What you should know about CD-ROM, CD-R and CDRW discs. What is CD-ROM Main characteristics of CD-ROM
How is a CD structured?
A standard disc consists of three layers: a polycarbonate substrate on which the disc's relief is stamped, a reflective coating made of aluminum, gold, silver or other alloy sprayed onto it, and a thinner protective layer of polycarbonate or varnish on which inscriptions and drawings are applied. Some discs from “underground” manufacturers have a very thin protective layer or do not have it at all, making the reflective coating quite easy to damage.
The information relief of the disk consists of a spiral path running from the center to the periphery, along which depressions (pits) are located. Information is encoded by alternating pits and spaces between them.
What recording formats are used in CD-ROM?
CD-ROM uses the same technology as a conventional CD-DA sound system. The standards for recording arbitrary data on CDs released by Philips and Sony are known as Yellow Book("yellow book") Green Book("green book") Orange Book(“orange book”), White Book(“white paper”) and Blue Book("Blue Book"); all of which complement the core CD-DA standard described in Red Book(“red book”).
Separate “sound tracks” are used to record data. The mentioned standards do not apply to the disk as a whole, but only to the format of individual tracks, and tracks of different formats can coexist on the same disk. To read them, you need a player that supports either all formats presented on the disk, or skips unknown ones (many players and CD-ROM drives cannot skip tracks of unknown formats).
Yellow Book defines the basic formats for recording data on disk: CD-ROM mode 1 and CD-ROM mode 2. In both formats, within each frame of a 2352-byte track, also called sectors, 12 bytes of synchronization and 4 bytes of sector header are allocated and 2336 bytes for data recording. Thanks to the presence of synchronization bytes and a header, it is possible to accurately find the desired data sector, which is extremely difficult in a regular audio disk.
In the mode 1 format used in most CD-ROMs, 288 bytes are allocated from the data area to write EDC/ECC codes (Error Detection Code/Error Correction Code), thanks to which data discs are read much more reliably than sound discs with the same manufacturing quality. The remaining 2048 bytes are allocated for data storage.
In mode 2 format, correction codes are not used, and all 2336 bytes of sector data are allocated for recording information. It is assumed that the recorded information either already contains correction codes, or is insensitive to minor errors remaining after correction by the low-level Reed-Solomon code. This format is primarily intended for recording compressed audio signals and images.
A mode 1 format disc on which audio programs and data are combined is called Mixed Mode Disk. In this case, data is recorded on the first track, and audio information is recorded on all subsequent tracks. Most audio players do not distinguish between track formats and, when data hits a track, they try to play it, which can damage amplifiers and speaker systems.
The mode 2 format in its pure form is practically not used - on its basis, CD-ROM/XA (eXtended Architecture) formats of two variants (Green Book) have been developed. In the first option, from a data block of 2336 bytes, 8 bytes of subheading, 4 bytes EDC and 276 bytes ECC are allocated, leaving 2048 bytes for data, as in the “mode 1” format; in the second option, ECC is not used and 2324 bytes remain for data. On one track of the XA format there can be sectors of both the first and second options. The advantage of this approach is the ability to simultaneously read data and audio and/or video information in real time, without unnecessary movements between tracks.
The CD-I format (CD-Interactive - interactive CD), described in the Orange Book, provides for recording a video image on XA format tracks and playing it back using a special CD-I player on a household TV in parallel with listening to an audio program. CD-I format tracks are not included in the disc's table of contents (TOC), so they are not visible on equipment that does not support this format.
For compatibility with standard audio players, the CD-I Ready format (“ready for playback on a CD-I player”) was proposed, in which an extended pause before the first audio track, ignored by most conventional players, is used to record the image.
For compatibility with disk reading equipment in the XA format, the CD-Bridge format (“CD-bridge”) was proposed, which is CD-I format tracks included in the general table of contents of the disk, containing address marks of both formats - CD-I and XA.
Orange Book also defines the format of recordable CD-R (CD-Recordable) discs, which can be recorded in several steps (sessions), and also have an initial session stamped during manufacturing (the so-called Hybrid Disk). Each session contains an introductory record (Lead In), the actual data and an output record (Lead Out).
The White Book describes the VideoCD format, based on CD-Bridge and used for storing moving images encoded as AVI, MPEG and the like. Blue Book describes the CD-Xtra format as consisting of two sessions - an audio session and a data session.
The organization of the file system on a CD-ROM is described by the ISO 9660 standard. Level 1 of this standard includes the MS-DOS and HFS (Apple Macintosh) file system formats. The nesting of MS-DOS directories cannot exceed 8, and the name length cannot exceed 8+3 characters. Level 2 describes a file system with long names and nesting levels up to 32. The Rock Ridge extension describes the UNIX file system format.
A special case of CD-R is the Kodak Photo CD format, used for multi-session recording of photo collections. Photo CD uses the CD-Bridge format, formatted in the ISO 9660 file system. Photo CD discs can be played by special players on a household TV or read by computer CD-ROM drives.
How does a CD-ROM drive work?
A typical drive consists of an electronics board, a spindle motor, an optical read head system and a disk loading system.
The electronics board contains all the drive control circuits, the interface with the computer controller, the interface connectors and the audio signal output. Most drives use one electronics board, but in some models separate circuits are placed on small auxiliary boards.
The spindle motor is used to drive the disk into rotation at a constant or variable linear speed. Maintaining a constant linear speed requires changing the angular speed of the disk depending on the position of the optical head. When searching for fragments, the disk can rotate at a higher speed than when reading, so a good dynamic characteristic is required from the spindle motor; The motor is used for both acceleration and braking of the disk.
A stand is attached to the axis of the spindle motor, to which the disk is pressed after loading. The surface of the stand is usually covered with rubber or soft plastic to prevent the disc from slipping. The disk is pressed to the stand using a washer located on the other side of the disk; the stand and the washer contain permanent magnets, the attractive force of which presses the washer through the disk to the stand.
The optical head system consists of the head itself and its movement system. The head contains a laser emitter based on an infrared laser LED, a focusing system, a photodetector and a pre-amplifier. The focusing system is a movable lens driven by an electromagnetic voice coil system, similar to the movable loudspeaker system. Changes in the magnetic field strength cause the lens to move and the laser beam to refocus. Thanks to its low inertia, such a system effectively tracks the vertical runout of the disk even at significant rotation speeds.
The head movement system has its own drive motor, which drives the carriage with the optical head using a gear or worm gear. To eliminate backlash, a connection with an initial voltage is used: with a worm gear - spring-loaded balls, with a gear - pairs of gears spring-loaded in opposite directions.
The disc loading system is carried out in two versions: using a special case for the disc (caddy), inserted into the receiving hole of the drive, and using a retractable tray (tray), on which the disc itself is placed. In both cases, the system contains a motor that drives the tray or case, as well as a mechanism for moving the frame on which the entire mechanical system is mounted, together with the spindle motor and the optical head drive, into the operating position when the disk rests on the spindle motor stand.
When using a regular tray, the drive cannot be installed in a position other than horizontal. In drives that allow installation in a vertical position, the design of the tray includes latches that hold the disk when the tray is extended.
The front panel of the drive usually contains an Eject button for loading/unloading a disc, a drive access indicator, and a headphone jack with an electronic or mechanical volume control. A number of models have added a Play/Next button to start playing audio discs and switch between audio tracks; The Eject button is usually used to stop playback without ejecting the disc. On some models with a mechanical volume control, made in the form of a handle, playback and transition are carried out by pressing the end of the control.
Most drives also have a small hole on the front panel designed for emergency removal of the disk in cases where this is impossible to do in the usual way - for example, if the tray drive or the entire CD-ROM fails, if there is a power failure, etc. You need to insert a pin or a straightened paper clip into the hole and press gently - this will release the lock of the tray or disk case, and it can be pulled out manually.
What interfaces do CD-ROMs work through?
SCSI, IDE - CD-ROM is connected directly to the SCSI or IDE (ATA) bus by specifying the device number for SCSI or Master/Slave - for IDE. IDE CD-ROMs usually operate in the ATAPI (ATA Packet Interface) standard.
Sony, Mitsumi, Panasonic are the three most common interfaces, supported by many sound cards and individual adapters. Mitsumi and Panasonic use a 40-pin connector cable, similar to IDE, while Sony uses a 34-pin connector cable, similar to floppy drives.
There are also CD-ROMs with the so-called Proprietary Interface - the manufacturer's own interface, supplied complete with an adapter and connecting cable.
