What is a CD-ROM and DVD drive? Secrets of choosing a CD-ROM for a computer Basic types of optical discs

Information is read using a focused laser beam.

Now let's see how this DVD Rom... Today it is still relevant, since many people still use discs as storage media. Therefore, you need to navigate this issue. But we will not pay attention to other drives for now.

In general, only the advent of high technology has made it possible to do such a thing as an optical drive. The disc has a reflective layer on which the laser beam is focused. It must be flawlessly precise and directed. The layer on the disk seems to us to be smooth and shiny, but there are microscopic depressions there, which are nothing more than recorded information. The laser beam reads the reflected light from these "irregularities".

First of all, order

But to make it clearer, we will consider everything in order.

Does everyone know what the abbreviations we already know mean? I think not. So let's figure it out first.

The abbreviated word CD Rom is CD. The full name is Compact Disc Read-Only Memory and is read-only.
Also, a short DVD Rom is a more versatile disc. However, it is also read-only. The full name is Digital Versatile Disc read only memory.
There is her "blue ray" or Blu-ray. The information is recorded on this disk by a short-wavelength blue-violet laser beam.

The picture clearly shows what exactly we call a DVD optical drive.

Installing the DVD Rom yourself is easy. Usually it does not cause difficulties. But it is important that the connection standard matches the device. There are two standards: "SATA" and "IDE".

The first is considered the most modern, and the second is already outdated.

The most important is indicated by numbers in the order of one to three.

The first is the "master / slave" section of the jumper on the disk.
The second number is the pin interface for connecting ATA / ATAPI devices. All nineteen holes.
The third four-pin connector connects to the "molex".

Now let's turn our attention to the back side. This is the "SATA" DVD standard Rom drive but.

The first connector accepts a fifteen-pin power cable.
A data cable is installed in the second connector. It's flat and short. The connection is made to the "SATA" controller located on the motherboard.

It should be noted that not all devices have a DVD Rom drive. For example, a netbook or tablet. In this case, an optical drive such as a USB DVD Rom will help out. After all, insert a disc, in case of a change operating system, for example, nowhere. Then the optical drive is connected via the USB port.

It is not uncommon for this kind of optical drive to be needed. For example, this netbook requires an operating system to be installed, which can be done using this USB drive.

How is information recorded?

Many people more or less imagine how recording on gramophone records takes place. In the beginning, CD recording was done in a similar way. And the name of the records was CD-R (Recordable). It was impossible to record something a second time on such a disc. But then the disks became more and more perfect and it became possible to rewrite the information several times. This is CD-R discs W (ReWritable). And it's all about the nuances of production. Previously, the recording took place directly on the plastic layer. Now a layer was made of an alloy of metals. And this layer is capable of changing properties under the influence of a laser beam. You can even notice dark and light streaks on the surface. This technology allows you to rewrite information many times, maybe even a thousand times.

The platter of the disc has a layer on which the recording is made. This layer can be seen on all recording and rewriting discs. If the disc cannot be rewritten, then this can be determined by the layer on the platter. If the disc is recorded, the layer will change color. The process occurs from exposure to a laser beam, and it is irreversible.

Rewriting discs are equipped with a layer of alloy that can change the reflective layer under the influence of the same laser beam.

All discs have a standard diameter of 120mm. The thickness does not exceed 1.2 mm. In the center, a small diameter hole of 15 mm is required. The surface of the disc must never be scratched. And to prevent this, there is a protrusion on the outside of the disc. It is small 0.2 mm, but strictly fulfills its functions. On a flat surface, the disc will no longer receive any damage.

Any disc is a multi-layered cake. But the cake is just over a millimeter thick. However, each layer has its own function and fulfills it. See how the disc looks like in the diagram and how many layers it has from different materials.

No matter how complex the information is from our point of view, all of it will be recorded in the form of pits and lands. These are actually pits and lands. In general, a wavy track is obtained. The recesses are pressed into the polycarbonate layer, and the plane remains unchanged. When the beam is focused on the track, the light from the plane and the bumps is reflected differently. And the difference is barely noticeable, but all this is recorded.

