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Your Computers MemoryStan Gelber
Memory in the computer is vital to its operation and can be described in several ways. RAM and ROM memory are created on silicon chips, and are electronic rather than mechanical. They are used for the functions that follow.
ROM, or read-only memory is installed by your computer or board manufacturer and contains permanent instructions that tell other programs and hardware components how to use one anther's capabilities. An example would be your systems board (motherboard) which is the heart of your computer. The ROM instructions on this board tells other programs and hardware components what kind of disk drive you have, how to talk to the keyboard, and what kind of video display system is installed. The instructions placed on the ROM memory chips are considered permanent.
RAM, or random-access-memory, can be written to and read from. It's like a person's short term memory and is used for things we're doing right now. An example of how RAM is incorporated would be the use of a word processing program. The word processing program is copied into RAM from a disk drive or CD-ROM drive and the instructions are accessed by the microprocessor. Obviously the more RAM we have the better our computer will function. Programs and data placed in RAM remain there only as long as the power is turned on.
We also have other types of memory but these are electro-mechanical memory devices. They include Disk Drives, CD-ROM and DVD drives, Tape Drives, and Optical Drives. We can view these devices as long term memory ones. We use them for storing data files, programs, data files, graphics files, and sound files so that when we need them, we place them into RAM and use them. All these devices can be written to as well as read from.
Disk Drives.These devices are the most used on our computer system and come in a variety of capacities and sizes. Some are removable like the floppy disk and some are permanent like the hard disk. Most can access and transfer data and programs into RAM very quickly (in a few microseconds), and all use magnetics to read and write the files (like a cassette or video tape). With the exception of the floppy disk, most hard disks have sizes that range from 540 million bytes up to 10 billion bytes.
(CD-ROM and DVD Drives and Media)(Compact Disk Read-only-Memory). These types of drives and disks are primarily used for storing large amounts of data (like music CDs) and are usually read only. The CD-ROM disk has a storage capacity greater than 660 million bytes and is often used to contain things like video clips, program installation files, or databases. Drive access times are not as fast as the disk drive however CD-ROMs are inexpensive to produce and easy to transport.
DVD Drives and MediaThe DVD (Digital Video Disk) drive and its disk are somewhat smaller than the CD-ROM disk but it can contain a much greater amount of data. The DVD format will be used in the future to replace laser disks and CD-ROMs and will have storage capacities into the billions of bytes. DVD will primarily be used for storing complete movies and massive databases. Access times are faster than DVD and CD-ROMs but still slower than hard disks. Like the CD-ROM, the DVD drive will primarily be used for read-only activities. Both the CD-ROM and DVD use optics and lasers to read the media and both have write as well as read capability.
Tape Drives.The object of installing a tape drive in your computer is not just to have another storage device but rather to have backup capability if and when your hard disk drive fails or you accidentally loose a file. Tape drives are mostly used for storing copies of files and data that reside on your hard disk and are used for backup in case something happens. They are inexpensive and operate much slower than disk drives however they provide an insurance policy against loosing programs and data.