Currently, CD-ROMs are available only with SCSI and IDE interfaces.
Why does the CD-ROM drive rotate at different speeds?
Information on a CD is recorded with a constant linear density, therefore, to achieve a constant reading speed, the rotation speed changes depending on the movement of the reading head. The standard disk rotation speed is 500 rpm when reading from internal zones and 200 rpm when reading from external zones (information is written from inside to outside).
What does "n-speed" CD-ROM mean?
At standard rotation speed, the data transfer rate is about 150 kb/s. In two- and higher-speed CD-ROMs, the disk rotates at a proportionally higher speed, and the transfer speed increases proportionally (for example, 1200 kb/s for an 8-speed).
Due to the fact that the physical parameters of the disk (heterogeneity of mass, eccentricity, etc.) are standardized for the main rotation speed, at speeds greater than 4-6, significant fluctuations of the disk already occur, and reading reliability, especially for illegally produced disks, may get worse. Some CD-ROMs can reduce the disk rotation speed when reading errors occur, but most of them cannot then return to maximum speed until the disk is changed.
At speeds above 4000-5000 rpm, reliable reading becomes almost impossible, so the latest models of 10-speed or higher CD-ROMs limit the upper limit of the rotation speed. At the same time, on external tracks the transmission speed reaches the nominal one (for example, 1800 kb/s for 12-speed models, and as it approaches the internal ones, it drops to 1200-1300 kb/s.
Why are “illegal” discs often read worse than “branded” ones?
The CD standard defines their physical and optical parameters: the thickness and reflectivity of the aluminum layer, the depth and shape of the pits (recording elements), the distance between tracks, the transparency of the protective layer, eccentricity, etc. Leading companies producing CDs have proven technologies and reliable equipment that allow them to comply with these parameters; The equipment and technologies of illegal manufacturers often do not provide this.
The mechanics and optics of different CD-ROM models have different tolerances and adjustment capabilities, which is why some models can confidently read discs that are practically unreadable by other models. Also, as a result of operational wear, the drive parameters deteriorate over time, which leads to deterioration in the reading of discs that could be read with confidence on a new drive.
Is it possible to visually determine the quality of a disc?
Approximately - it is possible. You need to carefully examine the working surface of the disk - it should be smooth, and there should be no scratches, cloudy areas, bulges or depressions, as well as “stains” on the reflective layer. Then hold the disk up to the light (with the working side facing you) - it may be slightly transparent, but without obvious holes in the reflective layer. The more transparent the disk, the higher the likelihood of it being read unsurely.
Cheap discs (especially those made in China) usually do not have a protective varnish layer on the back side - even a small scratch on this side can lead to a complete failure to read the corresponding area of the disc.
What is the quality of playing audio discs on CD-ROM?
Playing audio discs is a side function for CD-ROMs, and is usually done “by the residual principle” - a simple (often 12- or 14-bit) DAC and a simple output amplifier. Mass-produced CD-ROMs are significantly inferior to stationary Hi-Fi players; some models are closer to inexpensive portable players. In any case, the signal quality at the headphone output (front panel) is worse than at the line output (rear wall) - due to additional distortion during amplification.
In addition to the quality of the DAC, most CD-ROMs do not perform any oversampling of the digital signal to improve the signal-to-noise ratio, nor interpolation and masking to smooth the curve and partially compensate for uncorrected errors. The lack of interpolation and masking leads to noticeable distortions and clicks when discs are read incorrectly, while on an audio player, reading errors are not so noticeable.
Many modern CD-ROMs have an additional digital audio output on the back wall (S/PDIF - Sony/Philips Digital Interface Format), which can be connected to studio or home equipment that has an S/PDIF or AES/EBU, which allows you to reproduce sound from a disc with virtually no distortion (some distortion may be introduced by the CD-ROM decoder).
What is the maximum capacity of a CD?
Approximately 650 MB (* 1024 * 1024 bytes) - 74 minutes of recording, data flow - 153600 bytes/s. This recording duration is determined by the standard, however, with a denser arrangement of tracks or pits themselves on the disk, a larger playing time or data volume can be obtained. Such discs with deviations from the standard may be read unstable by some drives, or may not be read at all.
What are CD-R and CD-E?
System of single (CD-Recordable - recordable CD) and multiple (CD-Erasable - erasable CD) recording of CDs. The terms CD-R and CD-E refer to both recording devices and the discs themselves.
For one-time recording, so-called “gold” discs are usually used, which are a regular compact disc in which the reflective layer is made of gold film, and the transparent layer of plastic immediately adjacent to it is made of a material that darkens when heated. During the recording process, the laser beam heats areas of the plastic, which darkens and stops transmitting light to the reflective layer, forming a “gap” between the “pits” - unchanged transparent areas of the plastic.
To make it easier to track the information track during the recording process, CD-R discs are manufactured with auxiliary markings. When reading, tracking is carried out, as usual, along the recorded pit track.
Some versions of the software (eg CDR Publisher) allow you to burn bootable discs. To boot from such disks, the computer's BIOS must support this feature (latest versions of AWARD and Phoenix BIOS).
Why does noise appear when recording pure WAV to CD-R?
Perhaps the reason is that some sound editors (for example, Cool Edit and Sound Forge) place their service information at the end of the WAV file, formatting it as an additional record in full accordance with the RIFF format. However, some CD-R software ignores the audio fragment length field, treating the entire remainder of the file after the title as a single audio fragment, as a result of which the service information ends up on the disk in digital audio format and is reproduced as noise or clicks at the end of the program. To eliminate this phenomenon, it is necessary to either prohibit sound editors from saving service information in a WAV file, or remove it using other programs.
During multi-session recording of individual audio tracks, input and output zones are formed at the beginning and end of each session, and entering them during playback causes a random signal to appear. It is recommended to record audio discs in one session, forming a complete audio file in advance, if the CD-R software does not allow merging files during the recording process.
In addition to the above, interference on recorded audio discs can occur due to instability of the data stream in the CD-R (internal buffer overflow or stream interruption), deviations from the normal parameters of the recorded signal, laser operating mode or disc rotation speed, manufacturing defects of the disc, as well as due to the fault of players unable to reliably read specific copies of disks. In case of poor-quality recording of data discs, the situation is often saved by large volumes of correction codes provided in CD-ROM formats.
Is it possible to use a driver from another model with an IDE CD-ROM?
In most cases - yes, if the CD-ROM operates in the ATAPI standard. However, some drivers may not work correctly with other CD-ROM models.
To read video discs, you need support from the drive itself and its driver, as well as the video format unpacking program (player). Some combinations of drive, controller, driver and unpacking program are incompatible with each other. You can try changing the driver or unpacking program. There are also cases when, when installing a CD-ROM on the same channel as the HDD, video discs play much slower.
You can - for this you need a CD-ROM that supports the Read Long command and is capable of finding audio sectors in direct access mode (for example, many of the drives with a SCSI interface, most Panasonic models), and a special program - grabber - for reading complete audio sectors, for example, CDGRAB, CDDA, CDT, etc. Often such programs are accompanied by a list of CD-ROM models that support the long read command. Due to slight differences in interfaces, some drives will not work with some of these programs, but may work with others.
One of the main problems when reading audio discs is synchronization errors between sectors. They occur when the disk reading program does not have time to issue a read command to the next sector before the internal CD-ROM buffer overflows and data from the beginning of the sector is lost. In this case, the CD-ROM is forced to perform positioning, and the frame-by-frame structure of audio discs does not make it possible to start reading exactly from the right place. As a result of such failures, dropouts or appearance of several extra signal samples occur in the file generated by the program. To combat synchronization errors, some programs have a mode in which the correct joining of adjacent sectors is checked. When using a CD-ROM with a larger buffer capacity, the likelihood of errors is reduced.
Synchronization disturbances resulting from positioning are often mistakenly called "jitter". In fact, the term jitter is usually used to denote the jitter of the phase of a digital signal due to rapid fluctuations in the flow rate generated by changes in the rotation speed of the disk and its vertical runout. In a sense, synchronization errors are also higher-level phase errors, but applying the term jitter to them is not entirely correct.
What are the reasons for poor performance of Samsung-631 CD-ROM drives?
