Hello everyone! I think that many of you are interested in the question What class memory card is better to choose for a camera, camcorder, tablet, mobile phone or some other digital device that uses SD format card for storage. Surely you know that there are several generations of cards in SD format with a speed classification and memory. So each type of memory card has its own specification, which direct affects the scope of application and compatibility mode with a particular device.

Many consumers choosing a drive for their digital device perfectly vain ignore the SD cards of memory cards taking into account only the type and large amount for storing information. Recently, the manufacturers themselves are already clearly and clearly in the specifications to the device indicate which memory card class is needed to collaborate with the device. However, some consumers are still difficult to figure out the types, classes, volumes and compatibility of SD drives. I will try in this article as simple as possible and detail about the digital memory card in the SD format.

I will start with the fact that the SD format came to replace the MMC portable flash card ( Multimedia Card) with which they physically have the same size (32 × 24 × 2.1 mm), but technically have different execution. The considered format has its own controller and a special protected area from unauthorized access, as well as a manual switch to prevent unintently erasing or overwriting existing information. Keep in mind that the protection against accidental erasure is activated not by the SD card itself, and the device in which it is, provided that it has support for this function.

The volume and format of the SD memory card.

There are several types of memory cards in SD format (Secure Digital Memory Card), which I listed below in reverse compatibility. That you mean the previous memory card format in the list of the list is compatible with the following and not interconnect in the reverse order.

SD (Secure Digital Memory Card) - This is the very first format of a safe digital memory card. This type is compatible with all digital devices that support all the following formats (SD, SDHC, SDXC).

• Maximum memory: 4 GB;
• Initially file system: FAT16.

SDHC (SD HIGH CAPACITY) - This is the following SD high capacity memory card. This format works a little different than the previous representative and has no backward compatibility with devices that support SD format.

• Maximum amount of memory: 32 GB;
• Information exchange rate: 12.5 MB / s;
• Initially file system: FAT32.

SDXC (SD EXTENED CAPACITY) - The next descendant of the SD memory card of the extended capacity. This format has another file system and therefore does not have backward compatibility with digital devices that work only with SD. Many devices released after 2010 must be compatible with this format. To finally verify the compatibility of the memory card with the device, find the SDXC logo on the map and device. In addition, the card reader can work with a format not higher than SDHC will not be compatible with SDXC cards. This format is not supported by all operating systems.

• Maximum memory amount: 2 TB;
• Information exchange rate: 25 MB / s;
• Initially file system: EXFAT.

SDHC I, SDXC I, SDHC II, SDXC II - A card with one of these logos has an increased data exchange rate due to the UHS bus interface enhancement. In a simple and understandable language, we can say that UHS (Ultra High Speed) is an addition to the original interface of the SD format, which from time to time is improved by developers. It should be said that the host device will receive the highest possible UHS speed only if the memory card and the receiving device support UHS, otherwise the slower speed provided in SD format will be available.

• UHS I - has two architectures for the maximum rapid data exchange of 50 MB / s and 104 MB / s. Here the developers overdered the assignment of some contacts to implement four bit exchange data.
• UHS II - the following improved generation also has two architectures for high-speed data exchange of 156 MB / s and 312 MB / s. Also used four bit data exchange mode.

Here the maximum possible data exchange rate for the interface is specified, and you can find out the supported data transfer rate for a particular memory card you can from the specification on the manufacturer's website or from the information sticker on the map packaging. Complete compatibility of UHS cards with digital devices are not having high-speed UHS protocol.

Since this SD format is aimed mainly on portable devices, it consists of three types. Each type of card has its own size.

For example, a standard SD format has a size of 32 × 24 × 2.1 mm, and MINISD has a size of 21.5 × 20 × 1.4 mm. The small MicroSD format has the most compact size of 11 × 15 × 1 mm, and with the help of special adapters, this type of memory card can be adapted to the desired slot form factor.

SD Card Memory Cards.

Now let's understand with you what means the class of memory cards and which sense load this information carries in itself for the consumer. So, the classes contain information about the minimum recording speed to the memory card. In other words, the higher the memory card class, the faster you can record and save the bulk information, play large audio and video files without interruptions and scraps of sound.

And so that the consumer is easier to navigate the speed capabilities of the memory cards, the International SD Card Association Association classified them by high-speed features (multiplier) along with digital devices that can work with them called SD SPEED CLASS. The speed on the memory cards is indicated through a special multiplier called the rating.

This indicator is constantly growing, but on this moment SD Multiplier from 6x to 633x. To be clear, I will say that 1x \u003d 150 kb / s. It turns out that maps initial level They have a speed of 6x \u003d 900 kb / s, and the SD cards of the highest level are comparable to the speed of 633x \u003d MB / s. According to the speed specification from SD Card Association, all memory cards are divided by minimal high-speed signs of the record as follows:

• SD Class 2: recording speed of at least 2 MB / s - multiplier 13;
• SD Class 4: recording speed of at least 4 MB / s - multiplier 26;
• SD Class 6: record speed of at least 6 MB / s - multiplier 40;
• SD Class 10: recording speed of at least 10 MB / s - multiplier 66;
• SD Class 16: Recording speed of at least 16 MB / s - multiplier 106.

It is the memory card class that is one of the important parameters when choosing a removable SD drive. In the previous publication, I touched upon the topic of unscrupulous manufacturers and this case SD memory card has not exceeded.

Unfortunately, there are "honest" manufacturers that the multiplier does not correspond to the actual speed indicate the map. That you mean the card in fact may have the declared speed by the manufacturer, but in read mode, not record.

To determine the SD multiplier of the memory card, you can spend your independent test using a cartrider and a specialized program (for example, for Windows - H2TestW; Linux - F3), and after the results obtained are compared with the table. You can also see how we conducted, which can also be used to test SD and MMC cards.

Rating / Multiplier (X)	Speed \u200b\u200b(MB / s)	SDHC class
6x	0,9	n / A.
13X.	2,0	2
26x.	4,0	4
32x	4,8	5
40x.	6,0	6
66x	10,0	10
100x.	15,0	15
133x	20,0	20
150x.	22,5	22
200x.	30,0	30
266x	40,0	40
300x.	45,0	45
400x.	60,0	60
600x.	90,0	90

The speed class rating plays an important role for the HD video mode, because in this case the digital device is in constant storage of the data stream to the memory card. It is the resolution and format that affect the amount of stable data streams. Therefore, be sure to look at the digital device instructions Requirements for the minimum speed class for the HD video mode.

How to choose an SD card.

As a rule, the high-speed class of the memory card on the simple SD format is indicated by the number inside the letter C, and for the UHS standard, the speed class is determined by the digit inside the letter U. Scope of classes and compatibility with devices.

Class	Record speed	Purpose
Class 2.	at least 2 MB / s	Writing video data for standard SD format resolution
Class 4.	at least 4 MB / s	To record HD video format (high definition), as well as Full HD format (detectable resolution from 720p to 1080p / 1080i). Digital Entry Level Cameras, Gaming Consoles and other devices with SDHC format cards.
Class 6.	not less than 6 MB / s
Class 10.	at least 10 MB / s	To record video in Full HD format (1080p) and consistent registration HD Stills (High-Speed \u200b\u200bData Bus)
UHS Speed \u200b\u200bClass 1 (U1)	at least 10 MB / s	Video recording in Full HD format, three-dimensional video image, shooting photos in high definition format (HD) and record broadcasting in real time
UHS Speed \u200b\u200bClass 3 (U3)	not less than 30 MB / s	Record video files for television 4K - UHD television (UHS Bus). D-SLR and D-SLM cameras and 4K or 2K support camcorders.

And finally, I will say a few more words about the compatibility mode of the SD cards. SDHC memory cards are not compatible with those digital devices that are initially designed only to work with SD cards, but those host devices (camera, camcorder, telephone ...) which can work with SDHC cards are fully compatible with SD cards.

SDXC format memory cards should be used only with SDXC devices, since the SD / SDHC devices will not work, but the SDXC digital devices can use and support the SD, SDHC and SDXC memory card. The SDHC host device is supported by both SD and SDHC memory cards, and the memory cards in the SDHC format can be used with SDHC and SDXC digital devices.

I hope I managed to tell just about the difficult and you can now choose an SD card for your camera, camcorders, phone, tablet, reader, and so on. Subscribe to new articles, there will still be a lot of interesting things. If you can add material or express your opinion, then do it in the comments.

2019-09-18T23: 37: 08 + 00: 00

Bought recently map of samsung 256GB for 15 bucks on Ali on the promotion ... came, without packing a purely adapter and a card in a box. The recording speed of large 10 Mbps files, software shows 22 Mbps record, reading and there and there are 4-5 Mbps. H2TestW flooded 238GB files and read them, ranked all the procedure for about 20 hours. And now it is not clear, it seems to be real, but the speed is clearly not as u3? How else can you check fake this or not?

2019-07-04T12: 46: 10 + 00: 00

You would write the model of your tablet so that you can figure out ... Perhaps the manufacturer was mistaken, not the author of the post.

2018-04-22T16: 47: 00 + 00: 00

Sony usually apply MemoryStick cards

2017-06-01T22: 14: 44 + 00: 00

hello! Help please pick up a memory card for the Prestigio MultiPad PMP5080CPRO tablet

2017-05-16T13: 08: 47 + 00: 00

Does the Map of Memory with the label "for an action cameras" on the smartphone? To write video and photo

2017-05-10t10: 19: 35 + 00: 00

Hello. There is an old camera Sony Cyber-Shot DSC-W570 (2011 release). I would like to buy a memory card for 64 GB. Our store has several attractive SD card offers with class U1. But will this class work on the old camera? Or search for grade 10 (C10)?

2017-05-01T14: 35: 35 + 00: 00

Everything is relative. A high-quality thing can not be cheap. And the sellers really sometimes surprise with their prices.

