curriculum.naf.orgcurriculum.naf.org/packaged/assets/downloads... · Web viewThe technologies and devices listed on this slide are currently popular. For permanent data storage,

AOIT Computer Systems

Lesson 13Storage Technologies and Devices

Student Resources

Resource Description

Student Resource 13.1 Note Taking: Storage Technologies and Devices

Student Resource 13.2 Reading: Storage Technologies and Devices

Student Resource 13.3 K-W-L Chart: Connecting Storage Drives to Computers

Student Resource 13.4 Reading: Standard Interfaces for Storage Devices

Student Resource 13.5 Interactive Reading: Optical Storage

Student Resource 13.6 Worksheet: CD Scratch Test

Student Resource 13.7 Venn Diagram: Storage Technologies

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AOIT Computer SystemsLesson 13 Storage Technologies and Devices

Student Resource 13.1

Note Taking: Storage Technologies and DevicesStudent Name:_________________________________________________ Date:_________________

Directions: Use this table to take notes on the presentation about storage technology. You will use your notes later to complete a chart that compares and contrasts storage technologies.

Basic Technology for Storing Data

Main Advantages Main Use

Hard drive

Tape drive

SSD

Flash card

Thumb drive

CD, DVD, Blu-ray




Reading: Storage Technologies and Devices

This presentation examines the storage technologies and devices in common use.



Storage technologies and types of devices change rapidly. The technologies and devices listed on this slide are currently popular.

For permanent data storage, computers use devices that can be internal or external. Many types of internal storage devices are available, including hard drives, tape drives, optical disc drives (for DVDs and Blu-ray), and solid-state drives based on flash technology. Each type serves a particular data storage need.



Hard drives are the primary data storage component in notebooks, desktops, servers, and dedicated storage systems. They use sophisticated magnetic recording and playback technologies.

In addition to hard drives, many corporations and small businesses also use tape drives to store the company’s historical data.

A hard drive and a tape drive share certain similarities. They both record onto a magnetic medium and use the same magnetic recording techniques. A major benefit of magnetic storage is that the magnetic medium can be erased and rewritten easily. It is easy to store tape cartridges off-site for safekeeping.

Tape drives were once far more commonly used. But today the drives cost far more than the average home user needs to spend for backup storage. Nowadays you’ll only find tape in larger business environments, while most personal users rely on external hard drives and optical drives.



A hard drive is a sealed box with a circuit board on one side. The board controls the read/write mechanism and the motor that spins one or more flat circular disks called platters, onto which data is recorded. A hard drive reads from and writes to rapidly rotating platters with magnetic surfaces.

Hard drives record data by magnetizing the ferromagnetic material on the platters to represent a binary digit of 0 or 1. They read the data back by turning the magnetization of the material back into 1s and 0s.

Usually installed in a drive bay inside the system unit and nonremovable, the hard drive is the most important type of permanent storage in a PC. A hard drive is a nonvolatile device that stores digitally encoded data. It holds the operating system, applications, and user and system files.

In a hard drive, data is stored on a disk in named collections of bytes called files. When a program running on a computer requests a file, the hard drive retrieves the information and sends the bytes of data to memory.

Early magnetic drives used floppy disks, which were removable. But floppy disks have such a small storage capacity that they are no longer used. Today’s magnetic drives are hard disk drives in which the magnetic storage media are permanently installed inside the device.



Most commercial hard drives have a maximum of four platters. The mirror-smooth platters are usually made of aluminum alloy or glass and are coated with a thin layer of magnetic material such as a cobalt-based alloy.

The platters typically spin at 7,200 revolutions per minute in a laptop; in a desktop, hard drive speeds can reach 15,000 rpm. As the platters spin, small read/write heads float above and below each platter, operating very close to the magnetic surface without touching it. Each read/write head detects and modifies the magnetization of the material immediately under it, reading data from and writing data to the given surface.

