Motherboard

The motherboard is the backbone that ties the computer's components together at one spot and allows them to talk to each other. Without it, none of the computer pieces, such as the CPU, GPU, or hard drive, could interact. Total motherboard functionality is necessary for a computer to work well.

A motherboard provides connectivity between the hardware components of a computer, like the processor (CPU), memory (RAM), hard drive, and video card. There are multiple types of motherboards, designed to fit different types and sizes of computers.

Each type of motherboard is designed to work with specific types of processors and memory, so they don't work with every processor and type of memory. However, hard drives are mostly universal and work with the majority of motherboards, regardless of the type or brand.

Below is a picture of the ASUS P5AD2-E motherboard with labels next to each of its major components. Clicking on the image directs you to a larger and more detailed version.

What was the first motherboard?

The first motherboard is considered to be one used in the IBM Personal Computer, released in 1981. At the time, IBM called it a "planar" instead of a motherboard. The IBM Personal Computer and the motherboard inside it would set the standard for IBM-compatible computer hardware going forward.

Motherboard components

• Expension Slots
• 3 pin case fan connectors.
• Back pane connectors.
• Heat Sink.
• Inductor.
• Capacitor.
• CPU socket.
• Northbridge.
• Screw Hole.
• Memory Slot.
• Super I/O.
• Floopy Connection etc.

The Characteristics of a Motherboard

While many people think of the CPU as their computer's brain, the motherboard is like its nervous system and spinal cord. Not only does the motherboard provide a place for the CPU to sit, but it also handles every bit of data that passes in and out of the CPU.

Form Factor

While you can get capable motherboards in any size, its form factor is an important factor in choosing a motherboard. If you want to build a very small computer, a small form-factor board like a 9.6-inch square micro-ATX or 6.7-inch square mini-ITX board is your best choice. Larger motherboards, like the 11.2-by-8.2 inch mini-ATX or 12-by-9.6 inch full-size ATX board, not only fit in larger cases, but also have room for more components, connectors and expansion slots.

CPU Socket and Chipset

When choosing a motherboard, look for one with a CPU socket that will accommodate your chosen type of CPU. Not only do processors from Intel and AMD have different socket requirements, but different processors from the same manufacturers will also require a specialized socket. In other words, an Intel motherboard won't support an AMD processor and won't support certain Intel processors as well. In addition to choosing a compatible socket, the chipset on the motherboard will determine how quickly the computer can run, what additional features it supports and how much memory it can access.

Slots

Motherboards typically have three types of slots. Memory slots let you plug RAM modules into the computer. The more slots you have, the more memory you can add. The slots are also specific to a given type of RAM, so a motherboard with double data rate type 3 slots will only accept DDR3 memory modules. Motherboards also have high-speed PCI Express slots for graphics cards as well as regular PCI slots for expansion cards. While devices that once would have plugged into a PCI slot, like video capture cards or modems, are frequently now available as USB devices, the high-speed PCI-Express x16 slots are still necessities for graphics cards.

Connectors

Motherboards have a broad range of both internal and external connectors. At a minimum, you can expect to find internal USB headers and external USB ports, internal serial advanced technology attachment ports for drives, connectors for case LEDs and switches, and external audio ports. Some motherboards add support for USB 3.0, graphics connectors for their on-board graphics system, an external eSATA port for high-speed connections to external drives and even legacy ports like parallel or serial connectors.

 

ROM

ROM (read only memory) is a flash memory chip that contains a small amount of non-volatile memory. Non-volatile means that its contents cannot be changed and it retains its memory after the computer is turned off.

History of ROM

Read-only memory were employed as non-volatile storage for programs in most early stored-program computers, such as ENIAC after 1948. ... Most home computers of the 1980s stored a BASIC interpreter or operating system in ROM as other forms of non-volatile storage such as magnetic disk drives were too costly.

Types of ROM

• Programmable read-only memory (PROM), or one-time programmable ROM (OTP), can be written to or programmed via a special device called a PROM programmer. Typically, this device uses high voltages to permanently destroy or create internal links (fuses or antifuses) within the chip. Consequently, a PROM can only be programmed once.