2017-05-01T10: 18: 41 + 00: 00

the price of the memory card depends only on the arrogance of the seller! Not from quality! It is necessary that you can check on the computer to check its quality through the H2TestW program - it will be very reliable! It should also be a guarantee for a flash drive or a refund of the money on Aliexpress. By the way, if you do not want to overpay and buy cheaper than you buy sellers of your stores, use the function of returning the cost from purchases from Aliexpress. Important! Read reviews before buying goods on Ali!

2017-04-21t17: 49: 35 + 00: 00

What exactly and why? Do you think so will be logical and more convenient? P.S. It is important to me the opinion of visitors.

2017-04-21T17: 28: 31 + 00: 00

Place the table to the beginning of the article

2017-03-12T23: 46: 18 + 00: 00

Please tell me what's the matter? I bought several different micro-SD cards on the sample. The sample is this: turning off the MP3 player - only with the kingmax card, the volume level and the approximate position of the track is dry. The rest of the cards are reset at the beginning and on the minimum volume - very uncomfortable! What does Kingmax differ from others? Capacity is the same 2GB, the class is not specified on any card.

2017-01-31T14: 06: 24 + 00: 00

I saw a map already with a multiplier of 1833x 275MB / s)) and if someone plans to record 4K video, 64GB is not enough for an SD card, quickly clogs))

2017-01-07T06: 29: 51 + 00: 00

Capacity Capacity 64 and above go from the plant formatted in EXFAT. Not all devices understand this format, so it was originally in the tablet did not work. After reformatting in FAT32 and EXT4 (on the Figa ext4? You have an infinite number of overwriting cycles to keep the FS journaling on the flash drive? In this case, only EXT2, only the speed to the detriment of excessive reliability) ExFat has shown and the device saw familiar FS.

2016-10-27T18: 18: 28 + 00: 00

Such a question why the manufacturer writes that supports the tablet MicroSDHC card up to 128 GB, although you have written that this type of card has a volume of up to 32 GB

2016-10-06T08: 58: 57 + 00: 00

A recordable memory card is designed primarily for shooting video in high-definition format 4K and 8K, as well as panoramic videos, the files of which occupy a lot of space. The first memory card in the world volume of 1 terabyte released SanDisk, but until it remains a prototype. I think that soon it can be seen in online stores.

2016-07-24T16: 51: 26 + 00: 00

And what kind of program, tell me?

2016-06-26T18: 01: 02 + 00: 00

Look at the technical characteristics. If you want to help you, specify the device model.

2016-06-25T10: 07: 37 + 00: 00

Of course, I understand everything, but you can find out how to find out what kind of SD cards support my smartphone?

2016-06-02T14: 44: 38 + 00: 00

Hey! Bought Lumia 640 XL. What card will you advise to buy?

2016-04-04T11: 37: 48 + 00: 00

Completely ... The card class affects the speed of reading and writing. But before you choose an SD card, you should find out what maximum volume supports your device.

2016-04-04T08: 35: 19 + 00: 00

I managed to shove the smartphone first, then in the tablet incompatible Micro SD! It is done very simple: I have a 64 GB card of the 10th grade. Did not work at the initial installation. I am through the program (there is such) divided into two sections FAT 32 and EXT 4. Inserted and earned! Then I roasted the device. Changed the USB drive with Micro SD. So do not work cards not because of the class, but because of the volume!

2016-03-31t11: 38: 22 + 00: 00

Good day! Phone Samsung Gelaxi 5. Bought a micro SD 64 GB. set!!! I download on the phone through Yustor. On the internal memory The phone is downloaded with a speed of 10 MBS, and on micro SD more1.5 does not rise !! What can be done, so that the files are also swore for micro SD !!! Thank you!

2016-03-31T02: 34: 27 + 00: 00

what card is better than CDXC or Memori Stik from Sony?

2016-03-16T10: 06: 17 + 00: 00

Thank you for the article! Very promotion, structurally and just written!

2016-03-04T12: 20: 48 + 00: 00

Good day! Thank you for the article. Useful. In the article, write how to choose a map. I have a question. We simulate the situation: there is a smartphone writes or reproduces from a video card with a speed of 4 MB / s, which means there is no point in buying a Class 6 Card Card. Question: How to buy a card to determine the speed of video transmission? Thanks for attention.

2016-02-07T22: 19: 36 + 00: 00

Unfortunately, I do not have the ability to test for compatibility and speed of all smartphones with SD cards. I think that there will be no problems.

2016-02-07T18: 16: 56 + 00: 00

Hello !!! Tell me please flash drive on 32 GB on the Lenovo K3 W device (it is Lenovo A6000), perhaps where the thread I will put it. While I looked at: Microsd 32GB SanDisk Class 10 Extreme 90MB / S + SD Adapter manufacturer SanDisk model SDSQXNE-032G-GN6MA Do you think? The phone stands with it will work or what easily?

Technical characteristics of the CD-R disc.

CD-R is a thin disc from transparent plastic - polycarbonate - 1.2mm thick, diameter 120mm (standard) or 80mm (mini). Capacity of the standard CD-R is 74 minutes of audio or 650mB data. However, at the moment (2006) standard can be considered a CD-R capacity of 702MB data (more precisely 736 966 656 bytes) or 79 minutes 59 seconds and 74 frames. Such a capacity is achieved by a small exceeding the tolerances described in the Orange Book Standard (CD-R / CD-RW). Also on the market there are 90 minutes / 790mb and 99 minute / 870MB discs that have received much less distribution.

The polycarbonate disk has a spiral track for the direction of the laser beam when recording and reading information. On the other side where this spiral track is located, the disc is coated with a recording layer, which consists of a very thin layer of organic dye and then reflective layer of silver, its alloy or gold. This reflective layer is covered with protective photopolymerizable varnish and curable with ultraviolet radiation. And already on this protective layer, various inscriptions of paint are applied.

Clean CD-R is not completely empty, there is a service track with ATIP servometers - Absolute Time In Pregroove - Absolute time in the service path. This service track is needed for the tracking system, which holds the laser beam when recording on the track and monitors the recording speed (i.e. it monitors that the pit is constant). In addition to the synchronization functions, the service path also contains information about the manufacturer of this disk, information about the material of the recording layer, the length of the track for recording, etc. The service path is not destroyed when writing data to the disk and many copy protection systems use it to distinguish the original from the copy.

The first companies that started the production of "DOOLANKS" CD-R were Taiyo Yuden, Kodak, Maxell and TDK. Since then, the CD-R standard has been subjected to further development to ensure all high recording rates and at present (2006) the maximum possible CD-R recording speed is 52x, i.e., 52 times more than that defined in the Orange Books "(1x \u003d 150 kb / s). These improvements are mainly in new materials for the recording layer, the best geometry of the track and technology of applying the recording layer. Low-speed recording 1x is still used to record special "audio CD-R", since record decops on CDs were standardized precisely on this speed.

Clean "blanks" CD-R have a service path with recorded data. This track contains temporary tags and is used when recording so that the laser beam is written along the spiral track as on ordinary CDs. Instead of printing pites as physical recesses in the "Dawnki" material, as in the case of CD, when recording CD-R, the data is written to the laser disk with a laser of high power so that the organic dye of the recording layer is physically "burning". When the dye heats up above a certain temperature, it is destroyed and dark, changing the reflectivity of the "spotted" zone. Thus, when recording, driving a laser power, the record layer is obtained by alternating dark and light spots, which are interpreted when reading as pita.

When reading the laser has a significantly less power than when recording, and does not destroy the dye of the recording layer. The beam reflected from the reflecting layer falls on the photodiode, and if the beam falls on the dark - "spotted" - a plot, the beam almost does not pass through it to the reflective layer and the photodiode registers the weakening of the light flux. While reading the "Double" in the drive spinning on the spindle, and the reading beam remains stationary and sent by the tracking system to the track with data. The alternating light and dark areas of the track generate a change in the light flux of the reflected beam and are transferred to the change in the electrical signal, which is further converted to the information bits of the electric drive system - "decoded".

Station of the recording layer is an irreversible chemical process, i.e. one-time. Therefore, recorded by CD-R information You can not erase, unlike CD-RW. CD-R, however, can be recorded in parts that are called sessions.

The three main types of the recording layer for CD / DVD are used:

Cyanine (eng. Cyanine) - Cyanin dye has a blue-green (color "sea wave") with a tinge of the working surface. This material was used in the very first "duals" CD-R and patented by Taiyo Yuden. This dye is chemically reluctantly, which causes a short term of guaranteed storage of recorded information. The dye can fad in a few years. Although many manufacturers use additional chemical additives to increase the stability of cyanine, such discs are not recommended for purposes reserve copy and long-term storage of archival data.
AZO - metallized azo-dye, has a dark blue color. Its formula is patented by Mitsubishi Chemicals. This dye is chemically racks and its ability to store information is calculated by decades (firms themselves write about 100 years).

Ftalocian (eng. Phthalocyanine.) - a little later development of an active layer recorded. Phthalocian Practically blunder, with a pale shade of salad or golden color, which is why the discs based on the phthalocyanic active layer are often called "golden". Phthalocian - Some more modern development. Discs based on this active layer are less sensitive to sunlight and ultraviolet radiation, which contributes to an increase in the durability of recorded information and somewhat more reliable storage in adverse conditions (firms approve hundreds of years).
Unfortunately, many manufacturers use various additives into the recording layer so that cyanine blanks are similar in color to phthalocyanine. Therefore, it is impossible to determine the material of the recording layer in color. Also, the reflecting layer of "gold" color does not guarantee that it is a phthalocyanin CD-R.
There are several data recording methods on CD-R:

Disc-AT-Once, DAO (Disc at a time) - the entire disk is recorded by one session, from beginning to end without interruptions. First, special information denotes the start of the recording (eng. lEAD-IN.), After that, the data is "burning", and then the disk "closes", i.e., a special sequence of bits is recorded, which reports the impossibility of adding information to this "blank" (eng. lEAD-OUT.). This method is well suited for recording concert speeches "live", without a pause between songs, as well as as master discs for subsequent replication at the factory.

