What is Memory in Computer?

What is memory in computer?

Computer memory refers to any physical device capable of temporarily storing information, such as RAM (random access memory), or permanently storing information, such as ROM (read-only memory) (read-only memory). Integrated circuits (ICs) are utilised in memory devices, which are used by operating systems, software, and hardware. Computer memory is faster than storage, which is slower but less expensive and has a bigger capacity. Apart from keeping opened applications, computer memory also acts as a disc cache and write buffer, allowing for faster reading and writing.

The terms memory and major storage or main memory are frequently used interchangeably. The word store is an old synonym for memory. Memory is similar to the human brain. It’s where you keep your data and instructions. The storage space in a computer where data to be processed and instructions to be processed are stored is referred to as computer memory. The memory is broken down into a vast number of little components known as cells. Each place or cell has a distinct address that ranges from 0 to memory size minus one. This memory unit, for example, has 64 * 1024 = 65536 memory places if the machine has 64k words. These places’ addresses range from 0 to 65535.

Volatile vs. non-volatile memory

Memory is classified as either volatile or non-volatile.

When a computer or hardware device loses power, the contents of volatile memory are lost. Volatile memory, such as computer RAM, is an example. It’s why, if your computer stalls or reboots while you’re working on a programme, anything you haven’t saved is lost.

 Non-volatile memory, also known as NVRAM, retains its contents even after the power is turned off. Non-volatile memory, such as EPROM, is an example.

Memory is primarily of three types −
  1. Primary Memory/Main Memory
  2. Secondary Memory
  3. Cache Memory

Primary Memory (Main Memory)

Primary memory stores only the data and instructions that the computer is now processing. It has a limited capacity, and when the power is turned off, the data is lost. Semiconductor devices make up the majority of it. The speed of these memories is slower than that of registers. The main memory stores the data and instructions that must be processed.

Memory is divided into two subcategories: RAM and ROM.

Characteristics of Main Memory

  • These are memories made of semiconductors.
  • The primary memory is what it’s called.
  • Memory that is usually volatile.
  • If the power is turned off, the data is lost.
  • It is the computer’s working memory.
  • Secondary memories are slower than primary memories.
  • Without primary memory, a computer cannot function.

(Random Access Memory):

It’s a short-term memory. Information is stored in volatile memory depends on the power supply. All data and information on this memory will be lost if the power supply fails, is interrupted, or is turned off. RAM is utilised to start or boot up the computer. It temporarily stores programs/data that the processor must execute. There are two types of RAM:

S RAM (Static RAM):

It employs transistors, and the memory’s circuits are capable of maintaining their state for as long as power is applied. This memory is made up of the number of flip flops, each of which stores one bit. It is faster since it has a shorter access time.

D RAM (Dynamic RAM):

It employs capacitors and transistors, with the data being stored as a charge on the capacitors. There are thousands of memory cells in them. After a few milliseconds, the charge on the capacitor must be refreshed. This memory operates at a slower speed than S RAM.

ROM (Read Only Memory)

It’s a non-volatile storage device. Non-volatile memory saves data even if the power source is lost, interrupted, or turned off. The information needed to operate the system is stored in the ROM. We can only read the programmes and data saved on read-only memory, as its name implies. It has a few electronic fuses that can be programmed for a specific piece of data. The information is saved in binary format in the ROM. Permanent memory is another name for it. There are four types of ROM:

MROM(Masked ROM):

Hard-wired devices with a pre-programmed collection of data or instructions were the first ROMs. Masked ROMs are a type of low-cost ROM that works in this way.

PROM (Programmable Read Only Memory):

The user can only change this read-only memory once. The user buys a blank PROM and fills it with the required information using a PROM application. Its content can’t be changed after it’s been written.

EPROM (Erasable Programmable Read Only Memory):

The written contents can be electrically deleted here. EEPROM can be erased and reprogrammed up to 10,000 times. Erasing and programming take only a few milliseconds, or about 4 to 10 milliseconds (milliseconds). Any portion of an EEPROM can be selectively cleaned and programmed.

EEPROM (Electrically Erasable Programmable Read Only Memory):

The written contents can be electrically deleted here. Up to 10,000 times, an EEPROM can be deleted and reprogrammed.Erasing and programming take only a few milliseconds, or about 4 to 10 milliseconds (milliseconds). Any portion of an EEPROM can be selectively cleaned and programmed.

