Today we continue our talk on Main memory as part of Computer Hardware. Earlier computers used magnetic core memory. However all modern computers use semi-conductor memory. Semi-conductor memory is faster and cheaper than magnetic core memory. Semi-conductor memory is also available in small board. These characteristics have made semi-conductor memory more popular and attractive. The only drawback of semi-conductor is that it is volatile. That is it loses its content is the event of power failure. However, it is not a serious drawback and can be easily overcome by having back-up power units.
Semi-conductor memory is known as RAM (random access memory). This means that any parts of memory can be accessed for reading and writing. A magnetic core memory is also called random access memory. However the terminology RAM has been used in the literature with invention of semi-conductor memory. Another part of main memory is ROM, (Read Only Memory). ROM allows its contents to be read only and dose not allow users to store their programmes supplied by the manufactures frequently used by the users.
RAM capacity is a useful indicator to compare the main memory capacity of various computers. Earlier computers, provided a memory of 16 KB, but a memory capacity of 512 KB is very common in today’s micro-computers.
Computers in Management 