Which is called as data memory?
Since random-access memory (RAM) is principally used as temporary storage for the operating system and the applications, it does not much matter that some types of RAM lose data when they are powered off. What matters more is the cost and the read/write speed. There are mainly two types of RAM: one is DRAM (dynamic RAM), and the other is SRAM (static RAM). DRAM stores information in capacitors, and since the capacitors slowly discharge, the information fades away unless the capacitor charge is refreshed periodically. In practice, the data on DRAM need to be read and rewritten (i.e., refreshed) dozens of times per second. In contrast, SRAM needs no refreshing because it uses flip-flop circuits* to preserve the data. SRAM is more expensive than DRAM because of the complex circuitry involved, but is also faster. Show
*Flip-flop circuit: An electronic circuit that stores a single bit of data that represents either 0 or 1. In computers, memory is the most essential component of the normal functioning of any system. The computer system categorizes the memory for different purposes and uses. In this section, we have discussed the classification of memory in detail. Also, we will discuss types of memory, features of memory, RAM, ROM, SRAM, DRAM, and its advantages and disadvantages. What is computer memory?Computer memory is any physical device, used to store data, information or instruction temporarily or permanently. It is the collection of storage units that stores binary information in the form of bits. The memory block is split into a small number of components, called cells. Each cell has a unique address to store the data in memory, ranging from zero to memory size minus one. For example, if the size of computer memory is 64k words, the memory units have 64 * 1024 = 65536 locations or cells. The address of the memory's cells varies from 0 to 65535. Why do we need a computer memory?In the computer system, we need computer memory to store various types of data like text, images, video, audio, documents, etc. We can retrieve it when the data is required. For example, when we write and execute any computer program, it is initially stored in primary memory. If the processor does not need particular items for a longer time, the program or data is automatically saved into the permanent or secondary memory. Then the data is called from secondary memory to main memory and performs the execution of codes. Features of MemoryFollowing are the different features of the memory system that includes:
The following figure represents the classification of memory: Primary or Main MemoryPrimary memory is also known as the computer system's main memory that communicates directly within the CPU, Auxiliary memory and the Cache memory. Main memory is used to kept programs or data when the processor is active to use them. When a program or data is activated to execute, the processor first loads instructions or programs from secondary memory into main memory, and then the processor starts execution. Accessing or executing of data from primary memory is faster because it has a cache or register memory that provides faster response, and it is located closer to the CPU. The primary memory is volatile, which means the data in memory can be lost if it is not saved when a power failure occurs. It is costlier than secondary memory, and the main memory capacity is limited as compared to secondary memory. The primary memory is further divided into two parts:
Random Access Memory (RAM)Random Access Memory (RAM) is one of the faster types of main memory accessed directly by the CPU. It is the hardware in a computer device to temporarily store data, programs or program results. It is used to read/write data in memory until the machine is working. It is volatile, which means if a power failure occurs or the computer is turned off, the information stored in RAM will be lost. All data stored in computer memory can be read or accessed randomly at any time. There are two types of RAM: DRAM: DRAM (Dynamic Random-Access Memory) is a type of RAM that is used for the dynamic storage of data in RAM. In DRAM, each cell carries one-bit information. The cell is made up of two parts: a capacitor and a transistor. The size of the capacitor and the transistor is so small, requiring millions of them to store on a single chip. Hence, a DRAM chip can hold more data than an SRAM chip of the same size. However, the capacitor needs to be continuously refreshed to retain information because DRAM is volatile. If the power is switched off, the data store in memory is lost. Characteristics of DRAM
SRAM: SRMA (Static Random-Access Memory) is a type of RAM used to store static data in the memory. It means to store data in SRAM remains active as long as the computer system has a power supply. However, data is lost in SRAM when power failures have occurred. Characteristics of Static Ram
SRAM Vs. DRAMSRAMDRAMIt is a Static Random-Access Memory.It is a Dynamic Random Access Memory.The access time of SRAM is slow.The access time of DRAM is high.It uses flip-flops to store each bit of information.It uses a capacitor to store each bit of information.It does not require periodic refreshing to preserve the information.It requires periodically refreshing to preserve the information.It uses in cache memory.It is used in the main memory.The cost of SRAM is expensive.The cost of DRAM is less expensive.It has a complex structure.Its structure is simple.It requires low power consumption.It requires more power consumption.Advantages of RAM
Disadvantages of RAM
Read-Only Memory (ROM)ROM is a memory device or storage medium that is used to permanently store information inside a chip. It is a read-only memory that can only read stored information, data or programs, but we cannot write or modify anything. A ROM contains some important instructions or program data that are required to start or boot a computer. It is a non-volatile memory; it means that the stored information cannot be lost even when the power is turned off or the system is shut down. Types of ROM There are five types of Read Only Memory:
Advantages of ROM
Disadvantages of ROM
