Computing Essentials 2006 Chapter 8 Secondary Storage, Study notes of Music

Download Computing Essentials 2006 Chapter 8 Secondary Storage and more Study notes Music in PDF only on Docsity! Computing Essentials 2006 Chapter 8 Secondary Storage I.Ch 8 Secondary Storage A.Competencies page 210 1.Distinguish between primary and secondary storage. 2.Describe the traditional floppy disk and compare it to high capacity floppy disks. 3.Compare internal hard disks, hard-disk cartridges, and hard-disk packs. 4.Describe ways to improve hard-disk operations, including disk caching, redundant arrays of inexpensive disks, and data compression and decompression. 5.Describe the different types of optical disks. 6.Describe solid state storage, Internet drives, and magnetic tape. B.Introduction page 211  Secondary storage devices are used to save, to back up, and even to transport files consisting of data or programs from one location or computer to another.  The need for storage continues to grow due to higher demands of users to store more digital media such as videos, music, and images.  Data is stored on secondary storage in digital or machine code, so it doesn’t need to be translated from the 1s & 0s when it is sent to the CPU for processing. C.Storage page 212  RAM (Random Access Memory) is called primary storage since it is used directly by the CPU for processing data and program instructions.  RAM is volatile or temporary storage (once the power is turned off, the contents are lost).  Secondary storage provides permanent or non-volatile storage.  Secondary storage devices read and write the data onto the storage medium.  Reading is the process of retrieving/accessing the data.  Writing is the process of storing/saving the data.  Important characteristics of secondary storage include:  Media or medium: the physical material that holds the data CE06_IM08-1 Computing Essentials 2006 Chapter 8 Secondary Storage  Capacity: measures how much the media can store, typically measured in MB, GB, and TB  Storage devices: hardware that reads (and often writes) to storage media  Access speed (aka access time): measures the amount of time to read and/or write to the storage medium D.Floppy Disks  Floppy disks (aka floppies, diskettes, disks or flexible disks) are portable, removable storage media.  The use flat circular pieces of Mylar plastic coated with a magnetic material to store data.  Floppy Disk Drives (FDD) store/retrieve data by magnetizing spots according to an encoding scheme such as ASCII, EBCDIC, or Unicode. 1.Traditional Floppy Disk page 213  Traditional disk is the 1.44 MB 3 ½” disk, introduced in the 1980’s  2HD disks are “two sided, high density”  Density refers to how tightly the bits can be packed on the medium  A Shutter slides to provide access to the plastic medium  Labels can be applied to the external surface of the disk to identify the contents  A Write-Protection Notch can be moved to protect the disk from accidentally writing over it.  Floppies store the data in a series of Tracks and Sectors – each sector can store up to 512 bytes or characters. 2.High Capacity Floppy Disks page 214  High Capacity Floppy Disks (aka floppy-disk cartridges) have capacities of much higher than traditional floppies. Three leading types include:  Zip Disks (sold by Iomega) have 100, 250, or 750 MB capacities and connect to the PC via USB cable. The disks are slightly thicker than traditional floppies, so they require special disk drives.  HiFD disks (from Sony Corporation) have 200 MB or 720 MB capacities. The main advantage is the drives can also read traditional 1.44 MB floppies.  SuperDisks (from Imation) have a 120 MB or 240 MB capacity, and the drives can also read traditional 1.44 MB floppies. E.Hard Disks page 215  Hard disks save files by altering magnetic charges of the disk’s surface  Hard disks use a thicker, rigid metallic platter for the base medium CE06_IM08-2 Computing Essentials 2006 Chapter 8 Secondary Storage  Disks are typically single session – all images are written once, but may be read many times  Photo CDs are now multisession – images can be added later 2.Digital Versatile/Video Disc (DVD) page 220  A newer format that is replacing CD optical disks  DVDs can store 4.7 GB to 17 GB on a single disk a)Read only - DVD-ROM  Written at manufacturing plant, read many  Typically used for video distribution b)Write once - DVD-R DVD+R  Write once, read many  Tend to cost more than CD writable disks  Used for archiving data and writing video files c)Rewriteable - DVD-RW DVD+RW DVD-RAM  Write many, read many  Still working on setting a standard format G.Making IT Work for You – Music from Internet page 222  This section briefly describes how you can find music on the Internet, and transfer it to a portable player. 