TRACK-AT-ONCE, TAO (track at a time) - data is written on one track (session) at a time and left "open" (i.e., a "closing" record is not done), which indicates the possibility of further recording information on this disk. In addition, it allows you to record audio discs with an additional "computer" track. The audio disc will be able to read on the CD player only after the content table is recorded (TOC - Table Of Content). After recording TOC, adding tracks becomes impossible.

Packet Writing - not a very common type of recording, in which the disk "formatted" and in the future it can be written to it or make previously recorded data "invisible", i.e., such a CD-R becomes like discs with arbitrary reading and writing. However, if any data change (delete, recording, changing) on \u200b\u200bthe disk, you must write additional packages, and after all packages are recorded, the disk will be inaccessible for further changes - read-only. It is not supported by all drives, which leads to compatibility issues.

SESSION-AT-ONCE, SAO (session at a time) - SAO mode is used when recording the CD-EXTRA format. When using this format, the disk is assigned to record both audio information (CD-DA) and the program part. When recording, the audio tracks are "burning" first, and then the data.

MultiSession - recording mode that allows you to further add information to the disk. Each session contains the start-in session information (LEAD-IN), then the data and information about the end of the session (LEAD-OUT). When writing in multi-session mode, information about the structure of previous records is copied to a new session and can be edited. Thus, the user can destroy information about the structure of already unnecessary or outdated records without including it in a new content table (TOC - Table of Content). There is an opportunity to "erase" information from it from the CD, although in fact physically it continues to remain on the CD disk. Information can be restored with a special software.

Storage conditions and the average life of recorded CD-R.

At the moment (2006), the average CD-R lifetime is only estimated on the basis of accelerated aging tests, since this technology of optical carriers is too young and does not have practical data on this matter. It is believed that with proper care CD-Rs must withstand at least thousands of reading cycles and store recorded information several hundred years. Unfortunately, some generally accepted practices of incorrect disk treatment can reduce this figure to one to two years. Therefore, if the main purpose of the recording is the long-term storage of information, it is necessary to carefully handle the "blanks" CD-R.

The characteristics of the material recorded CD-R over time are affected by deterioration, however, like most other recorded carriers. Optical discs for a single record, CD-R, are used in the reciprocating layer, which changes the properties affecting the data storage under heat. The degradation process can lead to moving the recorded track with data inside the layer, as a result of which the drive will not be able to read the data from the disk.
Many cheap recorded "blanks" of little-known firms, as well as unnamed, "bald", "technological" blanks, have a lifetime of about two years. Some of these "bools" are higher than a longer service life - about five years. The distinguished low-quality "blanks" from high quality is very difficult, as only a few manufacturers (for example, Taiyo Yuden) care about the life of their products. Due to price wars, the quality of the disks is often sacrificed to the achievement as low cost as possible.
Recommendations for storage and work with "Dwarves" CD-R:

Store vertically, each in a separate case or slim-case. Being in them, the discs do not come into contact with the surface with the record layer on the wall of the case.

Avoid bending "Dawks". To remove the disk from the case, in no case cannot be "tightening" by the edges. Instead, you need to click on the spindle on which it holds, which will allow you to remove the disk without effort and bending.
"Dawk" must be kept for thin edges around the perimeter, and try not to touch the transparent protective layer so as not to contaminate this surface fingerprints.

Store in a cool dry place. The optimal temperature is 5-20 ° C (41-68 ° F), humidity 30-50%. Also unwanted sharp drops of these values.
Avoid straight sunlight. It can heat the case and the disc, which is located in it. The continuous impact of direct ultraviolet light (including solar) on the disk also negatively affects its characteristics. However, small doses of X-ray radiation, for example, when passing control at the airport, or magnetic fields should not have significant damage to discs.
If possible, use markers or markers with water solvents and a soft pen when writing marks on the surface for records. The best place for the mark is a small space on the disk around the central opening of a width of the order of one centimeter, usually completely transparent. Flomasters on alcohol solvents are considered less harmful to the disk than on xy or toluene. Usually permanent markers are made on the basis of xylene or toluene, and therefore it is not recommended to use them for marks on the disk. Many manufacturers produce markers specially designed to apply inscriptions on optical media (CD / DVD).

Never use stickers on disks. Adhesive stickers can be chemically affected by a disk, and in high-speed drives, the stickers lead to the disk beating. There are cases when the disk is scattered on the part inside the drive, which led to the loss of information and the output of the drive.
Unacceptable the appearance of scratches on any of the surfaces of the disk. Even a small scratch on the "external" surface with a recording layer can lead to partial or complete loss of information. Contrary to popular belief, small scratches with the "transparent" ("internal") disk side are less dangerous, but can also lead to the problems of reading and writing. It is impossible to write on the disks with ballpoint handles, since the mechanical effect on the disk usually leads it to disrepair.
Contact with water is also undesirable for the disk, especially for the "technological" "duals".
Cleaning disc
Usually clean cD-R disc It is only necessary if problems with reading information from it arise. Error correction codes used in CD-R are usually well coped with fingerprints and scratches on the transparent side.
The accumulated dust can be removed, the rubbish disk with a soft cloth movement from the center to the rod of the disk in the radial direction. You can not wipe the disk with circular motions, since the circular scratches will be parallel to the track and it is more difficult to cope with them than with radial scratches. More preferable another way to remove dust - blow it away with a jet of air from a sphailed air can, which is sold in stores.
Fingerprints or dirt can be removed with a soft tissue moistened with denatured alcohol (ethyl or isopropyl), after which the disk wipe the disk with the same radial movements.
You should never use acetone, nail polish solvent, kerosene, gasoline or other solvents based on petroleum products. Such aggressive solvents can literally dissolve the disk itself or make it the surface of muddy and unsuitable for work. Use only alcohol solvents.
CD-RW discs.
Technical specifications.
CD-RW (Compact Disc-Rewritable, Overwritten CD) - a CD variety developed in 1997 for multiple information record.
CD-RW is the further development of the recorded CD-R laser CD, however, in contrast to it, it allows not only to record information, but also to erase already recorded data. This format was introduced in 1997, and in the development process was called CD-Erasable (CD-E, washed CD). CD-RW is largely similar to its predecessor CD-R, but its recording layer is manufactured from a special alloy, which can be heated to lead into two different stable aggregate states - amorphous and crystalline. This alloy is usually made of silver (AG), India (IN), antimony (SB) and Tellur (TE). When recording (or erasing), the laser beats the path of the track and translates it into one of the stable aggregate states, which are characterized by various degrees of transparency. The reading beam of the laser has less power and does not change the state of the recording layer, and alternating areas with different transparency form a picture of similar powers and sites of ordinary stamped CDs.

"Dwarf" CD-RW allows you to overwrite information about 1000 times. With the exception of the ability to erase recorded information, for the user, work with "duals" CD-RW is very similar to work with single-writable CD-R. The data is recorded by sessions, you can add new files and "hiding" already recorded. With each new session, the free disk space decreases, and when it is over, it will be possible to completely erase information from the entire disk or part of it, after which it will again be available to record a new one. The new CD-RW - Universal Disk Format (UDF, Packet Writing) recording (UDF, Packet Writing) appeared later, which hides the user's technical difficulties and allows you to "format the" blank "and work with it as with a conventional large floppy disk / write / removal /the change. The volume of such UDF formatted dumplings is approximately 530MB, unlike the usual 700MB when recording sessions (more precisely, write 700MB can only with one session on the entire disk).

The recorded CD-RW does not fully meet the requirements described in the "Red Book" standards (CD-ROM) and "Orange Book Part II" (CD-R) - more specifically, they have a weaker reflected signal. And therefore such discs are not read in old CD drives issued until 1997. CD-R is considered a more suitable standard for backup media, because The information recorded on them can no longer be changed and manufacturers of "Dolls" indicate greater storage time for CD-R discs than for CD-RW.

With a regular entry on CD-RW - not UDF, periodically need to wash the disk. There are two types of erasure - "full" and "fast." As the name follows, with the "full" erasure, the entire information track is overwritten, roughly speaking, zeros, and the old information is destroyed. And the "fast" erase purifies only a small part of the disk from the beginning, which is much faster, but there is a technical ability to restore the data. Therefore, if there is a need to preserve the confidentiality of information, then you need to use complete erasing.
CD-ROM format discs.
CD ("CD", "CD-ROM", "CD ROM") - an optical medium of information in the form of a disc with a hole in the center, the information from which is read by the laser. Initially, the CD was created for digital storage audio (T.N. Audio-CD), however, is currently widely used as a wide-purpose storage device (T.N. CD-ROM). Audio-CDs on the format differ from CDs with data and CD players can usually play only them (on the computer, of course, you can read both types of disks). There are discs containing both audio information and data - they can be listed on the CD player, and read on the computer. With the development of MP3, manufacturers of household CD players and music centers began to provide them with the ability to read MP3 files from CD-ROMs.
The abbreviation "CD-ROM" means "Compact Disk Read Only Memory" and denotes a CD as a carrier of wide use information (unlike audio-compact disc). "CD ROM" means "CD, constant storage device". CD-ROM is often mistakenly called the CD-ROM drive.
DVD-R / RW discs.
Technical characteristic DVD-R disc
Externally, DVDs are almost impossible to distinguish from conventional CDs. They have the same dimensions and externally similar to each other. However, read the DVD disk on the usual CD drive will not succeed. To do this, you will need a drive with the support of a DVD format, which, by the way, the usual CDs read without problems.
All information on the DVD is stored in the MicroDF file system (Micro Universal Disk Format). She was officially approved in 2000. Microudb supports high capacity carriers and files large sizes. File names are recorded in Unicode format, which ensures DVD compatibility with all PC operating systems, as well as with a variety of home appliances.
The essential difference between the DVD from the CD is the possibility of two-layer records of the disks. On one one-sided disk (there are two-way, with an information surface on each side) can be stored twice as much information. Both layers have a reflective surface, only one of them has high transparency (up to 40%). When recording / reading, the beam simply changes focus, which allows you not to fall on both layers at the same time.