In addition to the low quality of the mechanism itself and the reading system, in these drives there is insufficient pressing of the disk to the spindle, which is why the disks slip during acceleration and braking. The reason for weak clamping is the large gap between the spindle magnet and the metal disk, which is attracted by the magnet. Michael Svechkov (2:460/140@FidoNet) recommends gluing a 1-2 mm thick steel washer to the magnet, choosing it so that the gap between the magnet and the metal disk is minimal, however, with the thinnest disks they should not touch each other, otherwise The operation of the tray ejection system will be disrupted.
This is a device for reading data that is recorded on an optical CD.
The storage medium on the CD is relief polycarbonate substrate 120, 80 mm, on which a thin layer of light-reflecting metal (aluminum, sometimes gold) is applied. When recording a CD matrix, a laser beam “burns” tiny holes in it - pits, leaving reflective surfaces of the metal disk - lands. After this, the matrix (master disk) is sent to the production workshop, where many polycarbonate copies are stamped from it. Then the relief base is metallized, and another, thinner layer of varnish is added to protect the metal layer.
When reading a disc, a different reading beam is reflected from the pits and lands in different ways. More precisely, it is not reflected from the pits - the pits absorb the beam and do not allow it to be reflected. Thus, the pit gives a “zero” signal, and the land gives a “one”. And the combination of zeros and ones is the essence of any computer information. From the center to the edge of the CD, one track 0.4 µm wide is applied in a spiral with a pitch of 1.6 µm.
The entire surface of the CD is divided into three sections in the form of rings, located from the center to its edge. The Lead-In area is located closer to the center of the disk. When a disk is initialized in a personal computer, the Lead-In area is read first. This area contains the disk title, Table of Contents, a table of addresses of all records, the disk label and some service information. The middle area contains the main information on the CD and occupies the bulk of the disc. The Lead-Out disc area contains the end of disc mark.
What does a CD-ROM consist of?
The CD-ROM drive consists of the main components:
- an electric motor that rotates the disk;
- an optical system, which consists of a laser emitter, optical lenses and sensors, designed to read information from the surface of a compact disc,
- microprocessors that control the mechanics of the drive, the optical system and decoding the read information into binary code.
The CD is spun by an electric motor. The beam from the laser emitter is positioned in the desired area using an optical drive system. The beam is reflected from the surface of the disk and passes through a prism to a special sensor. The stream of rays is converted by the sensor into an electrical signal, which is processed.
CD-ROM capacity. The capacity of CD-ROM is 650-700 MB (on disks with a diameter of 80 mm - 180-210 MB). This type of disc can hold 74 minutes of audio or up to 2 hours of television-quality video in MPEG-4 format.
CD-ROM transfer speed. Data Transfer Rate is a value that characterizes the maximum speed at which the drive transfers data read from a CD to RAM. The data transfer rate increases from the initial sectors to the final ones. The transfer speed of the inner disk ring is called the Inside Data Transfer Rate, and the outer ring is called the Outside Data Transfer Rate. The technical data sheet provides the external speed. Thus, the Sony 52x drive is a 52-speed drive from Sony. Data is read 52 times faster than disk drives (or a conventional audio player), whose read speed is 150 kB/s. That is, multiplying 52 by 150, we get the data transfer speed of the Sony 52x drive equal to 7800 kB/s.
Design features of CD-ROM drives.
As you know, most drives are external and built-in (internal). CD drives are no exception in this sense. Most CD-ROM drives currently offered are built-in. External storage is noticeably more expensive. This is easily explained, since in this case the drive has its own housing and power supply. The form factor of a modern embedded CD-ROM drive is determined by two parameters: half-height (HH) and a horizontal size of 5.25 inches. The front panel of each drive provides access to the CD loading mechanism. One of the most common is the CD-ROM loading mechanism using a tray mechanism. The tray mechanism really looks like a tray that slides out of the drive, usually after pressing the Eject button. A CD is installed on it, after which the “tray” is pushed into the drive using a button located on the front panel of the drive. On the front panel of the drive, in addition, there is a device operation indicator (busy); there is also a hole with which you can remove the CD even in an emergency, for example, if the Eject button does not work or the power supply is suspended.
Access time.
Data access time for CD-ROM drives is determined in the same way as for hard drives. It is equal to the delay between receiving the command and the moment the first bit of data is read. Access time is measured in milliseconds and its standard rating value for 4-speed drives is approximately 200 ms. This refers to the average access time, since the actual access time depends on the location of the data on the disk. Obviously, when working on the internal tracks of the disk, the access time will be less than when reading information from the external tracks. Therefore, drive data sheets provide an average access time, defined as the average value when performing several random reads of data from the disk. Obviously, the shorter the access time, the better, especially in cases where data needs to be found and read quickly. The access time to data on a CD-ROM is constantly decreasing. Note that this parameter for CD-ROM drives is much worse than for hard drives (85-500 ms for CD-ROM and 10 ms for hard drives). Such a significant difference is explained by fundamental differences in designs: hard drives use several heads and the range of their mechanical movement is smaller. CD-ROM drives use a single laser beam and it travels along the entire disk. In addition, the data on a CD is written along a spiral, and after moving the reading head to read a given track, you still need to wait until the laser beam hits the area with the necessary data. When reading external tracks, the access time is longer than when reading internal tracks. Typically, when the data transfer rate increases, the access time decreases accordingly.
Data transfer rate (dats-transfer rate).
At standard rotation speed, the data transfer rate is about 150 kbps. In two- and higher-speed CD-ROMs, the disk rotates at a proportionally higher speed, and the transfer speed increases proportionally (for example, 1200 kb/s for an 8-speed). Due to the fact that the physical parameters of the disk (heterogeneity of mass, eccentricity, etc.) are standardized for the main rotation speed, at speeds greater than 4-6, significant fluctuations of the disk already occur, and reading reliability, especially for illegally produced disks, may get worse. Some CD-ROMs can reduce the disk rotation speed when reading errors occur, but most of them cannot return to maximum speed until the disk is changed. At speeds above 4000-5000 rpm, reliable reading becomes almost impossible, so the latest models of 10-speed or higher CD-ROMs limit the upper limit of the rotation speed. At the same time, on external tracks the transfer speed reaches the nominal one (for example, 1800 kb/s for 12-speed models, and as we approach the internal ones, it drops to 1200-1300 kb/s. To indicate the CD reading speed compared to the Audio CD standard ( CD-DA) usually use the numbers 24x, 32x, 34x, etc. However, recently the technology has changed a little.The first CD-ROM models used a constant linear reading speed (CLV), which required changing the rotation speed of the disk as the head moved. 1x devices (150kb/s) this speed was in the range of 200-530 rpm. 2x-12x high-speed devices simply increased the rotation speed. However, already increasing the speed to 12x requires a rotation speed of 2400-6360 rpm, which is very high for removable media (often also poorly centered). In addition, different rotation speeds for different areas of the disk increase access time, since when moving the head it is necessary to change the disk rotation speed accordingly. Further increasing the speed in this way is very problematic, so manufacturers switched to P technology -CAV and CAV. The first involves a transition from constant linear velocity to constant angular velocity (CAV) on the outer tracks of the disk, and the second uses constant angular velocity for the entire disk. In this regard, numbers like 32x lose their meaning a little, because usually refer to the outer side of the disk, and information on the CD is written starting from the internal tracks and on completely empty disks this speed is not achieved at all. This technology is very clearly visible in the internal and external track read speed test below.
Modern drives support reading speeds for CDs up to 56x; the situation with DVD discs, speeds have also increased, and for different read/write formats there are a variety of, quite high, speeds.
Data block size.
Data block size refers to the minimum number of bytes that are transferred to the computer via the interface card. In other words, this is a unit of information that the drive controller operates with. The minimum data block size in accordance with the MPC specification is 16 KB. Since the files on a CD are usually quite large, the gaps between blocks of data are negligibly small.
Buffer size.
Many CD-ROM drives have built-in buffers, or cache memory. These buffers are memory chips installed on the drive board for recording read data, which allows large amounts of data to be transferred to the computer in one message. The typical buffer capacity is 256 KB, although models are available with both larger and smaller capacities (the larger the better!). As a rule, faster devices have a larger buffer capacity. This is done to achieve higher data transfer rates.
Modern DVD-RW drives usually have a buffer size of at least 2 MB. Drives that have a buffer have a number of advantages. Thanks to the buffer, data can be transferred to the computer at a constant speed. For example, data to be read is typically scattered across the disk, and because CD-ROM drives have relatively long access times, this can cause read data to arrive at the computer with delays. This is almost unnoticeable when working with texts, but if the drive has a long access time and does not have a data buffer, the pauses that occur when outputting images or audio are very annoying. In addition, if fairly complex driver programs are used to manage drives, then the table of contents of the disk can be pre-recorded into the buffer, and accessing a fragment of the requested data is much faster than when searching from scratch.
