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...

Thank you.

 

Monitors

▫️Monitors, commonly called as Visual Display Unit(VDU), are the main output device of a computer. It forms images from tiny dots, called pixels that are arranged in a rectangular form. The sharpness of the image depends upon the number of pixels.

▫️There are two kinds of viewing screen used for monitors.⤵️

• 1.Cathode-Ray Tube (CRT)
• 2.Flat-Panel Display
• 
  

1.Cathode-Ray Tube (CRT) Monitor

▫️The CRT display is made up of small picture elements called pixels. The smaller the pixels, the better the image clarity or resolution. It takes more than one illuminated pixel to form a whole character, such as the letter ‘e’ in the word help.

▫️A finite number of characters can be displayed on a screen at once. The screen can be divided into a series of character boxes - fixed location on the screen where a standard character can be placed. Most screens are capable of displaying 80 characters of data horizontally and 25 lines vertically.

▫️There are some disadvantages of CRT −

• 🔹️Large in Size
• 🔹️High power consumption
• 
  

2.Flat-Panel Display Monitor

▫️The flat-panel display refers to a class of video devices that have reduced volume, weight and power requirement in comparison to the CRT. You can hang them on walls or wear them on your wrists. Current uses of flat-panel displays include calculators, video games, monitors, laptop computer, and graphics display.

▫️The flat-panel display is divided into two categories −

• 🔸️Emissive Displays − Emissive displays are devices that convert electrical energy into light. For example, plasma panel and LED (Light-Emitting Diodes).

• 🔸️Non-Emissive Displays − Non-emissive displays use optical effects to convert sunlight or light from some other source into graphics patterns. For example, LCD (Liquid-Crystal Device).

http://raj1725.blogspot.com

Thank you.

CPU 🎚

 

Central Processing Unit

The computer's central processing unit (CPU) is the portion of a computer that retrieves and executes instructions. The CPU is essentially the brain of a CAD system. It consists of an arithmetic and logic unit (ALU), a control unit, and various registers. The CPU is often simply referred to as the processor.

➡️Central Processing Unit (CPU) consists of the following features −

🔸️CPU is considered as the brain of the computer.

🔸️CPU performs all types of data processing operations.

🔸️It stores data, intermediate results, and instructions (program).

🔸️It controls the operation of all parts of the computer.

➡️CPU itself has following three components.

🔶️Memory or Storage Unit

🔶️Control Unit

🔶️ALU(Arithmetic Logic Unit)

Memory or Storage Unit

This unit can store instructions, data, and intermediate results. This unit supplies information to other units of the computer when needed. It is also known as internal storage unit or the main memory or the primary storage or Random Access Memory (RAM).

Its size affects speed, power, and capability. Primary memory and secondary memory are two types of memories in the computer.

 Functions of the memory unit are −

▫️It stores all the data and the instructions required for processing.

▫️It stores intermediate results of processing.

▫️It stores the final results of processing before these results are released to an output device.

▫️All inputs and outputs are transmitted through the main memory.

Control Unit

This unit controls the operations of all parts of the computer but does not carry out any actual data processing operations.

Functions of this unit are −

▫️It is responsible for controlling the transfer of data and instructions among other units of a computer.

▫️It manages and coordinates all the units of the computer.

▫️It obtains the instructions from the memory, interprets them, and directs the operation of the computer.

▫️It communicates with Input/Output devices for transfer of data or results from storage.

▫️It does not process or store data.

ALU (Arithmetic Logic Unit)

This unit consists of two subsections namely,

◽Arithmetic Section

◽Logic Section

Arithmetic Section

Function of arithmetic section is to perform arithmetic operations like addition, subtraction, multiplication, and division. All complex operations are done by making repetitive use of the above operations.

Logic Section

Function of logic section is to perform logic operations such as comparing, selecting, matching, and merging of data.

http://raj1725.blogspot.com

Thank you.

Types of Keyboard ⌨

Types of keyboards

Most computer users use the standard keyboard, which connects to the computer. Although there are many types of a computer keyboard, such are as follows:

1. Flexible keyboard: 

It is a type of keyboard that is made of soft silicone with highly portable. It is water and dust-resistant and does not require constant cleaning. It acts the same as a standard keyboard and connects to the computer via a USB connection serial port. These types of keyboards can also be more durable in terms of some ways, as compared to a traditional keyboard.

The flexible keyboard is made of soft silicone that saves it from a number of different substances. For instance, if you use the keyboard near the liquid spaces, the silicone skin provides excellent protection against spills. Furthermore, it does not make a sound when being used; that's why it is also called a silent keyboard. These keyboards are useful for traveling time because they can be rolled up into a bag and flexible in outdoorsy situations.

2. Ergonomic Keyboard: 

This type of keyboard is beneficial for your body posture. Instead of adjusting yourself to fit the keyboard, it is designed to fit you easily, ease of use, and reduce strain. It is designed in that way; instead of bending their hands, it allows users to straight their hands. Generally, the space-bar is bigger as compared to a regular keyboard, which allows for fast typing.

3. Wireless Keyboard:

 It is a computer keyboard that is connected to computers, laptops, or tablets without any cables. It uses radio frequency (RF), infrared (IR), or Bluetooth technology to connect with devices. Users can move the wireless keyboard around without having to put it on a desk as it provides portability and flexibility to the users. It is designed by stainless steel material that increases its life for a long time. It can set up very easily by plugging the USB receiver into the computer.

It utilizes light waves to transmit signals to other infrared-enabled devices as it is based on infrared technology. Some wireless keyboards use radio frequency technology, which communicates via signals with a range from 27 MHz to up to 2.4 GHz.