The higher capacity of DVDs is obliged not only by the possibility of two-layer recording of disks, but also greater density of information recording. A higher record density was achieved by reducing the distance between the information paths on the helix. This distance in the CD discs is 1.6 microns. DVD disks - 0.74 microns. The volume of DVDs, depending on their specific type, can be from 4.7 to 17 GB.
Types DVD:

DVD on data structure There are three types:
DVD-Video - contain movies (video and sound);
DVD-AUDIO - contain high quality audio data (much higher than on audio CDs);
DVD-DATA - contain any data.
DVD as carriers are four types:
DVD-ROM - stamped on the factory disks;
DVD + R / RW - once (R - Recordable) and multiple (RW - REWRITABLE) recording;
DVD-R / RW - ONED disks (R - Recordable) and multiple (RW - Rewritable) entries;
DVD-RAM - multiple access repeat disks (RAM - Random Access Memory).
DVD can have one or two working parties and one or two working layers on each side. The capacity of the disk is dependent on their quantity:

• single-layer unilateral (DVD-5) accommodate 4.7 gigabytes of information,
• two-layer unilateral (DVD-9) accommodate 8.7 gigabytes of information,
• single-layer double-sided (DVD-10) accommodate 9.4 gigabytes of information,
• two-layer two-sided (DVD-18) accommodate 17.4 gigabytes of information.

Capacity can be defined by eye - you need to see how many workers (reflecting) disk sides and pay attention to their color: two-layer sides usually have a gold color, and single-layer - silver, like a CD. Any of media can have any data structure (see above) and any number of layers (two-layer DVD-R and DVD-RW appeared at the end of 2004).

The DVD-R recording standard was developed by DVD-Forum as the official specification (re) of the recorded discs. However, the price of a license for this technology was too high, and therefore several manufacturers of writing drives and recording media were united in "DVD Plus RW Alliance", which developed the standard DVD + R (W), the license cost to which was lower. At first, "blanks" (pure discs for recording) DVD + R (W) were more expensive than "Dwarfs" DVD-R (W), but now prices are equal.

The standards of recording "+" and "-" are partially compatible. Currently, they are equally popular - half of the manufacturers supports one standard, half - the other. There are disputes, whether one of these formats will be supplanted or they will continue to coexist peacefully. All DVD drives can read both disk formats, and most typewriting can also record both types of "duals".
Unlike CDs in which the audio structure is fundamentally different from the data disk, the UDF file system is always used in DVD.
DVD read / write speed indicates a multiple 1350 Kb / s, that is, a 16-speed drive ensures reading (or write) disks in 16? 1350 \u003d 21600 KB / s (21.09 MB / s).
Regional binding DVD.
Film studios are interested in controlling the dissemination of their films released on DVD, different countries. This is due to the fact that the release time of films in the cinema and the time of their release in a wide video rental in different countries is different. It is believed that the video rental cinema should be published only after his premiere will be held in cinemas. So, for example, a film that came to the video rent in the United States can only begin to appear in European cinemas, which violates this rule.
That is why, when approving the DVD standard, a code that limits the use of a DVD-Video disk within one zone was introduced.
Thus, the DVD-VIDEO disk and the DVD player is assigned to the regional code. And if these codes do not match when playing a disk, the film will not be played.
Regional protection is optional and can be used at the discretion of the disk manufacturer. It is not a cryptographic system, but only one byte in the header of the disk that is checked before playing the disc. The DVD player can have several regional codes, in this case it can play discs of several different "zones". Many Chinese players generally ignore regional protection.
In total, 8 regional zones were introduced:

The code	Territory
0	Universal code for playback in all regions.
1	Bermuda, Canada, USA
2	Western Europe, Central Europe, Middle East, Egypt, Greenland, Japan, Lesotho, South Africa, Switzerland
3	East Asia, Hong Kong, Macau, South Korea, Taiwan
4	Central America, Pacific Islands, South America, Mexico, Australia, New Zealand
5	Africa, Eastern Europe, South Asia, Mongolia, North Korea,
6	China
7	Reserved for future use
	For special international use (aircraft, cruise liners, etc.)

Remove the restriction can be edited by the firmware (firmware) of the drive, which, however, leads to a warranty loss. Usually, when firmware, the region code changes to 0. However, there are DVDs with a special check code of the regionwhich cannot be reproduced with such a zone code. DVD players with a variable DVD area can solve this problem (usually a change is possible only up to 5 times, you can continue to change only after flashing Firmware).
Such protection is used only in DVD-Video disks.

Blu-ray Disc disks.

Blu-ray Disc or Abbreviated BD (from Blue Ray - Blue Ray and Disc - Disc) - these are the following generation of optical disk format - used to store high-definition video (with a resolution of 1920x1080 points) and data with high density.
Blu-ray standard was jointly developed by a group of companies for the production of consumer electronics and computers led by Sony, which entered the Blu-Ray Disk Association (BDA). Compared to its main competitor, the HD DVD format, Blu-ray has boas? We have an information container on the layer - 25 instead of 15 gigabytes, but at the same time it is more expensive to use and support.

At the International Consumer Electronics Exhibition Consumer Electronics Show (CES), which was held in January 2006, it was announced that the commercial launch of Blu-ray format will be held in the spring of 2006.
Technical characteristics BD.
A unilateral Blu-ray disk (BD) can store 23.3, 25, or 27 GB - this volume is enough to write approximately four hours of high-definition video with sound. A two-layer disk can accommodate 46.6, 50, or 54 GB - enough to write for approximately eight hours HD video. Also in the development there are disks with a capacity of 100 GB and 200 GB using a four and eight layers, respectively. The TDK corporation has already announced the prototype of a four-layer disk with a volume of 100 GB.
The BD-RE standard will be available on a par with BD-R (written) and BD-ROM formats. Almost all manufacturers of optical media declared their readiness to be released overwritten and recorded discs simultaneously with the yield of the BD-ROM format.
In addition to standard disks 12 cm size will be released options for 8 cm discs for use in digital photo and video cameras, it is planned that their volume will be 15 GB for a bilateral version.
The table below shows the dimensions of the current and scheduled Blu-ray format disks.

The Blu-ray technology is used to read and write a blue-purple laser with a wavelength of 405 nm. Conventional DVDs and CDs use red and infrared lasers with a wavelength of 650 nm and 780 nm, respectively.

Such a decrease made it possible to narrow the path twice as compared with the usual DVD disk - up to 0.32 microns - and increase the density of data recording.

The shorter wavelength of the blue-violet laser allows you to store more information by 12 cm discs of the same size as CD / DVD. The effective "spot size" on which the laser can focus is limited to diffraction and depends on the light wavelength and the lens numeric aperture used to focus it. Reducing the wavelength, the use of a larger numerical aperture (0.85, compared with 0.6 for a DVD), a high-quality two-liter system, as well as a decrease in the thickness of the protective layer six times (0.1 mm instead of 0.6 mm) provided the possibility of carrying A better and correct flow of read / write operations. This made it possible to record information into smaller points on the disk, and therefore store more information in the physical area of \u200b\u200bthe disk, as well as increase the read speed of up to 36 Mbps. In addition to optical improvements, Blu-ray discs also have improved data coding technology that allows you to store a larger information.

Technology solid coating.

Due to the fact that on Blu-ray disks, the data is too close to the surface, the first versions of the discs were extremely sensitive to scratches and other external mechanical influences Because of what they were enclosed in plastic cartridges. This disadvantage caused a lot of uncertainty about whether Blu-ray format is opposed to the HD DVD standard - its main competitor. HD DVD in addition to its lower cost can normally exist without cartridges, as well as CD and DVD formats, which makes it more understandable for buyers, as well as more interesting for manufacturers and distributors that can be concerned about additional costs due to cartridges.

The solution to this problem appeared in January 2004, with the advent of a new polymer coating, which gave discs with incredible protection against scratches and dust. This coating developed by TDK has been called "Durabis", it allows you to clean the BD using paper napkins - which can cause CD and DVD damage. The HD DVD format has the same drawbacks, since these discs are made on the basis of old optical media. According to the press "Naked" BD with this coating, they keep the performance even by scratched scratching.

HD DVD discs.

HD DVD (eng. High Definition DVD. - DVD high definition) - TOSHIBA record technology (in collaboration with NEC and Sanyo companies). HD DVD is similar to the Blu-Ray Disc rival technology, which also uses the same standard size discs (120 millimeters in diameter) and a blue laser with a wavelength of 405 nanometers. Microsoft and Intel also joined the HD DVD Alliance, as well as non-exclusive support for three major film studios: Paramount Pictures, Universal Studios and Warner Bros.

Single-layer HD DVD has a 15 GB container, two-layer - 30 GB. Toshiba also announced a three-layer disk that will store 45 GB data. It is less than the capacity of the Blu-Ray basic opponent, which supports 25 GB per layer and 100 GB for four layers, but HD DVD defenders claim that Blu-Ray multi-layer discs are still in development. Both formats are inversely compatible with DVD and both use the same video compression techniques: MPEG-2, Video Codec 1 (VC1, based on Windows Media 9) and H.264 / MPEG-4 AVC. HD DVD is often incorrectly written "HD-DVD", as people think that this name is similar to the previous generation "DVD-R / RW".

Blu-Ray Disc or Abbreviated BD (from English Blue Ray - Blue Ray and Disc - Disk) - these are the following generation of optical disk format - used to store high-definition video (with a resolution of 1920? 1080 points) and data with high density.

Blu-ray standard was jointly developed by a group of companies for the production of consumer electronics and computers led by Sony, which entered the Blu-Ray Disk Association (BDA). Compared to its main competitor, HD DVD format, Blu-ray has a greater information capacity on the layer - 25 instead of 15 gigabytes, but at the same time he is more expensive to use and support.

Blu-ray (letters. Blue-beam) received its name from a short-wave 405 nm "blue" (technically blue-violet) laser, which allows you to record and read much more data than on the DVD, which has the same physical volumes, But uses a red laser for recording and playing a larger wavelength (650 nm).

