What is an optical disk in a PC? All types and types of optical drives: their characteristics and which ones exist? CDs, their types, history of creation

A data carrier in the form of a plastic or aluminum disk, intended for recording and/or playback of sound (CD), images (video), alphanumeric information, etc. using a laser beam. Recording density St. 108… … Big Encyclopedic Dictionary

A disk containing digital data readable using optical technology. [GOST 25868 91] Equipment topics. periphery processing systems information EN optical disk...

OPTICAL DISK, in computing, a compact storage device consisting of a disk on which information is written and read using a laser. The most common type is CD ROM. Audio CDs also represent... ... Scientific and technical encyclopedic dictionary

A data carrier in the form of a plastic disk designed for recording and playing back sound (CD), images (video disc), alphanumeric information, multimedia (CD ROM, DVD), etc. using a laser beam. The first optical... ... Encyclopedia of technology

Data carrier in the form of a disk made of transparent material (glass, plastic, etc.) with metallization. layer, on which microscopy, recesses (pits) are formed using digital optical recording, collectively forming spiral or annular... ... Big Encyclopedic Polytechnic Dictionary

A storage medium intended for recording and/or reproducing information using focused laser radiation. It consists of a rigid (usually optically transparent) base, on which a photosensitive or reflective layer is applied and... ... encyclopedic Dictionary

147 optical disk: A disk containing digital data read using optical technology Source: GOST 25868 91: Peripheral equipment for information processing systems. Terms and Definitions … Dictionary-reference book of terms of normative and technical documentation

According to GOST 25868–91, “Peripheral equipment for information processing systems. Terms and Definitions” – a disk containing digital data read using optical technology... Records management and archiving in terms and definitions

Blu Ray Discs (BD) are a new generation of storage media for storing high-definition video (HDTV) and high-density data. The Blu Ray standard was jointly developed by a group of consumer electronics and computer companies... Technical Translator's Guide

Books

, Kuzmenko Galina. IN textbook the content side of the manifestation of the psychological and pedagogical skill of a trainer in the development of social and emotional intelligence in a system of significant qualities is presented...

Recovery optical disks

1. Research part

1.1 Some history

All the things we use in everyday life have their own fascinating history. The optical disk we are familiar with appeared in 1958. On for a long time, determining the development of optical information storage devices, such as CDs, DVDs and, more recently, Blu-Ray discs. At first, the optical disc was used for video recordings. Over time, a disk was invented, which began to be used as a storage medium for music files.

Despite the fact that the first CD format discs went on sale back in 1982, they are still used to this day for recording music files. The DVD format is actively used to record films.

1.2 Types of optical discs

To disks CD-R(they are sometimes also called “blanks”) you can record your information, but it will be impossible to erase or change it. If there is free space left on the disk, and you enabled the option to add information when recording, you can add files to the disk.

Discs CD-RW support deleting and rewriting information, but such discs will not be readable by all drives. Writing and reading disk information is carried out using a laser. CD thickness - 1.2 mm, diameter - 120 mm, capacity - 650 or 700 MB (corresponding to 74 or 80 minutes of sound).

DVDs allow you to store more information than CDs due to the use of a laser with a shorter wavelength. The capacity of a standard size DVD (120 mm) can range from 4.7 GB to 17 GB, and the capacity of a mini DVD (80 mm) is 1.6 GB.

Depending on the capacity of DVD, the following types of discs are distinguished:

· DVD-5- single-layer, single-sided disk, capacity - 4.7 GB

· DVD-9- double-layer single-sided disk, capacity - 8.5 GB

· DVD-10- single-layer double-sided disc, capacity - 9.4 GB

· DVD-14- double-sided disc, double-layer on one side and single-layer on the other, capacity - 13.24 GB

· DVD-18- double-layer, double-sided disc, capacity - 17.1 GB

Where possible, recording, overwriting and deleting DVD information Disks, like CDs, are divided into ROM, R and RW. But additionally, the following types of disks are distinguished:

· DVD-R for general, DVD-R(G)- a recordable disc designed for home use.

· DVD-R for authoring, DVD-R(A)- a recordable disc for professional purposes.

· DVD-RW- rewritable disc. You can overwrite or erase information up to 1000 times. But you cannot erase part of the information, you can only erase the disk completely and completely rewrite it.

· DVD-RAM use phase change technology. They can be rewritten up to 100,000 times, with a theoretical service life of up to 30 years. But they are expensive, are produced mainly in special cartridges and are not supported by most drives and players.

· DVD+RW are based on CD-RW technology and support rewriting information up to 1000 times. This format appeared later than DVD-RW.

DVD+R- a recordable disc similar to DVD-R.

HD DVDs (High Density DVDs) can have a capacity of up to 15 GB, and double-layer ones - up to 30 GB. Their main competitor is BD, Blu-ray Disc holds from 23 to 66 GB depending on the number of layers. A prototype of a four-layer disk with a capacity of 100 GB has been announced, and it is also planned to release ten-layer disks with a capacity of up to 320 GB.

.3 Optical disk device

In its structure, a CD-R disc resembles a layer cake, the “filling” of which consists of active, reflective and protective layers, which are sequentially applied to a polycarbonate base - a plastic circle with a hole for fixing on the spindle of the reading drive. Wherein CD-R base The design of the disc is no different from that used in the injection molding technology of compact discs: the characteristics of the plastic must be such that the laser beam passing through it is properly focused and does not cause destruction of the disc.

The active (or recording) layer is the layer on which, in fact, information is recorded, i.e. it is he who is exposed to a laser beam, which “burns” the pits that encode information (logical zeros and ones). In other words, during recording, the active layer changes its structure under the influence of a laser beam, and the subsequent irreversibility of the change in the active layer is the essence of the reliability of information storage. One of the types active layers The one widely used today is cyanine. Cyanine is the original type referred to in the Orange Book standard and is widely used.