Secondary Memory

This form of memory is also known as non-volatile memory or external memory. It operates at a slower rate than the main memory. These are used to store data and information indefinitely. These memories are not accessed directly by the CPU; instead, they are accessed through input-output procedures. The contents of secondary memories are first transferred to main memory, where they can then be accessed by the CPU. For instance, a disc, a CD-ROM, a DVD, and so on.

Characteristics of Secondary Memory

  • Magnetic and optical memory are the two types.
  • The backup memory is what it’s called.
  • It’s a non-volatile storage device.
  • Even if the power is turned off, data is saved indefinitely.
  • It is a type of computer storage device.
  • The computer can function without the need of secondary memory.
  • Primary memories are slower than secondary memories.
Secondary memory is of two types:

Fixed storage

A fixed storage device in secondary memory is an internal media device used to store data in a computer system. Fixed storage is sometimes known as hard drives or fixed disc drives. In most cases, the data of the computer system is saved in a fixed storage device incorporated into the system. Fixed storage does not preclude their removal from the computer system; with the assistance of an expert or engineer, you may remove the fixed storage device for repairs, upgrades, or maintenance, among other things.

Following are the types of fixed storage:

  • Internal flash memory (rare)
  • SSD (solid-state disk)
  • Hard disk drives (HDD)

Removable storage

Removable storage is an external media device that is used to store data on a computer system in secondary memory. Disk drives or external drives are common names for removable storage. It’s a removable storage device that can be inserted or withdrawn from the computer as needed. We can effortlessly uninstall them from the computer system while it is still running. We can simply transfer data from one computer to another using removable storage devices because they are portable. Furthermore, removable storage devices provide the high data transfer speeds that storage area networks are known for (SANs).

Following are the types of Removable storage:

  • Optical discs (like CDs, DVDs, Blu-ray discs, etc.)
  • Memory cards
  • Floppy disks
  • Magnetic tapes
  • Disk packs
  • Paper storage (like punched tapes, punched cards, etc.)

Secondary memory devices

Following are the commonly used secondary memory devices are:

Floppy Disk: A floppy disc is a magnetic disc that is housed in a square plastic container. It’s used to store information and transfer it from one device to another. There are two sizes of floppy discs (a) Size: 3.5 inches, 1.44 MB storage capacity (b) Size: 5.25 inches, with a 1.2 MB storage capacity. Our computer must have a floppy disc drive in order to use a floppy disc. This storage device is now obsolete, and CDs, DVDs, and flash drives have taken its place.

Compact Disc: A Compact Disc (CD) is a type of secondary storage media that is widely utilised. Its surface is covered in tracks and sectors. It is composed of polycarbonate plastic and has a round form. CDs have a data storage capacity of up to 700 MB. A CD is also known as a CD-ROM (Compact Disc Read-Only Memory), because computers can read the data on it but not write new data to it. We need a CD-ROM for a CD-ROM. There are two sorts of CDs:

CD-R (compact disc recordable): It is not possible to remove data that has been written onto it; it can only be read.

CD-RW (compact disc rewritable): It’s a particular kind of CD that allows us to wipe and rewrite data as many times as we desire. It’s also known as an erasable CD.

Digital Versatile Disc: DVD stands for Digital Versatile Disc. It resembles a CD in appearance, however it has a larger storage capacity than a CD, storing up to 4.7 GB of data. To utilise DVD on a computer, you’ll need a DVD-ROM drive. Video files, such as movies or video recordings, are typically saved on DVD, which may be played with a DVD player. There are three sorts of DVDs:

DVD-ROM(Digital Versatile Disc Read only): The manufacturer writes the data on the DVD-ROM, and the user can only read it; he or she cannot create new data on it. For example, a movie DVD has already been written by the maker, and we can only watch it; we cannot add new data to it.

DVD-R(Digital Versatile Disc Recordable): You can write data on a DVD-R, but only once. It is not possible to remove data that has been written onto it; it can only be read.

DVD-RW(Digital Versatile Disc Rewritable and Erasable): The data can only be written once on a DVD-R. It is impossible to remove data once it has been written to it; it can only be read.

Blu-ray Disc: A Blu-ray disc resembles a CD or DVD, but it can hold up to 25 GB of data or information. You’ll need a Blu-ray reader if you wish to use a Blu-ray disc. The name Blu-ray comes from the technology used to read the disc: ‘Blu’ comes from a blue-violet laser, and ‘ray’ comes from an optical ray.

