CU: Portable Storage Device FAQ

Before you start…

Several different types of portable storage devices are avaliable, and each can best be used in various situations. This help page will explain the advantages/disadvantages of each device so that you can decide which is right for you.

CD-R Disc

Definition:

A CD-R (Compact Disc-Recordable) is mainly used to store data or music.

Storage Amount:

Currently, 74 minute/650 MB, 80 minute/700 MB (12 cm), and 21 minute/185 MB (8 cm) discs are the market standards.

How Does It Work?

Once the CD-R disc is placed within the computer, the laser heats and the dye reveals the areas to diffuse light just as a regular CD would. The CD-R drive does not actually create pits on the CD; instead, the burner creates reflective sections on the CD causing the computer's CD-ROM laser to interpret it as a pit.

Permanent or Reusable?

Because of the method of creating a CD-R, CD-R drives are only capable of recording to the CD once. However, you can buy multiple sessions CD-R discs, which allow you to continue to burn data to the disc until it is completely full. To use multiple sessions CD-R discs, you must have a XA-compliant or XA-ready CD-ROM drive to read all the sessions on a CD-R disc.

Recommended Use

If you are permanently archiving data, you can usually use a CD-R successfully between two machines (for example, save data using one and read it on the other), so a CD-R has proven to be a reliable portable storage device. It is also recommended for routine backups because of its stability and lower cost.

Vulnerability?

In order to keep CD-Rs working for as long as possible, they should be stored upright in cool dark conditions with little humidity. Labels should be avoided as well as inserts (unless they use water-based ink). CD-R's may be readable for up to or over 1000 times.

Other Considerations:

The "write-once" nature of CD-Rs also ensures that data cannot be accidentally modified or tampered with and is good for use in archiving. CD-Rs are more economical than CD-RW discs. For more information on CD-Rs, view this Understanding CD-R and CD-RW PDF.

CD-RW Disc

Definition:

The CD-RW (Compact Disc-ReWritable) is an erasable/rewritable version of a CD-R disc.

Storage Amount:

Currently, 74 minute/650 MB, 80 minute/700 MB (12 cm), and 21 minute/185 MB (8 cm) discs are the market standards.

How Does It Work?

Click here for a detailed evaluation of how a CD-RW works.

Permanent or Reusable?

A CD-RW can be written to multiple times (reusable); however; it is only guaranteed 1,000 uses.

Recommended Use:

A CD-RW disc is best suited for use on one machine only. There have been unfortunate instances of fac/staff burning a CD-RW on one machine and discovering that it cannot be "read" on a different machine. Therefore, a CD-RW should be considered a "non-portable" storage device.

Vulnerability?

In order to keep CD-RWs working for as long as possible, they should be stored upright in cool dark conditions with little humidity. Labels should be avoided as well as inserts (unless they use water-based ink).

Other Considerations:

CD-RWs are more expensive than CD-Rs. However, CD-RW disc manufacturers claim longer durability and better data safety of CD-RW discs. For more information on CD-RWs, view this Understanding CD-R and CD-RW PDF.

USB Flash Drive

Definition:

Also known as a key drive, pen drive, thumb drive, and stick drive, a flash drive is a small removable data storage device that uses flash memory and a USB connector. Flash drives typically consist of a small plastic package (around 30 to 40 mm long). One end is fitted to a USB connector. Many flash drives also feature an LED activity indicator.

Storage Amount:

USB flash drives are currently available with up to 4 GB storage capacity and are available in a variety of storage sizes for different needs. A 2 GB USB flash drive can hold about 250 songs in MP3 format.

How Does It Work?

Flash drives are plugged into a normal USB socket on a computer. They take their power from the USB connection of the PC and do not need batteries.

Permanent or Reusable?

Reusable, stable, simple to use (no formatting or extra setup needed).

Recommended Use:

A flash drive is recommended for those who want to save and resave data repeatedly as well as have the portability of using it on multiple systems and carrying something lightweight. It is also recommended for those who carry data between home and school or work.

Click this link for some examples and pricing: Office Depot.

Vulnerability?

Flash drives are impervious to the scratches and dust that have plagued previous forms of portable storage media like cds and floppy disks. Most are lightweight and small - about the size of a key or a thumb, so there is a greater possibility for losing the actual flash drive (another good reason to back up your data!).

Other Considerations:

In ideal conditions, the flash memory in the drives can retain data for 10 years. However, like all flash memory devices, flash drives can sustain only a limited number of write/erase cycles before failure. In normal use, mid-range flash drives currently on the market will support several million cycles, although write operations will gradually slow as the device ages. Some flash drives have a physical "write protect" switch, so they may be plugged with impunity into a system that might harbor a virus or worm (when set to write protected). For more information, view this USB Flash Drive FAQ PDF.

External Hard Drive

Definition:

An external hard drive is a hard drive that sits outside the main computer tower in its own enclosure and acts as a back up hard drive.

