Difference between ROM, RAM, and Storage Capacity?

4 Pages 1100 Words

Difference between ROM, RAM, and storage capacity?
These days, it's hard to function without knowing how to use a computer. They've become indispensable tools in most schools, at many jobs, and even at home. It seems that there are few machines, from telephones to cars to cash registers, that can't be hooked up to computers in order to make them more efficient. And if computers aren't already complex enough to strain our brains, the folks who work with them seem to have a fondness for impenetrable acronyms: RAM, ROM, CPU, DIMM, SIMM, IDE, CMOS, BIOS, TSR, MHz -- the list goes on. Plus, they have a penchant for using the same units of measurement for different things.
The most glaring example of the latter is the use of the term "byte" and its larger relatives to describe three different (if related) issues: RAM, ROM, and storage capacity. All are important to understand if you really want to know how your computer works, and unfortunately it's easy to get them confused. The most common error is to assume that the RAM and the disk drive storage capacity are the same; they're not, and ROM is something else altogether. All are memory of a sort, but not the same kinds of memory. The purpose of this article is to clarify the differences between them, in language that's easy to understand.
Let's start with basics: the units used to measure the different flavors of computer memory. A byte (B) consists of a grouping of eight binary digits ("bits"), and is typically considered the smallest addressable unit of data. A byte is usually enough to indicate a single character in a file -- say, a letter or a number. A grouping of 1024 bytes is called a kilobyte (KB); 1000 KB, or 1,024,000 bytes, equals a megabyte (MB). Larger units include the gigabyte (GB), which equals 1,000 MB, and the terabyte (TB), which is way up there at 1000 GB -- 1,024,000,000,000 bytes. In the old days (before 1990), KB were usually sufficient for discussing the capacity...