Support for playing audio CDs.
Audio CD support means you can listen to regular music CDs using your CD-ROM drive. Almost all modern drive models have this capability. Some models do not require special programs for this - audio CD playback is performed at the “hardware” level. To enable this mode, there is a special button on the front panel of the drive. Any modern optical drive plays any music format.
CD-ROM/XA format support.
This implies the use of disks in the XA format, which supports storing audio and video data as a single block, which also includes information about audio synchronization. Data on audio discs and CD-ROMs is stored on tracks that hold 24-byte "frames" played back at 75 frames per second. The stored data may include audio, text, static and dynamic images. When content is in the normal format, each type must be located on a separate track, while in the XA format, data of different types can be stored on the same track.
Disk loading mechanism.
There are two fundamentally different types of mechanisms for loading CDs: into storage containers and into pull-out trays. Today they also produce drives in which you can load several CDs at once. These devices are similar to multi-disc players for cars.
Containers - This disk loading mechanism is used in most high-quality CD drives. The disk is installed in a special tightly closed container with a movable metal flap. It has a lid that is opened solely for the purpose of placing the disc in or removing it from the container; the rest of the time the lid remains closed. When installing the container into the drive, the metal flap is moved to the side by a special mechanism, opening the path for the laser beam to the surface of the CD. Containers are the most convenient way to load discs. If all your disks have containers, then all you have to do is select the one you need and insert it into the drive. You can safely pick up the container without fear of staining or damaging the surface of the CD. In addition to the fact that the container protects the disk from contamination and damage, with this method it is installed into the drive more accurately. This reduces reader positioning errors and ultimately reduces data access time. The only drawback of containers is their high cost. Another important advantage of drives designed for disks in containers is that they can be installed even sideways. This operation cannot be performed with drives with drawer trays.
Pull-out trays. Most simple CD drives use pull-out trays to install the disc. These are the same devices that are used in CD-DA class audio CD players. Since the discs do not need to be placed in separate containers, the loading mechanism is cheaper. True, every time you install a new disk, you need to pick it up, and this increases the risk of getting it dirty or scratched. The tray itself is a very unreliable design. It is quite easy to break, for example, by carelessly hitting it with your elbow or dropping something from the top at the moment when it is pulled out of the drive. In addition, any dirt that gets on the disk or tray is drawn into the device when the mechanism returns to its operating position. Therefore, drives with trays cannot be used in industrial or other unfavorable external conditions. In addition, the disc does not sit as securely on the tray as it does in a container. If a CD is placed on a tray at an angle, loading it may damage both the disc and the drive.
All modern standard drives have a tray mechanism for loading the disc. As the simplest (and therefore least expensive) it has supplanted almost all other types.
Reading CD-RW.
In addition to write-once devices for golden discs, which can be read on any CD-ROM device, devices for reading and writing rewritable CDs (CD-RW = CD ReWritabe) have also recently appeared. Due to their different reflectivity, reading them requires the use of special technology, it was called MultiRead. The ability of CD-ROM devices to read such discs must be taken into account (the following CD-ROMs have this ability: Hitachi CDR-8335; Samsung SCR-3230; Sony CDU-711; Teac CD-532E; NEC CDR-1900A; ASUS CD-S340 - now this can make almost all drives). For full operation, the operating system also requires support for the CD-RW UDF 1.5 file system.
Dustproof.
The main enemies of a CD device are dust and dirt. If they get into an optical device or mechanism, it leads to data reading errors or, at best, to a decrease in performance. In some drives, lenses and other vertical components are located in separate sealed compartments, in others, to prevent dust from entering the drive, unique “gateways” consisting of two shutters (external and internal) are used. All these measures help extend the life of the device. Disk drives in containers are much better protected from adverse factors than models with pull-out trays. In industrial conditions, only they can be used. Nowadays, special protection against dust is practically not used, except that some manufacturers supply the lids of the retractable tray with rubber gaskets - the noise is reduced and less dust gets inside the device. Since drives now cost mere pennies, there is no point in complicating and therefore increasing the cost of the drive - it’s easier to buy a new one after some time - a year or two... By the way, these same reasons explain the general low level of quality of even expensive and prestigious drive models.
Automatic lens cleaning.
If the laser device's lens is dirty, reading data is slower because it takes a lot of time to repeatedly search and read operations (in the worst case, the data may not be read at all). In such cases, it is necessary to use special cleaning discs. Some modern high-quality drive models have a built-in lens cleaner. It is very useful when the computer operates in difficult external conditions or you cannot keep your work area clean.
External and internal drives.
When choosing a CD drive model (external or internal), you need to consider how it will be used and whether you plan to upgrade your computer. Each of these types of drives has its own advantages and disadvantages. Here are some of them: external drives - these portable devices are stronger and larger than built-in ones; it is recommended to purchase them only if there is a lack of space inside the computer or if you need to connect the drive to one computer or another. If each of them has a SCSI adapter, then this procedure comes down to disconnecting the drive from one computer and connecting it to another. Internal drives - these devices are recommended to be purchased if the computer has a free compartment or the drive is planned to be used on only one computer. All modern computers have CD-ROM drives. This question is practically meaningless today for PC owners - there is enough space and everything else in computers. A narrow contingent of consumers of such products consists of owners of old laptops (or those laptops in which the drive is broken or is not fully functional). The SCSI interface is practically not applicable in home PCs - its destiny is only sometimes, in some server systems, and even then only for hard drives.
Interfaces.
Quite often, manufacturers supply a CD-ROM drive with a mandatory controller card, which implements the so-called (own) proprietary interface. Typically this is a proprietary implementation of one of the versions of the IDE or SCSI interfaces. Often, when purchasing a CD-ROM drive as part of the Multimedia Kit, the sound card contains a proprietary interface. The de facto standards for CD drive interfaces have become the Mitsumi, Panasonic and Sony specifications. One of the popular interfaces for all drives, including CD-ROM drives, is SCSI or SCSI-2. As you know, a distinctive feature of the IDE interface is the implementation of the controller function in the drive itself. That is why such drives are connected to a computer through a fairly simple adapter board. This interface usually supports software I/O. The drive is connected to the interface board using a flat cable, which usually differs in the number of contacts depending on the drive manufacturer (Sony - 34-pin, Panasonic - 40-pin cable). Western Digital has developed the so-called Enhanced IDE specification. This document was supported by almost all leading storage companies. This interface allows you to connect up to four hard drives simultaneously. But most importantly, the Enchanced IDE specification allows not only to increase the number of connected devices, but also to use other types of devices, such as CD-ROM drives or tape drives. In particular, Western Digital offers the ATAPI (ATA Packed Interface) protocol to support CD-ROM drives with an IDE interface. ATAPI is an extension of the ATA protocol and requires minor changes to the system BIOS. In general, a special driver is used. Recently, drives have appeared that support not only the IDE interface, but also EIDE/ATAPI.