HVD format discs

Holographic disk (Holographic Versatile Disc) is an improved technology for the production of optical disks, still under development, which will significantly increase the storage amount compared to Blu-ray and HD DVD. It uses technology known as holography that uses two lasers, one - red, and the second is a blue-green, collimating in one beam. The blue-green laser reads the data encoded in the form of a grid from a holographic layer close to the surface of the disk, while the red laser is used to read the servo signals from the regular CD layer in the depth of the disk. Servo-information is used to track the read position, like the CHS system in the usual hard disk. On CD or DVD, this information is implemented in the data.

These discs have an information container to 3.9 terabytes (TB), which is comparable to 6000 CD, 830 DVD or 160 single-layer Blu-ray discs. HVD also has a data transfer rate of 1 GB / s. OptWare is going to release a 200GB disc in early June 2006 and Maxell in September 2006 with a capacity of 300GB.

Holographic Disc Structure (HVD)

1. Green read / write laser (532nm)
2. Red Positioning / Index Laser (650NM)
3. Hologram (data)
4. Polycarbonate layer
5. Photopolimer (PHOTOPOLIMERIC) layer (containing data)
6. Separating layer (Distans Layers)
7. Layer reflective green (Dichroic Layer)
8. Aluminum reflective layer (reflective red light)
9. Significant basis
PIT PIT (PIT)

Types of printing on disks

At the moment, the following types of printing on the surface of CD / DVD-R discs are presented in the technology market:

Offset printing method.

Silkography.

Terminate on CD / DVD-R discs.

Inkjet printing (ink-jet) on CD / DVD-R discs.

Offset printing method - most often used to print industrial circulation on CD and DVD. Its main feature is that the technology of the image on the CD, DVD is practically no different from the traditional printing printing, so the image is obtained full-color and high quality, albeit somewhat inferior in the brightness of colors. Over the image, a protective layer of transparent varnish is usually applied.

Silk-screen printing is a printing method, in which paint application on paper occurs by putting it through a special grid (stencil). Hence the second name of the silk screening - screen printing. Silkographic is the main way to apply images on CDs manufactured by average circulations, and most suitable for printing simple images with no more than five colors, while ensuring high definition and color quality. Hence the main drawback - silk-screen printing is bad for transmitting photographic quality images. However, before the ninety percent of all the optical disks produced in the world are scratched by screen printing.

Terminate on CD, DVD discs.
The thermal printing technology consists in combination of high temperature and short-term pressing (pressure) on the printhead, as a result of which the dye from the coloring tape is transferred to the surface of the disk, and the size of each portion of microscopic. Naturally, the paint is selected so that it is introduced almost into anyone and stay on it very well. Therefore, such devices the best way Suitable for printing mainly inscriptions or complex drawings (for example, logos).

The most important advantage of CD, DVD thermal printers over the jet is that almost all of them can print on any CDs, without needing special coverage, as well as high moisture resistance and durability of the obtained images.

Inkjet printing (ink-jet) on CD, DVD discs.
This is the highest quality and fast way to print on CD, DVDs, ideally suitable for creating small erases. When using this method, it becomes possible to accurately display photos with small elements, complex ornament or small text.

Inkjet printing is possible not on any, but only on special, "printed" CD / DVDs with a micro-helped coating (INK-JET Printable), well-insulated ink sprayed with print head. Attempting to print on dwarves, on the packs of which are not written "printable", even if they seem to be suitable for printing, most likely they will end the deplorable: the ink droplets will not be able to absorb the surface of the disk and "spread" on the sides, as soon as it is inserted into drive. In addition, the printed surface is very sensitive to moisture. To secure the image, the disks can be covered with special varnish or laminate, while the disc surface is to become a glossy. However, many consumers, especially "typing" disks for personal use, quite satisfy the image and without fixing with varnish.

Dictionary Terminos

Universal Disk Format (Universal Disk Format) - the file system used on rewritable CDs.

Wheels with marking - "Termo Printable" (with a white layer) - are used for thermal printing.

Wheels with marking - "No Printing" - silk screen and offset printing.

Marking discs - "Ink-Jet Printable" - inkjet printing.

Packaging with disks - "Spindl"

Directory DVD.

DVD

DVD is a family of optical disks, the same size with CDs (CD), but significantly greater storage capacity achieved by increasing the record density.

The appearance of DVD. DVD-forum

At the heart of appearance DVD discs I had an idea to develop such a carrier of information that could be equally successfully used in sound and video equipment, in computer technician, game consoles. It would ensure the rapprochement of different electronics regions.

DVD originally meant a digital video disk (DIGITAL VIDEO DISC). Later in connection with the decision on the expansion of the DVD functions, the abbreviation began to read otherwise - a digital universal disk (Digital Versatile Disk).

The development of DVD format was officially announced in September 1995 by a group of 10 companies: Hitachi, JVC, Matsushita, Mitsubishi, Philips, Pioneer, Sony, Thomson, Time Warner and Toshiba. In May 1997, a DVD-forum was created on the basis of this consortium - an organization currently consistent with more than 200 members.

The main tasks of this organization are the development and promotion of DVD format, developing coordinated specifications, as well as licensing activities of enterprises in the field of DVD technology. The forum employs special working groups on various aspects of DVD technology. International standards adopted on a number of specifications.

The most important advantages of DVD technology

Today, DVD is already widespread, tested by time and at the same time dynamically developing technology with enormous potential.

• recording and reproducing high-quality video and real-time audio, efficient work with computer multimedia information, as well as ensuring effective arbitrary data access, stored in the form of a plurality of small files;
• the volume of the disk is up to 4.7 GB (about 2 hours of MPEG-2) to the side to record into one layer and 8.5 GB to the side for a two-layer record;
• the ability to record information in two layers to each of the parties;
• unified UDF file system;
• the ability to record and multiple Revitaliss DVDs;
• backup compatibility with existing CDs - Geometric DVD sizes and CDs are identical, all DVD equipment can read CD-AUDIO and CD-ROM wheels (Multyread specification).

The first DVD formats

DVD technology originally relied on 3 main formats, the presence of which is determined by specific requirements for various areas of DVD applications:

• DVD-ROM is used to record data, including multimedia used in computer technologies;
• DVD-Video is used when writing video for their further viewing on video engineering or using a DVD-ROM drive attached to a computer. The format provides protection against illegal copying information;
• DVD-Audio is used when writing high-quality multi-channel sound. In addition, the DVD forum recommended additional support for video, graphics and other information.

These formats described read-only discs. Information on such discs is placed once - in the process of their production. With the development of DVD technology, disk specifications appeared, providing disk users Recording and overwrite information. However, the main members of the forum could not agree on a unified specification for such discs due to the desire to maintain independent control over their author's technical developments. As a result, several competing specifications appeared (DVD-RAM, DVD-RW, DVD + RW formats). Consider a list of DVD DVD formats developing today.

Developed DVD formats

Only for reading

• DVD-ROM
• DVD-Video.
• DVD-Audio.

For multiple overwriting

• DVD-RAM
• DVD + RW (not supported by a DVD forum)
• DVD-RW.

For one-time recording

• DVD-R (G)
• DVD-R (A)

For video

• DVD-Vr.

Compatibility

The developers could not achieve a single approach when developing the format of the recorded disks. Competition predetermined the lack of support by one device of several recording formats. Therefore, discs recorded in one of the formats are usually not read on the actuators of other recorded formats. An attempt to overcome the disunity of recording formats has been made by Panasonic, which in April 2001 presented a device operating with DVD-RAM and DVD-R (G) formats.

Some devices may not understand the DVD disk format, which has been proposed after their release. Naturally, household electronics can be focused on a very specific consumer market segment (DVD-Audio, DVD-Video, both format), and it does not have to provide reading computer discsAs defined by the DVD forum. At the same time, computer drives are equally well operating with video, audio, multimedia and other computer discs.

UDF file system

A great achievement of compatibility in DVD technology has become the unified Microudf file system adopted in 2000. The Microudf file system is an adapted version of the UDF file system in the DVD, which, in turn, is based on the International Standard ISO-13346. This file system gradually goes to replace the outdated ISO9660 created at one time to use in CDs. On the transition period (until computer devices and discs that work in the ISO9660 format) will be used from the circulation) UDF Bridge file system, which is some combination of MicroudF and ISO9660. Only Microudf can be used to record AUDIO / VIDEO DVDs.

The features of the microudf file system are as follows:

• independence from the software and hardware platform used (in this sense UDF is the optimal choice in archival systems);
• large container. The entire disk can be represented as a single volume;
• optimal transmission rate. The speed of reading and writing data in UDF format may be higher than the performance of many "native" file systems when large files indulge (for example, in multimedia systems)
• maximum possible file sizes;
• using Unicode font format, which ensures efficient international support;
• support for advanced file attributes, which is used in some "native" operating systemsoh;
• support for long file names with the extension of the restrictions of the operating system. Maximum length of the file name 255 characters;
• interchangeability of DVD discs in consumer electronics and computer systems.

When using Microudf on one DVD, you can simultaneously store videos, audio recordings, digitized photos and computer files. This ensures interceptor compatibility, i.e. the DVD becomes a single media for Macintosh, DOS / Windows, OS / 2, UNIX.

DVD prospects

The presence of different standards and specifications does not mean that DVD technology is in place. The efforts of various companies today are aimed at introducing the technology of the Blue Laser - with a smaller wavelength. This will increase the recording density on the disks with the improvement and other characteristics arising from here.
Calimetrics Inc invited ML technology (Multilevel), which allows three times to increase the capacity of standard DVD / CD. At the same time, there is no need to perform any refinement in the mechanism and optics of existing drives. To implement a new technology, it is enough to use a set of chips developed by this company. The essence of the technology is to be able to use as information characteristic The depth of the pit (up to 8 levels) when working with disks. Note that similar technology, but for CD discs, is developing a TDK company in collaboration with other firms.

