Basic ComputingQuestion BankTechnology

All DVD: Types. History. Care

For years, the optical disc format par excellence has been  DVD, which for more than two decades has served as the ideal transport for digital content of all kinds, especially for the commercialization of products for the film industry. That is why DVD was the undisputed successor to VHS, which for many years was the only medium that allowed the reproduction and recording of  analogue audiovisual material through beloved VCRs.

With the advancement of technology in the field of computing,  audiovisual content that until now had been analog,  began to migrate towards the future, that is, towards the new era of digital multimedia files. In this context, several alternatives arose to respond to new consumer needs,  giving rise to the birth and subsequent massification of the DVD optical format. 

all-about-dvd-cd- (1)

DVD history

At the beginning of the 1990s,  the creation of a medium capable of storing digital content became imperative , which is why the most prominent electronics companies in the world began the path towards the development of a new medium. After a series of trial and error, two types of high-density optical media emerged, struggling to become replacements for VHS.

On the one hand, the MMCD, which stands for Multimedia Compact Disc,  powered by Philips and Sony, and the SD, from the English Super Density Disc, which had the support of Toshiba, Time-Warner, Matsushita Electric, Hitachi, Mitsubishi Electric, Pioneer, Thomson and JVC.

After several discussions, the leading companies decided that the best thing was to offer consumers a single standard format, in order to avoid competitions in which users would be disadvantaged, so the development of an optical disc was launched that meet features of the Philips MMCD, SD, and EFM Plus.

all-about-dvd-cd- (2)

In this way, after months of research, the first version of the DVD was born, which was launched on the market in 1996, together with  the creation of the DVD Forum consortium, where all interested companies participate, and its function is to control and maintain the standards. referring to the technical specifications concerning the disc.

Over the years, various modifications to the format arose, which led to the development of what is now known as DVD + R and DVD + RW,  which were created outside of the official standards specified by the DVD Forum association, already that belong to a group of companies that gave rise to the Alianza DVD consortium.

At present, DVD, which stands for Digital Video Disc or Digital Versatile Disc, is undoubtedly the most widely used optical disc format in the world, not only because it enables the storage of high quality audio and video, but also it can also be used to store any type of digital file.

all-about-dvd-cd- (3)

Although they resemble popular CDs, since they have the same size dimensions of 12 cm in diameter,  the truth is that DVDs have been created and encoded differently from CDs, so they allow a higher density and have superior storage capacity.

DVD types and their characteristics

DVD, also known as Digital Video Disc or Digital Versatile Disc ,  has been for years the most widely used optical media format at the business level, at home and in all disciplines  and for storage uses that we can think of.

Although at first it was released mainly to contain audiovisual files, and  was incorporated with total acceptance in the film and entertainment industry, the truth is that with the passage of time DVDs became the ideal medium to store a large amount of data of all kinds.

all-about-dvd-cd- (4)

No doubt that  e l DVD knew to prevail in the market for optical formats to its competitor, the CD due to a number of aspects that characterize and became the means more choice for users for large storage volumes of information .

In principle, since DVD uses a much more efficient encoding and error correction method in its physical layer than the system implemented by CDs, it makes DVD 50% more efficient and accurate than CD.

On the other hand, the use of a high-precision red laser beam, which has a wavelength of 650 nm, less than that used by CDs, and a numerical aperture greater than the previous format,  makes the DVD have a greater read resolution than CD. 

One of the most important characteristics of DVD, in the face of competition with CD, is its storage capacity,  since it multiplies the capacity through layers, so that in a conventional DVD,  that is, the one known as DVD5, it allows store up to 4.3 Gb real, which is multiplied according to the number of layers and faces that the medium has.

all-about-dvd-cd- (5)

The types of DVD

Currently there are a  wide variety of DVD discs, which differ according to their features and the storage capacity  they have.

Because the DVD format has been created to be able to contain several faces and layers on a single surface, according to the number of faces and layers that the medium has, the storage capacity of the DVD will be determined.

According to their storage capacity and reading and writing characteristics,  DVDs are classified as follows:

  • DVD-ROM:  this type of medium is manufactured using a special press to record the content it will include,  so it can only be read and cannot be written. It is commonly used by film production companies to release home versions of their films. Depending on the number of layers available on the disk, it is possible to store on it from 4.7 Gb to 17 Gb.

all-about-dvd-cd- (6)

  • DVD-R:  This is the type of format that  allows one-shot recording,  and it is not possible to use rewriting functions on this disc. In this case there are also the so-called DVD + Rs and the double-layer DVD + R DLs.
  • DVD-RW:  This medium in addition to allowing recording, also offers the possibility of rewriting. They are also those called DVD + RW.
  • DVD-RAM:  Like the previous one, it  allows rewriting but randomly,  and always at the end of the recording of the information, it performs a data integrity check, to verify that the process has been correct.

