Chapter 7 Storage

What is storage? Holds data, instructions, and information for future use Storage medium is physical material used for storage Also called secondary storage  What is a storage device? It is the computer hardware that records and/or retrieves items to and from storage media.  What is reading? It is the process of transferring information from a storage medium into memory.

Magnetic Disks Magnetic Disks: they use magnetic particles to store items such as data, instructions and information on a disk’s surface. Formatting: it is the process of dividing the disk into tracks and sectors so the operating system can store and locate data and information on the disk. Track: it is a narrow recording band that forms a full circle on the surface of the disk. Sectors: the disk storage locations consist of pie-shaped sections which break the tracks into small arcs. A sector stores 512 bytes of data. Clusters: for reading and writing purposes, sectors are grouped into clusters. It is the smallest unit of disk space that stores data and information. Also called allocation unit.

Magnetic Disks What are tracks and sectors? Formatting prepares disk for use and marks bad sectors as unusable Track is narrow recording band that forms full circle on disk Sector stores up to 512 bytes of data

Magnetic Disks What is a hard disk? Also called the hard disk drive It is a storage device that contains one or more inflexible circular platters that magnetically store data, instructions and information. It is inside an airtight, sealed case inside the system unit. hard disk installed in system unit

Magnetic Disks What are external hard disks and removable hard disks? External hard disk—freestanding hard disk that connects to system unit Removable hard disk—hard disk that you insert and remove from hard disk drive Used to back up or transfer files

Online Storage What is online storage? –It is a service on the web that provides hard disk storage to computer users for a monthly fee. –Files can be accessed from any computer with Web access –Large files can be downloaded instantaneously –Others can be authorized to access your data

Floppy Disks Floppy disks are also called a diskette. It is Portable, inexpensive storage medium. Thin, circular, flexible film enclosed in 3.5” wide plastic shell. Floppy disk drive is a device that reads from and writes on a floppy disk. It is also called a secondary storage. It is assigned to as DRIVE A:/ shutter shell liner magnetic coating flexible thin film metal hub

Push the same button to close the tray. Optical Discs What are optical discs? It is a type of storage media that consists of a Flat, round, portable metal discs made of metal, plastic, and lacquer Can be read only or read/write Most PCs include an optical disc drive Insert the disc, label side up. Push the button to slide out the tray.

Optical Discs How is data stored on an optical disc? Typically stored in single track Track divided into evenly sized sectors that store items single track spirals to edge of disc disc sectors

Types of Optical Discs CD-ROM CD-R CD-RW DVD-ROM DVD-R DVD+R DVD-RW DVD+RW DVD+RAM

Optical Discs What is a CD-ROM? Compact disc read-only memory It is a type of optical disc that users can read but not write or erase. Typically holds 650 MB to 1 GB Commonly used to distribute multimedia and complex software

Optical Discs What is a Picture CD? Film developers offer Picture CD service Can be modified using photo editing software Stores digital versions of roll of film

Optical Discs What are CD-Rs and CD-RWs? Must have CD recorder or CD-R drive Cannot erase disc’s contents CD-R (compact disc-recordable) — c disc you can write on once CD-RW (compact disc-rewritable) — ce erasable disc you can write on multiple times Must have CD-RW software and CD-RW drive

Optical Discs What is a DVD-ROM (digital versatile disc- ROM or digital video disc-ROM)? Must have DVD-ROM drive or DVD player to read DVD-ROM Stores databases, music, complex software, and movies Blu-ray discs have storage capacity of up to 27 GB HD-DVD discs have storage capacity of up to 45 GB UMD can store up to 1.8 GB

PC Cards What is a PC Card? Adds capabilities to computer Credit-card-sized device commonly used in notebook computers

Miniature Mobile Storage Media It allows mobile users easily to transport digital images, music, or documents to and from computers and other devices. Storage for small mobile devices

Miniature Mobile Storage Media What is a USB Flash Drive? Also called as a pen device Plugs in a USB port on a computer or mobile device It is convenient for mobile users because they are small and lightweight enough to be transported on a key chain or in a pocket. Storage capacities up to 4 GB May eventually make the floppy disk obsolete

Miniature Mobile Storage Media What is a smart card? It is similar in size to a credit card. Stores data on microprocessor embedded in small card It contains: Processor Input, Process, Output, and Storage capabilities