Hard Disk: A hard disc is one of the components of a hard disc drive. It’s designed to hold a lot of information. Hard discs, often known as hard disc drives, are available in a variety of storage capacities. (For example, 256 GB, 500 GB, 1 TB, and 2 TB). It is made up of platters, which are a collection of discs. The serving dishes are stacked one on top of the other. They have a magnetic coating on them. Each platter is made up of a number of invisible circles, each of which has the same central track. Internal and external hard discs are the two types of hard discs.

Flash Drive: A flash drive or pen drive is available in a variety of storage capacities, including 1 GB, 2 GB, 4 GB, 8 GB, 16 GB, 32 GB, 64 GB, and 1 TB. Data is transferred and stored using a flash drive. To utilise a flash drive, it must be plugged into a computer’s USB port. A flash drive is quite popular nowadays because it is simple to use and small in size.

Solid-state disk: SDD is another name for it. It is a data storage and retrieval device that is non-volatile. It’s faster, makes no noise (since it doesn’t have any moving parts like a hard drive), uses less electricity, and so on. If the price is right, it’s a perfect replacement for regular hard drives in desktops and laptops, and it’s also ideal for tablets, notebooks, and other devices that don’t require a lot of storage.

SD Card: A Secure Digital Card is what it’s called. It is commonly used to store data in portable devices such as cell phones and cameras. It comes in a variety of capacities, including 1 GB, 2 GB, 4 GB, 8 GB, 16 GB, 32 GB, and 64 GB. You can access the data on the SD card by removing it from the device and inserting it into a computer using a card reader. The data on the SD card is kept in memory chips (which are included in the SD card) and there are no moving elements like there are on a hard disc.

Cache Memory

Cache memory is a type of high-speed semiconductor memory that can help the CPU run faster. Between the CPU and the main memory, it serves as a buffer. It is used to store the data and programmes that the CPU uses the most frequently. The operating system transfers portions of data and programmes from the disc to cache memory, from which the CPU can access them.

The advantages of cache memory are as follows –

  • Memory in the cache is faster than memory in the main memory.
  • When compared to main memory, it takes less time to access.
  • It keeps track of programmes that can be run in a short amount of time.
  • It saves information for later use.

The disadvantages of cache memory are as follows –

  • The capacity of cache memory is restricted.
  • It is really costly.

Frequently Asked Questions (FAQs)

What happens to memory when the computer is turned off?

Because RAM is volatile memory, anything saved in RAM is lost when the computer loses power, as previously stated. For example, a document is stored in RAM while it is being worked on. If data was not saved to non-volatile memory (e.g., the hard drive) before the computer lost power, the data would be lost.

Why is memory important or needed for a computer?

Each component of a computer runs at a variable pace, and computer memory allows your computer to swiftly retrieve data. A computer would be substantially slower if the CPU had to wait for a secondary storage device, such as a hard disc drive.

How is memory used?

When you open a programme, such as your Internet browser, it is loaded into RAM from your hard disc. This procedure enables the programme to interface with the processor at a faster rate. Any files you save to your computer, such as photos or videos, are stored on your hard drive.

Are some types of memory faster than others?

Yes. Some memory devices can store and access information more quickly than others. When purchasing RAM, for example, the DDR (double data rate) version makes it simple to evaluate different possibilities. DDR4 RAM is roughly twice as fast as DDR3 RAM. RAM bears a megahertz (MHz) number next to it as a more precise indicator of its speed; the greater the MHz, the faster the RAM speed.
While the quantity of data your computer can manage at one time is determined by RAM capacity, the speed at which data is stored and accessible varies amongst memory devices.

Where is the memory in a computer?

Main memory, which consists of ROM and RAM, is positioned near the CPU on the computer motherboard, allowing the CPU to read data from primary memory very quickly. It’s used to store data that the CPU requires right away so that it doesn’t have to wait for it to arrive.

What Technology is Between Primary and Secondary Memory?

A novel memory medium dubbed 3D XPoint has been invented in the last year or two, with features that fall somewhere between main and secondary memory.
3D XPoint is more expensive than secondary memory but faster, and less expensive but slower than RAM. It’s also a sort of non-volatile memory.
Because of these qualities, it can be used as a replacement for RAM in systems that require large amounts of system memory but are too expensive to develop using RAM (such as systems hosting in-memory databases). The trade-off is that such systems do not benefit from all of RAM’s performance benefits.
Because 3D XPoint is non-volatile, systems that utilise it for system memory can quickly recover from a power outage or other interruption, without having to read all of the data back into system memory from secondary memory.
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