1.4 Re-writable discs (CD- RW)

The difference between such discs and CD-Rs lies in the design of the recording layer. The intermediate layer of special organic material can be either amorphous or crystalline. Amorphous substances tend to crystallize over time. No matter how we store a CD-RW, after a few years the recording will be irretrievably lost. In addition, such discs can easily be erased by simple heating.

Structure of DVD discs

The principle of burning a DVD is not much different from the principle of burning a CD. The basis for recording and storing data on DVD-RAM and DVD-RW discs is the technology of changing the phase state of matter. The layer-by-layer structure of one half of the disk is shown in the figure.

The principle of recording on a DVD disc

A record of amorphous regions is shown in this graph. A short, high-power laser pulse melts the recording material. This is followed by cooling below the crystallization temperature. The result of cooling is to prevent the formation of crystallization centers. Thus, the growth of the crystalline phase does not occur, and the substance remains in an amorphous state.

.5 Erase fromDVD-disk

To erase, the substance must be returned to its crystalline state. Again, using a laser, the amorphous substance is heated to temperature T. Heating (or rather, annealing) continues for a time sufficient to restore the crystalline state of the substance. This time must be longer than the so-called crystallization time.

.6 Advantages of optical discs

The advantages of optical disks include: relatively large volume, ease of use, prevalence, low cost, resistance to magnetic influences.

1.7 Disadvantages of optical discs

Perhaps the disadvantages include the lack of resistance to mechanical damage (scratches, ultraviolet radiation, temperature...).

1.8 Difficulties in device design

The main problems of the device that need to be solved are:

Select suitable power electric motors

When rubbing, the plastic clogs the pores of the sponge, to avoid this you need to moisten the sponge with water.

1.9 Alternative

Sanwa Supply will offer a very unique innovation called CD-RE1AT.

This miracle of technology restores damaged optical discs, as it is able to apply a special protective layer to their surface that fills scratches. Externally, the product weighs like a regular portable CD/DVD player with a hinged top cover, under which there are two seats to accommodate the two recovery and two cleaning heads included in the package. The cost of this disk restorer in Japan is about 50 euros. Nothing is known about the sale of such devices in Kazakhstan.

2. Experimental part

.1 Calculations for demonstration model

The operating principle of the device is to smooth out scratches and clean the optical disc. I used two electric motors, one rotating disk, the second lapping, a sponge, parts from a DVD, a lower pulley, a rubber casing, goyim paste, an empty can from disks, rubber glue, solvent, a power supply from a phone.

I cut the sponge in the form of a cylinder,

Goyim paste dissolved in solvent

I glued the resulting dried sponge cylinder soaked in a solution of goya paste onto the lower pulley for attaching the disk.

I cut the disc cover in the shape of a disc, cutting out the top part.

I screwed the electric motor 3 centimeters from the edge and put the pulley with the sponge on the electric motor rotor.

A second motor was screwed to the bottom of the box onto the rotor, which was covered with a thick rubber cambric so that the disk placed on the finger would rotate.

Since this is just a demo model, I used two 12 volt motors from the DVD, one spinning the disk, the second lapping, motor speed (250 rpm) and power (0.1a).

I connected two electric motors in parallel to the power supply from the phone.

3. Diagram of a working device for disk recovery

.1 Manufacturing and assembly of a disk cleaning device

For the frame of the device I took a 15x15 corner

To rotate the disk

1. I took the electric motor from a breeze heater 220 (v) 0.7 (w)

2. Two pulleys from a tape recorder

Bushing with bearings from the radio

Passenger from a tape recorder.

DVD parts for mounting the disc.

To wipe the disk

6. I took the second electric motor from a 12 (v) 2 (a) screwdriver.

7. The pulley from the tape recorder is small.

Paste GOI

Rubber glue,

Solvent

Power supply from a tape recorder.

.2 Practical work on making a model

1) First, we cut the corners to 15x15x300

2) An electric motor was welded onto the corners to rotate the disk, and a pulley from a tape recorder was placed on the rotor of the electric motor.

A pulley from a tape recorder was glued onto the bushing with bearings from the radio, and parts from the DVD for attaching the disk were glued onto the pulley.

Holes were drilled in the metal plate to attach the bushing.

The plate was welded to the frame so that the belt was tensioned.

Checking in action, fastening the disk and what speed the disk is gaining.

Holes were drilled in the plate for mounting the second electric motor at 12 (v) 2 (a), a small pulley from a tape recorder was put on the rotor of the electric motor, and a cylinder-shaped sponge soaked in a mixture of goya paste was glued on.

2 pieces of corners 15x15x150 were welded vertically to the frame.

We welded a plate horizontally to the corners and drilled two holes for mounting the motor.

In the plate on which the electric motor is screwed, oval holes were cut out to adjust the surface of the drive, and the electric motor was removed to replace the sponge soaked in the goya paste mixture.

To give the look, the frame was lined with plywood and painted.

9. The power supply was made of plywood; a 12-volt transformer with a diode bridge was screwed into the box inside. There are two sockets screwed on the outside, one with 12 volts, the other with 220 volts and a common switch for turning off and on the power.

Conclusion

Recovering data from an optical disc is a reality thanks to special programs. The fact is that operating system, if it cannot correctly read information from some part of the disk, it instantly interrupts copying and completely deletes the already copied part of the data. To bypass this function, special programs help that use mechanisms for reading disks and make it possible to copy necessary files(100% recovery of all information from damaged disk they do not guarantee).