There is one head for each magnetic platter surface on the spindle. The read/write heads are mounted onto an actuator arm that holds the heads in position over the platters. The arm moves the heads in an arc from the hub to the edge of the platters as they spin.

A voice coil actuator moves the arm, typically from hub to edge and back, up to 50 times per second. Most hard drives have multiple platters and read/write heads to increase the amount of information the drive can store.



SAS and SATA are the standards used in most of today’s hard drives. SAS is an evolution of parallel SCSI that uses a serial point-to-point design. This design provides a dedicated signal path for each device to ensure maximum bandwidth. Like SAS, SATA uses a serial point-to-point design and has a maximum bandwidth of 6.0 gigabits per second (Gbps). Transfer rates for SAS and SATA range up to 750 megabits per second (Mbps).

Your school may still have older computers that use a wide ribbon cable attachment to the hard drive. These computers use a PATA (parallel ATA) interface.



Operating systems include utilities that help you keep a computer performing well. Some utilities scan the hard drive to locate and fix any bad sectors, damaged files, and other problems. In some OSs this is called error-checking (or chkdsk); on older versions of Windows, it is called scandisk.

To run error-checking on a Windows system:

1. Double-click My Computer (or click Start > Computer).

2. Right-click the hard drive you want to check, and select Properties.

3. Click the Tools tab, and then click Check Now to check the drive for errors. The utility will run the next time the computer is booted.

Over time, as files are saved to disk, the blocks that make up the files are further and further distributed across the surfaces of the hard disk platters. For instance, if you save a Word document and then save it again 20 minutes later, the newest blocks will almost certainly be stored in other locations than the original set of blocks. The more scattered a file’s blocks become, the less efficient it is to read the full file.

Defragmenting a drive puts the file segments back in sequential order, which optimizes the time it takes to read and write files to and from the disk. Windows has a disk defragmenter (often called defrag) that rearranges files to occupy sequential sectors on the drive. Optimization makes fragmented files contiguous and moves them to the outside of the disk. This can result in increased access speed and sometimes increases the amount of usable space on the drive. This program runs automatically on Windows 7, 8, and 10, but you can also run the program manually from the same Tools tab that you use to run the error-checking utility.



The driver software is installed the first time the device is connected to the computer, and then the operating system sees the drive automatically via plug-and-play.

An external drive is an ideal solution for backing up your hard drive. Special software built into Vista and Windows 7 and 8 allows you to save an image of your entire hard drive or selected files and directories. Third-party software can provide the same function with additional features.

External hard disk drives that can store 1TB or more are available for under $100.

Image retrieved from http://en.wikipedia.org/wiki/File:External_hard_drives.jpg on June 19, 2012, and reproduced here under the terms of the Creative Commons Attribution-Share Alike 3.0 Unported license (http:// creativecommons.org/licenses/by-sa/3.0/deed.en ). Image courtesy of TonyTheTiger.


http://creativecommons.org/licenses/by-sa/3.0/deed.en


http://en.wikipedia.org/wiki/File:External_hard_drives.jpg


The biggest difference between tape and hard drives is that with tape, you have to fast-forward or rewind through a length of tape to get to a particular point. This is called sequential access. With a long tape, this can take several minutes. On a hard drive, you can find the data you want in far less than a second.

The reason for this difference is that the tape heads are stationary. A tape drive must pull the tape between the reels to read a piece of data. In a cassette tape deck, the read/write head touches the tape directly. The tape in a cassette moves over the read/write head at a rate of about two inches per second.

Despite their slow seek time, tape drives have a fast data transfer rate. In fact, modern Ultrium tape drives can reach data transfer rates that are almost as fast as the fastest hard drives.

A tape drive connects to a computer using SCSI, SAS, IDE, USB, FireWire, and other interfaces. Fibre Channel, which is a high-speed technology used primarily for storage networking, is also used, mostly with extremely high-end computers.