• Erasable programmable read-only memory (EPROM) can be erased by exposure to strong ultravoilet light (typically for 10 minutes or longer), then rewritten with a process that again requires application of higher than usual voltage. Repeated exposure to UV light will eventually wear out an EPROM, but the endurance of most EPROM chips exceeds 1000 cycles of erasing and reprogramming. EPROM chip packages can often be identified by the prominent quartz "window" which allows UV light to enter. After programming, the window is typically covered with a label to prevent accidental erasure. Some EPROM chips are factory-erased before they are packaged, and include no window; these are effectively PROM.

• Electrically erasable programmable read-only memory (EEPROM) is based on a similar semiconductor structure to EPROM, but allows its entire contents (or selected banks) to be electrically erased, then rewritten electrically, so that they need not be removed from the computer (or camera, MP3 player, etc.). Writing or flashing an EEPROM is much slower (milliseconds per bit) than reading from a ROM or writing to a RAM (nanoseconds in both cases).

Where is the ROM on a computer?

For the computer, the main EEPROM and BIOS is on the computer motherboard.

How does ROM work?

ROM is sustained by a small, long-life battery in the computer. It contains two basic components: the decoder and the or logic gates. In ROM, the decoder receives input in binary form; the output will be the decimal equivalent. The OR gates in ROM use the decoder's decimal output as their input.

ROM performs like a disk array. It contains a grid of rows and columns that are used to turn the system on and off. Every element of the array correlates with a specific memory element on the ROM chip. A diode is used to connect the corresponding elements.

When a request is received, the address input is used to find the specific memory location. The value that is read from the ROM chip should match the contents of the chosen array element.

 

 

 

RAM

Alternatively referred to as main memory, primary memory, or system memory, RAM (random-access memory) is a hardware device that allows information to be stored and retrieved on a computer. RAM is usually associated with DRAM, which is a type of memory module. Because data is accessed randomly instead of sequentially like it is on a CD or hard drive, access times are much faster. However, unlike ROM, RAM is a volatile memory and requires power to keep the data accessible. If the computer is turned off, all data contained in RAM is lost.

History of RAM

The first form of RAM came about in 1947 with the use of the Williams tube. It utilized a CRT (cathode ray tube); the data was stored on the face as electrically charged spots.

The second widely used form of RAM was magnetic-core memory, invented in 1947. Frederick Viehe is credited with much of the work, having filed for several patents relating to the design. Magnetic-core memory works through the use of tiny metal rings and wires connecting to each ring. One bit of data could be stored per ring and accessed at any time.

However, RAM, as we know it today, as solid state memory, was first invented in 1968 by Robert Dennard. Known specifically as dynamic random-access memory, or DRAM, transistors were used to store bits of data.

 

Types of RAM

• DRAM (pronounced DEE-RAM), is widely used as a computer’s main memory. Each DRAM memory cell is made up of a transistor and a capacitor within an integrated circuit, and a data bit is stored in the capacitor. Since transistors always leak a small amount, the capacitors will slowly discharge, causing information stored in it to drain; hence, DRAM has to be refreshed (given a new electronic charge) every few milliseconds to retain data.
• SRAM (pronounced ES-RAM) is made up of four to six transistors. It keeps data in the memory as long as power is supplied to the system unlike DRAM, which has to be refreshed periodically. As such, SRAM is faster but also more expensive, making DRAM the more prevalent memory in computer systems.

What are the common types of DRAM?

• Synchronous DRAM (SDRAM) “synchronizes” the memory speed with CPU clock speed so that the memory controller knows the exact clock cycle when the requested data will be ready. This allows the CPU to perform more instructions at a given time. Typical SDRAM transfers data at speeds up to 133 MHz.
•  Rambus DRAM (RDRAM) takes its name after the company that made it, Rambus. It was popular in the early 2000s and was mainly used for video game devices and graphics cards, with transfer speeds up to 1 GHz.
• Double Data Rate SDRAM (DDR SDRAM) is a type of synchronous memory that nearly doubles the bandwidth of a single data rate (SDR) SDRAM running at the same clock frequency by employing a method  called "double pumping," which allows transfer of data on both the rising and falling edges of the clock signal without any increase in clock frequency.

Computer Memory

In computing, memory refers to a device that is used to store information for immediate use in a computer or related computer hardware device. It typically refers to semiconductor memory, specifically metal–oxide–semiconductor memory, where data is stored within MOS memory cells on a silicon integrated circuit chip.

Types of Computer Memory: Primary and Secondary

Although many types of memory in a computer exist, the most basic distinction is between primary memory, often called system memory, and secondary memory, which is more commonly called storage.

The key difference between primary and secondary memory is speed of access.