4. Mechanical Keyboard: 

It is made with high quality that commonly used in both home and office. It is designed for long life with high durability and responsiveness. It provides crisp click sound, medium resistance, and better feedback for gaming performance and ultimate typing. It offers framing, switches, type print methods, functionality, PCB board, key construction, LED lighting, or more other better features as compared to traditional rubber dome keyboards.

5. Virtual Keyboard: 

It is a software-based keyboard that enables users to type without the need for physical keys. It is an alternative for a physical keyboard or a digital representation of a QWERTY keyboard. These types of keyboards commonly have many pages of characters, including numbers, letters, punctuation, and symbols. Some virtual

keyboards also include options to insert emojis, stickers, or animated GIFs on the basis of the device's operating system. The devices that contained virtual keyboard are tablets, smartphones, and other portable devices, because these devices do not require the constant use of a physical keyboard.

Examples of virtual keyboards

Gboard: Google created a virtual keyboard for Android and iOS that includes features like GIFs, customizable themes, and translation capabilities.

OSK: It stands for an on-screen keyboard. It is commonly found in Microsoft Windows.

6. Projection Keyboard:

 It is a form of computer input device that can be connected via Bluetooth to the mini PC, tablet computer, or even smartphone. In projection keyboard, the image of a virtual keyboard is projected onto a surface. The device records the corresponding keystroke when a user touches any key from the shown keyboard on the surface. Some devices are connected via Bluetooth devices such as tablets, smartphones, mini-PC with Android, Windows operating system or iOS, etc.

7. Gaming Keyboard: 

A keyboard that contains a few specific keys used for gamers is known as a gaming keyboard. The W, S, D, A, and arrow keys are widely used for games on the standard QWERTY keyboard. Gaming keyboards (mostly mechanical keyboard), the key switches needless depression that provides faster action for games.

Here, it is covered types of keyboard in this BLOG.

http://raj1725.blogspot.com

Thank You.🙃

Invention of Keyboard♒

Invention of the first keyboard

There were different types of invention, as well as the typewriter, keypunches, and teleprinters that helped to develop the computer keyboard. In the 1700s, the first writing devices were designed, and Henry Mills filed patented in London, England, in 1714.

Invention of the typewriter

The different typing and writing devices were created around the world in the late 1700s and the beginning of the 1800s. Although, in 1868, Christopher Sholes developed and patented the first practical typewriter and the word Type-Writer that is considered to be the first typewriter.

Additionally, the QWERTY keyboard design was introduced by the Type-Writer, which is still

mainly used on US keyboards today. Samuel W. Soule, Christopher Sholes, and Carlos Glidden created a Type-Writer that picture shown in the below:

In 1878, the first keyboard with a Shift key was invented that had one Shift key on the left side of the keyboard. The Underwood typewriter is considered the first successful modern typewriter, till 1939, five million of its typewriters were sold. The first Underwood typewriter was invented by Franz Xaver Wagner, and on 27 April 1893, he filed to patent the typewriter U.S. patent 523,698. The biggest improvement of Underwood typewriter, it was capable of seeing the writing it was typed. Later in 1895, Franz Xaver Wagner created the Underwood company with the help of John Underwood and introduced its first typewriter in 1896.

Before introducing the IBM Selectric typewriter by IBM on 27 July 1961, typewriters from all manufacturers began to become more alike. Unlike other typewriters, the IBM Selectric typewriter used a typeball, which containing characters that would strike an ink ribbon. Furthermore, this typewriter was sold more than 13 million until 1986.

The invention of keypunch, the telegraph, and teleprinter

Joseph Marie Jacquard developed the Jacquard Loom in the late 1700s, which was expanded by Herman Hollerith with his keypunch inventions in the late 1800s and the beginning of the 1900s.

In 1832, Pavel Schilling invented the first electrical telegraph and to send Morse code messages over a line, allowing for a single key to be used. Later in 1846, a printing telegraph was patented by Royal Earl House, which used 28 piano-style keys. The keys made it easy to send messages by representing each letter in the alphabet. In 1874, the Baudot code was invented by Emile Baudot; later, it was extended by Donald Murray (inventor of thetelegraphic typewriter). Charles Krum helped invent the teleprinter by working to continue on Frank Pearne that was developed from 1902 to 1918. In August 1907, he filed patent U.S. patent 862,402. Also, he filed patent 888,335 in May 1908, and patent 1,286,351 in May 1910.

Early computers with keyboards

After many years, in 1964, the introduction of Multics and video display terminals (VDTs), which enabled users to see typing on the screen what they are typing.

The DataPoint 3300 began to ship by the Computer Terminal Corporation in 1969. It was the first computer terminal designed to replace the teleprinter. Some other versions of this terminal were also introduced as well as HP 2600A, DEC, and VT06. The DataPoint 3300 was a terminal that was able to move the cursor using arrow keys, and it used a screen display to show typed text. Also, it had the ability to clear all text on the screen.

At the beginning of the 1970s, keyboards began to use what we use today. Those keyboards were heavy mechanical or reconstructed electric typewriters from companies such as IBM. Apple, Radio Shack, and Commodore introduced their computers in the late 1970s that come included keyboards. Later, IBM PC and the Model F keyboard introduced by IBM in August 1981.

The Model M keyboard was introduced by IBM in 1986, which contained function keys like today's keyboards have across the top of the keyboard. The Model M is still considered a high keyboard as it has a standard US layout with 101-key, which is used for full-sized keyboards today. It is also designed for windows keyboards that have 104-key with the Menu keys and windows keys.

Since IBM introduced the Model M keyboard, many changes have been in the keyboard that is in use today. A membrane helps to manufacturer computer keyboards easily and reduce manufacturing costs. Furthermore, the membrane keyboard makes the keyboard lighter, thinner, and quieter as compared to the first mechanical keyboards.

← PrevNext →

http://raj1725.blogspot.com

Thank you.