Because tape media is generally a cost-effective way to achieve long archival stability, tape drives are often used in large enterprise environments. Autoloaders and tape libraries automate the process of loading, unloading, and storing multiple tapes, increasing ease of use and archive capacity. However, the cost of the tape drives themselves usually precludes tape from being used in a home or school environment.



Data rates between 5 and 40 Mbps are common for disks. Most tape drives can equal and greatly exceed these rates.

Seek times between 4 and 8 milliseconds are common for disks. Seek times are typically faster for disk drives than for tape drives. To read or write data to a certain place on the disk, the read/write head must physically move to that place. This process is known as seeking. Seek time varies depending on how far the destination is from the origin at the time of each read or write instruction.

For tape, as noted, sequential access means that you have to fast-forward or rewind the tape from its current position to the location you need to access. The seek time could take minutes, depending on the length of the tape and the location you are trying to reach.

Storage capacity of magnetic tape cartridges varies greatly, but recent tape cartridges can store over 100TB apiece.



The two types of magnetic storage devices, hard drives and tape drives, have advantages and disadvantages. But both types of devices work well to serve the purpose for which they were designed.

• A hard drive is used to store data that needs to be accessed quickly.

• A tape drive is used for long-term archival storage of data that is not accessed frequently.

• Tapes are easily removable and can be stored off-site.



A solid-state drive (also called solid-state disk or electronic disk) is a data storage device that uses integrated circuit assemblies as memory to store data persistently. SSDs do not use any moving mechanical components. This is what distinguishes them from magnetic disks like hard drives, which are electromechanical devices with spinning disks and movable read/write heads. Flash also supports random access just like DRAM; disk and tape do not.

SSDs are typically less susceptible to physical shock, are silent, and have lower access time and latency (that is, SSDs are faster). However, they are much more expensive per byte, and very large capacity drives (greater than 500GB) are not yet widely available.



An SSD does much the same job as a hard drive (storing your data while the system is off, booting your system, etc.). But on the outside, an SSD is noticeably smaller than a traditional hard drive. It uses the SATA interface so that it can easily be placed into any PC as a hard drive would. It is placed in a hard drive slot and then wired to the motherboard via a SATA cable.

A “best of both worlds” hybrid disk drive (SSHD) that combines both a magnetic disk drive and an SSD in one package is also available. Programs that are used often for tasks such as booting the computer can be placed in the flash memory, while files that are needed less frequently are stored on the mechanical drive. Windows 7 and newer OSs provide software support for hybrid drives.

Because of their lower power consumption, SSDs are replacing hard drives in new laptop computers. However, SSDs have a relatively small capacity, so when they are installed in a desktop, they are almost always accompanied by a much larger HDD as a secondary drive.

Image retrieved from http://commons.wikimedia.org/wiki/File:Disassembled_HDD_and_SSD.JPG on January 28, 2013, and reproduced here under the terms of the Creative Commons Attribution-ShareAlike 2.5 Generic license (http://creativecommons.org/licenses/by-sa/2.5/deed.en). Image courtesy Rochellesinger.



http://commons.wikimedia.org/wiki/File:Disassembled_HDD_and_SSD.JPG


Solid-state drives have several advantages over magnetic hard drives. Most of these advantages stem from the fact that an SSD does not have any moving parts. While a traditional drive has drive motors to spin up the magnetic platters and move the drive heads, all the storage on a solid-state drive is handled by flash memory chips. This provides two distinct advantages:

• Less power usage

• Faster data access

In terms of reliability, it is true that hard drives can suffer mechanical failure, but SSDs have been known to suffer controller failure, and complaints that they slow down over time are common. Flash is also susceptible to errors when adjacent locations are accessed. Error correction is built into flash devices but is not typically required in magnetic devices.



Solid-state drives and USB flash drives use the same type of nonvolatile memory chips that retain their information even when they have no power. The difference is in the form factor and capacity of the drives. While a flash drive is designed to be external to the computer system, an SSD is designed to reside inside the computer in place of a more traditional hard drive.



