An Optical Disk is a computer disc that uses optical storage techniques and technology to read and write data.
With the explosion of CD audio and CD-ROM discs today, most people are aware of optical discs and most likely use some form of optical disc technology, whether it’s a home CD audio player or a terabyte. Optical Disk. Optical discs are currently making a significant impact on how we store, manage and receive and distribute information. .
The purpose of this article What is Optical Disk? is to present an overview of optical disc technology, with a specific focus on the many different types of digital optical discs.
What are optical discs? |What is Optical Disk In Hindi?
It is a computer storage disk that stores data digitally and uses a laser beam (transmitted from a laser head mounted on an optical disc drive).
Optical disks are mainly used as portable and secondary storage devices. It can store more data than previous generation magnetic storage media and has a longer life.
Compact disks (CD), Digital Versatile/Video Discs (DVD) and Blu-ray disks are currently the most commonly used types of optical discs.
What is the size of the optical disc?
Size of Optical Discs in English
The diameter of optical discs is typically between 7.6 and 30 cm (3 to 12 in), with 12 cm (4.75 in) being the most common size. A typical disc is about 1.2 mm (0.05 in) thick, while track pitch (the distance from the centre of one track to the centre of the next) ranges from 1.6 µm (for CDs) to 320 µm (for Blu-ray discs). .
How to make an optical storage disk
Its base is built using a hard-plastic substrate, and a reflective layer of metal foil is used to encode the digital data. Next, a clear polycarbonate layer secures the foil and enables the laser beam to move through the reflective foil layer.
The sandwich of optical discs includes various materials, depending on the type of disc, whether it is rewritable or one-time writable. In Write-Once CD-ROMs, an organic dye layer lies between the polycarbonate and the unwrapped reflective foil. Because they replace aluminum foil with an alloy that is a phase-reflective material, rewritable optical discs can be erased and rewritten multiple times.
How is data stored in an optical disc?
Optical storage, an electronic storage medium that uses low-power laser beams to record and retrieve digital (binary) data. In optical-storage technology, the laser beam encodes digital data on an optical, or laser, disc in the form of small pits arranged in concentric tracks on the surface of the disc. A low-power laser scanner is used to “read” these pits, converting the pits into electrical signals that vary the intensity of the reflected light.
This technology is used in compact discs, which record sound; CD-ROM (compact disc read-only memory), which can store text and images as well as sound; In WORM (write-once read-many), a type of disk that can be written to once and read multiple times; And in newer discs that are completely rewritable.
Optical storage provides greater memory capacity than magnetic storage because the laser beam can be controlled and focused more precisely than smaller magnetic heads, allowing data to be stored in a very small space. Large data can be stored.
For example, a complete set of encyclopedias can be stored on a standard 12-centimeter (4.72-inch) optical disc.
In addition to higher capacity, optical-storage technology also provides more authentic duplication of sound and images.
Optical discs are also inexpensive to make: plastic discs are simply molds pressed from a master, as used to record phonographs. The data stored on them cannot be destroyed by a power outage or magnetic disturbance. The discs themselves are relatively strong for physical damage, and unlike magnetic discs and tape, they do not need to be stored in tightly sealed containers to protect them from contaminants.
Optical scanning tools are equally durable because they have relatively few moving parts.
Early optical discs were not erasable—that is, the data encoded on their surfaces could be read but not erased or rewritten.
This problem was solved in the 1990s with the development of WORM and writable/rewritable discs. The main remaining drawback for optical equipment is the slow rate of information retrieve compared to conventional magnetic storage media. Despite its slow speed, its superior capacity and recording features make optical storage ideal, especially those that still store large amounts of animated graphics, sound, and text.
Multimedia encyclopedias, video games, training programs, and directories are usually stored on optical media.
What are optical disc drives?
Optical drives retrieve and/or store data on optical discs such as CDs, DVDs, and BDs (Blu-ray Discs).
Optical drives are commonly known by other names such as disc drive, ODD (abbreviation), CD drive, DVD drive, or BD drive.
Some popular optical disc drive manufacturers include Samsung, LG, HP, and Dell. In fact, one of these companies may have manufactured the optical drive for your computer or other device, even if you don’t see their name on the drive.
Optical Disc Drive Description
An optical drive is a piece of computer hardware about the size of a thick soft cover book. There’s a small Open/Close button on the front of the drive that pulls the drive bay door out and in. This is how media such as CDs, DVDs, and BDs are inserted and removed from the drive.
The side of the optical drive has threaded holes in the 5.25-inch drive bay for easy mounting on the computer case.
The rear end of the optical drive has a port for cables that connect to the motherboard. These vary depending on the type of cable used, such as IDE or SATA.
What is the history of optical discs?
The first recorded historical use of an optical disc was in 1884 when Alexander Graham Bell, Chichester Bell and Charles Sumner Tenter recorded sound on a glass disc using a beam of light.
