The capacity to store a huge amount of data and show while commanded is a great and most valuable feature of a computer. Computer memory indicates the devices that are used for the storage of data or programs. The data may be permanent or temporary, but whatever it is, computer save this data as binary code and read this in the same manner.
Computer memory is a digitally stored data which contains a sequence of instructions for the storage which is in binary mode. Computer can read only two binary codes ‘0’ and ‘1’. So when data is stored in this manner, then a data is kept in a sequence of 0s and 1s. Each binary digit is termed as a ‘bit’. This long sequence of binary code represents a set of data which is shown according to the user commend with a huge modification by software programs.
In early 1940s, computer could hardly permit a few bytes which were slightly developed in the last years of 40s. The first ever programmable digital computer ENIAC came across with a capability of analyzing 20 digits of 10 decimals. The invention of glass tube made a revolution in the memory technology of the computer.
The rank of data stored in the computer memory can be classified into four types:
•Primary Storage: Primary storage is termed as the memory that is readily accessed by the CPU (central processing unit). Primary memory is also termed as internal memory. CPU reads the data files and goes for execution.
•Secondary Storage: Secondary storage is not directly accessible by CPU. The data input/output manner is the method of accessing secondary storage. Secondary storage is termed as external memory.
•Tertiary storage: Tertiary storage is the third level of storage which includes a robotic mechanism of inserting removable storage and dismounts it.
Mainly computer memory is classified into two terms: Volatile and non-volatile.
•Volatile storage: The memory which requires power to store data and maintain it is termed as volatile storage. Presently ‘Static RAM’ (SRAM) or ‘Dynamic RAM’ (DRAM) is mainly used as volatile memory. Z-RAM, TTRAM and A-RAM is going to replace the present RAMs in the market.
•Non-volatile storage: Non volatile memory is that type of memory which can be stored without any power supply. Read-only-memory (ROM), flash memory, magnetic memory (hard disk, floppy drive), punch card etc. are the examples of non-volatile memory. FeRAM, CBRAM, PRAM, SONOS, RRAM, Racetrack memory, NRAM and Millipede is going to take the current market very soon.
Memory storage is a very important factor for the efficiency of work and speed of computing.