DVD formats read only

DVD-ROM (Digital Versatile Disc Read Only Memory)

DVD-ROM disks are designed for use in computer technology. Information is entered on the disk only time - in its production.

The progress of DVD devices largely repeats the path passed by CD, and is directed by the main obsession to improve the speed characteristics and the introduction of the recording function. The first generation DVD-ROM devices used the CLV mode and read from the disk at a speed of 1.38 MB / s (in the traditional designation for DVDs it is 1x). The second-generation devices could read the DVD from twice the speed - 2x (2.8 MB / s). Modern DVD-ROM - third-generation devices - use the rotation control mode (CAV) with a maximum read speed of 4x-6x (5.5 - 8.3 MB / s) and more. Modern DVD-ROM drives (drives) support reading almost all formats, including CD discs.

DVD-Video.

DVD-Video format is designed to store and play video. Like a DVD-ROM, this specification determines the ability to read information only - playback of records using video player (video discoders). The specification is based on the DVD-ROM format, but provides for a special way to place data that prevents the disk copying option. Video films in the encoded form are placed on the disk in the process of its production. Playing a DVD-Video is possible only on household video player (video discs) or on DVD drives connected to a computer. When using computer equipment, information decoding is carried out either hardware or software. Modern specification provides an entry to a high-quality video disk (up to 2 hours in MPEG-2 compression format), as well as multichannel audio support in 8 languages, selection of on-screen format, titers in 32 languages, Interactive control via the on-screen menu, up to 9 corner directions viewing, protection against illegal copying, distinction of viewing of video products by region, children's access control to video materials.

DVD-Audio.

New generation of musical format after CD. The format specification defines high-quality multichannel sound, support for a wide range of sound quality (quantization 16, 20, 24 bits at a frequency of 44.1 to 192 kHz), dVD playback CD players, support for additional information (including video, text, menu, screensavers, convenient navigation system), communication with information support Web sites, expanding opportunities when new technologies appear.

There are two versions of DVD-AUDIO format: just a DVD-Audio - only for sound content and DVD-Audiov - for sound with additional information.

Special disk protection measures from pirated copying are developed.

DVD formats for multiple recording

Multiple recording

All known specification of rewritable DVD discs use multiple recording technology based on the physical principle of the phase state change (crystalline / amorphous) information layer under the influence of a laser with a wavelength of 650 (635) Nm (Phase-Change Recording). The reading of information is carried out by determining the optical characteristics of the information layer in its various phase states when reflecting the laser rays (the same as when recording).

Material for multiple

As a working, the AVIST material created by TDK in 1995 is used. The characteristics of this material almost perfectly satisfy the requirements of the DVD Rewaging Technology:

• high reflective ability - up to 25-35%, which is quite enough to compatibility DVDs during playback;
• the ease of replacing the phase state both at high and low speeds Entries, which is especially important when working with various applications. Applications operating with overwritten CDs (for example CD-E) carry out a recording at a rate of less than 3 m / s. Working with DVD-RAM data requires a working layer of a higher recording speed - from 3 to 6 m / s. When working with video information subjected to compression, the recording speed must exceed 6 m / s;
• the excellent ratio of signal-noise and phase change characteristics allowed TDK to achieve ultra-low dimensions of the marker (less than 0.66 mm);
• Avist maintains at least 1000 cycles of rewriting even at speeds less than 3 m / s. At higher speeds, the number of cycles of rewriting increases.

Each of the formats has its advantages and disadvantages, which determined their scope. The most common today is the DVD-RAM format due to the lower cost of working with it drives and disks.

DVD-RAM (Digital Versatile Disc Random Access Memory)

Overwritten format developed by Panasonic, Hitachi, Toshiba.

The format is approved by the DVD forum in July 1997. Equipment and disks of this format were tested for 3 months in more than 20 computer manufacturing companies around the world. Over 160 forum participants voted for the adoption of the specification. Today it is the most common DVD format in the computer industry.

DVD-RAM drives read DVD-ROM discs. In turn, DVD-RAM discs can be read only by the DVD-ROM drives of the so-called third generation, manufactured from mid-1999.

The first generation of DVD-RAM discs contained 2.6 GB to the side. Modern - second-generation discs are 4.7 GB on the side or 9.4 GB for bilateral modification.

Two types of one-sided DVD-RAM disks are available - in the cartridge and without a cartridge. Cartridge discs are mainly designed for household video equipment, where it is necessary to eliminate the effect of external factors with intensive manual use. Cartridges in turn can be two species - open and solid.

The most important advantages of DVD-RAM disks are the ability to overwrite up to 100,000 times and the presence of a recording error correction mechanism.

The largest number of overwriting cycles among all DVDs, error correction mechanism and arbitrary disk access both during recording and when reading predetermined the maximum efficiency of this format in secondary storage devices. The overwhelming majority of mass storage devices are robotic DVD libraries - uses this technology.

DVD-RAM wheels can be used to record and play streaming video on hardware supporting DVD-VR specification (see below).

DVD + RW. (Digital Versatile Disc Rewritable)

The DVD + RW format is progressing only by its developers - Hewlett-Packard, Mitsubishi Chemical, Philips, Ricoh, Sony and Yamaha (not supported by the DVD forum).

On DVD + RW drives, you can write both streaming video or sound and computer data. DVD + RW discs can be overwritten about 1000 times.

The DVD + RW database has created a streaming video recording format - DVD + RW Video Format. Devices and discs operating in this format are positioned in the market as fully compatible with equipment operating in DVD-Video formats. This means that DVD + RW discs containing video materials can be played on a previously released DVD household apparatus.

Philips announced the start of the release of its DVD video recorder in September 2001 DVD + RW discs recorded on this device are also read by conventional DVD-Video players. This decision was proposed as a response step on the DVD adopted DVD specification of the DVD-VR (see below).

DVD-RW. (Digital Versatile Disc Rerecordable)

There are other names of this format: DVD-R / W and less often DVD-ER.

DVD-RW - multiple format developed by Pioneer. DVD-RW discs contain 4.7 GB to one side, are available in one-sided and double-sided modifications and can be used to store video, audio and other data.

DVD-RW discs can be overwritten up to 1000 times. Unlike DVD + RW and DVD-RAM formats, DVD-RW discs can be read on the first generation DVD-ROM drives.

TDK declares that the durability of the DVD-RW discs produced by it is about 100 years.

DVD formats for one-time recording

DVD-R. (Digital Versatile Disc Recordable)
DVD-R is a format of a single record developed by Pioneer. Devices based on this format were the first to be recorded on DVDs. The technology of recording is similar to those used in CD-R and is based on an irreversible change under the influence of the laser of the spectral characteristics of the information layer, covered with a special organic composition.

DVD-R discs can be recorded both computer data, multimedia programs and video / audio information. Depending on the type of recorded information, discs can be read on other compatible with the recorded device types, including DVD-Video video players and most DVD-ROM drives. Unilateral DVD-R discs accommodate 4.7 or 3.95 GB to the side. Double-sided discs are available only to a total capacity of 9.4 GB (4.7 GB to the side). Currently, the format does not support recording technology in two layers.

DVD-R disk durability is estimated for more than 100 years.

To protect against illegal copying, two specifications have been developed: DVD-R (A) and DVD-R (G). Two these versions of one specification use a different laser wavelength during information recording. Thus, discs can only be recorded on their appropriate equipment specifications. Playback of discs can be performed equally successfully on any equipment that supports DVD-R format.

DVD-R (A) (DVD-R for Authoring) is used in professional applications. In particular, the support of a special format (Cutting Master Format) allows you to apply these discs to record the source replica of information (pre-mastering) instead of normal use for these purposes DLT tapes.

DVD-R (G) (DVD-R for General) is designed for wider use. Disks of this format are protected from the possibility of beaten copying information from other disks. The format is supported in mass storage devices (for example, in robotic DVD libraries offered by Pioneer itself).

The DVD-VR specification is based on DVD-RAM and supported by the DVD forum. DVD-VR format allows you to record in real time up to 2 hours of high-quality video in MPEG-2 format per one-sided DVD-RAM disk with a capacity of 4.7 GB and provides features such as editing already recorded video materials, recording different types static images. Electronics based on this format is released, for example, Panasonic, Toshiba, Samsung, Hitachi.

Reference tables

Table 1. Capacity DVD discs

Format	Specification	Number of parties	Number of layers	Capacity, GB *
DVD-Video and DVD-ROM	DVD-5.	1	1	4.7, or more than 2 hours video
	DVD-9.	1	2	8.5, or more than 4 hours video
	DVD-10.	2	1	9.4, or more than 4.5 hours video
	DVD-14.	2	1+2	13.2, or more than 6.5 hours video
	DVD-18.	2	2	17.1, or more than 8 hours video
DVD-RAM (DVD-VR)	DVD-RAM 1.0	1	1	2.6
		2	1	5.2
	DVD-RAM 2.0	1	1	4.7
		2	1	9.4
DVD-R.	DVD-R 1.0	1	1	3.9
	DVD-R 2.0	1	1	4.7
		2	1	9.4
DVD-RW.	DVD-RW 2.0	1	1	4.7
		2	1	9.4

* 1GB - 1 billion byte

Table 2. Basic DVD parameters of the latter modifications

Parameter	Disc type
	DVD-ROM	DVD-RAM	DVD-RW.	DVD + RW.	DVD-R.
Capacity one side	4.7 GB	4.7 GB	4.7 GB	4.7 GB	4.7 GB
Laser wavelength	650	650	650	650	650 (g) 635 (a)
Reflective ability	18-30% (two-layer)	15-25% (2,6)		18-30%
Recording method	Printing with matrix in production	Phase change	Phase change	Phase change	Change color dye
Record form	Not applicable	Wobbled Land & Groove	Wobbled Groove.	Wobbled Groove.	WOBBLE PRE-GROOVE
Interdrodial distance	0.74 microns	0.615 microns		0.74 microns	0.74 microns
Minimum launch length	0,40	0,28			0,40
Number of zones	Not applicable	35	Not applicable	Not applicable	Not applicable
The method of controlling the rotation *	CAV.	Zclv CAV within zone	CLV.	CLV (for video) or CAV (for data)	CLV.
Data recording speed	up to 8.31 MB / s (reading)	2.77 MB / s		11-26 Mbit / s,	2.77 MB / s
File system	Micro UDF and / or ISO9660	UDF / UDF Bridge	UDF / UDF Bridge	UDF / UDF Bridge	Type1 UDF Bridge Type2 UDF
The cost of one-sided disk (drive)		$20-30($500)			$10-15 ($1000)