Speaking more simple language, then all information looks like zero - a plane and one - a tubercle.

Notice how it looks under strong magnification.

Now see what's on the surface that seems perfectly flat?

DVD Rom writes and reads information using a red laser. The wavelength is measured in nanometers and is 650nm. But the step is only 0.74 micrometers. For comparison, in CD discs all indicators are twice as high. It is clear that the decrease in the laser wave made it possible to more accurately “examine” the surface of the disk and fix all the pits. Constantly shrinking and making the DVD virtually dimensionless. At one time, when it began to fit more than 4 gigabytes of information, it looked fantastic!

Here are some numbers for comparison.

In a DVD disc, compared to a CD, the size of the pits is 0.4 microns versus 0.83.

The CD has a 1.6 micron track, while a DVD has only 0.74.

Some discs can hold just a huge amount of information. For example:

bilateral,
two-layer.

Some discs can be double-layer or double-sided. This sandwich will fit all 17 gigabytes.

More about each

Double layer DVD discs are produced by pressing the first layer. Then the second layer is sprayed on top. The coating is translucent. The laser beam, when reading information, focuses on each layer, moving from one to another automatically.

If the DVD has a double layer, each layer can be up to 0.6mm thick. When gluing the layers, the same 1.2 mm is obtained. It is very similar to a record, listening to one side you can turn it over.

On the diagram, it looks like this:

Disk layout

Blue ray

Remember Blu-ray Discs? They are somehow different from the usual DVD and CD discs. They are read using a blue-violet laser beam. Its length is less than required for reading. DVD discs Rom and CD Rom (RW). They use a beam with a length of 650 and 780 nanometers, respectively. And a Blu-ray disc needs a beam of only 405 nm. And all because technologies using a red laser beam can be said to have reached the limit. But the blue-violet ray is a real leap in development.

For such a beam, the width of the track is required less, therefore, the amount of information can be recorded more. However, due to the thinness of the relief on the information layer, it has become more difficult to read records at high speed. Therefore, it was necessary to reduce the protective layer of polycarbonate. Previously, it was 0.6, and now it is 0.1 mm. As a result, the speed of work and the accuracy of information reading have increased.

April 19, 2014 | comments: 0

Despite the fact that a flash drive is superior to a disk in all respects, you will still one day come across disk media and get the opportunity to compare.

To work with discs, you will need an optical drive, without which reading information from discs is not possible, otherwise such a drive is called a CD-ROM. Here are some tips for choosing a CD-ROM for your computer.

There are internal and external drives. It follows that the initial advice would be right choice internal drive.

After all, the quality of the drive depends on the quality of work and significant savings in energy consumption. The efficiency of the drive depends on the speed of writing or reading information from the disk media.

— CD-ROM (-RW) drives are used for reading from CD (-R, RW) disks. CD-RW differs from CD-R in that it is possible not only to read, but also to repeatedly write information with the help of a carrier;

— DVD-ROM (-RW) drives are designed to read information from CDs and DVDs (many types) of disks.

DVD speed is 9 times faster than CD drive.

With regard to the media themselves, then optical media also have differences:

— CD-ROM-discs that can only read information. This format has two sizes: 3.5 "and 5.25", which, respectively, contain 190-210 and 650-700 MB of memory. Data are recorded industrially on them;

— CD-R disks are designed for one-time recording of information, that is, it is only readable. The capacity is the same as that of CD-ROMs;

— CD-RW discs are overwritten, that is, record, erase and re-record information many times. The capacity is the same as that of the above storage media; CD-RW discs are designed for frequent use: you can record, erase and rewrite information multiple times. The amount of information is the same as for CD-ROM discs;

— DVD-ROM disks are used only for reading information. The difference is that the drives have more capacity: 4.7 GB for single-sided and 8.5 GB for double-sided drives. The size of this media is 5.25 inches;

— DVD-R disks write data once at a size of 3.95 MB;

— DVD-RW discs have an advantage in volume and can be rewritten many times;

— DVD-Dual discs record information in two layers. In spite of double advantage in volume, they didn't get spread;

— DVD-RAM disks are an additional type of rewriting devices that allow recording and reading data at the same time;

The second tip - decide on the type of media that you often use, and, depending on this, the required device. But it is profitable to supply a DVD drive at once for the following companies: ASUS, NEC, Samsung, Pioneer, Sony, LG, Toshiba.