These programs read information from damaged disks by directly accessing them. At the same time bypassing standard means Windows OS. Utilities repeatedly try to read the damaged disk sector, and at the same time, if read errors occur, they can continue copying (or reading) information, which makes it possible to “pull” lost files from disks in their original form. If some sectors are not readable, some programs simply replace them with zeros, which in turn leads to a defect in the file.

Recovering data from an optical disk is not a simple and labor-intensive process, often taking a lot of time. In practice, not all files recovered in this way will be usable. For example, if a couple of paragraphs disappear in a text document, then this is much better than losing the entire text that you wrote for a whole month.

With music and video, everything can also be quite decent - it’s unpleasant, of course, if at some point while listening to your favorite song or watching a video plot you see strange squares on the screen, or you hear some strange sound, but again, this much better than losing your favorite materials altogether.

To restore the physical part of the disk plane, our optical disc cleaning device will help.

Bibliography

optical disk laser restoration

1. http://strana-sovetov.com/computers - types of disks.

2. http://ergosolo.ru/reviews/gadgets/ - smart gadgets.

Http://www.datars.ru/recovery/optics-disc/ - disk recovery

Optical storage

Optical drives are designed to read and usually write/rewrite from optical discs. Optical disks are round and flat plates made of dense material (usually consisting of polycarbonate) with applied layers that allow information to be stored in the form of tiny pits (pits, frompit - hole, deepening). The reading process is carried out by a laser beam, which, reflected from the surface of the disk, enters a photocell, where the light is converted into an electrical signal, the magnitude of which allows the recorded information to be decoded.

The most common optical disc formats for use in personal computers are CD, DVD, Blu-ray.

CD-ROM ( Compact Disc Read Only Memory, read-only CD) a type of CD,which appeared in 1982 as a result of research by two companies - Sony and Philips. The first discs used the "Red Book" format, in which the playing time of one cassette was 74 minutes 33 seconds, which corresponds to the playing time of Beethoven's 9th Symphony, which was very popular in Japan at that time. The signal sampling frequency is 44 kHz for stereo sound and the bit depth is 16 bits. They had a capacity of 650 MB and allowed storing 75 minutes of music (starting from 200, discs with thinner recording tracks appeared, which made it possible to increase the capacity to 700 MB with recording 80 minutes of music). CD-ROM discs initially developed as an analogue of vinyl discs and were intended for recording and playing music information. They also have a single concentric track that runs from the outer edge to the inner, making many turns. The principle of reading information is optical, that is, the laser beam reads data that is recorded on an aluminum (or other type) substrate. In addition, the information is recorded on the disc, unlike a vinyl disc, in digital rather than analog form, and after reading it is decrypted and converted into sound. To protect the disc from damage, the aluminum substrate is covered with transparent plastic.

Creation technology CD-ROM drives next. First, a disk is made on which only those places where a unit of information is located are burned out, and places with zero values remain unchanged. After this, a matrix is made, with the help of which the blanks are stamped, a layer of metal (aluminum, silver, gold, etc.) is sprayed onto the information surface to increase the reflectivity of the laser beam, and they are coated with transparent plastic (varnish) to protect the data. When a disk is inserted into the drive, a laser beam slides along the concentric circle of the disk and by the reflected light it is determined whether it is recorded: a zero or a one.

Initially, CD-ROM discs were designed to store only music information. Due to the fact that disks use digital information rather than analog, they began to be used in computers.

Usually , storage device CD-ROM supports modes : Audio CD, Music Disc, Super Audio CD, CD-ROM (mode 1 & mode 2), CD-ROM/XA (mode 1, form 1 & form 2), Super Video CD, CD-Text, Video CD, CD -I/FMV, Photo-CD (Single & multisession), CD- i and others . The first drives could only handle certain formats, but eventually they could handle all formats. Therefore, the user does not need to know the format. As a rule, it is enough to know that there are audio, video discs and discs with programs (or text).

Next, the “Yellow Book” standard was developed, which contains a header that determines the type of disc: music or software. The music format was already well developed, and the software format was determined by each manufacturing company itself. Due to the rapid development of this technology, the discrepancy in the standard could not last long, so the High Sierra advisory standard arose, on the basis of which the ISO standard 9660. According to this standard, the disk has a table of contents and a data area. The first track contains parameters for synchronizing the drive and disk with each other, followed by a table of contents in which the description of each file contains the direct address on the disk.

There are three types of such disks:

CD - ROM The disk is usually written in an industrial manner, and in the future it can only be read. It measures 120x1.2 mm and has a capacity of 650-879 MB. Service life 10-50 years. Such discs are often supplied with computer devices; they contain software, music discs, etc.

CD - R The disc has the same characteristics as a CD-ROM, but allows information to be written to them once.

CD - RW the disc has the same characteristics as a CD-ROM, but allows you not only to write information on them, but also to write more of it, also to erase previously recorded data and write new ones.

To work with them, CD drives were used, which have several types:

CD- ROMthe drive can only read CD disks. One of the most important characteristics of this device is reading speed information. Normal (single) speed corresponds to the speed of reading audio discs, which is 150 kb/sec. Then came CD-ROMs with 2, 4, 6, 8, 10, 12, 16, 24, 32, 36, 40, 52 times the speed. The data transfer rate is accordingly a multiple of 150 kb/sec. For example, for a 40x drive it will be equal to 40x150 = 6,000 Kb/sec, and here the maximum speed is indicated, which is equal to or lower for different types of drives, which depends on the manufacturer. The six-speed drive allows for video output at frame rates of 25 frames per second or higher, which is fast enough for on-screen viewing. Discs for use with this device are sometimes also called compact discs (this concept also includes CD-R discs, CD-RW) or CD-ROM discs (Compact Disk - CD; see figure below).

CD - R drive is a write-once optical drive. It allows you to read CD-ROM, CD-R, CD-RW discs, but also allows you to write CD-R discs once. This drive has the ability not only to read discs, but also to write them. For example, the read speed is 40 times, and the write speed is 6 times.