All optical storage systems work with reflected light to detect changes in light intensity. Digital video disc (DVD), compact disc (CD), and Blu-ray Disc (BD) technology uses lasers to record and retrieve information. Drives that use this technology are called optical drives.

A DVD, CD, or Blu-ray Disc is a thin piece of plastic with a reflective aluminum covering. Data is stored in tiny indentations (called pits) arranged in a tight spiral track that starts in the center. The flat areas between pits are known as lands. The disc is then coated with a protective polymer, with a label sitting on top.

When you play an optical disc, a read head emits a laser beam that passes through the plastic layer, reflects off the aluminum layer, and is read by a sensor that detects changes in light. Because the disc is read from its underside, the laser reads a pit as a tiny raised bump. The bumps reflect light differently from the flat lands. The lands read as a digital value of 1, and the bumps (or pits) read as 0. To write new data to a disc, the laser’s power must be increased. For this reason, optical drives that can only read discs are cheaper than those that can read and write.

Blu-ray is a high-definition format that uses blue-violet laser technology, whereas traditional CD and DVD formats use red laser technology.



Optical storage technology is potentially more reliable than magnetic storage because the distance between the read/write heads and the spinning media is greater, meaning less wear and tear on the discs. The media is also relatively inexpensive and immune from stray magnetic fields.

Newer technologies allow data to be stored on two layers instead of one, essentially doubling the capacity of the platter. Special readers and writers are needed to read this multilayered media.



It’s important to know which storage technology a storage device uses. This knowledge will help you determine which device is the best fit for a given situation.




K-W-L Chart: Connecting Storage Drives to Computers

Student Name:_______________________________________________________ Date:___________

Directions: Write down anything you already know about connecting storage drives to computers in the “What I Know” column. Then write down anything you would like to learn about this topic in the “What I Want to Know” column. Finally, as you read Student Resource 13.4, Reading: Standard Interfaces for Storage Devices, add to this chart in the “What I Learned” column.

What I Know What I Want to Know What I Learned




Reading: Standard Interfaces for Storage DevicesTo work with the rest of the system, both hard drives and solid-state drives (SSDs) are designed with a standards-based interface that allows them to communicate with the system bus. These standards determine the performance characteristics of the drive, such as bandwidth and data transfer speeds. Newer drives have integrated controllers mounted on the base of the drive that control data transfers. Because hard drives and SSDs use the same standards, an SSD can replace a hard drive and use the same interface.

The interfaces most commonly used for internal hard drives and solid-state drives (SSDs) are serial attached SCSI (SAS) or serial ATA (SATA), which are high-speed serial interfaces. The Small Computer System Interface (SCSI) is also in use.

SAS and SATAMost of today’s hard drives and SSDs use SAS or SATA high-speed serial interfaces.

SAS is an evolution of parallel SCSI that uses a serial point-to-point design, which provides a dedicated signal path for each device to ensure maximum bandwidth. SAS currently offers bandwidth of 6.0 gigabits per second (Gbps). That maximum raw bandwidth will likely increase, because advances in technology usually result in increased bandwidth for all interfaces every year or two.

SATA is an evolution of the ATA (advanced technology attachment) interface. Like SAS, SATA uses a serial point-to-point design and has a maximum bandwidth of 6.0 Gbps. Transfer rates for SAS and SATA range up to 750 Mbps.

External DrivesAn external hard drive is a removable self-contained unit that connects to the PC through a USB, FireWire, or eSATA (external SATA) port. These ports usually are located on the outside back or side panel of the computer case. Like internal drives, these portable devices have the drive mechanism and the media in one sealed case. External drives provide a simple and inexpensive way to add extra hard drive storage space.




Interactive Reading: Optical Storage Student Name:_________________________________________________ Date:_________________

Directions: This reading includes built-in comprehension questions about optical storage. First, read these questions to see what you think you know already about this topic. Then complete the reading and answer the questions.