Besides, the price range between CD-RW or DVD-ROM and DVD drive is not that great.

Third tip. When choosing a CD drive, do not try to chase a higher speed. This is because every time, in the process of reading, we strive to accelerate to the maximum speed for it. If at this speed it was not possible to read various damages, not the best coverage, defects, then the drive reduces the speed required for reading. The advantage is that the higher the speed, the better quality recording media. But these reasons can lead to the fact that your disc is torn apart, because with repeated use, the edge of the disc opening becomes covered with small cracks. For this reason, at high shaft speeds (from 10,000 rpm), the disc may not withstand such a high voltage and "burst" into parts. This will cause a lot of trouble for the user.

How to ensure quiet operation and avoid disc rupture? The fourth tip is derived from this. Made by special programs which will ensure that the drive speed is set accordingly. In these programs, you need to select the speed of 8 for comfortable video viewing, and for the mp3 format, it is enough to reduce the speed to 2.

It makes sense to mention the Blue-ray Disk (BD-ROM). A versatile drive that is capable of reading all formats and is specially designed for Blu-ray media. This drive beat was created by new technology using a blue-violet laser beam. Thanks to this, the recording is much denser, as a result of which the disk capacity increases to 50 GB. This is a great advantage over infrared DVD laser. Of course, this technology is the future. But the cost of BD drives and BD media does not allow for mass distribution.

When looking for a device for reading audio CDs (this is the last tip), focus on the existence of control buttons. This will allow you not to resort to using system resources.

Here, perhaps, are all the tips for choosing a computer drive.

Meet in our time a computer without CD-ROM / DVD drive almost impossible. A wide variety of programs, music, documents, digital photographs, etc. are recorded on CDs and DVDs. It is possible to purchase both discs with data already recorded (for example, a music CD or DVD with a movie), and special discs, on which you can (one or more times, depending on the disk and drive) write any information you need.

In addition to the not entirely correct name “ drive», CD / DVD reading and writing devices are also called optical drives. Word storage device generally refers to all devices intended for storing or reading data. For example, HDD can be called disk drive... Optical refers to a method for reading data from discs. In CD / DVD drives, reading and writing data from discs is carried out using a special laser beam.

There are several types in total CD-ROM and DVD drives, with and without recording support. Let's consider them in more detail.

Regular floppy drive CD— ROM only reads data from disks CD, CD— R and CD— RW. It cannot be used to write data to any disks. Such drives are the cheapest, but they are outdated and are not installed in new computers.
Drive CD— ROM with the ability to record. Unlike the previous version, this drive can be used to write data to discs with write-once (CD-R) or multiple (CD-RW) recording.
Drive DVD. This drive combines the capabilities of the two previous drives, i.e. allows you to write and read data from CDs, and can also read data from DVDs.
Drive DVD with the ability to record. This is the most versatile and popular drive option and is recommended for purchase. With this drive, you can read and write any discs, including CD, CD-R, CD-RW, DVD + -R / RW.
Also, every year, drives with support for reading Blu-rey discs are becoming more and more popular.

Basic types of optical discs

As you already understood, the recording capabilities depend not only on the drive, but also on the discs themselves. Let's study the main ones that exist in currently types optical discs.

