Many people are confused about the various parts and functions of computer storage devices and equipment. There are to basic types of computer storage; volatile and non-volatile. Volatile storage will lose its information when power is removed. Non-volatile storage will keep the information when power is removed.
Volatile Storage: Random Access Memory (RAM), Memory Cache
Non-Volatile Storage: Hard Drive, Diskettes, Flash Drives, External Drives, Tape Drives
Random Access Memory (RAM) is what is called the main memory or memory of a computer. It is the memory that stores programs when the program is running. Windows and all of its applications are loaded into RAM to run. When power is turned off this memory is lost and Windows and all of its applications have to be reloaded. One of several reasons a computer runs slow is because you don’t have enough RAM memory. RAM memory is measured in MegaBytes or MB. 256MB is small today, 1000MB or 1 GigaByte (GB) is typical and 4GB is recommended. Older computers rarely will allow more than 1GB of RAM. Upgrading RAM is usually easy and costs about $50 per 1GB.
Internal Hard Drives are used to store installed programs when they are not running. Hard drives are measured the same as RAM however the storage capability is much larger. 250 GB, 500 GB, 1000 GB (or 1 TeraByle) is typical today. If too many programs are stored on the hard drive they do fill up but that is rare today. Hard drives are also used to store documents and photos and any other data required by the user. Photos can take a lot of space on a hard drive. Some users will add an external hard drive just to store photos.
ALL volatile storage devices are prone to failure. DO NOT depend on them lasting forever. Have two or more methods of backing up your critical information at all times