In such devices, a laser beam burns grooves on the surface of the disk, while the areas that reflect light are called “lands”, and the non-reflected areas are called “pits”. The combination of these sections makes it possible to encode information in a two-bit representation.

For various reasons, in practice, when recording, it is impossible to achieve an ideal location of the burnt grooves, and during playback, sound defects and jitter appear, which is called “jitter”. To a certain extent, you can get rid of such unwanted distortions by using a special Audio Master mode, when the burned grooves are forcibly increased in length. This mode is used in cases where you need to improve the quality of the recorded sound.

Typically recording is done at constant angular velocity (CAV). However, when the rotation speed changes several times (x2, x4, x8, etc.), the recording pauses and so-called “connection points” are formed, which deteriorates the quality of the recording. In such cases, a buffer underrun protection called SafeBurn is used. As a rule, it turns on only when the disk rotation speed changes, and the recording mode with constant angular velocity (CAV) is mainly used. This method of improving the quality of playback audio is called Zone Constant Line Velocity (Z-CLV) recording.

A very interesting feature on some devices for recording digital information on discs is the ability to burn text onto the surface of a laser disc, be it a list of music files or your data. For this, the DiscT2 mode is used, in which any text is typed that is worthy of reproduction on the surface of a music or other type of disc created by oneself.

CD - RW (Compact Disc-ReWritable) storage device is a reusable optical storage device. It allows you to read CD-ROM, CD-R, CD-RW discs, write CD-R discs once, but also write and re-write, as well as rewrite previously recorded CD-RW discs. This drive has the ability not only to read discs, but also to write them. For example, the read speed is 40 times, and the write speed is 6 times. There could also be a speed of additional recording.

A CD-RW device works on a different principle, that is, when writing to them, the beam does not burn out, but transforms the substrate into an amorphous state, which allows you to establish a different reflective effect. Therefore, they can write data multiple times. However, discs dissipate information worse than standard CD-ROM discs, so they cannot always be read on standard media.

The more capabilities a device has, the more limitations it has. How easier wheels, the greater the reflective effect they have. CD-ROM discs have the best reflective effect, which can be read in CD-ROM, CD-R and CD-RW drives.

CD-RW format discs have even less reflectivity and may not be readable on all older CD-ROMs and CD-R drives (old drives). It is quite difficult to say definitely which drives will be readable and which will not, since it depends on the device model. Currently, CD-R compact discs are sold on which information can be recorded. If after recording there is still free space on the disk, then additional information can be written to the disk, and so on. CD-RW discs allow you not only to record information, but also to delete unnecessary data, that is, write data repeatedly and are somewhat more expensive than CD-R discs.

In 1996 they appeared DVD -discs(Digital Versatile Disc - digital universal disk, originally stood for Digital video Disc - digital video disk. Now it is not decrypted in any way), which had a capacity of 4.7 Gigabytes due to compaction of recording tracks, that is, 7 times more than the capacity of CD-ROM disks. This is the most common type of disc, which is single-layer and single-sided. However, there are discs that have two layers on one side and have a capacity of 8.5-8.7 Gigabytes (they may be called DVD 9, the number means rounded capacity), there are discs with one layer, but with recording on two sides, with a capacity of 9.4 Gigabytes (they may be called DVD 10), double-layer and double-sided with a capacity of 17.08 Gigabytes (they may be called DVD 18). Double-layer discs have two translucent layers with powerful beam focusing, allowing information to be read from either the first or second layer. Higher data density is achieved by reducing the disk area per bit and using compression techniques. But in practice, the most common are single-sided, single-layer ones.

After the creation of a single DVD standard for recording video films on them, the whole world was divided into six zones so that films recorded in one zone could not be read in others. Therefore, an old DVD drive may have a pictogram showing an image of the globe with numbers indicating which zones this drive works with, or ALL (all) - to work with discs in all zones. Modern DVD drives do not have such a partition.

The information on the disks is located in sectors that contain data and 882 bytes for the error correction code, which makes it possible to increase the reliability of reading information, since in case of failures the values are calculated using the correction code. If there are bad sectors, the reading speed slows down and repeated reading occurs, and so on up to a certain number of attempts. As a result, either the code will be read, or a message will appear on the screen stating that it is impossible to read information from this disk, after which it switches to maximum speed again.

Unlike CDs, DVDs have their own file system, UDF, or ISO-9660 for data. Data is stored in 2048 byte sectors. Disks can be DVD-video, DVD-audio, DVD-Data and mixed types.

Discs DVD - ROM just like CD-ROMs are read-only. They have already been recorded somewhere and are sold with the recorded information.

The standard for recording on disk was developed in two ways, one standard called MMCD was developed by Philips and Sony, the second called Super Disc by Toshiba and several others. Therefore, two formats for recording data arose - DVD -R and DVD +R. These formats are close to each other, however, the plus format is better to use, since it takes less time to rewrite and the recorded data has fewer errors. Accordingly, there are two formats of rewritable discs DVD -RW and DVD +RW.

Write-once discs that have a double layer on one surface are designated by DL symbols, for example, DVD -R DL and DVD +R DL. They have a capacity of up to 8.5 gigabytes.

To work with DVDs, DVD drives are used, which have several types:

DVD - ROM The drive can only read both DVDs and CDs. One of the most important characteristics of this device is reading speed information. The multiplicity per unit is taken as 1.32 MB/sec, which is 9 times faster speed CD. They have different speeds reading CD and DVD discs, which is indicated in the device manual.

