What is the full form of CD

CD: Compact Disc

CD stands for Compact Disc. It is a flat, small-rounded recordable device which can store up to 700Mb data. It has a diameter of 4.75 inches. It is portable. Hence, they can be taken anywhere according to one's needs. We can run a CD for an uncountable time as its quality does not degrade with time and lasts long. CDs can store any type of data, like audio, video, text, pictures, etc., in digital format. The data is stored in the form of small notches on the disc, and when the disc is played, the data is read by a laser from an optical drive.

History

The Credit for inventing a CD can't be given to a single person, as every part of the CD has been discovered by different individuals. However, James Russell is the most attributed inventor of the CD. He discovered it in 1965, and the patent of the CD was sold to the Sony and Philips Company, which made it publicly on May 17, 1978, in Japan and by 1983, it further went on to the US and Europe. The first CD was produced on 17 August 1982, at the Philips factory in Germany.

Manufacture

CDs are made from 1.2 mm thick polycarbonate plastic weighing about 16 grams. A thin layer of Aluminium is applied to the surface to make it reflective. The data transform from the centre and proceeds to the edge. A CD has two sides. One side is a plane which tells us about the content of the CD, and another side shines as it has a laser beam on it through which it can be read. Replicated CDs are produced in bulk using Hydraulic Press.

The Working of a CD

A semiconductor laser with a wavelength of 780 nm is focused onto a single track of the disc to create a CD. The laser beam converts variations in how light is reflected off the polycarbonate layer at the bottom of the disc into sound as it turns.

CDs are delicate and prone to scratches; although they can be fixed, disc reading might be impacted.

Formats for Compact Disc

Different compact disc formats were developed to store data as personal computers (PCs) and other commercial technology proliferated. Due to the varied colours on the book bindings, these CD versions are known as Rainbow Books. Sony and Philips developed requirements for each product type. The criteria for a typical CD were laid down in the Red Book.

Variations of Compact Discs Include:

Read-Only Memory for CDs: The advent of the CD-ROM in 1985 marked the transition from audio to optical data storage. Any computer with a CD-ROM drive can read CD-ROMs. The CD-ROM adheres to Yellow Book requirements.

CD-interactive: When CD-i was introduced in 1993, a CD-ROM drive could not play it. Later, the format was changed to be readable by both. The CD-i adheres to the Green Book specification standard.

CD-ReWritable: Instead of using standard compact discs, the CD-RW used a metallic alloy that reflected light differently. Many early CD players were unable to read a CD-RW due to this change in reflectivity. The Orange Book standard is adhered to by the CD-RW.

CD-Recordable: A CD-R is a compact disc that may be read and written to once. It adheres to the Orange Book just like the CD-RW, but unlike the CD-RW, the CD-R can be read on CD players that were available before the CD-R was even introduced.

eXtended Architecture for CD-ROMs: The CD-ROM XA is an addition to the common CD-ROM that enables simultaneous access to audio, video, and computer data. It was developed as a link between CD-ROM and CD-i, and it adheres to the Yellow Book standard.

Picture CD: The photo CD was specifically developed by Kodak to store pictures in a digital format that could be accessed and altered on a computer. It was first introduced in 1992 and had a capacity of 100 high-quality photographs. It adhered to Beige Book guidelines.

Video CD: The White Book standard was used in the 1993 creation of the video CD, or VCD. Although it has a much lower resolution than a contemporary digital video disc, VCD quality was designed to be on par with VHS recordings in terms of quality (DVD).

The Potential for Compact Discs

The CD has steadily lost popularity as other technologies advanced, especially in the early 2010s.

In the domain of music, where streaming audio and digital downloads have significantly displaced physical mediums, digital forms have surpassed CDs. Although the music business made more money from compact disc sales, convenience and affordability have discouraged more people from using the physical medium.

PCs could barely hold about 10 MB of data when compact discs first gained popularity, leading many to use the CD as a storage medium. That is not the case now. Compact discs and tape cartridges are no longer the storage medium of choice for many users due to the constant introduction of greater-capacity hard drives and online storage choices.

The DVD format was developed in 1995 by Panasonic, Philips, Sony, and Toshiba as a potential compact disc replacement. The size of a DVD is identical to that of a CD, but it offers a substantially larger storage capacity of 4.7 gigabytes (GB). Although the software and other digital data are also stored in this format, video entertainment storage is arguably where it is most well recognised. Both a DVD-ROM in a computer and a DVD player can play DVDs.

Blu-ray was introduced in 2003 to take the role of DVD. Blu-ray discs have a 25 GB storage capacity, enabling greater image and video quality.