As you know, the SCSI interface has become one of the most important industrial standards for connecting peripheral devices such as hard drives, tape drives, laser printers, CD-ROM drives, etc. It should be noted that SCSI is a higher level interface than IDE. Physically, the SCSI bus is a flat cable with 50-pin connectors through which up to eight peripheral devices can be connected. The SCSI standard defines two methods of signal transmission - common-mode and differential. Differential signaling versions of the SCSI bus allow for longer bus lengths. To ensure signal quality on a SCSI bus, the bus lines must be terminated on both sides (a set of termination resistors, or terminator). The SCSI-2 interface version allows you to increase the throughput of the bus by increasing the clock frequency and reducing the critical timing parameters of the bus, using the latest LSIs and high-quality cables. Thus, the “high-speed” version of SCSI-2 is implemented - Fast SCSI-2. The “Wide” (Wide SCSI-2) version of the bus provides for an additional 24 data lines due to the connection of a second 68-wire cable (not used for CD-ROM drives). Typically, the data transfer speed on the SCSI(-2) bus for CD-ROM drives reaches from 1.5-2 to 3-4 MB/s. Despite the standardization of the SCSI interface, the problem of drive compatibility with SCSI adapters still remains. If you implement your own interface, connecting devices other than a CD-ROM drive is quite problematic. It should be noted here that there is an ASPI (Advanced SCSI Programming Interface) specification, which was developed by Adaptec, a leading manufacturer of SCSI adapters. ASPI defines a standard programming interface for the host SCSI adapter. ASPI software modules fit together quite easily. The main ASPI software module is the ASPI host manager. ASPI driver programs are associated with it, for example, for devices such as CD-ROM drives, floptical and removable hard drives, scanners, etc. If the SCSI device manufacturer provides an ASPI-compatible driver, it is compatible with all host adapters or interface cards from Adaptec and most other manufacturers. Unfortunately, in some cases, CD-ROM drive manufacturers supply their controller card with its own (non-ASPI compatible) driver, calling the interface SCSI. This is something to keep in mind if you want to connect other devices to SCSI. Which interface is preferable to use on IBM PC-compatible computers for CD-ROM drives? Although theoretically the SCSI interface can provide a transfer speed slightly higher than IDE, in practice everything is somewhat more complicated. We should not forget, for example, the fact that the IDE interface mainly uses software I/O, and SCSI devices in most cases use data transfer via direct memory access. On single-user systems, software I/O is often much more efficient. This is especially true when using improved caching algorithms. The advantage of SCSI adapters is undeniable, primarily in multitasking and multi-user systems. The fact is that commands for a SCSI device can be queued, which frees up the processor to perform other operations. In addition, if a CD-ROM drive is used on a local network as a shared device, there is probably no alternative to SCSI yet. On the other hand, installing an IDE drive is quite simple. In most cases, the principle of “plug and play” is valid. For normal operation, it is usually not necessary to add any additional software drivers to the system configuration files. For a SCSI adapter, the installation process is more complicated. First, you should remember about shared system resources: I/O ports, IRQs, DMA channels, areas in the upper memory UMB. Secondly, you need to correctly determine the SCSI ID for a specific device; thirdly, you should not forget the parity signal (prohibit or enable), install terminators, etc. In addition, the configuration files must be supplemented with the appropriate software drivers for the adapter and devices. As for the cost, a SCSI adapter is usually not included in the computer and you have to buy it additionally. As mentioned above, the SCSI interface, due to its high cost and complexity, has become less widespread, especially in the optical drive sector. Nowadays you can still find old SCSI devices, but these are mainly hard drives, printers and scanners. To this day, only HDDs with this interface are produced. So all the information in this chapter of the article is really useless.
Now the actual IDE/ATA standard is being replaced by the new SATA and SATA-2. The new standard simplifies the installation of the drive to elementary primitivism! At the same time, SATA devices are not only easy to install, but also more technologically advanced, etc.
Bottom view of the reading head of the drive model NEC1100A
We are primarily interested in small trimming resistors installed directly on the head. These resistors regulate the current through the laser diode and, by changing their value, you can change the brightness of the laser radiation within certain limits. In the figure they are circled and designated by numbers 1 and 2.
The location of these controls can vary greatly between different drive models. For example, this photo shows the optical head of a newer drive:
You need to take a thin screwdriver and slightly increase the brightness of the desired laser. You can find the right regulator experimentally. Let's assume that our drive reads CDs well and reads DVDs very poorly. We take a marker and make marks on the resistors to remember the position of the engine, which was made at the factory when setting up the head. Then, we twist one of the resistors, for example number 1, to its extreme position counterclockwise. We assemble the drive and check the reading of CD and DVD discs. To do this, it is convenient to use the program Nero CD-DVD Speed. If the reading of CDs, which were previously readable well, has sharply deteriorated, it means that we have turned the regulator of the laser responsible for reading this format. We return the resistor slider to its previous position. If the quality of reading CDs has not changed, then we guessed the brightness control of the DVD laser.
After we have found the desired regulator, we turn it approximately 5 - 10 degrees clockwise relative to the position that was set at the factory and which we marked with a marker. We reassemble the drive and check the readability of the DVD disc. If this does not help, we tighten the resistor further, ultimately achieving the best reading quality.
Bitsetting
The Bitsetting function allows you to change the bit responsible for the media type (ROM, -R, +R), the so-called Book Type. This bit is located in the Lead-in area of the disk and can take one of three values. But you can change it only if you use DVD+R discs, because for DVD-R it is registered by default. If you want the disc to be guaranteed to be readable on any player, even the most ancient one, you need to set the Book Type to DVD-ROM. It is recommended to set Book Type for two-layer (DVD+R9 DL) discs, because otherwise, they may well not be readable even on the most modern DVD players.
Lite-On IT DVD Drive – SOSW-833SX
SOSW-833SX Specifications:
Interface – USB 2.0
The maximum recording speed of DVD±R discs is 8x;
The maximum writing speed for DVD±RW discs is 4x;
The maximum recording speed of DVD±R DL discs is 2.4x;
The maximum writing speed of DVD-RAM discs is 5x;
The maximum writing speed for CD-RW discs is 24x;
The maximum writing speed for CD-R discs is 24x;
Buffer volume – 2 MB
Slim form factor
Weight - 362 gr.
DVD recorder DRW-1608P2S with support for recording on dual-layer media:
Lite-On IT releases a drive with LightScribe technology and 8X recording to DVD+R DL.
Characteristics of SHW-16H5S:
- Interface: ATAPI/E-IDE
- Support DVD+R / DVD+RW / DVD-R / DVD-RW / DVD+R9 / DVD-R9 / DVD-ROM / CD-R / CD-RW / CD-ROM
- Record to DVD+ / - R9
- SMART-BURN buffer underrun protection technology
- CD-DA/VCD/DVD SMART-X reading speed adjustment technology
- Noise and vibration suppression system for recording and reading VAS
- Supports Fixed Packet, Variable Packet, TAO, SAO, DAO, Raw Mode Burning & Over-Burn recording modes
- DVD reading: DVD single/dual layer (PTP/OTP), DVD-R (3.9 GB / 4.7 GB), DVD-R, DVD+R, multi-session DVD+R, DVD-RW and DVD+RW
- CD reading: CD-DA, CD-ROM, CD-ROM/XA, Photo-CD, multi-session, Karaoke-CD, Video-CD, CD-I FMV, CD Extra, CD Plus, CD-R and CD-RW
- Supports 80 and 120 mm CD and DVD
- Data exchange modes: PIO mode 4, DMA mode 2 and Ultra DMA mode 4
- Lightscribe support
ASUS CB-5216A1T: DVD/CD-RW drive with SATA interface
The CB-5216A1T supports proprietary ASUS FlextraLink, FlextraSpeed and DDSS II technologies.
FlextraLink technology prevents errors associated with buffer underload and eliminates the possibility of disk damage, and FlextraSpeed is designed to increase accuracy and reliability when reading/writing/rewriting media of different formats. In turn, the DDSS II Dual Dynamic Suspension System is designed to minimize vibration caused by the optical drive spindle motor and resonance between the drive and the computer case by stabilizing vertically and horizontally.
Technical characteristics of ASUS CB-5216A1T:
- CD-R writing speed: 52X
- CD-RW rewriting speed: 32X
- CD-ROM reading speed: 52X
- DVD reading speed: 16X
- FlextraLink technology
- FlextraSpeed technology
- DDSS II system
- AI Auto Speed Adjustment Technology
- Supports accelerated decoding of music CDs (max. speed - 52X) and Video CDs
- Mt support Rainier
- Supports DAO-RAW, TAO, DAO, SAO, Multi-Session, Batch Write and Overburn
- Supports CD-DA, CD-ROM, CD-ROM XA, Photo CD, Mixed Mode CD-ROM, CD-I, CD-Extra, CD Text, Video CD, DVCD and Bootable CD formats
- Vertical and horizontal installation possible
- SATA interface
Hitachi GSA-4166B
Hitachi introduced the drive - GSA-4166B supports all formats, including DVD-RAM.