DVD - R drive is a write-once optical drive. It allows you to read CD-ROM, CD-R, CD-RW discs, all types of DVD discs, and also allows you to write CD-R discs and DVD +R and DVD-R discs once. This drive has the ability not only to read discs, but also to write them. For example, the reading speed is 40 times, and the writing speed is 6 times, and the speed is indicated separately for CDs and DVDs and, accordingly, separately for DVD -R and DVD +R disks.

DVD - RW storage device is a reusable optical storage device. It allows you to read and burn all types of CD and DVD discs. Reading and writing speeds are indicated separately for CDs, DVD -R, DVD +R, DVD +R DL, DVD -R DL, DVD +RW, DVD -RW, DVD +RW DL, DVD -RW DL, that is, those operations , which the drive can conduct. Here it is also better to use the plus format, since the minus format requires you to first erase the information and then write it, and the plus format allows you to rewrite data in real time.

Standard Blu - ray Disc (BD ) (blue ray- blue beam and disc- disk; writing blue instead of blue- intentional)was developed by the BDA consortium, released in 2006. U this standard there was a competitor - HD DVD from Toshiba, however, this company abandoned further support for HD discs in 2008 after the “format war”. The information reading speed (single speed) is 4.5 Mb/s. Increasing the volume of recorded information is achieved by using a laser beam in the blue-violet range with a shorter length of 405 nm, while CD and DVD drives use red and infrared lasers with wavelengths of 650 nm and 780 nm.

A single-layer disk can store 25 gigabytes, a double-layer disk can store 50 gigabytes, a three-layer disk can store 100 gigabytes, and a four-layer disk can store 128 gigabytes. A disk can have more layers. So in 2008, 20-layer disks with a capacity of 500 gigabytes were demonstrated.

IN currently BD-ROM read-only, BD-R write-once, and BD-RE write-once discs are available. There are also double-layer disks with DL symbols in the name with a capacity of up to 50 gigabytes.

Drives for these disks are Blu - Ray Read-only discs that allow you to read and write all types of CDs and DVDs, as well as read-only BDs. Respectively Blu - Ray RE allow you not only to read, but also to write all types of CDs, DVDs and BD discs (single-layer, for multi-layer you need to read the instructions).

To insert a CD or DVD into the drive, first press the button on the front panel of the drive (picture below). At the same time, a tray is pulled out of the drive, into which you need to place the disk in a special recess for it with the working surface on which the data is located, down, or with the pattern facing up. Then press the button again, and the tray slides into the drive housing. Now you can work with the disk. The tray has a second recess for disks, approximately half the diameter and currently very rarely used (they are often shown in detective and science fiction films).

For normal operation, the drive must be in a horizontal position. There is a drive that can work in a vertical position. In this case, the disk is inserted into the slot by hand, after which a special mechanism holds it and inserts it into the drive.

The optical drive has an emergency eject hole for the tray if it does not eject. To do this, you need to insert a thin rod, for example, a straightened paper clip, and press on it. In addition, there may be a button to skip to the next song for audio CDs. A configuration switch can be installed at the back, it is advisable to install a Slave, and there is also a connector for testing the drive by the manufacturer. Some drives may come with microphones, headphones, or sound cards.

For boot disk need to:

Turn on the computer;

Press the tray open button and it will slide out;

Place the disc with the print side up on the tray;

Press the tray open button again. The tray slides in, after which you can start working.

Do not pull the tray out or in by hand. It is not advisable to keep the tray open for a long time when there is no work; you should not place foreign objects on the tray, for example, placing a cup of coffee; you should not put pressure on the tray when placing a disc.

When there is no operation, the drive goes into energy saving mode, and the drive noise stops. When a read command is received, the drive starts working automatically.

The production of a disk occurs as follows: first, a disk is made, which is called the “mother”, then a working copy is stamped - the “father”, then others are pressed on its basis.

Basic drive characteristics:

Type: interior or external. The internal drive is inserted into the system unit. The external one has a rectangular body, connects to a parallel port (in old computers), USB (in modern ones) and has a wire connected to the mains. There is also an external option for laptop computers, connected using a PCMCIA connector;

- baud rate(Data Transfer Rate, DTR), respectively indicated as two-speed, four-, thirty-two, etc.;

- buffer memory capacity(Buffer Memory). Cache memory is a RAM chip that is located on the drive board. They provide benefits, so the larger the volume, the better;

- average time between breakdowns(Mean Time Between Failure, MTBF). This characteristic available in many devices, but not described everywhere;

- interface type or bus to which it is connected;

- average access time(Access Time, AT). It is larger for CD-ROM drives than for hard drives, which is determined by fundamental differences in the design of the drive, and differs tens of times, and the greater the multiplicity, the shorter the access time. So, for a 4x drive it is approximately 150, and for a 32x it is 80 ms. This value can be found in the device passport;

- error rate(Error Time);

- list of supported formats.

There may also be other parameters, such as noise and vibration levels. In addition, when purchasing, you need to see whether the tray moves smoothly and whether it is firmly held open.

BIOS latest versions allows you to boot your computer from CD and DVD discs. The CD-ROM disk at the beginning of the track has a service area, which contains information for synchronizing the drive and disk, then the volume table of contents (VTOC), which contains data about the organization of directories and files on the disk, then data and a label end of the volume. Thus, knowing the path and file name, you can use the table to find the file’s location on the disk and directly position the head to read data, which reduces search time and read operations.

Connects device using two cables: power and information. There are three types of drives: those connected to the SCSI bus, to the IDE bus or to the SATA connector. It's better to have a drive that connects to the IDE connector if it supports it motherboard. Since there are usually few SATA connectors and, if you need to install several optical or drives for hard drives, then there may be a problem with the presence of a free connector.