An early optical disc system came into existence in 1935, named Littentorgel.
Sony and Philips developed the first generation of CDs with complete specifications for these devices in the mid-1980s.
The DVD disc appeared after the use of CD-ROM became widespread.
The third generation of optical discs was developed in 2000–2006 and was introduced as Blu-ray Disc. The first films were released on Blu-ray Disc in June 2006.
Blu-ray eventually prevailed over HD DVD as a competitor in the optical disc format war. A standard Blu-ray disc stores about 25 GB of data, where a DVD can store about 4.7 GB and a CD can only store about 700 MB of data.
How many types of optical discs are there?
Despite their similarity in appearance, there are many differences between these discs.
1) CD-ROM in English:
Compact Disk Read Only Memory
Compact Disk Read Only Memory drives were one of the first disc-based drives for modern personal computers.
It is an optical ROM in which, the data is already stored by the manufacturer and end-users can only read this data.
They are used to distribute software, programs and games.
2) CD-R in English:
These are Write- Once Read-Many (WORD) type optical discs.
In this type of CD, the user can write the data only once and read it multiple times.
3) Erasable Optical Disk or CD-ROM in English:
This is a read /write optical disk memory. Information is written to disk and can be read from disk. Disk contents can be erased and new data can be rewritten.
4) DVD ROM in English:
DVD stands for Digital Versatile Disks. DVD stores more data than a CD-ROM. Its capacity can be 4.7 GB, 8.5 GB, 20 GB.
Capacity depends on whether it is single layer, double layer single side or double side disc.
DVD ROM uses the same principle as CDROM for read and write. But a shorter wavelength beam is used. A lens system is used to focus the two different layers on the disc. Data is recorded at each layer. Thus, their capacity can be doubled.
What are the advantages of optical discs?
Advantages of Optical Disk in English
Optical discs have many advantages, which are as follows:
Only plastic and aluminum foils are used in the production of optical discs, making their manufacturing costs less expensive. Therefore, users have the advantage of purchasing optical discs in bulk, and also, optical disc drives are included with many computers by their manufacturers, and users may benefit from purchasing optical disc drives separately.
Comparing with volatile and non-volatile memory, optical discs are more durable. No power failure causes data loss. Hence, it can last for a long time. However, it is not much protected from any physical damage, including scratches and heat.
The process of backing up data becomes much easier with the help of optical discs. The data should be placed inside the drive icon; Data, which needs to be burned. And, users can easily back up the data by just clicking on “Burn Disc”.
A very high degree of stability is provided by the optical disc because it is not vulnerable to electromagnetic fields and other types of environmental influences, unlike the magnetic disc.
Optical discs are very portable; However, they are quite large in size. They can be used in various computers and devices and can be carried to different places as they can be placed inside bags and other small items.
What are the disadvantages of optical discs?
Disadvantages of Optical Disk in English
Although it has many advantages, it also has some limitations which are discussed below:
Optical discs need to be protected from the hands of thieves when you are using them for backup purposes. If thieves do succeed in stealing optical discs, it could be more damaging. Therefore, it can provide insecurity; And because of its size, optical discs are more likely to be lost and stolen.
Unlike flash drives, any plastic casing can damage optical discs. Therefore, they make the disc unreadable when there are scratches on the disc. After which the data stored on the optical disc can no longer be recovered.
Compared to other formats of storage drives, optical discs cost more per GB/TB. Also, it has less storage capacity as compared to any other form of storage medium. Optical discs have a maximum storage capacity of 4.7GB, excluding Blu-ray discs.
Like a USB flash drive, making a duplicate copy using an optical disc isn’t easy. The burning process requires a separate software and hardware. For this purpose, many third-party programs are also available. The writing software is equipped with the latest version of Windows.
Why is optical media not so popular today?
The popularity of all-optical media has waned greatly as almost all types of content available on the Internet can be downloaded and streamed anywhere with a network connection. Another reason optical media is no more common in use today is the decline in price of USB flash drives, which have the ability to store a lot of data, which has led to optical media becoming a less popular storage solution.
What are the differences between a magnetic disc and an optical disc?
|magnetic disc||optical disc|
|The media type used is multiple fix disc||The media type used is Single Removable Disc|
|intermediate to noise ratio||Excellent signal to noise ratio|
|sample rate is low||sample rate is high|
|it is implemented where the data is accessed randomly.||Implemented in streaming files.|
|Only one disk can be used at a time||Mass replication is possible|
|6 tracks in a magnetic disc are usually circular||In optical discs, the layers are formed spirally.|
|The data in the magnetic disk is accessed randomly.||In optical discs, data is accessed sequentially.|
|In magnetic discs, only one disc is used at a time.||Optical disc allows large-scale replication|
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