RAM Vs. ROMRAMROMIt is a Random-Access Memory.It is a Read Only Memory.Read and write operations can be performed.Only Read operation can be performed.Data can be lost in volatile memory when the power supply is turned off.Data cannot be lost in non-volatile memory when the power supply is turned off.It is a faster and expensive memory.It is a slower and less expensive memory.Storage data requires to be refreshed in RAM.Storage data does not need to be refreshed in ROM.The size of the chip is bigger than the ROM chip to store the data.The size of the chip is smaller than the RAM chip to store the same amount of data.Types of RAM: DRAM and SRAMTypes of ROM: MROM, PROM, EPROM, EEPROMSecondary MemorySecondary memory is a permanent storage space to hold a large amount of data. Secondary memory is also known as external memory that representing the various storage media (hard drives, USB, CDs, flash drives and DVDs) on which the computer data and program can be saved on a long term basis. However, it is cheaper and slower than the main memory. Unlike primary memory, secondary memory cannot be accessed directly by the CPU. Instead of that, secondary memory data is first loaded into the RAM (Random Access Memory) and then sent to the processor to read and update the data. Secondary memory devices also include magnetic disks like hard disk and floppy disks, an optical disk such as CDs and CDROMs, and magnetic tapes. Features of Secondary Memory
Types of Secondary MemoryThe following are the types of secondary memory devices: Hard Disk A hard disk is a computer's permanent storage device. It is a non-volatile disk that permanently stores data, programs, and files, and cannot lose store data when the computer's power source is switched off. Typically, it is located internally on computer's motherboard that stores and retrieves data using one or more rigid fast rotating disk platters inside an air-sealed casing. It is a large storage device, found on every computer or laptop for permanently storing installed software, music, text documentation, videos, operating system, and data until the user did not delete. Floppy Disk A floppy disk is a secondary storage system that consisting of thin, flexible magnetic coating disks for holding electronic data such as computer files. It is also known as Floppy Diskette that comes in three sizes like 8 inches, 5.5 inches and 3.5 inches. The stored data of a floppy disk can be accessed through the floppy disk drive. Furthermore, it is the only way through a new program installed on a computer or backup of the information. However, it is the oldest type of portable storage device, which can store data up to 1.44 MB. Since most programs were larger, that required multiple floppy diskettes to store large amounts of data. Therefore, it is not used due to very low memory storage. CD (Compact Disc) A CD is an optical disk storage device, stands for Compact Disc. It is a storage device used to store various data types like audio, videos, files, OS, Back-Up file, and any other information useful to a computer. The CD has a width of 1.2 mm and 12 cm in height, which can store approximately 783 MB of data size. It uses laser light to read and write data from the CDs. Types of CDs
DVD Drive/Disc DVD is an optical disc storage device, stands for Digital Video Display or Digital Versatile Disc. It has the same size as a CD but can store a larger amount of data than a compact disc. It was developed in 1995 by Sony, Panasonic, Toshiba and Philips four electronics companies. DVD drives are divided into three types, such as DVD ROM (Read Only Memory), DVD R (Recordable) and DVD RW (Rewritable or Erasable). It can store multiple data formats like audio, videos, images, software, operating system, etc. The storing capacity of data in DVD is 4.7 GB to 17 GB. Blu Ray Disc (BD) Blu Ray is an Optical disc storage device used to store a large amount of data or high definition of video recording and playing other media files. It uses laser technology to read the stored data of the Blu-ray Disk. It can store more data at a greater density as compared to CD/ DVD. For example, compact discs allow us to store 700 MB of data, and in DVDs, it provides up to 8 GB of storage capacity, while Blu-ray Discs provide 28 GB of space to store data. Pen Drive A pen drive is a portable device used to permanently store data and is also known as a USB flash drive. It is commonly used to store and transfer the data connected to a computer using a USB port. It does not have any moveable part to store the data; it uses an integrated circuit chip that stores the data. It allows the users to store and transfer data like audio, videos, images, etc. from one computer to any USB pen drive. The storing capacity of pen drives from 64 MB to 128 GB or more. Cache Memory It is a small-sized chip-based computer memory that lies between the CPU and the main memory. It is a faster, high performance and temporary memory to enhance the performance of the CPU. It stores all the data and instructions that are often used by computer CPUs. It also reduces the access time of data from the main memory. It is faster than the main memory, and sometimes, it is also called CPU memory because it is very close to the CPU chip. The following are the levels of cache memory.
Advantages of Cache Memory
Disadvantage of Cache Memory
Register Memory The register memory is a temporary storage area for storing and transferring the data and the instructions to a computer. It is the smallest and fastest memory of a computer. It is a part of computer memory located in the CPU as the form of registers. The register memory is 16, 32 and 64 bits in size. It temporarily stores data instructions and the address of the memory that is repeatedly used to provide faster response to the CPU. Which memory is used as data memory?Primary Memory (Main Memory)
It is generally made up of semiconductor device. These memories are not as fast as registers. The data and instruction required to be processed resides in the main memory. It is divided into two subcategories RAM and ROM.
Is ROM a data memory?Read-only memory, or ROM, is a type of computer storage containing non-volatile, permanent data that, normally, can only be read, not written to. ROM contains the programming that allows a computer to start up or regenerate each time it is turned on.
What is memory also known as?The term memory is often synonymous with the term primary storage or main memory. An archaic synonym for memory is store.
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