The connection to just such a bus is described below. Optical drives can be connected along with a hard drive. The data cable consists of 40 cores (shown in the figure above) and has three plugs. One is connected to the hard drive controller (on older boards) or directly to the motherboard (see also the description of the boards and hard drive). The second to the optical drive and the third to the hard drive. Do not forget that the edge of the cable, marked in red, when connecting the plug, should be located near the markings 1, 2, which indicate the first cores of the wire, the opposite end - near the numbers 33 and 34. The second power cable should be connected to the marking indicated on top of the plug, that is, red (5v), black, black and yellow.

If you have a sound card, to listen to sound from music discs, you must connect a third cord consisting of four wires. One end connects to the sound card, the other to the drive. They are marked with the symbols R and L. The wire coming from the sound card with the symbol R must match the R on the drive. The figure below shows the back of the drive, which has connectors for connecting wires.

The procedure for installing a new optical drive is the same as installing a floppy drive. If installed Windows system 9x, then a corresponding message about finding a new device will appear on the screen. In system Windows operating system the system itself recognizes new devices, including an optical drive.

When working with disks, you must do following rules:

Do not touch the work surface, otherwise greasy fingerprints may remain on it;

Take the disk by the outer edges, you can take it by the edges of the central hole;

Clean the disc from the center of the disc to the outer edge with a soft, dry cloth. Do not use strong solvents such as acetone, detergents, antistatic aerosols;

Store discs in a special box or disc sleeve;

Do not bend the disc;

Do not write on the working surface of the disc;

When storing the disc, avoid exposing it to sunlight or strong heat, which may cause the disc to warp.

Disks may have defects that prevent data from being read. If there is a displacement of the concentric tracks relative to the center of the disk, then such a disk will be difficult to read, and such a defect cannot be detected by eye. Reducing the disk rotation speed may help, for example, try doing this on a slower drive. If the disk is warped, sometimes noticeable to the eye, then reducing the rotation speed can also help to read such disks.

If there are specks on the disk, then, depending on their location and size, it is sometimes possible to use such a disk. Scratches that go from the edge to the center are often harmless, but scratches that run along the edge may prevent data from being read. Therefore, you need to wipe the disc from the center to the edge. Special test programs are used to check the disk. When installing, use an interrupt (IRQ) - 7 and higher, base addresses 300h to 340h, DMA1. CDs are quite reliable, however, if there are cracks on the CD, it is recommended to make a copy of the disc, as new cracks may appear in the future and the information on the disc will be unreadable.

Installing the drive. to install this device, need to:

Turn off computer;

Remove the protective cover system unit;

Insert the drive into the guides of the system unit. After installation, be sure to tighten the screws on the sides of the device. Sometimes, in order to reach with a screwdriver and tighten the screws, you may need to remove other devices. After this, connect the wires as described above, install the protective cover, turn on the computer and check the operation of the drive.

Technical installation optical drive similar to installing hard disk.

If the tray does not extend, the reason may be that the drive is tightly secured with screws inside the system unit, which causes the drive to become skewed. The sound during CD overclocking is not a sign of malfunction. After installing the optical drive for testing, you can try copying some files from the optical drive to your hard drive. You should not disassemble the drive yourself. The drive should not be exposed to rain or in a damp place.

Information carriers – material that is intended for recording, storage and subsequent reproduction of information.

Storage medium - a strictly defined part of a specific information system, used for intermediate storage or transmission of information.

Storage medium is the physical environment in which it is recorded.

The media can be paper, photographic film, brain cells, punched cards, punched tapes, magnetic tapes and disks or computer memory cells. Modern technology offers more and more new types of storage media. They use the electrical, magnetic and optical properties of materials to encode information. Media are being developed in which information is recorded even at the level of individual molecules.

All computer media are divided into:

1. Perforated – have a paper basis, information is entered in the form of punches in the corresponding row and column. The volume of information is 800 bits or 100 KB.

2. Magnetic media – they use flexible magnetic disks and cassette magnetic tapes.

3. (compact discs) is a metallized plastic compact disc, 120 mm in diameter and 1.2 mm thick. On one of its sides there is a reflective aluminum layer, which is coated with a protective varnish to prevent damage. Information is recorded and read by a laser beam on a path running in a spiral from the center.

Optical storage media– (compact discs) is a metallized plastic disc with a diameter of 120 mm. And 1.2mm thick. On one of its sides there is a reflective aluminum layer, which is coated with a protective varnish to prevent damage. Information is recorded and read by a laser beam on a path running in a spiral from the center.

Types of optical disks:

1. CD-ROM (Compact Disk Read Only Memory) – a compact disc without the ability to record information.

2. CD-R (Compact Disk Recordable) – a CD with the ability to record information once.

3. CD-RW (Compact Disk Rewritable) – a CD with the ability to record information multiple times.

4. DVD (Digital Versatile Disk) – a digital multilayer disk for recording large amounts of information (up to 18 GB).

ADVANTAGES: Reliability. Ability to record large amounts of information. Wear-free.

Compact Disk (CD) is a disc with a diameter of 120 mm (4.75 inches) or 80 mm (3.1 inches) and a thickness of 1.2 mm. The depth of the stroke is 0.12 µm, the width is 0.6 µm. The strokes are arranged in a spiral, from the center to the periphery. The stroke length is 0.9–3.3 µm, the distance between the tracks is 1.6 µm. Compact discs are made up of three to six layers. A standard five-inch disc can contain 650–700 MB of information, 74–80 minutes of high-quality stereo sound with a sampling rate of 44.1 kHz and a digitization depth of 16 bits, or a huge amount of audio in MP3 format. Three-inch disks hold about 180 MB of information. Sometimes there are disks called “business cards”. By appearance and they resemble a business card in size, but are actually three-inch disks, cut on both sides. Such a CD can store from 10 to 80 MB.