CD, or CD. The easiest option optical disc... These discs sell either music (music CDs) or various programs. You cannot write anything to such a disc.
CD-R disc... On such a disk, you can once write down the information you need. It is no longer possible to add it later. A single CD-R disc can store up to 880 MB of data, depending on the size of the disc. These drives are most commonly used for storage important information, which will not need to be changed in the future. This can be music, video files, etc.
CD-RW disc. This disc has the same capacity as CD-R discs, but you can write data on it many times and delete any data you do not need. In total, such a disc is designed for about 1000 rewriting cycles, which is more than enough, for example, for periodic recording. Word documents, their subsequent deletion and recording of new files. CD-RW discs are more expensive than CD-R discs.
DiskDVD-ROM,orDVD Video. It is on these discs that DVD movies are sold. You cannot record anything on such a disc. At the same time, the volume of a single-layer DVD is 4.7 GB, which is several times more than the volume of CDs.
DiskDVD— Rand diskDVD+ R. As with CD-R discs, the DVD-R discs and DVD + R can one just write the data you need. Unfortunately, at one time the companies - manufacturers of optical discs and drives took up arms against each other and became irreconcilable enemies, as a result of which two completely incompatible standards appeared, DVD + R and DVD-R. Fortunately, the manufacturers of optical drives have solved this problem and now for most drives it does not matter which disc to buy; both types of discs will be supported.
DiskDVD+ RWandDVD— RW. By analogy with CD-RW discs, DVD + RW and DVD-RW discs can be rewritable. Given the disc size of 4.7 GB, it is very convenient for storage and Reserve copy a wide variety of data, for example your music collection etc. The problem of incompatibility of standards exists here, and it was solved in the same way - by the release of universal small format drives that support any type of disc.
Diskblu— rey we have a huge volume that allows you to record up to 80 gigabytes of information! Agree this is a lot for optical drive! In most cases, I record video with high definition on such discs, which allows me to achieve the maximum quality of the film! The cost of such a drive can reach up to 2000 rubles!

Optical drive speed

The speed of the optical drive is usually indicated in this way 52x / 24x / 52x... This means that CD-R discs are written from 52x, disc recording CD-RW happens at a speed 24x, and reading CD-R / RW discs - also at 52x. In this case, the indicator 1x means a data transfer rate equal to 153 KB / s. Now let's calculate the speed of the drive with a read speed of 52 x. To do this, multiply 52 by 153, the result will be 7956 KB / s, i.e. almost 8 MB / s.

Compared to CD-ROM drives, rewritable DVD drives read and write data much faster. Speed 1x DVD-ROM drive equals 1.35 MB / s, which is the same as 9x speed for CD-ROM. Therefore, the speed of modern DVD-ROM drives with a read speed of 20x corresponds to the speed of 180x for CD-ROM drives (27 MB / s), although, of course, this speed does not exist for CD-ROM drives.

How to choose a DVD drive for your computer

The fact that DVD media are slowly but surely fading into oblivion is difficult to dispute. They repeat the fate of their predecessors - floppy disks and CDs. No "revolutionary" solutions like the release of double-layer or double-sided DVDs could radically change the situation, and the market digital media small batches go into the hands of the manufacturers of flash memory and Blu-ray discs. Nevertheless, the DVD format is still the most widespread in the distribution of movies, software, games and music (together with CDs), so the DVD drive is still considered an integral part of the personal computer.

Let's start, as usual, from the basics. "Scientifically" DVD-drive is an optical drive, a device designed to read and write data from digital media, which, in particular, include CD-R, CD-RW, DVD - / + R and DVD- / + RW. Many people still remember the days when a DVD burner was a luxury rather than a necessity. Today it is practically impossible to find a read-only drive on sale, and there is no particular need for it. Even if you rarely or never use this (recording) function, it has practically no effect on the final price, so it makes no sense to purchase a regular DVD drive or even a CD-ROM writer. Unless you collect them.

If you buy a computer from scratch, then by default an internal (packed in a system unit) DVD drive is included in the package. This applies to both stationary PCs and laptops with netbooks, although the latter are equipped with their own, thinner and more expensive, drive models. The need for a separate purchase of a DVD drive may arise for only two reasons. Either your floppy drive for some reason failed (there can be many reasons - from a factory defect to carelessness during the operation of the device), or this model you are not satisfied with some parameters (noise, speed, design, compatibility), but it was possible to find out only in the process of working with the drive.