1.Finding Music  Many sites on line – best to look for current sites 2.Creating a Custom CD  Several different programs can burn a CD for you  Look at the software that comes with your CD burner, or look for some on line. 3.Uploading to a Portable Player  Transfer the files to the portable player of your choice  You may need to find the file formats that work with your player: mp3, wav, au, etc. H.Other Types of Secondary Storage page 221 1.Solid-state storage  These devices have no moving parts, so they are fast and reliable CE06_IM08-5 Computing Essentials 2006 Chapter 8 Secondary Storage  Tends to have less capacity, and costs more per byte  Flash memory cards are used in notebook computers and digital cameras  Key chain hard drives (aka key chain flash memory devices) typically connect through a USB port, and can store up to 1 GB for easy, portable storage 2.Internet Hard Drives page 224  Special web sites that provide users with storage  Called i-drives or online storage  Advantage is it’s always available as long as you have an Internet connection  Disadvantage is speed is often slower, and there is some hesitation about storing sensitive data on these sites. 3.Magnetic Tape page 225  Tapes only provide sequential access, where disk systems provide either sequential or direct access  Advantage with tape is virtually unlimited storage (just add another tape), it’s reliable, and it’s inexpensive per MB stored.  Disadvantage is it’s somewhat slow, and limited to sequential access  Often used to back up disk storage, especially for networked systems  Mainframe systems used magnetic tape reels  Newer tape systems use tape cartridges or magnetic tape streamers for backing up data I.A Look to the Future page 227  Blu-Ray Technology Expected to Replace DVD.  Using a blue laser light rather than the current red light, capacities may be close to 50 GB per disk.  Additional material can be found at http://www.blu-ray.com/ J.Visual Summary at a glance – Secondary Storage page 228 1.Storage  Key terms:  RAM – primary storage, volatile  Secondary storage – nonvolatile  Writing – saving the information  Reading – retrieving the information  Media or medium  Capacity CE06_IM08-6 Computing Essentials 2006 Chapter 8 Secondary Storage  Storage devices  Access time or Access speed 2.Floppy Disks a)Traditional Floppy Disk b)High Capacity Floppy Disks (1)Zip disks (2)HiFD disks (3)SuperDisk disks 3.Hard Disks a)Internal hard disk b)Hard-disk Cartridge 4.Hard Disks a)Hard-disk Pack b)Performance Enhancements (1)Disk caching (2)RAID (Redundant Array of Inexpensive Disks) (3)File Compression/Decompression 5.Optical Disks a)Compact Discs (1)CD-ROM (2)CD-R (3)CD-RW (4)Photo CD CE06_IM08-7 Computing Essentials 2006 Chapter 8 Secondary Storage L.Chapter Review page 232 1.Crossword a)Across 3 FIXED Also known as the internal hard drive 8 SECTOR Invisible wedge-shaped division of a track 9 PITSANDLANDS Represent 1s and 0s 10 TRACK Rings of concentric circles without visible grooves 11 RAID Grouped disk drives treated as one hard disk by the computer system 13 ZIP Disk with 500 times the storage as a standard floppy 14 FLOPPY Portable and removable storage device 15 WRITING The process of saving information to the secondary storage device 16 PLATTER Rigid metallic part of a hard disk 17 DISKETTE Storage medium that contains a flexible plastic disk b)Down 1 DISKCACHING Improves hard-disk performance by anticipating data needs 2 MULTISESSION Meaning new images can be added to a CD at any time 4 CYLINDER Runs through each track of a stack of platters 5 ACCESSTIME Measures the amount of time required to retrieve data 6 SECTOR Invisible wedge-shaped section 7 ONLINESTORAGE Web based storage 12 DENSITY How tightly the bits can be packed next to each other 2.Multiple Choice page 233 1 A Nonvolatile storage 2 A Reading 3 D Access time 4 E All of the above 5 * None of these – DENSITY – see page 213 6 B Open 7 C C (drive) 8 B Fixed disk 9 D DVD-ROM 1 0 C Magnetic tape CE06_IM08-10 Computing Essentials 2006 Chapter 8 Secondary Storage 3.Matching page 234 TERM MATCH NUMBER HINT RAM Q 1 A type of storage that is volatile writing T 2 The process of saving a file to a secondary storage device access speed A 3 Time required to retrieve data and programs floppy disk I 4 Also known as a diskette or disk track S 5 Closed