Unit Eight - External Storage

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Unit Eight - External Storage

A microcomputer needs a way to provide permanent storage for program and data files, storage that stays intact even when the power is turned off. The most common and reliable form of storing large amounts of information is the hard drive. In recent years new removable storage technologies have been developed. These allow for the storage of large amounts of information on media that can be moved from one computer to another. The new removable storage technologies include CD-R and CD-RW, and flash memory.

Learning Objectives

  1. Describe the following parts of a hard drive - interface, read/write heads, platters, tracks, sectors, and cylinders.

  2. Describe two performance indicators for hard drives: Seek Time, and Data Transfer Rate (Data Rate).

  3. Describe the function and characteristics of the IDE interface.

  4. Compare the three major categories of removable storage devices: magnetic storage, optical storage, and solid-state storage.

  5. Compare examples of removable storage devices with respect to the following: capacity (how much information they can store) and cost of media per MB.

Activity One

Hard drives are complex mechanisms. Part 4 of the White text (Part III of the Glister text) and How Hard Disks Work will help you answer the questions about the major parts of a hard drive that are listed below. In addition, Installing storage drives will provide a look at how hard drives, as well as floppy drives and CD drives are connected to the motherboard. To use this site your computer needs Quicktime. Go to the "Student Resource Center" for a link to download a free Quicktime player for your computer.

  • What are platters? How many platters do some hard drives contain? what is the common size or "form" of a platter in the modern desktop computer?
  • What is the relationship between tracks, cylinders, and sectors?
  • Describe two common performance indicators for hard drives: Seek Time, and Data Transfer Rate.
  • What is the function of a hard drive interface? What is the most popular hard drive interface?

Activity Two

Recently a lot of interest has been shown towards new storage devices that provide removable storage. These have become very popular due to the rise of large data files that will not fit on the traditional removable storage device, the floppy drive. Some of these new technologies store information on a disk magnetically, in the same manner as floppy drives and hard drives. Other technologies store information on a disk optically, in a manner similar to CD-ROM's. A third technology does not use a removable disk but stores information on a device with no moving parts.

There are a large number of removable storage devices on the market. For purposes of this unit the focus will be on four of these - floppy drives, CD-R, CD-RW, and USB Flash Memory. For each of these devices you need to find the following information:

  • To what category of removable storage device does it belong - magnetic, optical, or solid-state storage?
  • How much information in MB can it store?
  • What is the cost of the media per MB? The best way to get this information is to go on the web as a consumer and find out how much a CD-R or a floppy disk costs and then do the math.

Information on these devices can be found at many locations on the web including the following websites:

Types of Removable Storage  

How Removable Storage Works

Evaluation

Take Quiz 8:  Open quiz8.pdf.  Place yourself under strict test conditions (no books, no help, etc.) and complete the quiz.  Email me your answers with "Quiz8" on the subject line.  Send it to me at vbmail@coedu.usf.edu

If you are tempted to "cheat", consider that you are only cheating yourself -- you won't be well prepared for the final exam, where you will really need this knowledge.  Besides, there's nothing to be gained because I'm going to allow you to do it over until you get it right and score all of the points credit!