Drive speed and major media formats

The question is, what can be bad about this or that drive? The main parameter that is supposedly worth paying attention to is the speed of reading and writing. For in fact, you can feel this speed only if you are going to read or write discs on a truly industrial scale. It is also worth deciding what media you will most often "feed" the device with, because the same CDs are read much slower (more than 9 times) than DVDs. It is logical to assume that if most of the information on the market today is sold on DVD media, then you will mainly shove discs of this format into the drive.

The drive speed is indicated in 1x, where 1 corresponds to 150 Kb / s for CD-ROM and 1.385 MB / s for DVD-ROM. The maximum volume of a standard CD on which music albums are most often found on sale now and small in size computer games(as well as databases and software) is 700 MB. By today's standards, the size is ridiculous, but quite sufficient for recording a dozen uncompressed music tracks, text files, programs or a disc with corporate information (catalogs, prices, instructions, etc.). Theoretically, the CD reading speed is limited to 56x, but in practice this figure does not exceed 40x, because the faster the disc spins in the drive, the more noise it creates during operation.

If you often and enjoy burning discs CD-R (disposable) and CD-RW (rewritable), then your ability to read these media will be limited to speeds of 40x and 48x, or even 24x (for CD-RW). As far as writing is concerned, by default the drive will run at the highest possible speed, which can be manually changed to a lower speed. 700 megabytes usually fill up within five minutes.

Now let's turn directly to the DVDs that you will encounter most often, both in the process of reading and in the process of writing. We remind you that data exchange with DVD-media can be carried out only by means of a DVD-drive, a regular CD-ROM will not cope with this function by definition.

At the moment, the following DVDs are distinguished. This is primarily the most common DVD-ROM, which is the base for film products, games, software and other data produced and sold in series. Writing to DVD-ROM at home is not possible, read only. DVD-ROMs are available in single-layer and double-layer capacities of 4.7 and 8.5 GB, respectively.

The most common disc format you will encounter is the one-off "blank" DVD-R and DVD + R, which are most often used to store "heavy" information such as video and software. Why plus and minus? It's simple, minus discs appeared a little earlier with the filing of the well-known company Pioneer, while the “plus” technologies belong to the pen of Sony and Phillips. The difference lies in the presence of special markings to facilitate positioning of the drive head, and the use of a different reflective material. At first, these differences were critical for the quality of repeated rewriting (of course, for DVD-RW and DVD + RW discs), but today most drive models can easily cope with any version.

The maximum speed of reading and writing to DVD-R and DVD + R discs is, depending on the drive model and the qualities of the disc, from 8x to 24x, which, when fully loaded with data, will take about 4 to 8 minutes. There are also two-layer disposable discs with a DL (dual layer) prefix in the name, with a volume of 8.5 GB. However, the write speed for these "giants" is no more than 12x.

In terms of rewritable media, DVD-RW, DVD + RW and DVD-RAM are distinguished. You've probably already come across the first two: 4.7 GB disks with a maximum write speed of 8x. As for DVD-RAM, which can be written to simultaneously with the data reading process, their widespread use is limited due to the prohibitive cost.

What else do you need to know about DVD drive speed? Considering the fact that this parameter Since the device directly depends on the media used in it, it is impractical to strive to buy the fastest drive. Blanks that support high read and write speeds are expensive and are not sold everywhere. Remember that discs are extremely fragile media that are prone to scratches, chips, and other physical surface deformations. At high rotational speeds, such interference can lead to destruction of the disc, which simply shatters into fragments and can cause irreparable damage to the drive. As the saying goes, you drive quieter - the further you will be.

Features of connecting a floppy drive and sales packaging

Probably everyone has seen an ordinary internal floppy drive. Rectangle (148x42x198 mm) without unnecessary design delights weighing under a kilogram. There are also shortened versions (for compact bodies) with lengths up to 170 mm and lightweight ones up to 750 grams. The most elegant are, of course, DVD drives for notebooks - square dimensions (130x130 mm) with a thickness of only 13 mm and a weight of 120 grams. Nevertheless, these devices are very expensive and capricious in terms of installation, which is best left to professionals.