Main characteristics of the device:
- Super Multi Drive supporting 5x DVD-RAM and 16x DVD±R recording
- Compatible with dual-layer ±R discs
- Speed formula: 16x/6x/5x/16x/8x (DVD-R/RW/RAM/+R/+RW)
- LightScribe technology support
- Buffer volume - 2 MB
- Media loading - horizontal, automated
- Interface: IDE/ATAPI/Ultra DMA66
- Power: 12V/5V
- Supported OS: Win9X,\Win2K,XP, Media Center Edition
- DVD-R: SL 2x, 4x CLV, 8x ZCLV, 12x PCAV, 16x CAV, DL 2x, 4x CLV
- DVD-RW: 2x, 4x CLV, 6x ZCLV
- DVD-RAM: 2x, 3x, 5x CLV (Ver.2.2)
- DVD+R: SL 2.4x, 4x CLV, 8x ZCLV, 12x PCAV,16x CAV, DL 2.4x, 4x CLV, 6x ZCLV
- DVD+RW: 2.4x, 4x CLV, 8x ZCLV
- CD-R: 10x, 16x CLV, 24x ZCLV, 32x, 40x, 48x CAV
- CD-RW: 4x, 10x,16x CLV, 24x, 32x ZCLV
- DVD-R/RW/ROM: 10x/8x/16x max.
- DVD-RAM (Ver.1.0/2.1) : 2x, 3x, 5x CLV
- DVD+R/+RW: SL - 10x max., DL - 8x max./8x max.
- CD-R/RW/ROM: 48x max./32x/48x max.
Data transfer rate:
- DVD-ROM: 22.16 Mb/s.
- CD-ROM: 6 Mb/s.
Data access time:
- DVD-ROM: 145 ms
- CD-ROM: 120 ms
Supported formats (media) and recording methods:
- DVD-RAM, DVD-R/RW, DVD+R (SL, DL)/RW, CD-R/RW
- DVD-RAM/+RW: random (any) recording
- DVD-R: Disk-at-once, incremental recording
- DVD-R DL: Sequential recording
- DVD-RW: Disk-at-once, incremental recording
- DVD+R, +R DL: Sequential recording
- CD-R/RW: Disk-at-once, Session-at-once, Track-at-once, batch recording
Reading discs (formats):
- DVD-ROM, DVD-RAM, DVD-R(SL,DL), DVD-RW, DVD+R (SL,DL), DVD+RW; CD-R, CD-RW, CD-ROM, CD-ROM XA, CD-DA, CD-I, CD-Extra, CD-Text, Photo CD, Video CD
* SL - one layer (single-layer disc), DL - two-layer.
Buffalo DVSM-X516FBS and DVSM-X516IU2
Buffalo begins selling two new DVD drives.
For internal installation, it is equipped with a SATA-ATAPI adapter and supports both standards. Dimensions: 146 x 170 x 42 mm, and product weight 760 g. When connected via serial ATA, the DVSM-X516FBS model is compatible only with Win2K/XP.
The DVSM-X516IU2 external drive has IEEE 1394/USB 2.0 interface connectors. Its dimensions are 160 x 279 x 55 mm, weight 1.8 kg. Full compatibility with Win98 SE/Me/2K/XP and WinXP Media Center Edition 2005 is provided.
Both models are built on the basis of Hitachi DVD super multiple drive GSA-4167B. They provide the following data recording speeds: DVD+R DL 6x, DVD-R DL 4x, DVD±R (1-layer) 16x, DVD-RAM 5x, DVD+RW 8x and DVD-RW 6x. CD-R matrices are written at 48x, and CD-RW at 32x. Reading speeds for DVD are: DVD-ROM 16x, DVD-ROM DL 8x, DVD±R (1-layer) 10x, DVD±R DL 8x, DVD±RW 8x, and for DVD-RAM 5x. CDs are read at 48x for CD-ROM and 40x for CD-RW. The set includes a set of software "Easy Media Creator 7 Basic" and "MyDVD 6".
Cost of internal drive DVSM-X516FBS - US$130
External DVSM-X516IU2 - US$160
Plextor begins sales of external DVD±R/RW drives. This model does not have a retractable “tray” element but uses “slot loading”.
For connection to a computer, a USB 2.0 and IEEE 1394 interface is provided. The recording speed on DVD±R matrices is 16x, DVD+RW 8x, DVD±R DL 6x, and DVD-RW 4x. Regular CD-R discs are written at 48x speed, while CD-RW discs are written at 24x speed. The drive buffer size is 8MB. The device is equipped with an “Intelligent Recording” function that automatically selects the optimal recording speed. The products will be produced in a limited edition of 500 pieces in white cases. Dimensions 167.1x253.5x53mm, weight 1.7 kg.
Another external DVD±R/RW drive.
The design of the device is similar to the PX-716UFL, but the body color is black, and a traditional retractable “tray” is used to accept the disk. There is also a USB 2.0 and IEEE 1394 interface, the recording speed for DVD±R is 16x, DVD+RW 8x, DVD+R DL 8x, DVD-R DL 4x and for DVD-RW 6x. CD-R matrices are written at 48x, and CD-RW at 32x. Buffer size 2MB. Dimensions 167.1 x 253.5 x 53 mm, weight 1.6 kg. All drives are guaranteed compatible with WinMe/2K/XP.
NU DDW-164
Specification
- Interface:IDE/ATAPI(UDMA33)
- Reading speed:
- CD-ROM: 40x Max.
- DVD-ROM: 16x Max.
- Write speeds:
- CD-RW: 24x
- CD-R: 40x
- DVD-RW: 4x
- DVD+RW: 4x
- DVD+R/DVD-R: 16x
- DVD+R DL: 4x
- Recording formats: CD Disc at Once (DAO), Session at Once (SAO) and Track at Once (TAO) recording, DVD+R Incremental Write, DVD+RW Random Write
- Data Buffer Size: 2MBytes
- Dimensions: 148mm x 42mm x 170mm
- Weight 0.92 kg
The drive is capable of working with almost all existing types of DVD media, with the exception of DVD-RAM and DVD-R DL media. Of course, the lack of support for the DVD-R DL format is not yet such a significant disadvantage, but, nevertheless, all modern drives support it.
NU DDW-164 clearly needs improvement; most of the problems are related to the fact that the manufacturer needs to refine the recording strategies for most blanks and rework the list of supported blanks. These problems, as a rule, can be solved in a new firmware version, so we can only hope that the developers will quickly make the necessary changes, but for now the drive will suit you only if you mainly use “branded” blanks.
Q. Decided to buy DVD-RW?
A. NEC-ND3520 Q. NEC DVD-RW ND-2500A stopped reading and writing DVDs (reads CD-R/RW)?
A.Reading and writing DVD requires more laser power than writing CD. That is, the most likely reason is a decrease in radiation power. First, clean the head. If it doesn’t help, it means the laser emission is reduced, change the drive.
Q. Combo CD-RW/DVD Samsung 352F (OEM), the drive does not see the disc (the problem is not the disc), there is also a problem with a 7.9 GB DVD, the computer is very strained, but cannot read the files. Mother ECS P6S5AT. Percent Celeron 1.0 GHz, Windows XP Home system?
A. To write a DVD, you need to install a disc burning program. As for reading double-layer DVDs: your drive simply does not support them or a firmware update is required (check the drive manufacturer's website). In addition, Samsung optical drives have never been of high quality.
Q. I bought 552 TEAC. Was it worth taking the NEC 1100A instead?
A. Instead of NEC - it was not worth it, the reliability and quality of NEC drives has recently been noticeably higher.
The TT-15S1 features a perfectly flat, milky 28mm thick acrylic base, a belt drive, an aluminum tonearm with an anti-skating system and, of course, no preamps.
Speed 33 x 1/3.45 rpm ±0.2%,
Signal to noise ratio - 80dB,
Frequency response - from 20Hz to 20kHz,
Impedance - 0.66 kOhm,
Power consumption - 5W
The dimensions of the TT-15S1 are typical for its class - w440 mm x t110 mm x d350 mm, weight - 8.9 kg.
Vinyl record player released in limited edition and priced at ~$2400.
Pioneer DVR-110
Model * records DL media on 8x DVD+R/-R, recording of regular DVD+R/-R discs is done on 16x. The remaining characteristics of the Pioneer DVR-110 are as follows:
Reading:
*Unfortunately, there is no mention of support for Blu-ray media.
Vinyl "blanks" CD-R
17/05/2005 The Russian company MIREX is launching CD-R MAESTRO blanks with VYNIL coating and a design stylized as vinyl records of yesteryear. MAESTRO is available in five versions, differing only in the color of the inner rings on the surface.
The disk capacity is 700MB and the maximum writing speed is 52x. According to the manufacturer, the main advantage of vinyl is double, enhanced protection of the information layer, which is especially important when the disc is frequently used and used in extreme conditions, for example, in high humidity or sudden temperature changes.
