When it comes to computer memory, there are two diffrent types:
Where programs and data are kept when the processor is actively using them. The programs and data are copied from secondary memory into main memory where the processor can interact with them. Main memory is connected to the processor, so moving instructions from the program and data into and out of the processor is very fast. Main memory is sometimes called RAM. RAM stands for Random Access Memory. "Random" means that the memory cells can be accessed in any order.
Where programs and data are kept on a long-term basis. Common secondary storage devices are the hard disk and floppy disks. Data and programs on the hard disk are organized into files named sections of the disk. The hard disk has enormous storage capacity compared to main memory. Although secondary memory has more storage capacity than main memory, it is much slower than main memory.
In both main and secondary memory, information is stored as patterns of bits. (A bit is a single on/off value. Only these two values are possible. The two values may go by different names, such as true/false, or 1/0) this binary Information does not change when it is copied from one medium to another. Thus, it makes exact copies.