Computer Storage Devices Principles of Information Technology Lytle High School Click to continue

Disk Drives, Hard Drives and Data Storage Welcome to this lesson on computer storage devices. There is much to know that the average computer user may not have learned. If you wish to use computers more effectively, read on. Click to continue

External Storage Random Access Memory is only temporary. Computer memory is cleared or erased when the computer loses it’s power It is for this reason that documents or projects you create be saved on disk. Disk storage is permanent. Any information saved on disk is recorded until needed at a later time and is not erased until you decide to erase it. Click to continue

Types of Disk Storage While there are many types of data storage devices for computers, we will discuss the most common ones first. Today’s computers share some common storage devices. Click to continue 3.5” Disk Drive Hard Drive CD-ROM drive

Recorded Information Today, information is recorded in a variety of ways. In a USB drive, information is recorded on a microchip. On a CD or DVD, the data bits are etched into the special coating of the CD or DVD. Click to continue On a hard drive, data is recorded with microscopic magnetic spots.

How is Data Stored? Before a diskette or hard drive can be used, it must be FORMATTED. The format process is a special initialization process. If a disk is not formatted to the computer’s specifications, it cannot be used. Click to continue

Tracks and Sectors The format process creates TRACKS and SECTORS. These sectors and tracks are the storage locations where data is actually recorded or saved. Click to continue

Recording Computer Data As mentioned earlier, Information is recorded on disk. Data is recorded with little magnetic impulses. Hard Drives are precision instruments. As the disk surface spins, the Read-Write head records the information. Click to continue Random bits are put in their proper byte sequence by the read-write head.

Recording Computer Data If the computer gets bumped hard enough, the Read-Write head can bump the surface of the disk. This is known as a Head Crash and all the data on the disk surface is scrambled and lost. The surface of the disk is scratched and ruined, and the hard drive itself must be replaced. All saved data is lost. The Read-Write heads are so close to the surface of the disk, extreme care must be taken not to bump the computer when it is in operation. Click to continue

Units of Measure The terms used to measure disk storage capacity are the same terms already learned in a previous lesson. Remember them? They are the same terms used to measure computer memory or RAM. KILOBYTE is equal to one thousand bytes of data. MEGABYTE is equal to a million bytes or characters of data. Today’s hard drives store GIGABYTES of data. A GIGABYTE is equal to one billion characters of data. Click to continue

The Hard Drive Computers today usually have three storage devices. The internal HARD DRIVE unit is a high capacity storage device. Click to continue

The Hard Drive Today’s HARD DRIVES are capable of holding millions of times the capacity of a single 3.5” diskette. The computers purchased today usually come with 100, or 200 Gigabyte hard drives. Click to continue

Disk Drives Hard Drives are found inside the computer cabinet. There are no diskettes to insert or remove. All information is permanently stored until you, the user, decide to delete it. Press ENTER to continue

Hard Drives Hard drives are installed in the computer cabinet. With other disk drives in the computer, the hard drive is identified by a letter. The letter C: is assigned to the hard drive. The C:Drive is the primary or default storage device for the computer. Click to continue

The Importance of the Hard Drive All of today’s computers have large hard drives in them. When you first turn on the computer, they power up, or BOOT UP, with the Operating System found on the hard drive. WINDOWS 2000 or WINDOWS XP is the operating system needed by the computer to run. Without it, the computer cannot be used. Click to continue

Floppy Diskettes These floppy diskettes are now obsolete and no longer being installed in computers. However, the 3.5” diskette is still used, but is slowly fading. Notice the 8” Floppy Disk. This is one of the first storage devices created for the computer. Click to continue

The 3.5” Disk Drive While hard drives can store billions of bytes of data, 3.5” diskettes are much more limited in there storage capacity. The capacity of a 3.5” diskette is 1.44 Megabytes. Click to continue

Disk Drives 3.5” Disk Drive The 3.5” disk drive is located in the computer cabinet. Press ENTER to continue 3.5” Diskette Remember, information once saved, is permanently stored and is not deleted until you the computer user decide to delete it.

Disk Care While 3.5” diskettes are pretty durable, care must be taken so they are not damaged. – Keep from extreme heat – Keep from extreme cold – Keep away from magnets – Keep from getting damp or wet – Keep from getting smashed – Do not touch the recording media Click to continue

The CD-ROM Drive Another common storage device is the CD-ROM drive. Compact Disks are capable of storing 600 to 700 megabytes of data. Click to continue

Disk Drives and Drive Letters The letters A: and B: are reserved and assigned to the 3.5” disk drives. The computer assigns the letter C: to the hard drive. The Compact Disk or CD player is usually assigned the letters D: or E:. Click to continue As mentioned earlier, the computer knows its disk drives by assigning a letter to each storage device.

Keeping Track of Saved Files When you save information on disk, it is up to you, as the computer user, to tell the computer where you want your data saved. Do you wish to save your document on the A:Drive, or C:Drive? Click to continue

Saving Data Many of today’s Compact Disk Drives allow you to record information on a blank CD. Today, computers come with CD-ROM drives that allow you record or save your documents or other files on a CD-ROM, or the D:Drive. Click to continue

Computers and Disk Drives Always be aware of where information is saved. If care is not taken, you will not know where your data or information is stored. It will be lost, and you will not be able to locate and open your file when it is needed. Click to continue

Other Storage Devices Computers have RAM. Ram also has a storage capacity. Can you tell how much information can be stored in this SD-RAM? Click to continue

Zip Disks While 3.5” diskettes have a 1.44 Megabyte storage capacity, other forms of storage have been developed. About the same physical size as a 3.5“ diskette, the ZIP Drive uses special disks that can hold 100 – 200 MB of data. Click to continue

Other Storage Devices Compact Disks hold about 5 times more than a Zip Disk. They can store between Megabytes of data on each CD. Press ENTER to continue

DVD Storage Today, computers come with DVD storage drives. Similar to a CD storage drive. They have a much larger storage capacity. They are used to store 4.7 Gigabytes or 8.5 Gigabytes of information. This is the reason they are used to record and view movies that are 2 – 4 hours long. This amount of storage capacity is just not available on a regular CD Drive. Press ENTER to continue

Tape Drives Tape drives use special tape cartridges that look similar to cassettes, but are physically smaller in size. Tape drives come in a variety of sizes and shapes. They are used for Backing Up large amounts of important hard drive data, and can store from 200 to 300 Gigabytes of data. Click to continue

Flash Memory There are various types of storage available for other electronic devices. Digital Cameras as well as certain copy and fax machines use special memory adapters. Additional storage devices are also available for Lap Top computers. Click to continue Flash Memory

Other Storage Devices Press ENTER to continue Flash Media Cards come in a variety of sizes, and are used in MP-3 players, digital cameras, printers, etc. Thumb or USB Drives come in a variety of sizes, and plug into the computer’s USB port. They come in a variety of storage capacity and sizes.

Flash Memory Can you tell how much data can be stored in these Flash Memory cards? This type of memory card is used in many of today’s digital cameras. Click to continue

In Conclusion Disk drive storage can be confusing to those who do not familiar with how things work. Take the time you need to learn about storage devices and how to save and retrieve files. The information you save on disk is important to you. Know where it is saved and know how to get it back. Good luck on your quest for better understanding. Click to continue

In Conclusion Now that you have completed this lesson on data storage, prepare to share what you have learned with others.