Benq with dual cooling system
Benq introduced the DVD+-R/+-RW burner drive. The model is called DW1640 and will be released with a front panel in black and white. The drive provides recording of dual-layer DVD+R DL discs at 2.4x speed. DVD-R DL support will be implemented via firmware. Other types of discs are written at 8x speed, so an 8.5GB disc is written in 16 minutes; only DVD-RW discs are written at 6x speed.
The new product is equipped with a dual cooling system Dual Cooling System (DCS) including the Air Flow Cooling System (AFCS), which enhances the heat transfer of metal parts due to constant air circulation and the Anti-Dust Cooling System (ADCS). The drive has an ATAPI interface and dimensions 146x178x42 mm.
JVC announced its development in the field of optical media with the development of dual-layer DVD-RW discs with a capacity of 8.5 GB on one side. By using highly sensitive recording layer materials and a new recording technology called N-Strategy, JVC engineers have significantly improved the rewritable disc manufacturing process and improved the quality of the latter.
The new drive allows you to store up to 8.5 GB of data or up to 11 hours of video on one side of the drive, i.e. the new product has 1.8 times more volume compared to traditional discs - single-sided and single-layer.
In addition, the method of pre-processing materials for recording layers, developed by JVC, will allow manufacturing companies to use existing equipment to produce new discs, if, of course, the proposal to standardize and adapt JVC's new DVD-RW discs receives a response in the DVD Forum, where JVC has submitted a corresponding application.
Unlike conventional dual-layer discs, JVC discs use a new material that improves both the read quality of the disc [from both layers] and improves their ability to erase and write.
In fact, physically, the disk consists of more layers [see Fig. below], but there are exactly two that are recorded - layers L1, L0, which in turn consist of reflective, protective, recordable, protective and the substrate itself.
JVC intends to continue to develop improvements to this technology with a view to future commercialization of this development.
Sony and Nichia demonstrate a prototype monolithic read/write unit
The presence of several ideologically similar formats for reading (writing) information from optical disks led to the fact that, starting from a certain moment (from the moment combo drives were released), laser heads with two separate diodes began to appear in drives (one for CD, the other for DVD), and then heads with pairs of crystals packed into a single diode housing, each of which emitted its own wavelength (such diodes, for example, are produced by Sony). The goal was quite specific: to replace a scattering of elements with a monolithic block, simplifying and reducing the cost of the design of the laser head, and simultaneously increasing its reliability.
The introduction of laser-recorded optical discs in the blue-violet range has become a real challenge for pick-up head designers. After all, now the reading unit needed to include another diode with its own matrix and its own beam path. In a surge of real enthusiasm, puzzling “three-in-one” designs began to appear one after another: from prisms, diodes and lenses. It's clear. First you need to make a device from what you have, and there were separate diodes and universal heads, and only then simplify this device.
It was the development of a prototype of such a “polished” universal laser head unit that the tandem from Sony and Nichia announced today. Let me remind you that this pair of manufacturers entered into a time-limited cross-licensing agreement in April of this year for the joint development of blue-violet laser diodes and pick-up heads based on them, which, however, they will each sell and produce separately. The created prototype will be sent into mass production by the end of 2005. By then, one must assume, his versatility will only increase. Because at the moment the new laser unit is not entirely universal: it emits only waves with a length of 660 nm and 405 nm. In other words, it only works with DVD and Blu-ray discs. Without CD support, the value of this module drops more than noticeably. However, the real advantage of the reader block is different: its execution is simply amazing in its “laconicism”:
The design principle is clear from the block diagram, and we will not dwell on it. We only note that this prism design is as reliable as possible (all three optical sections are enclosed in a monolithic block) and is easy to assemble. In addition, such a unit will only need one focusing lens, since the source of blue and red radiation is the same diode.
BenQ is releasing a "Pro" version of its "dual-layer" DW1620 drive.
BenQ issued an official press release announcing the release of a "Pro" version of its famous 16-speed DVD±RW drive, which also supports DVD+R DL discs:
Actually, there is only one difference between the DW1620 Pro drive and the DW1620 - the new product writes double-layer DVD+R discs at 4x speed, while its predecessor could only do this at 2.4x speed. That is why the company did not change the drive index, limiting itself to the suffix “Pro”. Also, both drives now come with a proprietary QScan utility, which allows the user to quickly check the quality of the disc and determine the optimal speed and recording parameters
However, if we remember the specifications and price of the expected super-universal drive GSA-4163B from LG, then everything described above becomes not too important. Q.For some time now I have been having problems playing DVDs and CDs. When watching videos or listening to audio with any program, “slips” periodically occur. Those. a movie is playing, for example, and then immediately skips forward a couple of seconds. It's the same with MP3 when played directly from the drive. The frequency of the phenomenon is 5-20 minutes. Everything is readable from the hard drive (SATA interface). It is copied from/to the hard drive, discs are written, discs are copied, and so on, normally and at the same speed. When playing AudioCD, everything is also fine, but I’m not using digital playback, but “analog”, i.e. The sound output does not go through the motherboard via the IDE cable, but through the digital audio output of the drive directly to the sound card, where it is decoded, while the drive works like a simple CD player. It turns out that the circle is closed on the IDE interface. The drives hang on the secondary IDE: Plextor PX-712A (Master) and Plextor PlexWriter Premium (Slave). ASUS P4C800 motherboard, PC3200 512 MB Kingston RAM, P4 Presscott 3GHz processor, WinXP Prof SP1 operating system.
A. Either the discs are a little scratched, or while watching a movie or listening to music, the system wants to access some services, so short-term disappearances and jumps occur. The laser head may be dusty (clean it). When reading an Audio CD, spin-up speeds (max - 4x) are not required as when watching movies. Advice - first rewrite movies onto a hard drive (with DVD, of course, it’s more problematic than with CD), otherwise you’ll slowly ruin your DVD/CD-Rom.
DVD-RAM (Digital Versatile Disc Random Access Memory)
In July 1997, the DVD Forum approved the multi-recordable DVD format - DVD-RAM (Digital Versatile Disc Random Access Memory), which was developed by three Japanese companies: Hitachi, Matsushita and Toshiba. But DVD-RAM has not gained significant popularity in the personal computer market. Perhaps this happened because the two opposing camps, one of which promoted DVD+RW, and the other DVD-RW, were so keen on promoting their own multi-recording formats for DVD media that they simply did not get around to the third format. Although there may be another reason why manufacturers began to turn away from DVD-RAM, namely, DVD-RAM discs were supplied both in cartridges and without, which somewhat complicated the work with discs (cartridges could be collapsible or non-separable) , and dictated the need to produce drives with a tray for cartridges.
The DVD-RAM format became more popular in the corporate sector when DVD-RAM drives were included in robotic data storage libraries. Corporations chose this format because the specifications of DVD-RAM, in terms of the number of maximum possible rewrite cycles, compared favorably with DVD±RW, promising 100 thousand erases and rewrites, which is significantly more than 1 thousand for DVD±RW discs. But even the potential possibility of such a huge number of rewrites, as we see, could not help the DVD-RAM standard gain popularity among ordinary users. After all, perhaps, only non-separable cartridges could guarantee the promised number of rewrite cycles at the expense of cost and ease of storage. What the mass market was not ready to do. In the end, support for DVD-RAM recording in some drives produced today only serves to strengthen the manufacturer's reputation, but not the standard.
However, now, according to some signs, the DVD-RAM format in a “cartridge-free” version is beginning to gain momentum. The most active efforts to return DVD-RAM to the market are being taken by one of its developers - Hitachi. According to the Internet resource Clubic, LG-Hitachi currently produces 2 million laser heads per month, capable of recording DVD-RAM discs, among other formats. And, most importantly, other manufacturers are also going to explore the market of DVD-RAM media and drives! Has reaching the upper limit of the writing speed of DVD±R discs really scared manufacturers so much that they are ready to introduce something new into DVD drives by any means, expanding their functionality, even at the expense of not very popular properties? It’s like with mobile phones, which from “just a call” have turned into a kind of “Swiss knives” for, not even communications, but for entertainment or something. Be that as it may, laser heads for drives compatible with DVD-RAM are going to be produced by Sanyo , which owns from 30% to 40% of the laser head market in general. DVD Super Multi heads, according to Clubic, Sanyo will release by the end of this year or early next year. Super Multi chipsets are supplied to the market by Matsushita, Renesas and MediaTek. If for the first two the DVD-RAM format is “native”, then MediaTek is its “voluntary” supporter, which indicates an increase in interest in DVD-RAM. Taiwanese companies Lite-On and Accesstek are developing their DVD-RAM-compatible drives, preparing for the launch of new products by the second quarter of 2005. But LG Electronics regularly produces such drives. In the spring of 2004, LG announced the Super Multi drive model, which actually supported all formats, including the latest dual-layer (GSA-4120B drive).