In the late 1970s, Sony and Philips began jointly developing a single standard for optical storage media. Philips created the laser player, and Sony developed the technology for recording on optical media. At the suggestion of Sony Corporation, the disc size was 12 cm, because... this volume made it possible to record Beethoven’s Ninth Symphony in its entirety. In 1982, in a document called the Red Book, a standard for processing, recording and storing information on laser disks was published, as well as the physical parameters of the disk, i.e.: 1. Physical size of the disk. 2. Disk structure and data organization. 2. Recording data in a single stream from the center to the periphery. 3. Read data at a constant linear velocity (Constant Linear Velocity, CLV).

All data on the disk is divided into frames. Each frame consists of 192 bits for music, 388 bits for modulation and error correction data, and one control bit. 98 frames make up one sector. Sectors are combined into a track. A maximum of 99 tracks can be recorded on a disc.

During recording and reading of information, when the laser beam moves from the center to the periphery, the rotation speed of the disk is ↓. This is necessary to ensure that the same amount of information can be read and written in the same amount of time. Therefore, without the use of CLV technology, when playing, for example, musical works, the performance speed would change.

Due to relatively small size laser discs Compared to vinyl records, they were called compact discs, or CD (Compact Disk) for short. The first CDs were designed for recording and playing music and could store up to 74 minutes of high-quality stereo sound. The standard for such discs was called CD-DA (Compact Disk Digital Audio).

With the development of the computer industry, a need arose for technology that allows storing on CDs not only digital audio, but also various data. Computer programs could not fit on floppy disks, and the volumes user files became more and more.

In 1984, a standard called the Yellow Book was published. Sony and Philips companies reorganized the structure of CDs and began to use new error correction codes - EDC (Error Detection and Correction) and ECC (Error Correction Code). The main unit of data placement was the sector. One sector contains: 12 bytes for synchronization, 4 bytes for headers, 2048 bytes for user data and 288 bytes for error correction. CAV (Constant Angular Velocity) technology was developed to read computer data. CAV technology allows you to read information from a disk faster than CLV technology, since the data flow increases as the laser beam moves from the center to the periphery. Modern CD drives support both technologies. Computer laser disks were called CD-ROM - Compact Disk ReadOnly Memory (literally, “read-only memory on CDs”). In the late 1990s, the CD drive became a standard component of any computer and the vast majority of programs began to be distributed on CDs.

The consumer market was rapidly expanding, production volumes were increasing, and the largest manufacturers began developing technology that allows the user to independently record any information on a CD. In 1988, Tajio Yuden released the world's first CD-R (Compact Disk Recordable). The biggest challenge faced by CD recorder designers is finding highly reflective materials. Tajio Yuden successfully completed the task. The gold-cyanine alloy they used to make these drives had a reflectivity of over 70%. The same company developed a method for applying an active organic layer to the surface of a disk, as well as a technology for dividing the disk into tracks.

DVDs, DVD-R, DVD-RW, CD, CD-R, and CD-RW are manufactured by various companies: AMD, Amedia, Digitex, HP, Imation, MBI, Memorex, Philips, Smartbuy, Sony, TDK, Verbatim.

DVD structure.

In December 1995, 10 companies united in the DVD Consortium officially announced the creation of a single unified standard - DVD. The abbreviation DVD first stood for Digital Video Disc, but later its meaning was changed to Digital Versatile Disc. The disc was fully compatible with the Red Book and Yellow Book standards. DVD is identical in appearance to CD, but allows you to record information that is 24 times larger in volume, that is, up to 17 GB. This became possible thanks to changes in the physical characteristics of the disk and the use of new technologies. The distance between the tracks was reduced to 0.74 μm, and the geometric dimensions of the pits were reduced to 0.4 μm for a single-layer disk and 0.44 μm for a double-layer disk. The data area has increased, the physical sizes of sectors have decreased. A more efficient error correction code, RSPC (Reed Solomon Product Code), was used, and more efficient bit modulation became possible. DVD technology provides a huge number of formats and four types of designs in two sizes. A disc of this standard can be either single-sided or double-sided. There can be one or two working layers on each side.

Burning single-layer DVDs is similar to burning CDs, but burning dual-layer discs is significantly different from the process described earlier.

Double-layer discs of types DVD-2 and DVD-9 have two working layers for recording information. These layers are separated using a special translucent material. To perform its function, such a material must have mutually exclusive properties: reflect the laser beam well when reading the outer layer and at the same time be as transparent as possible when reading the inner layer. At the request of Philips and Sony corporations, 3M created a material that meets the following requirements: having a reflectivity of 40% and the necessary transparency. DVDs are 0.6mm thick. For physical compatibility with CDs, a 0.6 mm thick polycarbonate backing was additionally glued onto the DVD.

The CD specification does not provide any copy protection mechanism - discs can be freely copied and played. However, starting in 2002, various Western record companies began attempting to create copy-protected CDs. The essence of almost all methods comes down to deliberately introducing errors into the data written to the disk, so that on a household CD player or music center The disc played, but not on the computer. The result is a game of cat and mouse: such discs are not readable on all household players, but on some computers they are readable, software is released that allows you to copy even protected discs, etc. The recording industry, however, does not give up hope and continues try more and more new methods.

There are also magneto-optical disks : FLOPTICAL = FLOPPY (floppy disk) + OPTICAL.

The surface of the magneto-optical disk is covered with a special material, the properties of which change under the influence of temperature and magnetic fields. All these disks differ from each other in diameter and number of working surfaces. The volume of information is up to 10 GB.

