Comparing Memory

There are four types of computer memory that i am comparing: ROM, RAM, Virtual and Caching. ROM stands for Read-Only-Memory. RAM stands for Random-Access-Memory. ROM uses diodes to connect the lines of intersection if the number is one and if the number is zero then the lines are not connected. These chips are also very reliable and do not use alot of energy and contain all the necessary information to control the device. RAM uses transistors to turn on and off the capasitors at each intersection to create a memory cell. The down side to this type of memory is that it needs to be refreshed often and if not refreshed it will forget what its holding. Plus all the refreshing takes time and slows the memory down; therefore, the more RAM you have the better off you are. Virtual memory is most common in operating systems and desktop computers. With virtual memory, what the computer looks at RAM for areas that have not been used recently and copy them onto the hard disk. This frees up space in RAM to load the new application. Modern computers have both L1 and L2 caches, and now computers also have L3 cache. L1, L2and L3 are levels and speeds at which your computer work. The idea behind caching is to use a small amount of expensive memory to speed up a large amount of slower, less-expensive memory.



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