Understanding Different Types of Data Storage: A Comprehensive Guide - Prof. Joseph Bullin, Study notes of Computer Science

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Discovering Computers 2009 Chapter 7 Storage Chapter 7 Objectives Differentiate between storage devices and storage media Differentiate between storage devices and storage media Describe the characteristics of magnetic disks Describe the characteristics of magnetic disks Describe the characteristics of a hard disk Describe the characteristics of a hard disk Discuss various types of miniature, external, and removable hard disks Discuss various types of iniature, external, and removable hard disks Describe the characteristics of optical discs Describe the characteristics of optical discs Differentiate among CD-ROMs, recordable CDs, rewritable CDs, DVD-ROMs, BD-ROMs, HD DVD- ROMs, recordable DVDs, and rewritable DVDs Differentiate among CD-RO s, recordable CDs, rewritable CDs, DVD-RO s, BD-RO s, HD DVD- RO s, recordable DVDs, and rewritable DVDs Identify the uses of tapeIdentify the uses of tape Discuss PC Cards, ExpressCard modules, and the various types of miniature mobile storage media Discuss PC Cards, ExpressCard modules, and the various types of miniature mobile storage media Identify uses of microfilm and microfiche Identify uses of microfilm and microfiche Next Storage Medium (hard disks, CDs, DVDs, USB flash drives, etc.) Storage How does volatility compare? p. 355 - 356 Next N o n vo la ti le  Storage medium is nonvolatile—contents retained when power is off Contents retained Contents available to user Memory (most RAM) (chips on motherboard) Screen Display ON OFF V o la ti le Display disappears Data and instructions available to user Display appears Data and instructions erased  Memory is volatile—holds data and instructions temporarily Writing Process of transferring items from memory to storage media riting Process of transferring items from memory to storage media Storage What is a storage device? p. 356 Next Reading Process of transferring items from storage media to memory Reading Process of transferring items from storage media to memory Hardware that records and retrieves items to and from storage media Functions as source of input Creates output Secondary Storage Primary Storage Hard Disk Flash Memory Cards and USB Flash Drives CDs and DVDs Tape Items waiting to be interpreted and executed by the processor Operating system, application software, user data and information Digital pictures or files to be transported Software, backups, movies, music Backups Memory (most RAM) Stores …Transfer rates Storage What is access time? p. 357 Fig. 7-4  Time it takes storage device to locate item on storage medium Next  Time required to deliver item from memory to processor faster transfer rates slower transfer rates Magnetic Disks What are characteristics of a hard disk? p. 359 Fig. 7-7 Next Sample Hard Disk Characteristics Advertised capacity 500 GB Platters 4 Read/write heads 8 Cylinders 16,383 Bytes per second 512 Sectors per track 63 Sectors per drive 973,773,168 Revolutions per minute 7,200 Transfer rate 300 MBps Access time 8.5 ms actual disk capacity Magnetic Disks How does a hard disk work? p. 360 Fig. 7-8 Next Magnetic Disks What is a cylinder? p. 360 Fig. 7-9 Next  Vertical section of track through all platters  Single movement of read/write head arms accesses all platters in cylinder platter read/write head platter sides cylinder track sector Next Magnetic Disks What is RAID? p. 362  Redundant Array of Independent Disks  Connects multiple smaller disks into a single unit that acts as a single large hard disk Click to view Web Link, click Chapter 7, Click Web Link from left navigation, then click RAID below Chapter 7 Next Magnetic Disks What is a miniature hard disk? p. 362 Fig. 7-13  Provide greater storage capacities than flash memory  Smaller than notebook computer hard disks  A pocket hard drive is a self-contained unit Click to view Web Link, click Chapter 7, Click Web Link from left navigation, then click Pocket Hard Drives below Chapter 7 Magnetic Disks What are external hard disks and removable hard disks? p. 363 Fig. 7-14 Next 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 Magnetic Disks What is a floppy disk? p. 365 Fig. 7-16 Next  Portable, inexpensive storage medium (also called diskette) Thin, circular, flexible film enclosed in 3.5” wide plastic shell Push same button to close tray Optical Discs What are optical discs? p. 366 Fig. 7-17 Next  Most PCs include an optical disc drive  Flat, round, portable metal discs made of metal, plastic, and lacquer  Can