It should be noted that ROM, R, RW and RAM type discs are those that were created by the DVD Forum consortium, therefore, as they are official standards, they include the printing of the DVD logo on their surface On the contrary, DVDs of the + R and RW type, which were developed by Alliance DVD,  are not part of the official standards, and therefore do not have the DVD logo, but rather the RW logo.

all-about-dvd-cd- (7)

As for  the symbols “+” and “-” that some types of DVD include, they are technical standards,  which although they have certain compatibility and coexist in the market, the truth is that some users assure that one or the other standard is better than its opposite, since the difference between both lies in the way implemented for writing and encoding the data.

Finally, it  is important to mention that according to the number of layers and faces that DVDs have,  which will ultimately be the specification that defines the storage capacity of the disc, they are classified as follows:

  • DVD-5 : It has a single layer side, so it offers a  capacity of 4.7 Gb.
  • DVD-9 : Single-sided, double-layer, with a  capacity of 8.5 Gb. 
  • DVD-10 : They have two sides of a single layer each, with a  capacity of 9.4 Gb. 
  • DVD-14 : Double-sided, one of them double-layer and the other single-layer,  with a capacity of 13.3 Gb. 
  • DVD-18 : It has two double-layer sides each, with a  storage capacity of 17.1 Gb. 

all-about-dvd-cd- (8)

¿ What is the duration of a CD or DVD recorded?

Twenty billion optical discs are recorded every year.  And lots of CDs and DVDs sleep peacefully in our drawers, until you wake them up. But will these DVDs be readable after a few years?  Manufacturers do not care about this. CD-R labels mention the Lifetime indication. They claim that a DVDR is long-lived, and can last 100 years, and even 200.

all-about-dvd-cd- (9)

Of course this is not true. These estimates are based on aging laws that “cannot be trusted at all,” reveals Santiago Perdereau, a researcher at the National Laboratory of Metrology and Testing (LNE): “No one tested the application of these laws. The only thing that is done is to carry out a simplified aging process, the real process is more complex. Our studies show strange but real chemical reactions, in total contradiction with these principles. Mutations that differ, from one brand of CD-R to another. And even from one area of ​​the disc to another “.

This means that manufacturers oversimplify durability testing.

How is an optic disc duration test performed?

Aging is accelerated. The discs are placed on surfaces subject to high humidity. Temperature and humidity are, in fact, the most damaging factors of aggression for an optic disc. 

all-about-dvd-cd- (10)

But the tests stop there. A pity, because other aggression factors should be simulated as well, such as acid sweat left by the fingers of users who manipulate the discs. Or aggressions caused by handling the disc (scratches, stains, etc.). The attacks of cigarette smoke or chemical vapors in the air. The factors are many.

The reality is that after three years, 15% of CD-Rs are unreadable. No optical disc will live 200 years . “According to the tests carried out, the CD-R last between nine months and a few dozen years,” says Santiago Perdereau. DVDs are roughly the same length . “We regularly carry out studies for various public establishments. From 2000 to 2003, we studied 60 CD-R references. After three years, 15% were illegible.”

From these analyzes and tests it appears that only an optical disc of a good and recognized brand passes the ten-year limit.

all-about-dvd-cd- (11)

How do you know which ones are good records?

It is almost impossible for the general public. No brand is entirely reliable . From year to year, the quality of discs varies. From store to store, the same CD-R reference is not produced in the same factory. On the internet, some fans attack the supposedly more durable brands and come up with the ones they consider to be the best.

But there is something worse.  The quality of a disc also depends on the recorder used. Certain DVDRs have exceptional durability when they have been recorded with a recorder A, and not with a recorder B. Also in this regard, there are tests carried out. The general public does not have the time to do so, and neither do the media.

The user of the general public seems to be lost. However, there are some strict rules to avoid catastrophes. For example, we can record each disc in duplicate, on two different brands, and prefer recent recorders over old recorders .

all-about-dvd-cd- (12)

Another trick: choose your engraving speed carefully. “A prudent attitude may be to halve the top speed advertised by the disc manufacturer,” advises Perderau.

8 rules to correctly burn an  optical disc

  • Don’t touch the tracks . Hold the record by placing a finger in the hole in the center.
  • Remove traces with a dry cloth , drying the disc from the center outwards.
  • Store CDs in traditional boxes.
  • Place boxes in an upright position,  like books, to avoid warping.
  • o protect the CD light  (this is very important).
  • Avoid humidity  (another fundamental rule).
  • Regulate the temperature between 4 ° C and 25 ° C
  • Do not write on the discs.

all-about-dvd-cd- (13)

How to clean CDs and DVDs

Optical discs have become one of the most popular storage media in recent years, due to their low cost and important functionalities. But the truth is that  both CDs and DVDs continue to be delicate objects, which can fail if they are affected by dirt. Therefore, here we tell you the best methods to clean your optical discs correctly.

