Updated March 30, 2023
Definition of Compact Disc
Compact Disc can be defined as a disc-like memory device, which is made from plastic material and used for storing data and accessing stored data back from the memory device. It was invented as an alternative option for floppy disks memory, as it is a modern way of providing quicker access with larger memory capacity. It is frequently used for storing, transferring, and getting back the stored media files, such as audio and video files. The accessibility of these memory devices is defined by the type of device, and they are CD –R, CD –RW, CD –MO, VCD and DVD.
History of Compact Disc
The idea of using a light to read the data from a surface pre-recorded, without physically touching the disk, was first originated from James T. Russell while he was working for Battelle Memorial Institute. After years of research on various prototypes built based on this concept, Russell finally invented the first digital storage device for optical recording and playback facility and got the patent for the same in 1970. These efforts, like any other digital invention, attracted many investors for developing it further and lead it into the commercial market. This includes the Philips Electronics and Sony companies.
Both Sony and Philips bought the idea by paying the respective royalties to the Battelle Institute. Sony then launched its first commercial device, named CDP -101, a CD player for accessing CDs, in the year of 1982. Further, in 1985, Russell came up with 26 more patent ideas for CD –ROM technology and got it registered with sole rights. Down the line, Russell continued his work on CDs and optical recording technology, which led up to owning 11 more patent rights for optical recording and playback specifically for Random Access Memory.
CDs then became the main source of storage and data access, as it is portable with quicker & higher storage capacity than any other storage device that was used at the time. It was mostly used for storing, retrieving, and transferring movies from one to another without having to pay every time, as it takes a one-time payment for buying the CD and reusing it as much time as required. Except for CD –ROM, all other types of CD can be reused, as ROM allows only readable access to the CD memory.
How Compact Disc Works?
Typically, the Compact Disc or CD comes in the size of 12 cms, that is 4.5 inches, in diameter. It is made up of four different layers. They are,
- Top Layer
- Lacquer Layer
- Reflective Layer
- Polycarbonate Disc Layer
The top layer is used for marking the identification marks on the disc, and it can also have a printed form of instructions or name to indicate what is stored inside the device. The Lacquer layer, located below the top layer, is used for preventing the device from getting exposed to the atmospheric air which can lead to oxidation. Below the lacquer layer is the reflective layer made of aluminum material, where the laser beam is directed for receiving a reflection, which in turn can read the contents of the disk. The bottom-most layer of the disc is made of polycarbonate where the data are encoded for the compact disc to work appropriately.
In order to access a compact disc, one needs to have a CD player or a disc drive. Inside a CD player, it consists of various hardware parts, including a small-sized laser beam and another small electronic light detector. Here, the laser beam is created using a semiconductor diode laser and a photoelectric cell acts as the electronic light detector. When the CD player or the Disk drive is powered on, the motor inside the instrument enables the compact disc for rotational motion, at the rate of considerable high speed, ranging from 200 to 500 rotations per minute.
Due to this, the semiconductor diode laser placed inside is powered up, for scanning the tracks of the disc, starting from the center to the outer tracks. This is passed through the disc, in order to read the data from the bottom-most layer. Hence the reflection created can fetch the data from the compact disc, and deliver it to the instrument accessing the CD. The electronic light detector can receive the reflection and read the digital contents that are already fed into the storage unit.
Uses of Compact Disc
Below are the fields where the Compact Disc is used efficiently for multiple applications,
1. Marketing/ Sales/ Advertising
The Compact Disc is generally used as a key element for promotional marketing for software products, as the CD storage area is capable of storing files of any format and type. Software products were loaded into the CD, along with readable instructions, supporting files, reference links, and keys for installation. This provides benefits with lesser manual efforts when it comes to software installation and portability.
2. Trainings/ Academic/ Educational
Since the compact disc can hold higher volume contents, can give faster access to the items in the disc, it aids in storing complete course packages in one place. Unlike other storage spaces, CDs can handle all the commonly used file formats, let the user read/ write/ overwrite on the same device over and over again. Hence, it is a go-to option for passing the training materials in the training, academic and educational institutions.
3. Work Place
In the workplace, the employees often need to share the files from one table to another, with respect to work that needs to be done. Instead of passing the paperwork, in the form of physical files, it is a convenient and well–organized way to pass the required documents, folders, and files using a portable storage device like the Compact Disc.
Advantages and Disadvantages
Some of the advantages and disadvantages:
Advantages
- Cost-Effective.
- Faster than a previous storage unit, that is, Floppy Disk.
- Readable & Read/ writable, as per user requirements.
- Allows any type of File.
Disadvantages
- Storage capacity increased for the latest device, hence these devices became useful due to technological growth.
- Delicate design, which can be easily damaged or scratched.
Conclusion
Compact Disc was once the famous storage option, before the invention of USB-based portable storage devices like Pen Drives. It was due to the flexibility that was provided by CD‘s in terms of the data formats allowed, the size of the storage, and the processing speed, for which the users got attracted to this convenient storage system.
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