* CLV - (Constant Linear Velocity) Permanent linear speed

CAV - (Constant Angular Velocity) Permanent Angle Speed

ZCLV - (Zone Constant Linear Velocity) Zone Permanent Linear Speed

DVD formats Disc	Types of DVD drives
	DVD-RAM		DVD-RW.		DVD-R (G)		DVD-R (A)		DVD + RW.		DVD-Video.		DVD-Audio.		DVD-Player (Univer.)
	C.	Z.	C.	Z.	C.	Z.	C.	Z.	C.	Z.	C.	Z.	C.	Z.	C.	Z.
DVD-ROM	+	−	+	−	+	−	+	−	+	−	+	−	−	−	+	−
DVD-R (G)	+	−	+	+	+	+	+	−	+	?	+	−	+	−	+	−
DVD-R (A)	+	−	+	−	+	−	+	+	+	−	−	−	+	−	+	−
DVD-RAM	+	+	−	−	−	−	−	−	−	−	−	−	+	−	+	−
DVD-RW.	+	−	+	+	+	+	+	−	+	−	+	−	+	−	+	−
DVD + RW.	−	−	+	−	+	+	+	−	+	+	+	−	+	−	+	−
DVD-Video.	+	−	+	−	+	−	+	−	+	−	+	−	−	−	+	−
DVD-Audio.	+	−	+	−	+	−	+	−	+	−	−	−	+	−	+	−
DVD-Audiov.	+	−	+	−	+	−	+	−	+	−	+	−	−	−	+	−

Note - In some cases, "+" means that reading or record does not contradict the forum DVD specifications, however, such devices can be not available on the market.
"-" means that the specification does not define a mandatory read or recording requirement, but the market may have devices providing this opportunity

CD - optical information carrier in the form of a disc with a hole in the center, the information from which is read by the laser. Initially, the CD was created for digital storage audio (T.N. Audio-CD), however, is currently widely used as a wide-purpose storage device (T.N. CD-ROM). The format audio-compact discs differ from the CDs with data, and the CD players can usually play only them (on the computer, of course, you can read both types of disks). There are discs containing both audio information and data - they can be listed on the CD player, and read on the computer. With the development of MP3, manufacturers of household CD players and music centers began to provide them with the ability to read MP3 files from CD-ROMs.

Abbreviation "CD-ROM" means "Compact Disc Read Only Memory" that in translation indicates a CD with the ability to read. "CD ROM" means "CD, constant storage device". CD-ROM often erroneously called CD-drive for reading CDs.

History of creation

CD was created in 1979 by companies Philips. and Bayer.. Philips developed a general production process based on their earlier laser disks technology. Sony, in turn, used its own PCM recording method - Pulse Code Modulation, previously used in digital professional tape recorders. In 1982, mass production of CDs, at the factory in the city Langenhagen under Hannover, in Germany. Significant contribution to the popularization of CDs made Microsoft. and Apple Computer. John ScullyThe then CEO Apple Computer, in 1987 he said that the CDs will revolutionize the world of personal computers.

There is a version that the CD invented not Philips and Sony, and american physicist James Russellworked in the company Optical Recording.. Already in 1971, he demonstrated his invention for storing data. He did it for the "personal" goals, wanting to prevent the scratching of his vinyl records to the needles of pickups. Eight years later, such a device was "independently" invented by Philips and Sony companies.

Technical details

CDs are made from polycarbonate with a thickness of 1.2 mm, covered with the finest aluminum layer (gold) with a protective layer of varnish, on which a graphical representation of the disk content is usually applied. Therefore, contrary to common opinion, the CD should never put up the legs (label down), since the reflective aluminum layer on which the data is stored, it is shown below, as mentioned above, 1.2 mm layer of polycarbonate, and from above - Only a thin layer of varnish. In addition, on the reflecting side there is an annular protrusion with a height of 0.5 mm, allowing the disk laying on a flat surface, does not touch this surface. In the center of the disk there is a hole with a diameter of 15 mm (if desired, the disk can be transferred, putting on a finger, without touching its surface).

CDs have 12 cm in diameter and initially accommodate up to 650 megabytes of information (or 74 minutes of audio). There is an assumption that the developers calculated the volume so that the Ninth Symphony of Beethoven (the most popular musical work in Japan in 1979 in 1979 according to a specially conducted survey) is fully placed on the disk. However, since about 2000, the volume of 700 megabytes was becoming increasingly distributed, which allow you to record 80 minutes of audio, afterwards the entire 650 megabytes disconnecting disc. The carriers of 800 megabytes are found (90 minutes) and even more, but they may not be read on some CD drives. There are also mini-CDs (not to be confused with mini-discs), with a diameter of 8 cm, on which about 140 or 210 MB of data or 21 minutes of audio, and CD, shape resembling credit cards (T.N. Disc-business cards).

The storage format on the disk, known as the "Red Book" ("Red Book", not to be confused with the Red Book in the usual understanding), was developed by Philips. In accordance with it, you can record the sound of two channels with a 16-bit pulse-code modulation (PCM) and a sampling frequency of 44.1 kHz. Due to the correction of errors using the Reda-Solomon code, light scratches do not affect the readability of the disk. Philips also owns all the rights to the "Compact Disc Digital Audio" sign, the logo of the format of audio CDs.

The information on the disk is written in the form of a spiral track of the so-called peit (recesses), extruded on the aluminum layer (as opposed to CD-ROMs recording technology where information is recorded cylindrically). Each pit has about 125 nm in the depth and 500 nm in width. Pita varies from 850 nm to 3.5 μm. The distance between the adjacent spiral tracks is 1.5 microns. Data from the disk is read using a laser beam with a wavelength of 780 nm, which shines the polycarbonate layer, reflected from aluminum and is read by photodiode. The laser beam forms a decrease in a reflective layer with a diameter of about 1.5 μm. Since the disk is read from the bottom, each pit looks for a laser as an elevation. There are no places where such elevations are not called platforms.

To make it easier for you to imagine the size of the size of the disk and pit: if the CD would be the value from the stadium, the pit would be the size of approximately with the sand.

Light from the laser entering the pad is reflected and catches the photodetector. If the light falls on the elevation, it is experiencing an interference with light, reflected from the site around the elevation and is not reflected. This is because the height of each elevation is equal to the quarter of the laser light wavelength, which leads to the difference in the phases half the wavelength between the light, reflected from the site and the light reflected from the elevation.

CDs are stamped at the factory (CD-ROM), CD-R for a single record, CD-RW for multiple recording. The disks of the last two types are designed to record at home on special writing drives. In some CD players and music centers, such discs may not be read (Recently, all manufacturers of household music centers and CD players include in their devices support to read CD-R / RW).

The read / write speed of CD is indicated by multiple 150 Kb / s (i.e. 153 600 bytes / s). For example, a 48-speed drive provides a maximum read speed (or recording) CDs of disks, equal to 48 × 150 \u003d 7200 Kb / s (7.03 MB / s).

The weight of the disk without a box is ~ 15.7 gr. The weight of the disk in the usual (not "slim") is equal to ~ 74 gr.

Shape CD.

Shape CD (Figure CD) - optical media of digital information type CD-ROM, but not strictly round shape, but with a curvatured configuration of an external circle in the form of a variety of objects, such as outlines of portraits, machines, aircraft, Disney characters, hearts, stars , ovals, in the form of credit cards, etc. Usually applied in show business as a carrier of audio and video information. Was patented by a record-producer Mario Cososa In Germany (1995). Typically, discs with a form different from the round, are not recommended to be used in CD-ROM computer drives, since at high speeds of rotation (up to 12000 rpm.) The disk can burst, which can lead to full drive output.

Copy protection

The CD Specification does not provide any copy protection mechanism - wheels can be proper free and reproduced. However, since 2002, various Western sound recordings began to attempt to create CDs protected from copying. The essence of almost all methods is reduced to intentional errors to the data recorded on the disk, so that the disk is played on the domestic CD player or the music center, and there is no computer. As a result, it turns out a game of a cat-mouse: such discs are not read far from all household players, and on some computers - read, the software comes out, allowing you to copy even protected discs, etc. The sound recording industry, however, does not leave hope and continues Testing more and more new methods.

Philips stated that on such discs that do not meet the "Red Book" specifications are forbidden to apply the "Compact Disc Digital Audio" sign.

Recording on CDs

Conventional CDs are molded by injection molding (casting under pressure) on plants using a glass matrix with a drawing of paths consisting of peits (protrusions) and gaps, with which the metal layer of the disk is formed. There are also disks intended for recording at home: CD-R (Compact Disc Recordable) for a single record and CD-RW (Compact Disc Rewritable) for multiple. In such disks, the reflective ability of the pit and the gaps between them should be mimicified by another method. This is achieved by adding a dye between the gold (aluminum) surface and a layer of polycarbonate. In the original condition, the dye level is transparent and allows a laser beam freely through it and reflects from the gold (aluminum) coating. During recording, the laser goes into high power mode (8-16mW). When the laser enters the dye, he heats it, destroying chemical bonds, and forms dark, opaque stains. When reading a laser beam with a capacity of 0.5 MW, a photodetector notices the difference between spotted spots and intact regions. This difference is interpreted in the same way as the difference between the excavations and smooth surfaces on ordinary CDs. Such discs in the spaciousness are called "duals" and are recorded on special writing drives for CDs (widely distributed today), in Slang, referred to as "writs" or "cutters". The recording process is called "burning" (from the English. "To Burn") or "cutting" disk. RW discs, in contrast to R, have a smaller reflectivity. 20% of the disk manufactured by the factory. CD R 40%.

