Digital and Optical Storage

Digital and Optical Storage

Abraham Le'i

Course Instructor: Ted Schnetker

IDS804

May 10, 2007

Abstract

Since the inception of computers in the 1940's, the computer has grown significantly in complexity, both in terms of tasks it can perform and usability. Over the years it has vastly increased the scope of tasks it can perform from simple mathematical calculations to the present-day complex weather forecasting or lab test of nuclear weapons. Today, with the advances in the storage space technologies, humans are able to document all the knowledge acquired over the centuries in a single computer. We are moving from Gigabytes to Terabytes in the personal computer. Now we can store all the movies, music and information we have ever read, seen or listen to on a single desktop.

This journey is long and arduous. The first step was taken in the 1970s with commercialization of the floppy disc to load microcode on IBM computers. Since then corporate needs and personal indulgence has led to the growth from magnetic base to hard drives and optical storage devices. In the 1970s Floppy disk drives were first introduced commercially as a read-only device. They became an instant hit in the industry as they could hold large IBM mainframe computer systems' microcode and diagnostics. They were followed by hard drives, which became an integral part of the personal computer's growth story. With the growth of media in homes, devices that could better cater to entertainment storage were developed. This lead to the growth of optical storage, starting with the compact disc, which can hold 650 MB, to the most current Blue-Ray technology, which can store at the least 25 GB of data.

Introduction

Since its inception in the 1940s, the computer has significantly grown in complexity both in terms of tasks it can perform and usability. Over the years it has vastly increased the scope of tasks it can perform from simple mathematical calculations to the present-day complex weather forecasting or lab test of nuclear weapons. There are two most critical aspects of which scientists and technologists are in continuous pursuit - (1) Increase in the storage space with minimum physical extension; (2) increase in the processing speed. From mainframes to microprocessors, the journey of processing speed is well documented, but advances in storage space are often taken for granted.

All computations in our computers, whether they are mechanical or electronic, require a storage system. It doesn't matter if the numbers are remembered in our brain or written on paper, counted by mechanical device or converted into electronic circuitry, it requires storage space. Any device that can store data to be retrieved and processed again is known as a storage device. A storage device can hold processed information, raw information, or both.

Today, with the advances in the storage space technologies, humans are able to document all the knowledge acquired over the centuries in a single computer. We are moving from away from Gigabytes towards Terabytes in the personal computer. Now we can store all the movies, music and information we have ever read, seen, or listened to on a single desktop. The study of storage devices is critical because the miniaturization of storage devices and the increase of storage capacity are primarily responsible for the computer not remaining on our desktops, but instead moving into our cars, classrooms, and even in our pockets (through the advent of the mobile phone and the PDA). This paper is aimed at reviewing the evolution of the storage systems, from early mechanical systems to the present-day optical storage technology.

Early History of Storage Devices

In 1957 the first storage device was developed by IBM, known as the commercial disk drive. Since then the density of data storage on a magnetic hard disk has increased more than a million fold. This phenomenal growth is responsible for most of the modern day innovations and lifestyle, as today there are very few areas in life which have not been transformed by computers.

Floppy disk

In the 1970s, floppy disk drives were first introduced commercially as a read-only device. They became an instant hit in the industry as they could hold large IBM mainframe computer systems' microcode and diagnostics. Originally the floppy disk drives used to have 8-inch floppy diskettes and could only be recorded on one side (Charles J. Bashe, 1986 p. 24).

Technicians used to load the latest revision of microcode by changing these diskettes of the floppy drives. It also facilitated the loading of diagnostics, and thus reduced the need of physical vicinity of computers. Even though they could load and transfer microcode and diagnostics, the storage capacity of these diskettes were merely 100 kilobytes (kb). Three years later, in 1973, a newer version of the 8 inch drive was released. It had both the capability to read and write and could store up to 250 kb. This became instantly popular and was widely used in IBM data entry systems (Hoskins, 2001 p 23).

Over time software engineers and designers learned how to reliably record the data on both side of the diskettes. And throughout the years, but before the invention of optical storage, it remained one of the most popular forms of data storage, due to the successfully increased density of data storage on these diskettes. In 1976 the first physical change came in the floppy diskettes, as the newer versions were released in 5.25 inch drives by Shugart Associates. Initially, like the 8 inch diskettes released in 1970, they were also read-only and single sided, low density format. But after feedback from the industry it had to adapt all the developments of the 8 inch disks. Later it became double-sided, read and write double density diskettes with a storing capacity of 1.2 MB. These drives were used in the IBM-AT personal computer.

Holistically these were the primitive version of 1.5 megabyte (MB) diskettes popular before the spread of internet, as they had some of the technical improvements that lead to the growth of storage devices. Modern day floppy drives and diskettes are 3.5 inches in diameter and evolved from a very small storage capacity to the present one. They were first introduced in 1980 by Sony and held off a number of challenges from other companies. Over time they established themselves as the

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