Super Multi drive LG GSA-4160B.
Not long ago this model was updated to version GSA-4160B. The update affected only the writing speed of DVD+R discs: it increased from 12x to 16x. All other parameters remained unchanged: recording speed of DVD-R discs – 8x, DVD-RAM – 5x, DVD+RW and DVD-RW – 4x, CD-R – 40x, CD-RW – 24x; CD reading speed – 40x, DVD – 16x.
Q.How to format a DVD?
A.Nero InCD - format your disc there, you will get a UDF format, and then you can work with it like a large floppy disk (most likely, this means not a formatted, but a blank DVD disc). If we are talking about DVD +/-RW , then when erasing in Nero, select “Full erase of a rewritable disc.”
Q.DVD-RW drive NEC ND2510A. It turned out that he does not read the blanks he himself wrote down. But, if you just insert a DVD disc, for example with a movie or game, then everything is OK. It seems to read the images written to the disk - that is, if there is an installer, it will launch it. But, before it gave a cyclic redundancy check error, but now: “Incorrect Function”. How do you think this can be solved?
What I tried:
A.Have you tried writing to normal Verbatim? All the NECs I have seen were characterized by an outright dislike for “left-handed” discs. And the cheapest Noname couldn’t even be read by Pioneer after recording (although household players BBKs somehow played them - albeit not for long: then the recording layer peeled off).
Q. DVD+RW NEC 2510A (new) does not write DVDs
A. DVD+R or DVD-R discs? If you give him the second type, then everything is simple - he doesn’t know how to work with them, but if the first type - go to the warranty. This device is very picky, it writes only those disks that it “knows” are in its firmware The names of the disk manufacturers are hardcoded, and those that he recognizes, he will write, and those that he does not “know,” he will not. And changing the firmware will not fix this - checked!
1. Check if the ASPI driver is installed.
2. Download new firmware from the manufacturer’s website.
3. Are the wheels good?
Plextor: PX-740A Dual Layer DVD Drive
Plextor has announced the PX-740A internal dual-layer IDE DVD drive. This is an ordinary, high-quality drive, i.e. without any special features, like the flagship PX-716A.
The recording time for an 8.5 GB disc on the PX-740A drive is ~15 minutes. In this case, the drive writes a single-layer disc in less than 6 minutes.
PX-740A Drive Specifications:
- Buffer capacity 2 MB
- Buffer Underrun Proof technology
- 16 x DVD±R recording
- 8x DVD+R DL recording
- 4x DVD-R DL recording
- 8x DVD+RW recording
- 6x DVD-RW recording
- 16x DVD-ROM reading
- 48x CD-R recording
- 32x CD-RW dubbing
- 48x CD-ROM reading
- Supports DVD±VR (Video Recording) direct recording method
4. CD/DVD-ROM drive
These days, a CD/DVD-ROM drive is an integral part of a computer, since almost all software is now distributed on CDs, and some multimedia programs are distributed on DVDs. DVD drives support both regular CDs and DVDs, making them more versatile. In modern systems, it has long been possible to boot from CD-ROM/DVD-ROM drives.
To achieve the desired effect when using a CD-ROM, it is recommended to choose a drive with an EIDE interface of at least 32x or 40x or a DVD-ROM with a speed of 8x.
I would recommend purchasing both CD-RW and DVD-ROM. These aren't the cheapest devices yet, but once you buy them, you'll immediately experience the benefits of using them: burning your own CDs, 4.7-17 GB of data on DVDs, and much more. Another reason to install a CD-RW drive and a CD-ROM/DVD drive at the same time is that you can save the contents of an optical disc without having to copy it to your hard drive.
Burning your own CDs will help you save your data with minimal effort. CD-RW drives are used to write both CD-RW (write many times) and CD-R (write once) media. Note that many older CD-ROM drives (not labeled MulliRead) do not support CD-RW discs, while virtually all CD-ROM drives are compatible with the CD-R standard.
Advice. To ensure maximum recording reliability on CD-RW discs, one technology is needed to prevent buffer overflows. Such technologies that eliminate the possibility of incorrect recording (and, therefore, damage) of discs include BURN-proof, JustLink or Waste-Proof.
5. Keyboard and mouse
Obviously, a computer will need a keyboard and a cursor positioning device, such as a mouse. The choice of a specific modification of these devices directly depends on the personal preferences of the user. Different users like different types of keyboards, so you'll have to try a lot of models before you find the one that suits you best. Some people like keyboards with springy keys that you can “feel” well, while others prefer “soft” keyboards that allow the keys to be pressed lightly.
There are two types of keyboard connectors, so when purchasing, make sure the keyboard connector matches the connector installed on the motherboard. The original 5-pin DIN connectors and the newer 6-pin mini-DIN connectors are electrically compatible, allowing you to adapt one type of keyboard connector to your existing keyboard. The most modern keyboard interface is the USB bus; USB connectors have become very widespread, not least thanks to "legacy-free" computers containing exclusively USB ports.
When using a USB keyboard, like any other device of this type, USB support is required at the Basic Input Output System (BIOS) level. If you want to use a USB keyboard outside of the Windows GUI, the system BIOS must support a technology called Legacy USB or USB Keyboard and Mouse. This feature is supported by almost all modern BIOSes. At the same time, try to find a model that works with traditional keyboard ports, allowing you to use a USB keyboard in both newer and older systems.
The same applies to other cursor positioning devices (such as a mouse). Everyone can choose the most suitable option among many different modifications. Before you finally decide what to buy, try several options. If your motherboard has a built-in mouse port, make sure the connector you select matches it. A mouse with this connector is commonly called a PS/2 mouse because this type of mouse port was first used on IBM PS/2 systems. Many computers use a serial port to connect a mouse, but if you have the option of using a mouse port built into the motherboard, it's better to use that. Some USB mice work without any problems with the PS"2 port, but mostly mice of this type are designed only for the USB port. I think the most acceptable option is a dual-mode mouse that works on any system. Do not forget also about the existence of wireless versions of the mouse.
Tip: Don't skimp on your keyboard and mouse! An “uncomfortable” keyboard and mouse can cause illness! Personally, I recommend high quality keyboards with capacitive sensors.
The Universal Serial Bus (USB) is gradually replacing all other standard I/O ports. The USB interface supports PnP technology and allows you to connect up to 127 external devices to one port, and the USB bus data transfer speed is about 60 MB/s. As a rule, a USB hub is connected to the USB port integrated into the motherboard, and all devices are connected directly to it. Currently, USB ports are present on almost all motherboards.
The range of devices connected to USB is unusually wide. These include modems, keyboards, mice, CD-ROM drives, speakers, joysticks, tape and floppy drives, scanners, video cameras, MP3 players and many others. However, when connecting multiple devices to one low-speed USB 1.1 port, there may be some problems that may require you to upgrade to USB 2.0. When purchasing a new system, pay special attention to the availability of USB 2.0 ports.
Batch mode, which allows you to perform a whole series of tests without operator intervention. You can create an automated diagnostic program that is most effective if you need to identify possible defects or perform the same sequence of tests on several computers. These programs check all types of system memory: basic (base), extended (expanded) and...
Different possibilities. Such a division of the PC could thoroughly confuse not only ordinary users, but also technical support specialists. However, even such a classification is still better than none. Today, there are five classes of computers, with mobile ones included in a separate group: the requirements for such devices are very specific. Dividing into categories will allow...
... (Wide Area Information Server) server; news - Usenet newsgroup; telnet - access to Telnet network resources; ftp - file on an FTP server. host. domain - domain name on the Internet. port - a number that must be specified if the method requires a port number. Example: http://support. vrn.ru/archive/index.html. The http:// prefix indicates that what follows is the address of the Web page, / ...
N OS-6). It should be noted that replacing computer parts is not profitable to consider as an upgrade. For an accountant, this is extra work. By the amount of modernization in accounting, you need to increase the initial cost of the computer. This means that modernization costs will not have to be written off immediately, but gradually, as depreciation is calculated. Therefore, in practice, upgrading a computer if possible...