be read only or read/write Insert disc Push button to slide out tray Optical Discs How does a laser read data on an optical disc? p. 367 Fig. 7-18 Next laser diode laser diode prism prism light- sensing diode light- sensing diode 0 1 lens lenspit land disc label Step 1. Laser diode shines a light beam toward disc. Step 2. If light strikes a pit, it scatters. If light strikes a land, it is reflected back toward diode. Step 3. Reflected light is deflected to a light-sensing diode, which send a digital signals of 1 to computer. Absence of reflected light is read as a digital signal of 0. Optical Discs What is a CD-ROM? p. 369 Fig. 7-22 Next  Compact disc read-only memory  Cannot erase or modify contents  Typically holds 650 MB to 1 GB  Commonly used to distribute multimedia and complex software Click to view Web Link, click Chapter 7, Click Web Link from left navigation, then click CD-ROMs below Chapter 7 Optical Discs What is the data transfer rate of a CD-ROM drive? p. 369 Next 75X Ranges from 48X to 75X or faster 75  150 KBps = 11,250 KBps or 12.25 MBps 75X is 150 KBps (KB per second) 48X: 48  150 KBps = 7,200 KBps or 7.2 MBps Optical Discs What are CD-Rs and CD-RWs? p. 370 Next Must have CD recorder or CD-R drive Cannot erase disc’s contents CD-R (compact disc-recordable) —cdisc you can write on once CD-RW (compact disc-rewritable) —ce rasable disc you can write on multiple times Must have CD-RW software and CD-RW drive Click to view Web Link, click Chapter 7, Click Web Link from left navigation, then click CD-Rs and CD-RWs below Chapter 7 Optical Discs What is a DVD-ROM (digital versatile disc-ROM or digital video disc-ROM)? p. 372 Fig. 7-24 Next  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 100 GB  HD-DVD discs have storage capacity of up to 60 GB  HD-VMDs have storage capacity of up to 40 GB or more  UMD can store up to 1.8 GB Optical Discs How does a DVD-ROM store data? p. 372 - 373 Fig. 7-25 Next  Two layers of pits are used, lower layer is semitransparent so laser can read through  Some are double-sided  Many types of recordable and rewritable DVDs are available  DVD-R and DVD+R  DVD-RW, DVD+RW, and DVD+RAM Click to view Web Link, click Chapter 7, Click Web Link from left navigation, then click Blu-ray and HD DVD below Chapter 7 Tape What is tape? p. 374 Fig. 7-27 Next  Magnetically coated plastic ribbon capable of storing large amounts of data at low cost  Primarily used for backup Miniature Mobile Storage Media What is miniature mobile storage media? p. 375 Fig. 7-29 Next  Storage for small mobile devices Miniature Mobile Storage Media What are common types of flash memory cards? p. 376 Fig. 7-30 Next Click to view Web Link, click Chapter 7, Click Web Link from left navigation, then click microSD Cards below Chapter 7 Miniature Mobile Storage Media p. 377 Fig. 7-31 Next How does one type of flash memory card work? Microfilm and Microfiche What are microfilm and microfiche? p. 379 Fig. 7-34 Next Images recorded using computer output microfilm recorder Store microscopic images of documents on roll or sheet of film Microfilm — 100- to 215-foot roll of film Microfiche — small sheet of film, usually 4”  6” Microfilm and Microfiche How do life expectancies of various media compare? p. 379 Fig. 7-35 Next  Microfilm and microfiche have longest life of any storage media Putting It All Together What are recommended storage devices for home users? p. 380 Fig. 7-37 Next  320 GB hard disk  Online storage  CD or DVD drive  Card reader/writer  USB flash drive Putting It All Together What are recommended storage devices for power users? p. 380 Fig. 7-37 Next  2.5 TB hard disk  Online storage  CD or DVD drive  Portable hard disk for backup  USB flash drive Putting It All Together What are recommended storage devices for large business users? p. 380 Fig. 7-37 Next  Desktop computer 1 TB hard disk CD or DVD drive Smart card reader Tape drive USB flash drive  Server or Mainframe Network storage server 40 TB hard disk system CD or DVD server Microfilm or microfiche Summary of Storage Internal hard disksInternal hard disks External and removable hard disksExternal and re ovable hard disks Floppy disksFloppy disks CD-ROMsCD-R s Recordable and Rewritable CDsRecordable and Rewritable CDs DVD-ROMsDVD-R s Blu-ray Discs (BDs)Blu-ray Discs (BDs) HD DVD discsD DVD discs Recordable and Rewritable DVDsRecordable and Rewritable DVDs TapeTape PC Cards and ExpressCard modules PC Cards and ExpressCard odules Flash memory cards and USB flash drives Flash e ory cards and USB flash drives Chapter 7 Complete Smart cards, microfilm, and microfiche S art cards, icrofil , and icrofiche