Primary Memory And Its Type

Storage Device

Storage device is a term used to describe a small space where data and information can be kept. Digital data is stored on computer hardware, which is what makes up a computer. It is the central purpose and foundational elements of computers. In most cases, the computer's storage unit is utilized to both store the data entered for processing as well as the outcomes of processing. Practically speaking, every computer employs a storage hierarchy that places faster, more expensive, and smaller storage alternatives close to the CPU and slower, more expensive, and larger ones farther away.

Memory:

The area of the computer called memory allows for the storage and retrieval of data. The information in fast-moving physical systems is referred to as primary memory. Memory can be thought of generally as the computer's equivalent of an electronic scratch pad. A program is loaded and run from memory when we run it. Additionally, the software loads its own data into memory for quick access. It serves as a conduit between CPU and secondary memory for storing. Data are initially loaded into memory before being used by the CPU, and vice versa.

Memory is typically quick, fleeting, and volatile. Contrarily, storage is slower, permanent, and nonvolatile. The contents of storage are kept when a computer's power is switched off, just like non-volatile memory. The contents of storage, however, can frequently be modified or deleted, unlike the majority of non-volatile memory. Computer memory is divided into two categories:

Primary memory:

It also goes by the name "primary memory." It is also referred to as internal memory and system memory at times. The memory is a semiconductor. Only the information and data in the main memory are directly accessible by the CPU. It is used to store information and programs while a computer is running them. When compared to secondary memory, it is usually more expensive, uses a lower capacity, and is faster for read/write operations. Depending on the user's needs, it can be upgraded to 512 MB, 1 GB, 2 GB, or 4 GB. Primary memory comes in two different forms:

• RAM:
  • Random Access Memory is what it stands for. It is in charge of keeping track of the data and instructions that the computer is now using. RAM's primary function is to store programs and data while they are being used. Since the memory is volatile, any data that was saved there will be lost if the computer is shut off. While they are being processed by the CPU, data and instructions are stored there. RAM instructions are transient in nature and only present while the program is running because memory can be modified in RAM immediately. It has read-write capabilities. SRAM and DRAM are the two different forms of RAM.
• ROM:
  • Meaning "Read Only Memory," The content of this form of memory is permanently etched into the memory chip during the manufacturing process. The data stored in ROM is constant. In actuality, "burning in the data" refers to the process of permanently storing information in this type of memory, which was often done at the factory. A computer needs ROM for a variety of reasons, including the necessity to know what to do when the power is turned on. ROM has a set of startup instructions that make sure the rest of the memory is operating correctly. ROM is found in special purpose computers found in autos, video recorders, and washing machines. The types of ROM include the following:
  • PROM (Programmable-Read Only Memory): Another sort of primary memory in a computer is called a PROM. It is the kind of ROM that is initially empty. The programmer can only enter instructions into it once, but they can later be read. Programs stored in PROM cannot be changed or removed. Low access time is PROM. They are therefore chosen over storage memory or program memory when used in a logic element.
  • EPROM (Erasable Programmable-Read Only Memory): For the purpose of outperforming PROM chips, EPROM chips were created. EPROM has solved the PROM problem. An EPROM chip's data and instructions can be removed with the aid of specialized equipment that uses ultraviolet light, and new data and instructions can be recorded in their place. By placing it under the UV light for around 20 to 25 minutes, it can be removed. Though more expensive than PROM, it is more adaptable.
  • EEPROM (Electronically Erasable Programmable-Read Only Memory): It is a cutting-edge addition to the ROM chip family. In reality, EEPROM is a more sophisticated version of EPROM and can be erased with the aid of an electrical signal. It is even more versatile but more expensive than EPROM because bit-by-bit wiping is allowed. A variation of EEPROM is flash memory, which functions like a memory chip or pen drive. Reading from a ROM or writing to a RAM is substantially faster than writing to or flashing an EEPROM (milliseconds per bit) (nanoseconds in both cases).

Difference between SRAM & DRAM:

Reference

Ghishing, Er.Ashim. Computer Science. Kathmandu, Nepal: Benchmark , 2008.