Computer Services - Help Pages
Portable Storage Device FAQs
Many of you have asked about the differences between portable storage devices and the advisability of using one product over another. Today, I'll try to shed some light on the advantages/disadvantages of each device.
CD-R DISC
Definition:
A CD-R (Compact Disc-Recordable) is a thin disc that is mainly used to store data or music.
Storage Amount:
A standard CD-R has a storage capacity of 600MB - 650MB.
How Does It Work?
A specially designed type of drive, called a CD-R drive, CD burner, CD writer, or a Combo drive (CD/DVD writer) can be used to write CD-Rs. A laser is used to burn small pits into the dye so that the disc can later be read by the laser in a CD-ROM drive or CD player.
Permanent or Reusable?
Once a section of a CD-R is written, it cannot be erased or rewritten because of the irreversibility of the use of the burning of the information into the dye. A CD-R can be recorded in multiple sessions, however; as the data is stored sequentially.
Recommended Use:
If you are permanently archiving data you can usually use a CD-R successfully between 2 machines (save data using one and read it on the other, etc.), so a CD-R has proven to be 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).
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.
CD-RW DISC
Definition
The CD-RW (Compact Disc-ReWritable), is an erasable/rewritable version of a CD-R disc.
Storage Amount
A CD-RW drive can write about 700MB of data to CD-RW media.
How Does It Work?
Unlike a CD-R, A CD-RW disc can be completely erased. Other than that feature, CD-RWs act very much like CD-Rs.
Permanent or Reusable?
A CD-RW can be written to multiple times (reusable), however; it will eventually wear out and need to be replaced.
Recommended Use
A CD-R/W 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?
(same as CD-R.)
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.
FLOPPY DISK
Definition
A soft magnetic disk. It is called a floppy because historically it flopped if you waved it (at least, the 5¼-inch variety did). The 3½-inch disk is made of two pieces of rigid plastic, with the magnetic field in the middle.
Storage Amount
3½-inch floppies have a storage capacity ranging from 400K to 1.4MB of data. The most common sizes for PCs are 720K (double-density) and 1.44MB (high-density).
How Does It Work?
When the disk is inserted, a part inside the floppy drive moves the metal cover aside, giving the drive's read/write heads the necessary access to the magnetic recording surface.
Permanent or Reusable?
Reusable, but subject to failure over time and repeated usage.
Recommended Use
None. Just Say No .... to floppies! There are now more stable portable storage devices (CDs or see flash drive below).
Vulnerability?
One of the chief problems of the floppy disk is its vulnerability. Even inside a closed plastic housing, the disk medium is still highly sensitive to dust, condensation, and temperature extremes. As with any magnetic storage, it is also vulnerable to magnetic fields. Blank floppies have usually been distributed with an extensive set of warnings, cautioning the user not to expose it to conditions which can endanger it.
Other Considerations
Cheap price. Costly if it fails. Imperative that you keep another copy of your data!
FLASH DRIVE
Definition
A small removable data storage device that uses flash memory and a USB connector. Such a device is also known under several other names: key drive, pen drive, thumb drive, stick drive. 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
Flash drive capacity ranges from a few megabytes in size up to a few gigabytes, although some computers have trouble reading and writing to devices that have more than 2 GB of storage.
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
If you just want to be able to save and resave data repeatedly and have the portability of using it on multiple systems, the flash drive is the recommended portable storage device. They are popular with people who carry data between home and school or work and are quickly replacing the floppy disk as a portable data device. They come in varying sizes. Here are 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 compact discs and floppy disks. Most are lightweight and small - about the size of a key or a thumb, so some find there is a greater possibility for losing the actual flash drive (another very good reason to keep 2 copies of 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).
Excerpted from:
http://en.wikipedia.org/wiki/CD-R
http://en.wikipedia.org/wiki/CD-RW
http://en.wikipedia.org/wiki/Floppy_disk
http://www.webopedia.com/TERM/f/floppy_disk.html
http://en.wikipedia.org/wiki/Flash_drive