How data is stored in compact disks


Posted On: January 20th, 2014    To  Technology

Compact disks are means of storing digital data (or information) that can be retrieved when needed. There are numerous recording media and computers that help in facilitating data storage. Data can be represented in various classes viz. mechanical, chemical, photochemical, electrical, thermodynamic, optical, and magnetic. Whatever be the form, it is paramount for all of us to have data available by any means as it gives us – employees, customers, partners the relevant information to succeed in our individual pursuits and in order to achieve business goals. And if we can implement intelligent data management and retrieval capabilities, it results in exponential growth of a related business. This ability also empowers us to manage better with limited resources.

Improvement of Technology from ancient storage process

In olden times data was stored on barks of trees and dried leaves which then gave way to paper. Punched cards were used as one of the earliest temporary storage of data which would then be transferred on to larger computer memories. We used to and still have magnetic tapes to achieve the purpose – better known as sequential data storage. With the passage of time, we had portable data storage abilities with the availability of floppy disks. Technology improvements later brought invention of floppy disks. Later we were introduced with more sturdy rugged means of portable data storage medium in the form of compact disks.

Floppy Disk

Reproduction of Compact Disk

There are two ways of getting data reproduced in compact disks commercially. One is what we know as the replication technique and the other one is duplication. Although it is difficult to tell the difference in the end product, it certainly has pros and cons. Let us examine how each of the process works.

Compact Disk

The source data is the starting point. This media, most likely in a compact disk, needs careful scrutiny and verification to ensure there are no defects. Does it play thoroughly without a single hitch? Once assured of the quality being top notch what is the next step? The next step produces what in the industry parlance is known as a glass master. Yet again, the quality of the glass master is key to the quality of next product, any blemish here and the time and money could be wasted resulting in great financial losses. In this process of replication, it is crucial to keep a keen eye on the precision and accuracy of each and every step of the production to ensure the end product is dot on – a perfect replica of the original; a single flaw could end up jeopardizing the whole project. The quality assurance has to be the best possible. Now that we have the glass master, we produce a stumper which is then used to load the molding machine to actually produce the bunch of compact disks. The disk, after the molding gets over, is applied with a micro thin layer of aluminum. It reflects the laser from the player to the audio reproducing apparatus. The penultimate step involves putting a protective layer of lacquer followed by application of the label that describes the content of the compact disk and finally all that remains is packaging and shipping. This whole process is the Replication process. There are appropriate equipments available in the market to perform all the above tasks in an automatic, commercial and professional way to avoid defects in the end product and generating more numbers of compact disks in less time.

Commercial Duplication of Disk

What we do at home when producing one compact disk on our computers is called “burning”. Industrially and commercially this would be called “Duplication”. Commercial or industrial duplication process would involve professional and automatic machines that would perform the work of duplication using a number of towers (depending on the affordability of the facility owner) and thus produce compact disks in a higher scale at the same time.

Compared to older means, compact disks are meant to pack more. It was designed for the same purpose – it allows storage of a million bits in the space that is no bigger than the head of a pin. And one such spot is worth one second of music or whatever reproducible material on a player. This storage ability for packing more was the key game changer in the world of data management tools. There was massive research and development involved in order to build the capability of reading the so highly compressed data with a durable and affordable means; here the integrated circuit technology came to the rescue.

Use of Compact Disk

Much like the lacquer music records, a compact disk too plays in a system of groves arranged in a circular fashion on the surface. It is the job of the player to use the laser to sense the pits and lands on the surface and use the computers to convert them into sound energies to channel out through the speakers.

While the 80 minute compact disk is the standard, disks of 74, 90 and 99 minutes were also made available.

8 Comments

  1. Ray Anthony says:

    I am happy to know about the history & generation of storage devices as I don’t know all part of this history. The development of technology has brought a revolutionary change in the process of saving data. Compact Disks are very useful as well as easy to store, carry & transfer data. The devices are used commonly for saving precious data which can be retrieved at any moment.

  2. digitadmin says:

    I’m glad that you were able to learn a few things. Thanks for reading and commenting.

  3. LiamBell says:

    I feel so nice to read this. I found your information so unique and also valuable. Discs are actually secured data storage device and are relatively cheap now days. Moreover, burning the files to discs as backup has one more advantage when the data are read only. This means if you are using CD drive in any computer, no one can able to modify or delete the files that are written on the disc.

    • digitadmin says:

      Thanks Liam for your reply. CD/DVD drives are really very useful for data storage and also used nowadays for keeping data files. Read only means one can only read the data, but can’t update or re-write or delete.

  4. Daniel Morgan says:

    Well described blog giving proper info about compact disk. It makes storage sense to the readers. Glad to know the history of ancient storage process. Most of the people use technical products but they do not have proper idea about them. After reading this blog, one can get some basic info about compact disk. DVDs and USB flash players are more demanded today as they are providing with some new features. But CDs are being used till now, due to its read only property. Thanks for the post.

  5. Michael Jones says:

    The “compact disc” was successor of gramophone it was the best thing to store digital music in 1983. At its initial stages it was considered as a music playing instrument rather than music storing. it was developed to store music initially but today we use compact disc as storing any information as a hard data storage device, beside this Sony and Philips are the two companies that have major hand in development of compact disc and reforming a simple personnel music storage device to a professional organizations usable product.

  6. James Long says:

    Almost everyone knows compact disks are meant for storing data. It was used previously but gradually it was replaced by DVDs, HD DVDs & Blu rays and now we are using USB flash drivers. This article is amazing & feeling pleasure to know much more about ancient storage process.

    Explanation of replication and duplication process is also quite impressive but I feel replication is much better because the CDs produced in duplication process are not of better quality and also doesn’t contain the entire copied data.

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