Introduction

In the previous units of this block, we have discussed the primary memory system, high speed memories, the memory system of microcomputer, and the input/output interfaces and techniques for a computer. In this unit we will discuss the secondary storage devices such as magnetic tapes, magnetic disks and optical disks, also known as backing storage devices. The main purpose of such a device is that it provides a means of retaining information on permanent basis. The main discussion provides the characteristics of hard-drives, formatting, drive cache, interfaces, etc. The detailed discussion on storage devices is being presented in the Unit. The storage technologies have moved a dimension from very small storage devices to Huge Giga byte memories. Let us also discuss some of the technological achievements that made such a technology possible.

Objectives

Storage is the collection of places where long-term information is kept. At the end of the unit you will be able to:

• describe the characteristics of the different secondary storage drives, i.e., their drive speed, access time, rotation speed, d~nsity etc.;
• describe the low-level and high level fowa#ing pfa blank disk and also the use of disk partitioning; 
• distinguish among the various types of drives, j.e., hard drives , optical drives removable drives and cartridge drive; and 
• define different type of disk formats.