Memory is a vital part of both machine and animal. Without it we as humans would not have any consciousness and the ability to create. Animals would not be able to survive. In machines, and especially in computers, memory allows the machine to function in various ways, for example software to be run and data to be saved and processed.
Memory is the ability to retain data for a period of time, short or long. This data can be of a complexity including imagery, sounds, sensations, smells and other sensations like human memory or it can be predetermined data as in computer memory. One of the differences between human and machine memory is that we can program and access machine memory through the use of software, but we cannot access human memory in the same straightforward manner.
In computing, memory refers to the physical devices used to store programsor data on a temporary or permanent basis for use in a computer or other digital electronic device. The term primary memory is used for the information in physical systems which are fast, as a distinction from secondary memory, which are physical devices for program and data storage which are slow to access but offer higher memory capacity. Primary memory stored on secondary memory is called virtual memory.
The computer memory is a temporary storage area. It holds the data and instructions that the CPU needs. Before a program can be run, the program is loaded from some storage medium into the memory. This allows the CPU direct access to the program. Memory is a necessity for any computer.
Computer memory is mainly classified into Random Access Memory (RAM) and Read Only Memory (ROM). Computer RAM is used as the working memory of a computer system. It stores input data, intermediate results, programs, and other information temporarily. It can be read and written. It is volatile, that is all data will be erased when the power is turned off. ROM is the permanent memory which is used to store important control programs and systems software to perform a variety of functions, such as booting up or starting up programs. ROM is non-volatile. That means the contents are not lost when the power is switched off. Its contents are permanently written at the time of manufacture.
Computer memory is extremely important to computer operation. Files and programs are loaded into memory from external media like fixed disks (hard drives) and removable disks (USB's). Computer memory can be built right into a system board, but it is more typically attached to the system board in the form of a chip or module. Inside these chips are microscopic digital switches which are used to represent binary data.
Computer RAM is classified mainly into Static RAM or SRAM and Dynamic RAM or DRAM.
Types of Static Random-Access Memory: - Non-volatile SRAM, Asynchronous SRAM, Bipolar Junction Transistor, Metal Oxide Semiconductor Field Effect Transistor (MOSFET), Quad Data Rate SRAM, DDR SRAM, Binary SRAM and Ternary SRAM.
Types of Dynamic Random-Access Memory: - SDRAM, DDR SDRAM, DDR2 SDRAM, DDR3 SDRAM, DRDRAM, PSRAM, RLDRAM, EDO DRAM, SGRAM and FPM DRAM.