Questions and Answers: What you need to know about the recording of CD-R and CD-RW disks.

1. What you need to have to write a CD?

You need a computer with a device installed in it, which is called CD-Writer. This device connects to a computer multiple possible ways. Most drives for recording disks has an IDE interface and are connected in the same way as conventional CD-ROM or hard drives and have internal execution. However, there are other executions, both external and internal - with sCSI interfaceconnected to the parallel port or to the USB bus.
The second necessary part to record disks is software. Its selection is very large - from the most popular commercial packages of the company ADAPTEC (Easy CD Creator, Easy CD Deluxe, Easy CD Pro) to observing free Nero or Cdrwin type programs.
And finally, you need an empty CD-R CD or CD-RW

2. What can be recorded on CD-R or CD-RW discs?

Traditionally, the discs can be recorded both sound and data. The data is saved on CDs in the usual form, in which they are stored on the hard disk. It should not be noted that it is possible to create mixed discs that combine sound with data.

3. What is the difference between CD-R and CD-RW discs?

CD-R is a CD-Recordable, that is, "recordable". This means that the information recorded on this disk cannot be removed from there. The main difference between CD-RW (CD-Rewritable) disks is that the information from them can be removed and recorded again. As a result, a more flexible CD-RW discs are somewhat more expensive than ordinary discs with a single record.

4. How much information can be recorded on a CD-R disk?

5. Why is the standard duration of 74 minutes?

In general, such a duration was chosen, because the CD developers wanted to have a format in which the nine symphony of Beethoven would be placed, they determined which to use the diameter, and the duration of some executions decided this issue.

Recorded discs can be used on the following devices:

CD Domestic CD Player Given the fact that household CD players appeared earlier than the CD-R disc recording devices, it does not have a guarantee that all recorded music CDs will be played in audio players. However, to achieve a better result, it is recommended to use CD-R discs, since they are much closer to traditional music discs, rather than CD-RW. DVD-ROM drive or DVD player The overwhelming majority of DVD players and all DVD-ROM drives (with the exception of the first samples of these devices) are able to read information from CD-R discs and CD-RW. CD-ROM drives

All modern cD-ROM drives Excellent read as discs with a single recording and CD-RW discs. The nuances exist only with old drives, which in some cases do not read CD-R discs, or read these discs, but do not read CD-RW discs. If your old drive is marked, as the MultiRead feature, this means that with it you can cope with this task. A good sign that the drive is able to work with the recordable disks is the read speed of the data by this drive. If the speed is 24 and higher, then usually such a drive is quite suitable for working with CD-R and CD-RW discs.

7. Why does the reflective side of the discs have different colors?

Different companies producing CDs have patents to various chemical schemes used by them in the manufacture of disks. Some companies themselves produce discs, some simply licented them with their technology. As a result, the reflective side of the CDs is obtained different colors. There are CD-R of the following composition combinations: gold / gold, green / gold, silver / blue, and silver / silver, and their numerous shades. The visible color is determined by the color of the reflective layer (gold or silver) and the color of the dye (blue, dark blue or colorless). For example, green / gold discs consist of a gold reflective layer and a blue dye, therefore, on the side of the label, the disc is a gold color, and from the side of the recording - green. Many have come to the conclusion that "silver" discs are made of silver, and, on the basis of this assumption, they tried to reflect on the reflection ratio and longevity carriers. Until the manufacturer's representative proceeds with a statement about the real composition of the disk, it is unreasonable to assume something specific. Some CD has an additional coating (for example, "InfoGuard" from Kodak), which makes CD more resistant to scratches, but does not affect the information storage method. About the top (label) side of the disk It is worth worrying most, because it is here "live" data, and it is easiest to damage the CD-R. Mustocate the disk from scratches allows you to stick to the entire area of \u200b\u200bround stickers for CD. CD-RW discs have a completely different structure. The data side (in contrast to the side of the label) silver dark gray, which is difficult to describe. You can also bring a brief list of which companies produce certain discs:

Taiyo Yuden manufactured the first "green" CD. Now they are also manufactured by TDK, Ricoh, Kodak, and probably some other firms.

Mitsui Tasssu Chemicals (MTC) manufactured the first "golden" CD. Now they are also manufactured by Kodak and, possibly, others.

Verbatim manufactured the first "silver / blue" CD.

Many CD-R brands (for example, Yamaha and Sony) are OEM versions of one of the main manufacturers. By and large, it is difficult to determine who it produces, since new enterprises are built, and sellers can change suppliers.

8. What do speeds mean (for example, 6x4x32) in the parameters of the device for recording CDs?

Conventional audio players lose musical CDs for 74 minutes. This speed is accepted for the database when measuring the speeds of playback and recording of CDs and is named once (1). Single speed corresponds to the transfer of 150 kilobytes per second. A CD-ROM drive having two multiple speed (2) transmits data at a speed of 300 kilobytes per second.

Three numbers in the CD-Writer parameters are speeds with which this device can write CD-R discs, CD-RW discs and read these discs accordingly.
For example, 6x4x32 means that this device records CD-R discs at a speed of 6-x (900 kb / s), writes CD-RW discs at a speed of 4 (600kb / s) and reads any types of CDs at speeds 32 (4800 Kb / s)

9. What are the formats when recording CD-R discs?

This is the most difficult issue to answer, considering that over the past few years there have been a lot of a wide variety of CD formats, and this is despite the fact that there are still historically established formats that exist for a long time and are applied in specialized applications. Below is a review of the main formats:

Musical disks (Audi O CD) or CD-DA or "Red Book"

To record ordinary music CDs, you need that the recorded disk corresponds to the CD-DA standard. During recording used, as a source of standard WAV type files (or AIFF - Apple Audio Interchange File Format)

ISO9660 Data CD.

This standard determines the form in which ordinary data is written to CD-R discs. This standard has a lot of restrictions, namely, the maximum number of nested directory cannot exceed 8, file names cannot have a large length, rather than 8 characters and 3 characters are returned to the file name extension. However, this standard is compatible with large quantity Computers and operating systems.

The format proposed by Microsoft simultaneously with the appearance of operating windows systems"95. The file name length is limited in this standard 64 characters, and this format is now supported, both in the Windows environment and MacOS and Linux. Joliet is based on the ISO9660 standard and discs recorded in this format can be read almost on any computer. . However, file names will be trimmed to the 8 + 3 scheme.

This format strictly refers to Macintosh computers. HFS CD can be read only on computers of this type.

UDF.or Pocket Writing.

UDF (Universal Disk Format) Radical Extension of the ISO9660 standard, in something resembling Joliet. The Adaptec DirectCD program (supplied in the Easy CD Creator Deluxe package, or sold separately for the MAC platform) and, for example, the Cequadratratratratratrat program allows you to record discs in this format. UDF is different from other formats by what you can work with a CD, like a large floppy disk, copying files to it using standard windows or macos. However, this format is poorly suitable for transmitting disks to other people, for to read the disks of this format, it will be needed to establish special software for reading such disks.

ISO 9660 ROCK Ridge

Expansion of the ISO9660 standard used exclusively in Linux and UNIX operating environments.

ISO LEVEL 2.

Several upgraded ISO9660 format, simplified in terms of restrictions. For example, the length of the file name in it is limited to 31 characters. However, the low compatibility of this standard does not allow it to be used as widely as, for example, the Joliet format is applied.

VideoOcd or VCD or "White Book"

VideoOCD format was designed in the mid-90s and was focused on using in such a device as Philips CD-I player. VideoCD disks contain video and sound compressed according to MPEG1. Despite the fact that the Philips CD-I Player has not been produced for a long time, these discs can be used on the overwhelming majority of DVD players if they support CD-R discs or CD-RW.

8. What format I need to use if I want ....

.... Exchange data with friends that use similar to my operating system?

Everything is simple here. Windows operating system users must use Joliet format, mAC users - HFS format.

.... Exchange data with people who use various operating environments and platforms?

For maximum compatibility, it is recommended to use the ISO9660 format. However, if you need to save long file names on the disk, then you should try to use Juliet format. Modern MAC and most operating systems now have the ability to read discs recorded in such a format.

.... Listen to music on the usual audio player?

Then you must record the CD-DA disk, which will ensure the highest level of compatibility with the audio player.

10. How to record discs with mixed contents?

There are two features to record such discs:

MODE I. - When using this format, the data is written at the beginning of the disk (in any known format), then followed by recorded sound tracks. If you need to combine sound and data, the use of this mode will provide the desired level of compatibility with various devices and operating environments.
CD-XA (Mode II) - This mode differs from the previous one by the fact that the data and sound can be recorded in an arbitrary order. However, this flexibility adversely affects the compatibility recorded by disks.

11. What is a multisession CD?

This technology allows you to add data or sound to the disk, on which something is written until the "closing" procedure is not performed. It was very relevant in the early 90s, when the cost of the empty disk CD-R reached $ 12, the CD-RW disks did not exist, and the hard drives had a small volume.

Disks recorded in such technology have some compatibility problems, and because it is not recommended to use it without good reason. UDF format makes this technology unnecessary; With Direct CD and such software, you can write data without worrying about compatibility. If you need to transfer the disk to other people, then simply write it at a time in Joliet format

12. What is the "closing" of the disk?

"Closing" disk means that after performing this procedure, something on this CD-R disc will be impossible. If you never use the ability to "MultiSession", then you do not make sense to think about it, because the disk will be closed automatically after writing information to the disk. Many old CD-ROM drives and audio players have problems with reading unclosed discs, so for greater compatibility it makes sense to "close" the disk.

If you want to write something on the "closed" CD-RW disc just run the "Clear" function and you can write data to this disc again. If you use the UDF format, then it does not have the concept of "closing" disk in the traditional sense of the word - simply copy and delete files from such a disk as with a simple floppy disk.