Optical Storage Technology

Question: What types of devices use optical storage? In one sentence, how does optical storage technology work?

All optical storage systems work with reflected light to detect changes in light intensity. Compact disc (CD), digital video disc (DVD), and Blu-ray Disc (BD) technology uses lasers to record and retrieve information. Drives that use this technology are called optical drives; the discs are called optical discs.

A CD, DVD, or Blu-ray is a thin piece of plastic with a reflective aluminum covering. Data is stored in tiny indentations (called pits) arranged in a tight spiral track that starts in the center. The flat areas between pits are known as lands. The disc is then coated with a protective polymer, with a label sitting on top.

When you play an optical disc, a read head emits a laser beam that passes through the plastic layer, reflects off the aluminum layer, and is read by a sensor that detects changes in light. Because the disc is



read from its underside, the laser reads a pit as a tiny raised bump. The bumps reflect light differently from the flat lands. The lands read as a digital value of 1, and the bumps (or pits) read as 0.

Optical storage technology is potentially more reliable than magnetic storage because the distance between the read/write heads and the spinning media is greater, meaning less wear and tear on the discs. The media is also relatively inexpensive and immune from stray magnetic fields.

The biggest disadvantage of optical storage when compared to magnetic storage, however, is slower random data access. The optical heads are larger and heavier than the read/write heads in a hard drive, and the disc spins more slowly than hard drive platters.

Your answer:

CD, DVD, Blu-ray Discs and DrivesQuestion: When should you use an optical disc to store data, and when should you use a hard drive?

A CD, DVD, or Blu-ray Disc can hold a large volume of data on a small surface that is inexpensive to manufacture. For these reasons, optical media is best used for permanent archiving and long-term file storage.

Most CDs have a storage capacity of 650MB to 750MB, although some CDs can hold up to 1GB of data. Although a DVD has the same diameter as a CD, it has a typical storage capacity that is more than six times what a CD can hold. A single-sided DVD holds up to 8.5GB of data; a double-sided disc can hold 17GB. A Blu-ray Disc can hold 25GB of data on a single-sided disc and 50GB on a double-sided one. Compared with a CD, a DVD has smaller pits and a smaller track pitch of the spiral groove that guides the laser beam. A Blu-ray has smaller pits and track pitch than a DVD does. As a result, more pits can be written on the same size disc.

ROM (CD-ROM, DVD-ROM, BD-ROM) indicates that a disc is read-only, which means that once data is burned (written by lasers) onto it, it cannot be changed. A ROM drive only reads the information on the disc that is in the drive; it doesn’t write any data to the disc.

There are several other types of discs available; the type of disc also identifies the drive. The differences between them depend on the standards used by the manufacturer of the drive or the disc. Various terms describe the physical formats, which are the ways data is stored on or written to the disc.

Your answer:

CD-Recordable (CD-R)Question: What are some of the advantages and disadvantages of rewritable media?

Blank CDs that you can write to yourself have an additional layer between the plastic and metallic layers. This layer is made of a dye that can be burned by a laser that is 10 times more powerful than the laser used for reading a CD. The dye layer either absorbs or reflects the beam of light emitted by the laser.



This type of disc is called a CD-Recordable (CD-R) disc (it was formerly called a WORM, for Write Once Read Many). The organic dye compound is reflective, but during the writing process, the laser focuses on a spot and burns the dye, causing it to darken.

CD-R discs are a good solution if you share data files, because they can be read by both CD-ROM and CD-R drives.

The biggest disadvantage with CD-R discs is that you can write data to a CD-R only once. After the dye has been burned in a spot, it cannot be changed back. Other drawbacks of CD-R drives are cost and speed. Although the discs are inexpensive, the CD-R drive is more expensive than a drive that can only read discs because of the CD-R’s more powerful laser. CD-R drives are also much slower than CD-ROM drives, reading data at double speed (2X) or quad speed (4X), while CD-ROM drives read at 6X, 8X, and 10X.