Optical disc

Optical disk

a data carrier in the form of a plastic disk intended for recording and reproducing sound (CD), images (video disc), alphanumeric information (CD-ROM, DVD), etc. using a laser beam. The first optical discs appeared in 1979. Philips created them for recording and playing back sound. An optical disc consists of a rigid, optically transparent base, on which a thin working layer and an additional protective layer are applied. Thanks to the optical reading method, optical discs are much more durable than gramophone records. The diameter of a standard CD is 120 mm (4.5 inches), thickness - 1.2 mm, center hole diameter - 15 mm. CDs are made from very durable transparent plastic - polycarbonate or polyvinyl chloride. A label is placed on one side of the disc, and the other side has a mirror surface that shimmers with rainbow colors. This is a recording zone, the spiral track of which consists of pits - recesses of various lengths. The distance between two adjacent spiral tracks is 1.6 microns, i.e. the recording density is 100 times greater compared to a conventional gramophone record. The width of the pits is 0.6–0.8 µm, and their length is variable. It reflects the length of the “1” sequences of the recorded digital signal and can vary from 0.9 to 3.3 µm. Information in the form of pits is protected from mechanical damage on one side by transparent disc material, and on the other by a layer of plastic and a label. Compared to mechanical sound recording, it has a number of advantages: a very high recording density and the complete absence of mechanical contact between the medium and the reading device during the recording and playback process. Music CDs are recorded at the factory. Like gramophone records, they can only be listened to. Using a laser beam, the signals are recorded digitally on a rotating optical disk. As a result of recording, a spiral track is formed on the disc, consisting of miniature grooves and smooth areas. In playback mode, a laser beam focused on a track moves across the surface of a rotating optical disk and reads the recorded information. In this case, the depressions are read as ones, and the areas that evenly reflect light are read as zeros.

Contactless reading of information from a CD is carried out using an optical head or laser pickup. The optical head consists of a semiconductor laser, optical system and a photodetector that converts light into electricity. The reading laser beam is focused on a spiral track with pits located deep in the disk. The head never comes into contact with the disk - it is always at a strictly defined distance from it, ensuring that the track of pits is in the focus of the optical system.

Multimedia technology allows you to combine personal computer text and graphics with sound and moving images. Optical CD-ROMs (Compact Disk Read Only Memory) are used as storage media in such multimedia computers. Outwardly, they do not differ from audio CDs used in players and music centers.

The capacity of one CD-ROM reaches 650 MB; in terms of capacity, it occupies an intermediate position between floppy disks and a hard magnetic disk (hard drive). A CD drive is used to read CDs. Information on a CD is written only once in an industrial environment, and on a personal computer it can only be read. A wide variety of games, encyclopedias, art albums, maps, atlases, dictionaries and reference books are published on CD-ROM. All of them are equipped with convenient search engines allowing you to quickly find the material you need. The memory capacity of two CD-ROMs is enough to accommodate an encyclopedia larger in volume than the Great Soviet Encyclopedia.

Information optical CDs are designed for single (so-called CD-R) and multiple (so-called CD-RW) recording of information on a personal computer equipped with a special drive. This makes it possible, like a tape recorder, to make recordings on them at home. CD-R discs can only be written to once, but CD-RW discs can be written to multiple times, just like magnetic disk or tape, you can erase the previous recording and make a new one in its place.

1 – CD; 2 – translucent coating that protects the information printed on the CD from damage; 3 – reflective coating (the recording medium itself); 4 – protective layer; 5 – focusing; 6 – laser beam; 7 – optical splitter; 8 – photodetector; 9 - ; 10 – electric motor rotating the disk

The existing CDs are being replaced by a new media standard - DVD (Digital Versatile Disc or digital disk general purpose). They look no different from CDs. Their geometric dimensions are the same. The main difference between a DVD disc is its tens of times higher recording density. This is achieved thanks to a shorter laser wavelength and a smaller spot size of the focused beam, which made it possible to halve the distance between tracks. The DVD standard is defined in such a way that future models of reading devices will be designed taking into account the ability to play all previous generations of compact discs, i.e. in compliance with the principle “ backward compatibility" In 1995, Philips developed CD replay technology. The DVD standard allows you to significantly increase the time and improve the quality of video playback compared to existing CD-ROMs. DVD drives are advanced CD-ROM drives.

Encyclopedia "Technology". - M.: Rosman. 2006 .

See what an “optical disk” is in other dictionaries:

optical disk- A disk containing digital data read using optical technology. [GOST 25868 91] Equipment topics. periphery processing systems information EN optical disk...

Working with optical discs Optical disc An image of an optical disc, ISO image Optical drive emulator Software to work with file systems optical disks Recording technologies Recording modes Batch recording Types ... ... Wikipedia

optical disk- 147 optical disk: A disk containing digital data read using optical technology Source: GOST 25868 91: Peripheral equipment for information processing systems. Terms and Definitions … Dictionary-reference book of terms of normative and technical documentation

OPTICAL DISC- according to GOST 25868–91, “Peripheral equipment for information processing systems. Terms and Definitions” – a disk containing digital data read using optical technology... Records management and archiving in terms and definitions

blue laser optical disc- Blu Ray Discs (BD) are a new generation of storage media for storing high-definition video (HDTV) and high-density data. The Blu Ray standard was jointly developed by a group of consumer electronics and computer companies... Technical Translator's Guide

Books

Methods for developing social, emotional and practical intelligence of a young athlete +CD, Kuzmenko Galina. The training manual presents the content side of the manifestation of the psychological and pedagogical skills of a trainer in the development of social and emotional intelligence in a system of significant qualities...

Popular

Set a password on your computer

« Please note: To follow most of the instructions in this article, you must use a local Windows account with... »

How to save photos from Instagram to your computer How to download a selection from Instagram

« Many people are now wondering how to download their favorite photo from Instagram or download it to their computer. In this article we will explain in detail... »

The best feature phones

« 2016 brought many new products to lovers of mobile digital technology. Advertisements on the Internet are full of posts about new developments in the field... »