Of course, in order for CDs and DVDs to remain legible over the years, it  is extremely important that we take proper care of them. Precisely from this point on we will tell you what are the aspects to take into account to keep the discs in good condition.

all-about-dvd-cd- (14)

But the truth is that despite taking all the necessary precautions, it is not surprising that CDs and DVDs sometimes fail.  When we notice that disc playback issues are occurring, it may be that the optical media is damaged, but also these issues could simply be an indicator that it is time to clean the discs.

In general,  if the optical disc is in good condition, all that is required is a simple and quick cleaning with a dry cloth ,  which will allow us to remove dust formations that have not yet adhered too much to the surface. For this we can use a special cloth, or a piece of dry cotton cloth that does not leave lint on the surface of the disc.

We must take the optic disk finger with our thumb and index finger, as a forceps, placing one of the fingers on the edge of the disk and the other in the hole in the center, without touching the shiny part, as seen in the following photograph :

all-about-dvd-cd- (15)

The cloth should move smoothly and in straight strokes from the center out. We should never rub the disc or clean with circular movements,  as well as avoiding wiping the cloth following the circular lines of the disc.

When we have finished this procedure, if the optical disc is still dirty,  we must opt ​​for a more thorough cleaning, for which we can purchase a special chemical product for this task,  or else do it at home with the cleaning products that we usually use. in our home.

all-about-dvd-cd- (16)

Although many say that alcohol is not recommended, since it can damage the surface of the disc,  the truth is that it is one of the best products to clean a CD or DVD, of course , to use it it must be previously diluted with water. But you can also use a mixture of neutral soap diluted in warm water. We must always avoid the use of any type of heavy solvent, as they can damage the disc.

all-about-dvd-cd- (17)

Now, whenever we want to clean a CD or a DVD with any of the aforementioned liquid materials, we must make sure that at the end of the cleaning task there are no traces of liquid on the surface of the disc before storing it in its envelope and even more so before insert it into the player tray. Therefore, we must let it dry completely, and when we do not observe traces of moisture, it will be ready to be used or stored.

If once we have finished with these cleaning processes, we still have problems playing the CD or DVD , it is likely that the disc has small scratches on its surface, for which there are a wide variety of products on the market designed to recover the discs, as it softens such scratches.

all-about-dvd-cd- (18)

Ultimately, depending on how severe the damage to the optical drive is, some of these products can be very effective,  although of course it is always an excellent idea to back up data as soon as the device has been repaired. disk, in case it fails again.

How to keep CDs and DVDs in good condition

Due to the material used to manufacture DVD and CD discs, these media are certainly fragile to damage from the passage of time and handling, so it is advisable to take a series of precautions that will allow us to keep our CDs and DVDs in good condition.

All those users who habitually use optical discs of the DVD and CD type to protect information, store videos, movies and music, we know that over time this type of medium can present certain failures that make access to the data stored on it be impossible.

all-about-dvd-cd- (19)

Although for years, different companies have begun to implement different methods to detect the useful life of the CDs and DVDs that they sell to inform users about this aspect, the truth is that it is extremely difficult to be able to calculate exactly how long it will last in good condition a DVD or CD.

It is true that depending on the type of recorder used to write data to discs, and the way in which users protect the media, the useful life of an optical medium can reach up to a hundred years. However, it should be noted that the way they are stored is usually very important, in order to avoid damage and loss of information.

Today, we users routinely use DVD or CD discs not only to store movies and music, but also as a special medium for storing critical personal data such as business documents, digital photos, and more.

all-about-dvd-cd- (20)

That is why the worst that can happen to us is that a disc cannot be read due to physical damage, thus making  permanent access to said information impossible. 

CD and DVD discs are really very fragile

The fragility of optical discs is such that a small scratch, a stain or even a fingerprint can  cause irreparable damage that will make it impossible to read  or rewrite them.

To avoid this type of inconvenience, it is advisable to take into account a series of precautions that will allow us to continue using these types of optical media without fear of possible loss of information.

The first thing we must do, when we require a medium to store important material such as our personal digital photos, is to  acquire a good quality recordable DVD disc , that is, manufactured by one of the leading brands in the market, avoiding the use of brand media. unknown and so-called alternative.

all-about-dvd-cd- (21)

The importance of choosing a good DVD or CD is that  most of the unknown companies that offer low-cost media, use poor quality materials and labor , and sometimes even non-existent quality inspection processes in the manufacture of their products. .

On the contrary, those leading manufacturers of optical media, such as Verbatim, TDK or Philips,  use cutting-edge technology and high-quality materials in the manufacture of their products , thus ensuring more durable and tamper resistant discs. daily.

