Often used to make back ups of large programs, and numerous files.
*if any particle were to get between the platter and the reader/writer head it would destroy the hard drive, usually sealed tightly to protect from particles. Important to back up your hard drive!
External advantages – transport large #s of files quickly, back up internal hard disk Add storage space, share a drive with multiple computers
Saves time by, and hard disk space, and allows others to access data.
Most often use one continuous track that spirals to the center of the disc.
CD-R – like music, data, pictures, etc.
DVD-ROM – quality surpases CD-ROM
Often used by business to store inactive files, or by banks to store transactions.
Chapter 7 - Storage By Chris Wilson
Storage <ul><li>Holds data, instructions, and information for future use. </li></ul><ul><li>Storage Medium (secondary storage) – The physical material on which a computer holds data. Ex: floppy disks, hard disks, CDs, DVDs, tape, ZIP disks, PC cards. </li></ul><ul><li>Capacity – Number of bytes a storage medium can hold. </li></ul>
Storage Device <ul><li>The computer hardware that records and/or retrieves items to and from storage media. </li></ul><ul><li>Writing – process of transferring data to a storage medium </li></ul><ul><li>Reading – process of transferring these items from a storage medium into memory. </li></ul><ul><li>Access time – amount of time it takes a storage device to locate an item on a storage medium. </li></ul>
Floppy Disks <ul><li>Floppy Disk (diskette) – A portable storage medium that consists of a thin, circular, flexible plastic Mylar film in a square plastic shell. </li></ul><ul><li>Magnetic media – Uses magnetic particles to store items in tracks and sectors. </li></ul><ul><ul><ul><li>Tracks – narrow recording band that forms a full circle on the disk </li></ul></ul></ul><ul><ul><ul><li>Sector – arc shaped storage locations that make the tracks. </li></ul></ul></ul>
ZIP Disk <ul><li>ZIP disk – A type of portable magnetic media that can store up to 500 times more than a standard floppy. </li></ul>
Hard Disk <ul><li>Hard Disk (hard disk drive) – A storage device that contains one or more inflexible, circular platters that store data, instructions, and information. </li></ul><ul><li>Platter – A 3.5 or 5.25in disk made of aluminum, glass, or ceramic and is coated with an alloy material that allows items to be recorded magnetically on it’s surface. </li></ul>
How a Hard Disk Works <ul><li>A platter will spin around at a rate of 5,400-7,200rpms, while a reader/writer head floats above the platter at ~two millionths of an inch. </li></ul><ul><li>Cache – location where frequently used items are store to improve efficiency. </li></ul>
Types of Hard Disks <ul><li>Internal – Permanently inside the CPU. </li></ul><ul><li>External – A separate freestanding hard disk that connects with a cable to a USB port. </li></ul>
Internet Hard Drives <ul><li>Internet Hard Drive – a service on the web that provides storage to computer users, usually for a minimal fee. </li></ul><ul><ul><ul><li>Allows users to to access files from any computer of device that has Internet access. </li></ul></ul></ul>
CDs and DVDs <ul><li>CDs and DVDs – storage media that consists of a flat, round, portable metal disc with a protective plastic coating. </li></ul><ul><ul><ul><li>An optical media that stores items by using microscopic pits (indentations) and lands (flat areas) </li></ul></ul></ul><ul><ul><ul><li>A high –powered laser light creates the pits, and a lower-powered laser reads items by reflecting light through the bottom of the disc. </li></ul></ul></ul>
CD-ROMs and CD-RWs <ul><li>CD-ROM – Optical disc that holds from 650MB to 1 GB of data. Users can read information from these discs but can not modify them. </li></ul><ul><li>CD-R (compact disc-recordable) – A multisession disc that users can record their own information once only </li></ul><ul><li>CD-RW (compact disc-rewritable) – A disc in which users can write, and then re-write new information. </li></ul>
DVD-ROM and DVD+RWs <ul><li>DVD-ROM (digital versatile disc-ROM or digital video disc) – an extremely high capacity optical disk capable of storing from 4.7 GB to 17 GB. </li></ul><ul><li>DVD+RW – A recordable version of DVD that allows users to erase and record more than 1,000 times. </li></ul>
Tape <ul><li>Tape – a magnetically coated ribbon of plastic capable of storing large amounts of data and information at a low cost. </li></ul><ul><li>Tape drive – Device that reads and writes data and information on tape. </li></ul>
PC Cards and Types of Miniature Storage Media <ul><li>PC Card – A thin credit-card sized device that fits into a PC Card slot to add storage or other capabilities to a desktop or notebook computer. </li></ul><ul><ul><ul><li>Examples : PDA;s, digital cameras, music plaers. </li></ul></ul></ul><ul><li>Miniature mobile storage media – Compact flash, Memory stick, Secure digital, Smart Media. </li></ul>
Microfilm and Microfiche <ul><li>Microfilm – A 100-215ft roll of film used to store back issues of newspapers, magazines, and records. </li></ul><ul><li>Microfiche – A small sheet of film usually about 4 by six inches used in the same fashion as microfilm. </li></ul>
A particular slide catching your eye?
Clipping is a handy way to collect important slides you want to go back to later.