Optical Media

In this video from ITFreeTraining, I will look at optical media. Optical discs have been around since the 70’s and gained a lot of market share in the 90’s. However, with the increasing use of online storage and storage such as flash memory, there has been a decline, but it is still something that you will come across from time to time.

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For the CompTIA exam, you most likely won’t get asked any difficult questions on optical media, if you get a question at all. So, I would not worry about memorizing the information in this video, just have a bit of an understanding. At the end of the video, I will cover what you need to know to support optical media in the real world.

Say ROM as Rom

The first optical media to take off in the marketplace was Compact Disc or CD. These were originally designed to store audio for music for use in CD players. Computers needed the ability to store data on a compact disc, so the standard was expanded to include data and was called CD-ROM.

These optical discs could store 650 Megabytes, which back then was a lot of data. For this reason, optical disc was widely used to distribute and backup data.

Optical discs have been around since the 70’s but did not get market acceptance. The other big optical disc standard attempting to gain market share was the laser disc. Although there were different sizes, the larger size was about the size of a vinyl record. They were designed with video in mind and stored about 60 minutes of video on each side, thus a total of about 120 minutes. This was enough space for some, but not all movies.

Although laser discs were popular for a little while in some countries, the technology quickly died out. It is unlikely that you will come across it nowadays. The big problem with CD-ROMs was they needed to store a lot more data in order to store decent quality video.

The original DVDs were able to store 4.7GB using a single side and single layer. By using both sides of the disc the amount of storage was able to be doubled. Also, using dual layer the storage was again able to be doubled. Dual layer is when the DVD is manufactured with a second layer that can be accessed by refocusing the laser to access the second layer. The problem with this is, tracking of the second layer takes a little bit of time and thus there may be a small pause during playback. Since this only happens when changing layers, it is usually not that noticeable.

You can see that a DVD could potentially hold 17GB of data which would be enough for high-definition video; however, doing this required both sides of the DVD to be used. Using both sides means that you can’t use one side to print information about what the DVD has on it and also the DVD is more prone to damage. For this reason, a new standard was required for high-definition video.

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References
“The Official CompTIA A+ Core Study Guide (Exam 220-1001)” Chapter 6 Paragraph 199-221
“CompTIA A+ Certification exam guide. Tenth edition” Pages 429 – 435
“Picture: Optical discs” https://pixabay.com/photos/background...
“Picture: CD ROM” https://en.wikipedia.org/wiki/CD-ROM#...
“Picture: Laser Disc” https://commons.wikimedia.org/wiki/Fi...
”Picture: DVD logo” https://upload.wikimedia.org/wikipedi...
“Picture: Video Camera” https://unsplash.com/photos/SpDOwp6PnBs
“Picture: DVD disc” https://en.wikipedia.org/wiki/DVD#/me...
“Picture: Blu-ray logo” https://en.wikipedia.org/wiki/Blu-ray...
“Picture: Blue-ray disc” https://en.wikipedia.org/wiki/Blu-ray...
“Picture: HD DVD logo” https://upload.wikimedia.org/wikipedi...
“Picture: Blue electronic” https://unsplash.com/photos/HdLYxUirwfI
“Picture: Ultra HD Blu-ray” https://en.wikipedia.org/wiki/Ultra_H...
“Picture: Laser lights” https://pixabay.com/photos/green-lase...
“Picture:
Archival Disc” https://en.wikipedia.org/wiki/Archiva...
“Picture: Archival” https://pixabay.com/photos/archive-fi...
“Picture: Stack optical CD’s” https://pixabay.com/photos/blank-cd-r...

Credits
Trainer: Austin Mason http://ITFreeTraining.com
Voice Talent: HP Lewis http://hplewis.com
Quality Assurance: Brett Batson http://www.pbb-proofreading.uk