When the user opens an application, it is loaded into RAM. RAM can be compared to a person's short-term memory and the hard disk to the long-term memory. The short-term memory focuses on work at hand, but can only keep so many facts in view at one time.
When the user saves a file and close the application, the file is written to the specified storage device, and then it and the application are purged from RAM.
Without RAM it becomes impossible to get very far, from the moment the PC is turned ON. The software applications installed on the computer depends largely on the RAM. It is responsible for holding the data while any application is running. Once the application is closed without saving, the data gets lost.
RAM is called "random access" because any storage location can be accessed directly. Externally, RAM is a chip that comes embedded in a personal computer motherboard with a variable amount of additional modules plugged into motherboard sockets. To add memory to the computer, just simply add more RAM modules in a prescribed configuration.
Whether it comes from permanent storage (the hard drive) or input (the keyboard), most data goes in random access memory (RAM) first. The CPU then stores pieces of data it will need to access, often in a cache, and maintains certain special instructions in the register.
The opposite of RAM is Serial Access Memory (SAM). SAM stores data as a series of memory cells that can only be accessed sequentially. If the data is not at the current location, each memory cell is checked until the needed data is found.
System RAM