concentric ring on a disk on which data is recorded sector N 6 Wedge-shaped section of a track floppy disk cartridge J 7 Zip disks, SuperDisks, HiFD disks cylinder C 8 Runs through each track of a stack of platters hard disk pack K 9 Several platters aligned one above the other, allowing greater storage capacity disk caching D 10 Hardware and software that anticipates data needs file compression F 11 Increases storage capacity by reducing the amount of space required to store data and programs jewel box M 12 Used to protect optical disks CD burner B 13 CD-R drive Picture CD P 14 Special CD format for storing digital pictures solid-state storage R 15 Stores data electronically and has no moving parts flash memory card H 16 Solid state storage device used in portable computers i-drive O 17 Free or low cost storage available at special service web sites disks E 18 Provide fast direct access tapes L 19 Provide slower sequential access fixed disk G 20 Also known as internal hard drive 4.Open-ended a)Describe the three most likely successors to the 1.44 MB 3 1/2 inch floppy.  May want to look at the three types of High Capacity Floppy disks: Zip Disks, HiFD disks, and SuperDisks  May want to argue for optical disks: CD or DVD since they are becoming cheaper  May also argue for portable solid state storage such as “key chain hard drives” b)What are the three types of hard disks? What is so disastrous about a head crash?  Three types include internal hard drives, hard-disk cartridges, and hard-disk packs (may also want to mention external hard drives and RAID systems)  A head crash occurs when a read/write head touches the disk surface, which can ruin a hard drive. c)Describe three ways to improve hard disk performance.  Disk caching: reading a portion of the disk into RAM to improve response time CE06_IM08-11 Computing Essentials 2006 Chapter 8 Secondary Storage  RAID: striping data across drives to provide backup and faster access times  File compression: reduce the amount of space used up for data storage – can also help reduce file transfer time d)What are the two most common optical disk formats? Describe the basic types for each format.  CD and DVD formats  CD-ROM: written by manufacturer, read many  CD-R: write once, read many  CD-RW: write many, read many  Photo CD: specialized image storage medium  DVD-ROM: video format  DVD-R, DVD+R: write once, read many  DVD-RW, DVD+RW, and DVD-RAM: rewritable e)Explain the concept of Internet storage. What are the advantages and disadvantages of this type of storage?  An i-drive is a web accessible hard drive  Advantage is it’s always available so long as you have an Internet connection  Disadvantage is they are slow (limited by the Internet connection) and security may be suspect M.Using Technology page 235 1.Music from the Internet  This section refers you to Making IT Work: Music from the Internet  Have students discuss the advantages and disadvantages of a music website such as Apple’s iTunes site (note: look into cost and copying issues) 2.iPod  Have students review the text’s Web site section about Apple’s iPod music player.  Use it as a review of storage media (iPod uses a portable hard drive for storage)  May want to discuss what the “target market” is for a product such as this. CE06_IM08-12 Computing Essentials 2006 Chapter 8 Secondary Storage  Access speeds are measured in milliseconds (ms) e.g. 10 ms  Disk rotation speeds are measured in RPM (rotations per minute) e.g. 5,400 RPM b)Hard-Disk Cartridges  Also known as removable hard disks  Limited only by the number of cartridges you use  Cartridges typically hold 10-40 GB of storage  See Iomega’s older Peerless system or the Rev system  PC Card Hard disks are credit card sized hard-disk cartridges  Examples include IBM’s Microdrive and Toshiba’s MK5002 drives which hold around 5 GB and are typically used on laptops c)Hard-Disk Packs  Hard disk packs are removable storage devices used to store massive amounts of information without duplicating the drive mechanism.  They may have up to 11 large disks with 20 recording surfaces.  Typical use is in large mainframe shops like banks and insurance companies. 3.List and describe three ways to improve the performance of hard disks.  Disk Caching: frequently used data is read into memory chips, which improves the transfer rate to the CPU by up to 30%.  Redundant Array of Inexpensive Disks (RAID): improves performance by expanding external storage, improving access speed, and providing backup. While it costs more to have a RAID system, it improves storage reliability. RAID systems are typically used for network servers.  