Storage Amount:

External hard drives come in various sizes and some are more portable than others. The smaller external hard drives range in capacity from 40-60 GB(GIGS), and the larger ones range from 100-300 GB.

How Does It Work?

The external hard drive’s portable encasement allows the user to store information on a hard drive that is not inside the computer but instead rests on a tabletop or surface nearby the computer that is connected to the computer via a high-speed interface cable. The interface cable allows the external hard drive to communicate with the computer so that data may be passed back and forth.

Permanent or Reusable?

Reusable. You can update or delete data as you wish.

Recommended Use:

External hard drives are especially recommended If you have a large amount of data that would be detrimental to lose. An external hard drive allows you to back up or store important information separate from the main internal hard drive, which could become corrupted. You can keep sensitive documents, large music files, DVD images, movies, disk images, and even a backup of the contents of your main internal hard drive safely on an external hard drive.

Vulnerability?

As external hard drives retain the platters and moving heads of traditional hard drives, they are much less tolerant of physical shocks than flash-based technology.

Other Considerations:

An advantage of an external hard drive is that it is portable and operates on a plug-and-play basis. Any computer with USB or Firewire capability will recognize the external hard drive as a storage device and assign it a letter to designate it. The drive can then be accessed like a normal internal hard drive. You can transfer huge files back and forth from work to home, to a friend's house, or between your desktop and laptop.

DVD-R/-RW & DVD+R/+RW Discs

Definition:

DVD+R and DVD-R are DVD formats that only allow you to write content to the disc one time. These formats are considered DVD-ROM because they cannot be edited after they have been written. DVD+R is a modern, similar version of DVD-R. The +R means the disc utilizes digital recording. There are no physical differences between the two. However, DVD-R is approved by the group DVD Forum while DVD+R is not. For more information on specific differences, please see About.com’s article DVD+R versus DVD-R: The Functional Differences.

DVD+R/+RW and DVD-R/-RW are all considered video DVD formats because they can be used to store video and other content.

Storage Amount:

Currently, single-sided/single-layered DVDs hold 4.7 GB of data. More space is available for dual-sided and dual-layered DVDs (up to 17.1 GB).

How Does It Work?

Click here for a detailed description of how a DVD works.

Permanent or Reusable?

Both DVD+R and DVD-R formats can only be written to once (permanent). Other DVD formats such as DVD+RW and DVD-RW can be erased and re-recorded multiple times.

Recommended Use:

A DVD+R format offers more functionality if you are looking to create your own movies and audio. However, the DVD-R format is officially approved by the DVD Forum. Either disc is a good option for storing or transferring large amounts of information between computers. If you are looking for a DVD that will function like a flash drive (constantly adding and deleting content on the disc) than you must use a -RW/+RW format.

Vulnerability?

All DVD discs should be stored in a cool, moderately dry environment. DVDs are also susceptible to scratches and smudges. Because of the thin laser that is used to read a DVD, scratches, dirt, and smudges can prevent the disc from playing properly.

Other Considerations:

DVD+R and DVD-R discs are similar in price. Although many of the changes are not noticeable to the user, many consider DVD+R technology to be more reliable.

DVD-A Discs

Definition:

DVD-A (short for DVD-Audio) is a DVD format meant to transfer high quality music content instead of videos. The DVD-A does not have a strong presense in today’s consumer market.

Storage Amount:

Currently, DVD-A discs hold up to 8.5 GB of data if it is dual-layered and 4.7 GB if it is single-layered.

How Does It Work?

Click here for more information on how a DVD-A works and what it is.

Permanent or Reusable?

DVD-A is a permanent format that can only be written once.

Recommended Use:

It is not recommended that you use DVD-A discs for everyday storage use. However, if you need a method to store high-quality music, DVD-A can be preferred over a CD because it can store more music and store content at a higher audio quality.

Vulnerability?

All DVD discs should be stored in a cool, moderately dry environment. DVDs are also susceptible to scratches and smudges. Because of the thin laser that is used to read a DVD, scratches, dirt, and smudges can prevent the disc from playing properly.

 

Return to the File Storage help page.

Excerpted from:

http://www.lakeland.cc.il.us/online/tutorials/flashdrive/print/flashdrive.pdf

http://en.wikipedia.org/wiki/USB_flash_drive

http://www.computerhope.com/help/cdrw.htm

http://www.computerhope.com/help/cdr.htm

http://www.pcmag.com/article2/0,2817,1912905,00.asp

http://www.osta.org/technology/cdqa7.htm

http://www.bccc.edu/887901125141019/lib/887901125141019/Microsoft_Word_-_USB_flash_drive.pdf

http://netforbeginners.about.com/cs/multimedia/a/DVD_explained_2.htm

http://en.wikipedia.org/wiki/DVD

http://www.pcdoctor-guide.com/wordpress/?page_id=247

http://en.wikipedia.org/wiki/DVD-Audio

http://www.pctechguide.com/dvd/dvd-audio

Keywords: store files

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