and program instructions for processing data. It also holds processed information before it is output. Memory is contained on chips connected to the system board and is a holding area for data instructions and information (processed data waiting to be output to secondary storage). RAM, ROM, and CMOS are three types of memory chips.

Access Speed

Measures the amount of time required by the storage device to retrieve data and programs.

Media

Media are the actual physical material that holds the data, such as a hard disk, which is one of the important characteristics of secondary storage. Singular of media is medium.

Disk Caching

Method of improving hard-disk performance by anticipating data needs. Frequently used data is read from the hard disk into memory (cache). When needed, data is then accessed directly from memory, which has a much faster transfer rate than from the hard disk. Increases performance by as much as 30%.

Secondary Storage

Permanent storage used to preserve programs and data that can be retained after the computer is turned off. These devices include hard disks, magnetic tape, CDs, DVDs, and more.

Optical Disk

Storage device that can hold over 17 gigabytes of data, which is the equivalent of several million typewritten pages. Lasers are used to record and read data on the disc. The three basic types of optical discs are compact disks (CDs), digital versatile or video disks (DVDs) and Blu-Ray disks (BDs)

File decompression

Process of expanding a compressed file.

File Compression

Process of reducing the storage requirements for a file.

Flash Memory

RAM chips that retain data even when power is disrupted. Flash memory is an example of sold state storage and is typically used to store digitized images and record MP3 Files.

Density

Refers to how tightly the bits(electromagnetic charges) can be packed next to one another on a disc.

Mass Storage

Refers to the tremendous amount of secondary storage required by large organizations.

Platters

Rigid metallic disk; multiple platters are stacked one on top of another within a hard-disk drive.

Sectors

Section shaped like a pie wedge that divides the tracks on a disk.

RAID System

Several inexpensive hard-disk drives connected to improve performance and provide reliable storage.

Network attached storage (NAS)

Similar to a file server except simpler and less expensive. Widely used for home and small business storage needs.

Internal Hard Disk

Storage devices consisting of one or more metallic platters sealed inside a container. Internal hard disks are installed inside the system cabinet of a personal computer. It stores the operating system and major applications like word.

Pits

The 1s and 0s are represented by bumpy areas called __________.

Land

The 1s and 0s are represented by flat areas called _________.

Optical Disk Drive

The disk is read by an ___________ using a laser that projects a tiny beam of light on these areas. The amount of reflected light determines whether the area represents a 1 or a .

USB Drives (Flash Drive)

The size of a key chain, these hard drives connect to a computer's USB port enabling a transfer of files.

Secondary storage device

These devices are used to save, back up, and transport files from one location or computer to another. Permanent storage used to preserve programs and data that can be retained after the computer is turned off. These devices include hard disks, magnetic tape, CD's, DVD's, and more.

Head Crash

When a read-write head makes contact with the hard disk's surface or particles on its surface, the disk surface becomes scratched and some or all data is destroyed.

Compact Disks (CD's)

Widely used optical disc format. It holds 650 MB to 1 GB of data on one side of the CD.