Technology: Storage in Computer

A computer can function with only processing , memory, input and output devices. To be really useful, however, it also needs a place to keep program files and related data when it is not using them. The purpose of storage is to hold data.

Think of storage as an electronic file cabinet and RAM as an electronic workable. when you need to work with a program or a set of data, the computer locate it in the file cabinet and puts a copy on the table. After you have finished working with the proram or data, you put it back into the file cabinet. If you make changes to data while working on it, the changed data replaces the original data in the file cabinet .

There are three major distinctions between storage and memory:

1. There is more room in storage than in memory , just as there is more room in a file cabinet than there is on a tabletop.

2. Contents are retained in storage when the computer is turned off, whereas the programs or the data you put into memory disappear when you shutdown the computer.

3. Storage is very slow compared to memory, but it much cheaper than memory.

Remember the distinction between storage and memory. Their functions are similar, but they work in different ways. Novice computer users often use the term memory when they actually mean storage or disk. This mistake can cause confusion.

The most common storage medium is the magnetic disk. A disk is a round, flat object that spins around its center. Read/write heads, which are similar to the heads of a tape recorder or VCR, are used to read data from the disk or write data onto the disk, Depending on the type of disk , the read/write heads may float just above the disk's surface or may actually touch the disk.

The device that holds a disk is called disk drive. Some disks are built into the drive and are not meant to be removed ; other kinds of drives enable you to remove and replace disks. Most personal computers have at least one non removable hard disk. In addition, there is also a diskette drive, which allows you to use removable disk or hard drive. In addition , there is also a diskette drive, which allows you to use removable diskettes. A hard disk can store far more data than a diskette can, so the hard disk serves as the computer's primary filing cabinet. Diskettes are used to load new programs or data onto the hard disk , trade data with other users , and make backup copies of the data on the hard disk.

Because you can remove diskettes from a computer from a computer, they are encased in a plastic or vinylcover to protect them from fingerprints and dust. Because the cover used in early diskettes was thin, the diskette was flimsy or "floppy" as a result they came to be called floppy disk.

The CD - ROM drive is the most common type of storage device after the hard and diskette drives . Compact disks are a type of optical storage device, identical to audio. CDs, that can store about 74 minutes of audio or 650 MB of data, or about 450 times as much information as a diskette. The type used in computers is called Compact Disk Read - Only Memory (CD-ROM). The name implies that you cannot change information on the disk, just as you cannot record over an audio CD.

If you purchase a CD-Recordable (CD-R) drive, you have the option of creating your own CDs. A CD-R drive can write data to and read data from compact disk. To use CD-Drive, you must use a special CD-R disk, which can be written on only once, or a CD- Rewrite-able (CD-RW)disk, which can be written to multiple times, like a floppy disk.

CD - Recordable

An increasingly popular storage technology is the digital versatile disk or Digital Video Disk (DVD) , which is revolutionizing home entertainment. Using sophisticated compression technologies, a single DVD which is the same size as a standard compact disk can store an entire fill length movie. DVDs can hold a minimum of 4.7GB of data and as much as 17GB. Future DVD technologies promise much higher storage capacities on a single disk. DVD drives can also locate data on the disk much faster than standard CD-ROM drives.

DVDs require a special player. The new players, however, can play audio, data and DVD disks, freeing the user from the necessity of purchasing different players for each type of disk. DVD drives are now standard equipment on many new personal computers. Users not only install programs and data from their standard CDs , but they can also watch movies on their PC's by using a DVD.