DATA STORAGE DEVICES GURU PRASAD REDDY BOGI REDDY

1. DATA STORAGE DEVICES GURU PRASAD REDDY BOGI REDDY INTRODUCTION MAGNETIC STORAGE DEVICES OPTICAL STORAGE DEVICES CLOUD STORAGE Data storage devices is used to store the data and retrieved back for the future use. This recording can be done using any form of energy like electronic, electromagnetic etc. Data storage is one of the key aspects in computing world. There are many ways to store data from punching cards to hard drives which can store a large amounts of data. They also provide the security of accessing data from other users. These are the devices which store the data on the magnetized medium and data is stored by using magnetization in the magnetized materials and is non-volatile. The surface of the disk is divided to small sized magnetized regions which has uniform magnetization. These include floppy disk, hard disk, magnetic tape, drum memory etc. Floppy disk: It is a storage medium which has thin and flexible disk composed of magnetic storage medium stored in a rectangular plastic carrier lined with fabric that removes dust particles. An LED is present at the centre of the disk to make sure that the disk is rotating at a proper speed. The capacity of the floppy disk was very small and was only limited to 256mb and that is why it was superseded by many of the modern storage devices. HARD DISK DRIVE: Hard disk drive is a data storage device used to store and retrieve the digital information. This uses the technology of rotating disk coated with magnetic material for storing the data. They are used to retain the data even when they are powered off. The largest capacity of the hard disk till now is about 6 terabytes. The device which is used to store data on optically readable medium are called as optical storage devices. Data is recorded in this device by precisely focussing a beam of laser light on a spinning disk that has marks in a pattern which can be read back under this light. Optical storage devices include CD, DVD and BLUE RAY DISC. COMPAC DISC: compact disc is a small, portable, round medium made of moulded polymer for electronically storing, recording and playing back audio, video, text and other information in digital form. CLOUD STORAGE: This is the online storage technique which is used to store the data in virtualised pools and hosted by third parties. The data in the data centres is operated by the hosting companies and the people who needs to access the data take the lease from hosting company and use it. The data stored is secured and can be accessed easily. This is the process uploading your files to the internet and there are a lot companies who provide the cloud storage. They are Apple icloud, Google drive, Dropbox, Amazon cloud drive and Microsoft Skydrive. Presently the blu-ray disc is capable of storing 25GB per a single layer, recently the progress was made in creating an ultraviolet solid state laser of 200nm which is capable of storing 100GB per a single layer. So that a large capacity of data can be stored on a single disc. EVOLUTION Selectron tube was the first storage device used for storing the data with a capacity of 32 to 512 bytes but this was proved expensive and suffered from production problems. Punch cards came into existence in mid 1970’s. It is observed that using punch cards predates computers. During the 20th century many of the data storage devices came into existence like magnetic drums, hard disk, diskettes, magnetic tapes and compact discs replaced floppy disks, after this digital video disk came into existence which is used to store video data which was followed by BLUE-RAY DICS. Online storage also came into existence. DVD:These are used to store the video data in the form digital optical disc storage format. This is an extension to the CD. They have more capacity when compared to the CD MOSTLY 4.7GB. BLU-RAY DISC: This is the advanced version of the DVD. This disc is capable of recording high definition videos. It has more capacity when compared to DVD. It is about 25GB per layer. Blue laser of wavelength 405nm is used to read the blu-ray disc. This is about 120mm in diameter and 1.2mm thick. FUTURE DEVELOPMENTS Floppy disk Hard disk