File Compression and File Decompression: increase the amount of storage available on the disks by removing repeating patterns of data. Popular programs for compressing files include WinZip and PKZip. The smaller size comes at a price, since it takes a little longer to uncompress the data C.Ch 8 page 220 1.How is data represented on optical disks?  Data is “burned” onto the medium using light (a laser).  The flat spots are called “lands” and the bumpy parts are called “pits” representing 0s and 1s respectively. CE06_IM08-15 Computing Essentials 2006 Chapter 8 Secondary Storage 2.Compare CD and DVD formats. Why are DVDs replacing CDs?  CDs typically hold up to 650 MB, while DVD formats can hold close to 17 GB (almost 30 x more than CDs).  CD formats are older and more established, but they are slowly being replaced by DVD formats  DVDs are replacing CDs because of their higher capacity and the cost of the technology has fallen. As users demand more and more data capacity for applications such as video, they will need higher capacity storage media. 3.What are DVD-RW, DVD+RW and DVD-RAM?  They are different formats for the DVD format – they differ in terms of how they can be written/rewritten. Once the standards shake out in the marketplace, many drives will need to support a number of these standards. D.Ch 8 page 225 1.What is solid-state storage? What are key chain hard drives?  Solid-state storage is electronic storage with “no moving parts” – the data is stored on silicon chips.  Examples include flash memory cards and key chain hard drives  Flash memory is solid-state memory often used for storing digital images from digital cameras.  Key chain hard drives are small storage devices that connect with a computer through a USB port. They can hold close to 1 GB of data, and offer a portable way to store data. 2.What are Internet hard drives? What are they used for?  Internet hard drives (aka i-drives) are regular hard drives that can be accessed via an Internet connection.  They are often used for portable storage – so long as you have an Internet connection, you can access the drive.  The drawbacks include the speed (limited by the speed of your connection) and privacy/security (do you feel safe with your data stored on someone else’s computer). 3.Discuss magnetic tape reels and tape cartridges.  Tape storage offers only sequential storage.  Tape reels were an older technology dating from the 1950s used to store large amounts of data for mainframe computers CE06_IM08-16 Computing Essentials 2006 Chapter 8 Secondary Storage  Tape cartridges have replaced many of the reel systems, and are used for backing up servers. III.List of Figures at a glance • Ch 8 page 212 figure 8-1 Secondary storage media o Photo of an optical disk being inserted into a computer o Media is the actual physical material that holds the data • Ch 8 page 213 figure 8-2 How charges on a disk store the number 3 o Drawing of how the decimal number 3 is stored as a series of bits on a floppy disk o This number is shown with the ASCII equivalent for the number 3. The first 4 bits indicate it is a number, the second 4 bits indicate the value 0011 = 0*8 + 0*4 + 1*2 + 1*1 • Ch 8 page 213 figure 8-3 A 1.44 MB 3 ½ inch floppy disk o Photo of the traditional floppy that was the standard for portable storage for close to 20 years • Ch 8 page 213 figure 8-4 The parts of a 3 ½ inch floppy disk o Cut away image of a traditional floppy disk showing  Metal shutter: opens to permit access to the media, closes to protect it  Data access area: small open “window” to allow the drives R/W heads to access the media  Hard plastic jacket: outside covering of diskette  Label: allows user to write notes about contents of the disk  Write protection notch: when open it prevents writing to the diskette  Inside of disk: diagram of tracks and sectors used to store data on the disk • Ch 8 page 214 figure 8-5 Zip disk and drive o Photo of an Iomega zip disk & drive, a higher capacity drive that can store anywhere from 100 – 750 MB on a diskette • Ch 8 page 214 On the Web Explorations o Encourages students to learn more about leaders in high capacity disk storage systems by visiting the text’s CD and/or Web site. • Ch 8 page 214 figure 8-6 Typical floppy disk capacities o Table listing some storage capacities of diskette media  2HD – 1.44 MB  Zip – 100/250/750 MB  HiFD – 200/720 MB  SuperDisk – 120/240 MB • Ch 8 page 214 TIPS box – rules for handling diskettes o Don’t bend o Don’t touch CE06_IM08-17