Stage Three of Computers - Explain the difference between read-only, write once, and write-rewrite media. What are examples of each?

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Read-only

Read-only media is prepared at the factory and cannot be altered by the consumer. The most prevalent examples of read-only memory today are the CD-ROM.

Write-once

Write-once media is blank when purchased and is written by the consumer. Once it is written to, the data on it cannot be changed. An example of write-once media is the CDR (or CD-R).

Write-rewrite

Write-rewrite media can be written, erased, and rewritten by the end user. An example is the CD-RW. This type if media is generally more expensive than the CD or CDR. In more modern times, the flash drive has taken the place of standard "Write-rewrite media.

CD - Compact disc formats

With the rise of personal computers (PCs) and other commercial technologies, various compact disc formats branched off to store data. Sony and Philips created specifications for these CD versions -- called Rainbow Books, due to the various colors on the book bindings -- to define each product format. The Red Book outlined the specifications for a standard CD.

• CD-Read-Only Memory. In 1985, the CD-ROM entered the market and went beyond audio to record optical data storage. CD-ROMs are readable by any computer with a CD-ROM drive. The CD-ROM follows the Yellow Book standard.
• CD-interactive. Released in 1993, CD-i could be played on CD players, but not in a CD-ROM drive. The format was later modified to be read by both. The CD-i follows the Green Book standard of specifications.
• CD-ReWritable. The CD-RW used a metallic alloy that reflected differently than regular compact discs. This change in reflectivity made a CD-RW unreadable to many early CD players. The CD-RW follows the Orange Bookstandard.
• CD-Recordable. The CD-R is a compact disc that can be written to once and read many times. Like the CD-RW, it follows the Orange Book, but unlike the CD-RW, the CD-R can be read on CD players released prior to its own introduction.
• CD-ROM eXtended Architecture. The CD-ROM XA is an extension of the standard CD-ROM that allows audio, video and computer data to be accessed simultaneously. It follows the Yellow Book standard and was created as a bridge between the CD-ROM and CD-i.
• Photo CD. Designed by Kodak, the photo CD was created for the express purpose of storing photographs in a digital format that could be accessed and edited on a computer. It launched in 1992, and was originally designed to hold 100 high-quality images. It followed the Beige Book standard.
• Video CD. The video CD, or VCD, was created in 1993 and followed the White Book standard. VCD quality was intended to have comparable quality to VHS recordings, but has a much lower resolution than a modern digital video disk (DVD).

The future of compact discs

As other technologies flourish, the CD has seen a steady decline in use, particularly during the early 2010s.

Reason - Faster Media Devices or sources like the DVD, Blu-Ray, Internet, USB or Thumb Drives, or more...

DVD - Digital Video Disk

DVD, is a type of optical disc used for data storage and as a platform for multimedia. Its most prominent commercial application is for playing back recorded motion pictures and television programs (hence the designation “digital video disc”), though read-only, recordable, and even erasable and rewritable versions can be used on personal computers to store large quantities of almost any kind of data (hence “digital versatile disc”).

Blu - Ray

The name "Blu-ray" refers to the blue laser (which is actually a violet laser) used to read the disc, which allows information to be stored at a greater density than is possible with the longer-wavelength red laser used for DVDs.

Do you understand how to take precautions on using delicate storage media for you computer.

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