Role of Memory in Computer System
Authors: Supriya Surve, Sameer Tadavi, Soham Tak and Mayur Talewar
Introduction
Memory is one of the basic requirements of a computer system. It is the electronic holding place for the instructions and data is stored by the computer to reach the data quickly when required. The memory is classified into two types: Primary memory and Secondary memory.
The two “memories” of the processor, which are built-in inside the Central Processing Unit (CPU) are Registers and Cache. Even if they work like memory, they are not counted into the memory structure system.
Registers
Registers are the small storage locations built into the processor itself, where the data and instructions are stored. These memory locations can be accessed by the processor directly which makes them the fastest accessible memory. This are measured according to the bits they are capable to hold, for example, “8-bit register”, “32-bit register”, “64-bit register”.
Cache Memory
Cache Memory is not a real but a copy of some parts of the main memory which is used frequently. It is a smaller and faster memory, located closer to a processor core, which stores the frequently used data from the main memory. The function of memory is to look at cached data when an attempt is made to read or write from a location in main memory. If the data is present in the cache memory the processor will directly read it from the cache, instead of the much slower main memory. This helps to reduce the average time and power to access data from the main memory.
Primary Memory
Primary memory is the one, which is directly accessible to the CPU. The data stored in it, is being continuously read by the processing unit and execution of this instructions from data is carried out when required. The data stored in the memory is uniform.
The Primary Memory is classified as RAM & ROM
RAM:
The RAM takes care of holding data and temporary instructions essential to load application. A good example of this is when the CPU loads an application program (such as a word processor or page layout program) into memory. This allows application programs to run as quickly and efficiently as possible. In practice, loading a program into memory means you can get your work done faster and spend less time waiting for your computer to perform a task. This process of putting things your CPU needs where they can be accessed faster is same as putting the various electronic files and documents you use on your computer into a single file folder or directory. This keeps all the files you need at your fingertips and eliminates the need to search in multiple places each time you need them. Again, the RAM is classified into Static and Dynamic RAM.
Static RAM:
SRAM (Static RAM) is a type of random-access memory (RAM) that retains bits of data in its memory till the power is being supplied. Unlike dynamic RAM (DRAM), which must be continuously updated, SRAM does not have this requirement, resulting in better performance and lower power consumption.
Dynamic RAM:
To function the processor needs DRAM (Dynamic Random Access Memory) to load the program code. It is a type of semiconductor memory. It is the commonly used memory in computer system like workstations and servers.
ROM:
ROM act as a container for the programming required by the computer to start up or regenerate each time it is turned on. It protects the software instructions. The data that stored in ROM cannot be altered.
Secondary Memory
The Secondary Memory is non-volatile. The computer accesses the secondary storage through input and output channels and transfer the required data to primary storage. The access time per byte for memory is measured in milliseconds, while the access time per byte for primary storage is measured in nanoseconds. Therefore, secondary storage is significantly slower than primary storage. Let’s take a look at various secondary storage devices used to store memory.
Solid State Drive (SSD):
Flash memory is used by the SSD to store the data, which means data in the memory is written, stored, erased electronically. SSDs permanently stores data in integrated circuits. Compared to their closed competitor, the Hard Disk Drive the SSDs are Faster in data read and write, run silently, and are more resistant to physical shock. SSDs use semiconductor memory cells to store data.
Hard Disk Drive (HDD):
The function of HDD in a computer system is to store software programs and operating systems. More specifically, hard disk drives control reading and writing of memory that provides data storage. HDDs are used as primary or secondary storage devices in computers. Large amount of digital data can be stored using HDDs. Data is stored in magnetic discs that is recorded electromagnetically in concentric circles. A head similar to a phonogram arm writes and reads data on these magnetic discs.
Optical Disc Drive (ODD):
The ODD use light, laser or other electromagnetic wave that behaves like light to perform actions like read or write data on the disc. The popular ODD are Compact disk (CD), Digital Versatile disc (DVD), Blu- Ray Disc (BD). Among which Blu- ray is the fastest and contains up to 25 GB Data.