Exterior of laptop DVD drive

DVD drive being internal device, is connected using a loop to the computer motherboard, and therefore there are two types of connection - through a parallel IDE interface or SATA serial interface. IDE today is being replaced everywhere by the more advanced SATA, so when buying a drive separately, you should check the insides of your computer, or rather, with the connectors on the motherboard, so as not to get into a mess. New motherboards are likely to already work with SATA, so you can safely purchase the appropriate floppy drive. What is the advantage? Theoretically - in speed. But in practice, you most likely will not notice the difference.

About packaging. The fact that used drives are not worth buying is, I hope, clear without further ado, because all computer components have their own limited resource. The store will offer you two options: OEM and Retail. OEM - "for the poor" package, which includes a plastic bag plus a disc with installation software. As part of the Retail kit, in addition to the drive itself, you will find wires (ribbon cable), bolts, screws, blank disks, and if the manufacturer is generous, then an audio cable and even replaceable panels. Naturally, the second option will cost you a little more than the "polyethylene" one.

Manufacturers and prices

It's no secret that in the DVD drive niche, a brand or trademark often becomes the determining factor in choosing a particular device. There are many elements in the system unit, ranging from motherboard, video card and ending with the power supply unit and, in fact, the case of the system unit itself. But all these components, as a rule, are impersonal, because not everyone would think of going inside to see the manufacturer of a sound or motherboard. Many, not too advanced, users are more focused on specific parameters, and not on the names of companies. With DVD drives it is different, they are just "face" to the consumer, proudly decorating the system unit with an inscription like NEC, Sony or Plextor.

There is always a lot of subjectivity in the selection of a specific brand, because few people have to test drives from different manufacturers... Usually, we stick with our souls to a specific model, after which we don't want to hear about its change to something else. Nevertheless, there are a lot of players in this market, which we will talk about at the end of the article.

DVD-ROM from Plextor

If you have to deal with the recording process often and in large quantities, then there are actually two options. Either constantly change cheap devices, or occasionally face the need to purchase expensive models... For both, the resource is a parameter with a finite value. If you are more satisfied with the second option, then pay attention to the quality of the company Plextor, the devices of which are distinguished by high reliability and productivity. The cost of Plextor drives is not the only, but the most significant reason why only a select few can afford to communicate with this brand (from 5000 rubles and more).

Roughly the same situation with the products of American companies Dell and Hewlett-Packard (HP)... Good, even remarkable quality, high speed of work, reliability, but the price in the region of 4000-5000 rubles will please not everyone. Moreover, their products are rarely found on store shelves, and the same Dell prefers to specialize in ultra-thin laptop models.

Actuators produced with the label ASUS and Sony Optiarc (since 2006, the official merger of two companies - Sony and NEC)- strong middle peasants. At a cost of around 1000 rubles, they demonstrate high quality recordings, and discs created with these drives are easily readable by devices from other manufacturers, as well as many DVD-players. Not noisy, stylish, practical - the best value for money.

Sony Optiarc DVD-RW Drive

The drives from Samsung, Toshiba and Pioneer are considered the most capricious in terms of the quality of the discs. LG and Lite-On drives are the best at handling scratched media. Of course, these conclusions were made during testing. specific models, which, as you know, can be both successful and not very good. In other words, you can be incredibly lucky and your Samsung DVD drive will be omnivorous and tireless, while the ASUS drive, which received high marks from the "experts", will stumble at every turn.

In any case, when buying a DVD drive, pay attention to three things: the package bundle (OEM or Retail), the connection method (IDE or SATA) and the speed characteristics. Well, the design, of course, because the black NEC sticking out on the white case will be striking. Each brand has its own advantages and disadvantages, but in this market, if we are not talking about elite semi-professional quality models, the main and determining factor is still the price of the device, which for the vast majority of DVD drives varies from 600 to 1500 rubles.