The amount of memory in the computer is crucial in that it determines how many programs can be running, and how much data is available for each program.
Memory is generally available as megabytes or MB .
A simple distinction of RAM vs. Hard Disk. RAM doesn't retain information when the power to your personal computer is turned off. Where as, the Hard Disk does retain information when the power to your personal computer is turned off. SIMMs are easier to install than a single memory chip.