Memory

A memory is just like a human brain. It is used to store data and instructions. Computer memory is the storage space in the computer, where data is to be processed and instructions required for processing are stored. The memory is divided into large number of small parts called cells. Each location or cell has a unique address, which varies from zero to memory size minus one. For example, if the computer has 64k words, then this memory unit has 64 * 1024 = 65536 memory locations. The address of these locations varies from 0 to 65535.

Memory is primarily of three types −

1.Cache Memory

2.Primary Memory/Main Memory

3.Secondary Memory

1.Cache Memory

Cache memory is a very high speed semiconductor memory which can speed up the CPU. It acts as a buffer between the CPU and the main memory. It is used to hold those parts of data and program which are most frequently used by the CPU. The parts of data and programs are transferred from the disk to cache memory by the operating system, from where the CPU can access them.

Advantages

▫️Cache memory is faster than main memory.

▫️It consumes less access time as compared to main memory.

▫️It stores the program that can be executed within a short period of time.

▫️It stores data for temporary use.

Disadvantages

▫️Cache memory has limited capacity.

▫️It is very expensive.

2.Primary Memory (Main Memory)

Primary memory holds only those data and instructions on which the computer is currently working. It has a limited capacity and data is lost when power is switched off. 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.

Characteristics of Main Memory

🔹️These are semiconductor memories.

🔹️It is known as the main memory.

🔹️Usually volatile memory.

🔹️Data is lost in case power is switched off.

🔹️It is the working memory of the computer.

🔹️Faster than secondary memories.

🔹️A computer cannot run without the primary memory.

3.Secondary Memory

This type of memory is also known as external memory or non-volatile. It is slower than the main memory. These are used for storing data/information permanently. CPU directly does not access these memories, instead they are accessed via input-output routines. The contents of secondary memories are first transferred to the main memory, and then the CPU can access it. For example, disk, CD-ROM, DVD, etc.

Characteristics of Secondary Memory

🔹️These are magnetic and optical memories.

🔹️It is known as the backup memory.

🔹️It is a non-volatile memory.

🔹️Data is permanently stored even if power is switched off.

🔹️It is used for storage of data in a computer.

🔹️Computer may run without the secondary memory.

🔹️Slower than primary memories.

⏩ Here it is Completely Explaination about Memory...

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 COMPUTER

A computer is a programmable device that stores, retrieves, and processes data. The term "computer" was originally given to humans (human computers) who performed numerical calculations using mechanical calculators, such as the abacus and slide rule. The term was later given to mechanical devices as they began replacing human computers. Today's computers are electronic devices that accept data (input), process that data, produce output, and store (storage) the results (IPOS).

Topic's are covered in this BLOG👇

Computer overview

History of the computer

How are computers used today?

What components make up a desktop computer?

What parts are needed for a computer to work?

Computer connections

Types of computers

Who makes computers?

Computer overview

Below is a picture of a computer with each of the main components. You can see the desktop computer, flat-panel display, speakers, keyboard, and mouse in the picture below. We've also labeled each of the input devices and output devices.

History of the computer

The first digital computer and what most people think of as a computer was called the ENIAC. It was built during World War II (1943-1946) and was designed to help automate the calculations being done by human computers. By doing these calculations on a computer, they could achieve results much faster and with fewer errors.

Early computers like the ENIAC used vacuum tubes and were large (sometimes room size) and only found in businesses, universities, or governments. Later, computers began utilizing transistors and smaller and cheaper parts that allowed the ordinary person to own a computer.

How are computers used today?

Today, computers do jobs that used to be complicated much simpler. For example, you can write a letter in a word processor, edit it anytime, spell check, print copies, and send it to someone across the world in seconds. All these activities would have taken someone days, if not months, to do before. Also, these examples are a small fraction of what computers can do.

What components make up a desktop computer?

Today's desktop computers have some or all the components (hardware) and peripherals below. As technology advances, older technologies, such as a floppy disk drive and Zip drive (shown below), are no longer required or included.

Optical drive: Blu-ray, CD-ROM, CD-R, CD-RW, or DVD.

CPU (processor)

Floppy disk drive

Hard drive

Keyboard

RAM (random access memory)

Microphone

Monitor, LCD, or another display device.

Motherboard

Mouse

Network card

Power Supply

Printer

Sound card

Speakers

Video card

Wearable

What parts are needed for a computer to work?

A computer does not require all the components mentioned above. However, a computer cannot function without having at the very minimum the parts listed below.

Processor - Component that executes instructions from the software and hardware.

Memory - Temporary primary storage for data traveling between the storage and CPU.

Motherboard (with onboard video) - Component that connects all components.

Storage device (e.g., hard drive) - Slower secondary storage that permanently stores data.

However, if you had a computer with only the minimum parts above, you would be unable to communicate with it until you connected at least one input device (e.g., keyboard). Also, you would need at least one output device (e.g., monitor) for you to see what is happening.

Computer connections

All computers have different types of connections. An example of the back of a personal computer and brief descriptions of each connection is found on our computer connections page.

Types of computers

Computers can be classified as one of three types of computers: a general-purpose computer, special-purpose computer, or specialized computer.

A general-purpose computer is what most people think of when thinking about a computer and is what this page covers.

A special-purpose computer is embedded in almost all electronic devices and is the most widely-used computer. This computer is designed for a specific task and is found in ATMs, cars, microwaves, TVs, the VCR, and other home electronics. See our special-purpose computer page for further information and examples.

A specialized computer is like a general-purpose computer but is designed only to perform one or a few different tasks. See our specialized computer for further information and examples of these computers.

When talking about a computer or a "PC," you're usually referring to a desktop computer found in a home or office. However, the lines of what makes these computers are blurring. Below are different examples of what's considered a computer today.

The picture above shows several types of computers and computing devices and is an example of their differences. Below is a complete list of general-purpose computers of past and present.

Who makes computers?

Today, there are two types of computers: the PC (IBM compatible) and Apple Mac. Many companies make and build PCs, and if you get all the necessary parts for a computer, you can even build a custom PC. However, with Apple computers, only Apple designs and makes these computers. See our computer companies page for a listing of companies (OEMs) that make and build computers.

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