Once we have purchased the correct disc and burned it, it  is important to implement some precautions to extend its durability.

all-about-dvd-cd- (22)

Precautions for caring for a CD or DVD

  • You should  avoid taking discs supporting fingers on the recordable surface . The correct way is to take it by the edges or by the central hole, to avoid in this way leaving the traces of our fingers impregnated, and therefore the accumulation of moisture and dirt.
  • It is advisable to  use envelopes and protective sleeves to store the discs , and when they must be handled we should never place them on any place with the corresponding data surface down, that is, the correct way is to always leave the recording surface up. .
  • It is advisable to  store them in a place where they do not receive excessive heat or sudden changes in temperature , as well as avoiding the accumulation of dust in the place where we usually place our discs.

The most important thing to keep in mind to take care of a CD or DVD 

The ideal is  to periodically clean the DVDs and CDs , especially after they have been used, for which you should use a soft, lint-free cloth, just moistened with water or some special product for this task.

It is also important to maintain constant cleaning of the recorders and players where the discs can be used.

all-about-dvd-cd- (23)

Bear in mind that keeping our DVDs and CDs in good condition is similar to what we used to keep our old vinyl records in good condition, since they are usually as fragile as these, but their benefit lies in the fact that taking these precautions they possess a much longer useful life than vinyls, reaching almost a hundred years.

How to recover damaged CDs and DVDs

As the vast majority of users know, the biggest problem with CDS and DVDs is the ease with which they are scratched and this ends up making it difficult to read the data stored on them. Another and more frequent factor is the problem of dirt. With the surface of the disc dirty or greased, the chances that the laser will not be able to read the surface properly is great.

Taking this into consideration, the first thing we have to try to recover a non-working optical disc is to clean the surface of the same with a clean cloth, of the flannel type (for example a clean cotton T-shirt), and wipe it over the surface, starting from the inside to the outside of the disc, from the center to the edges.

all-about-dvd-cd- (24)

If cleaning the CD with the cloth did not solve the problem, the lack or poor playback may be due to scratches or wear on the CD. 

The CD or DVD has scratches

CDs and DVDs are made of a plastic called polycarbonate, and as such they are very easy to scratch. The smallest lines are often corrected by the CD or DVD reader’s own error correction mechanism, however, when the lines are deeper, or cover a greater amount of information, they often make the CD or DVD unable to be reproduced.

Software Solutions for Damaged CD and DVD Data Recovery

On the market there are some programs and utilities that can be useful to recover data from a damaged CD. A good option is to first try to retrieve some of the content.

all-about-dvd-cd- (25)

Some programs that can help us to recover data from a CD or DVD:

CDR Diagnostic

CD-R Diagnostic allows you to test, examine, and recover data from CD, CD-R, and CD-RW discs. Includes support for discs recorded using Adaptec DirectCD and CeQuadrat PacketCD and other packet-writing programs.

It completely bypasses the installation of Windows and other CD player applications on your computer, allowing complete freedom to browse virtually any CD, including Macintosh and audio CDs.

all-about-dvd-cd- (26)

If you wish, you can obtain more information about this utility by clicking on this link.

Isobuster

This application allows us to explore the files on a CD, ignoring Windows and its limitations. It allows the reading of CDs considered unreadable by Windows and has its own mechanism for handling read errors.

all-about-dvd-cd- (27)

If you want to know more about Isobuster, you can do so by clicking on this link.

CD Data Rescue

This application was specifically designed for the purpose of recovering data from a damaged or faulty CDROM, CDR, CDRW. It uses algorithms that allow you to recover data that Windows cannot recognize.

In addition to that, although it is impossible to read certain data, CD Data Rescue allows you to recover a large part of the file that can later be recovered and it does so while maintaining the internal structure of the file.

all-about-dvd-cd- (28)

If you wish, you can obtain more information about CD Data Rescue by clicking on this link.

Unorthodox and Desperate Solutions to Recover Damaged CD or DVD

It may sound strange, but the cheapest way to try to repair a damaged CD is with toothpaste. Many people have recovered a CD in this way. The most efficient toothpaste is the one with the greatest whitening action. You should wipe with a cloth from the center to the outside of the CD, in the opposite direction of the CD reading direction.

all-about-dvd-cd- (29)

If the scratches are not large and deep enough, you can also use glass polishing wax (used in cleaning glasses and watches, for example).  You can get this product at the opticians.

Always try to perform CD recovery with a recorder instead of a common reader. CD / CDRW recorders are more accurate and tolerant,  allowing data to be read even when the player does not play it.

all-about-dvd-cd- (30)

In the case of CDR / CDRW, sometimes it is better to use a player of the same brand with which it was recorded.  For example, if it was recorded on an LG CD recorder, try to do the recovery on an LG recorder as well.

Related Articles

Leave a Reply

Your email address will not be published.

CAPTCHA


Back to top button