DVD-R and DVD+RLike a CD-R, a DVD-Recordable (written DVD-R and pronounced “DVD minus R”) disc is a DVD recordable format. A DVD+R (pronounced “DVD plus R”) disc is a once-writable optical disc that holds 4.7GB. It is less susceptible to interference and error than DVD-R. There are other technical differences between the “minus” and the “plus” formats, although it is difficult for most users to notice a difference.

DVD recording speeds are faster than the quickest CD-R and CD-RW speeds. DVD recorders use the same writing modes as CD-R drives, including constant linear velocity (CLV) and constant angular velocity (CAV).

DVD-R Dual Layer (DL) and DVD+R DL (also called DVD-R9 and DVD+R9) discs hold 8.54GB on each side by using two individual recordable dye layers. Each layer can store almost as much as a single layer disc (4.7GB), so the total disc capacity is almost doubled (15.9GB).

DVD DL drives cost about the same as single-layer drives, but the DL media are more expensive than single-layer media. Dual-layer media recording speeds are slower (up to 16X) than single-layer media speeds (up to 20X). The discs can be read in many newer DVD devices but can be written to only with dual-layer-compatible recorders.

CD-Rewritable (CD-RW) A CD-RW disc uses a metallic alloy instead of a dye in the middle layer. When the write laser heats this alloy, it crystallizes as it cools and becomes reflective.

Unlike CD-R discs, the crystallized alloy of CD-RW media gradually decrystallizes over time. As a result, CD-RWs are not as reliable as CD-R discs for long-term storage. If you store CD-RW discs in cool, dry places, they have a life expectancy of 20 years or more, compared to more than 30 years for CD-R discs.

One benefit of a rewritable disc is that if recording errors occur, the disc is not ruined. You can still use it by erasing the data. CD-RWs are versatile but also have disadvantages. The drives and discs are more expensive than other CD-ROM drives and media, and the discs cannot be read by all CD-ROM drives.

Note that you cannot erase individual files from any optical disc. You must erase the entire disc before you can write new content to it.

DVD-RW and DVD+RWA DVD-RW disc is a rewritable optical disc with a storage capacity around 4.7GB. The recording layer in DVD-RW and DVD+RW discs is not an organic dye but a special metal alloy. The alloy can switch between two phases, changing the reflectivity depending on the power of the laser beam.

The primary advantage of DVD-RW over DVD-R is the ability to erase and rewrite data. Because of their large capacity, DVD-RW discs are commonly used for very large files, especially home DVD videos.



Most CD- and DVD-burning programs finalize the media, which occurs after files are copied to the disc. After you finalize the disc, you can play it back in another device, but you can no longer add files to it.

DVD Video Recording (DVD-VR and DVD+VR)DVD Video Recording (DVD-VR) is a DVD standard that defines a logical format for recording and editing video on a DVD disc. It enables you to produce a DVD movie that can be edited directly to the disc. You don’t need to import the video content to an application in your computer. DVD-VR formats offer several features, including the ability to add video, change menus, add chapters, and remove video segments.

Your answer:

Blu-ray Question: How is Blu-ray technology changing the way people watch movies at home?

Blu-ray is a high-definition (HD) format that uses blue-violet laser technology (traditional DVD formats use red laser technology). A Blu-ray Disc is rewritable and can transfer data at 36 Mbps. A single-sided, single-layer Blu-ray Disc holds 25GB, for 12 hours of standard video or 2 hours of HD video.

A movie in Blu-ray format displays up to 1,080 lines of resolution on an HD television, compared to 480 lines of resolution from a movie on a traditional DVD. In addition to a better picture, a Blu-ray Disc delivers better sound and additional features.

Although you don’t need an HDTV to watch Blu-ray movies, you do need a Blu-ray player. Blu-ray players are backward-compatible with traditional DVDs and can double the output resolution of DVDs.

BD-RE and BD-RW are erasable and rewritable Blu-ray media. BD-R discs can be written to only once.

Your answer:

Optical Disc Surface Basic Care Question: What should you do first to try to save a scratched CD or DVD?

It is important to keep optical discs clean and unscratched, or the disc and data can be damaged and become unreadable. Handle them with care and store them in a case to prevent problems from dust, fingerprints, and scratches.

To prevent these problems, take these precautions:

Hold the disc by the edge. Use a soft, dry cloth to remove dust and fingerprints.



Don’t paste paper on the surface of an optical disc. Don’t subject a disc to heat or leave it in direct sunlight. Don’t make the center hole larger. Don’t bend a disc.

As a general rule, you should clean an optical disc only if playback is affected. If playback becomes compromised to the point that the laser cannot read the data layer, there are steps you can take to try to make the disc readable again.

1. Use compressed air to remove dust from the surface.

2. You can also clean the information side of the disc very gently with a soft cloth such as an eyeglass cleaning cloth. Do not use tissue or a paper towel. Wipe from the center of the disc in a straight outward direction. Wiping the information surface of any type of optical disc in a circular motion around the center can scratch the surface and cause data loss.

3. Rinse the disc with water. Make sure there is no dirt or grit that will make the damage worse.

4. Remove fingerprints or dirt from the data surface by dampening a soft cloth with isopropyl alcohol and wiping from the center outward. Never use acetone, nail polish remover, gasoline, or any other type of petroleum-based solvent to clean an optical disc, or it will become unreadable.

5. If you test the disc and it still does not play, try to gently polish out the scratch. Using a soft, lint-free cloth, gently rub a small amount of a mild abrasive such as toothpaste or car rubbing compound into the scratch. Do not press hard, but work carefully to remove the scratch. Rinse the disc and allow it to dry. Check whether the scratch has been removed (not necessarily completely).

6. You also can buy a bottle of plastic scratch repair or a repair kit at most automotive parts suppliers. These products are designed for automotive headlamps but can also work on other plastic surfaces. Use a small amount on a soft, damp cloth and wipe in one direction, from the inside toward the outside edge, to buff out the scratches.

Your answer:




Worksheet: CD Scratch TestStudent Name:_________________________________________________ Date:_________________

Directions: For this activity, you will actually scratch a CD in each of the ways described in this worksheet. In the space provided under each step, guess how you think this action will affect the CD. Write one reason to explain your guess. Then use something sharp like a paper clip or pin (provided by your teacher) to scratch the CDs as described. Finally, record what happens when you try to play the CD in a computer.

Step 1: Scratch the CD on the bottom (the shiny side).

My guess:

My reason:

Test results:

Step 2: Scratch the CD on the top (the side with the label).

My guess:

My reason:

Test results:

Step 3: Scratch the shiny side straight across (the radius of the circle).

My guess:

My reason:

Test results:

Step 4: Scratch the shiny side in an arc that follows the shape of the CD.

My guess:

My reason:

Test results:




Venn Diagram: Storage TechnologiesDirections: Think about what you have learned about storage technologies. How are they different? How are they similar? Use a Venn diagram to define and describe the similarities and differences. Look at the model below to get started. The left circle is for all the flash technology-only features or traits you can think of, the right circle contains the magnetic technology features, and the bottom circle contains all of the optical storage technology features. Any traits that storage technologies share go in the overlap areas. Draw your own diagram on chart paper and fill in the circles. You can use words from your taxonomy to fill out the diagram.


Flash storage

Magnetic storage

Electromechanical

Optical storage

Shared traits

SSDs

CDs, DVDs, Blu-ray

Documents

curriculum.naf.orgcurriculum.naf.org/packaged/assets/downloads... · Web viewThe technologies and devices listed on this slide are currently popular. For permanent data storage,