• Primary memory includes ROM and RAM, and is located close to the CPU on the computer motherboard, enabling the CPU to read data from primary memory very quickly indeed. It is used to store data that the CPU needs imminently so that it does not have to wait for it to be delivered.
• Secondary memory by contrast, is usually physically located within a separate storage device, such as a hard disk drive or solid state drive (SSD), which is connected to the computer system either directly or over a network. The cost per gigabyte of secondary memory is much lower, but the read and write speeds are significantly slower.

Primary Memory Types: RAM and ROM 

There are two key types of primary memory:

• RAM, or random access memory
• ROM, or read-only memory

Let's look in-depth at both types of memory.

RAM Computer Memory

The acronym RAM stems from the fact that data stored in random access memory can be accessed – as the name suggests – in any random order. Or, put another way, any random bit of data can be accessed just as quickly as any other bit.

The most important things to understand about RAM are that RAM memory is very fast, it can be written to as well as read, it is volatile (so all data stored in RAM memory is lost when it loses power) and, finally, it is very expensive compared to all types of secondary memory in terms of cost per gigabyte. It is because of the relative high cost of RAM compared to secondary memory types that most computer systems use both primary and secondary memory.

Data that is required for imminent processing is moved to RAM where it can be accessed and modified very quickly, so that the CPU is not kept waiting. When the data is no longer required it is shunted out to slower but cheaper secondary memory, and the RAM space that has been freed up is filled with the next chunk of data that is about to be used.

Types of RAM

• DRAM: DRAM stands for Dynamic RAM, and it is the most common type of RAM used in computers. The oldest type is known as single data rate (SDR) DRAM, but newer computers use faster dual data rate (DDR) DRAM. DDR comes in several versions including DDR2 , DDR3, and DDR4, which offer better performance and are more energy efficient than DDR. However different versions are incompatible, so it is not possible to mix DDR2 with DDR3 DRAM in a computer system. DRAM consists of a transistor and a capacitor in each cell.
• SRAM: SRAM stands for Static RAM, and it is a particular type of RAM which is faster than DRAM, but more expensive and bulker, having six transistors in each cell. For those reasons SRAM is generally only used as a data cache within a CPU itself or as RAM in very high-end server systems. A small SRAM cache of the most imminently-needed data can result in significant speed improvements in a system

The difference between DRAM and SRAM is that SRAM is faster than DRAM - perhaps two to three times faster - but more expensive and bulkier. SRAM is usually available in megabytes, while DRAM is purchased in gigabytes.

DRAM uses more energy than SRAM because it constantly needs to be refreshed to maintain data integrity, while SRAM  - though volatile – does not need constant refreshing when it is powered up.

ROM Computer Memory

ROM stands for read-only memory, and the name stems from the fact that while data can be read from this type of computer memory, data cannot normally be written to it. It is a very fast type of computer memory which is usually installed close to the CPU on the motherboard.

ROM is a type of non-volatile memory, which means that the data stored in ROM persists in the memory even when it receives no power – for example when the computer is turned off. In that sense it is similar to secondary memory, which is used for long term storage.

When a computer is turned on, the CPU can begin reading information stored in ROM without the need for drivers or other complex software to help it communicate. The ROM usually contains "bootstrap code" which is the basic set of instructions a computer needs to carry out to become aware of the operating system stored in secondary memory, and to load parts of the operating system into primary memory so that it can start up and become ready to use.

ROM is also used in simpler electronic devices to store firmware which runs as soon as the device is switched on.

Types of ROM

ROM is available in several different types, including PROM, EPROM, and EEPROM.

• PROM PROM stands for Programmable Read-Only Memory, and it is different from true ROM in that while a ROM is programmed (i.e. has data written to it) during the manufacturing process, a PROM is manufactured in an empty state and then programmed later using a PROM programmer or burner.
• EPROM EPROM stands for Erasable Programmable Read-Only Memory, and as the name suggests, data stored in an EPROM can be erased and the EPROM reprogrammed. Erasing an EPROM involves removing it from the computer and exposing it to ultraviolet light before re-burning it.
• EEPROM EEPROM stands for Electrically Erasable Programmable Read-Only Memory, and the distinction between EPROM and EEPROM is that the latter can be erased and written to by the computer system it is installed in. In that sense EEPROM is not strictly read-only. However in many cases the write process is slow, so it is normally only done to update program code such as firmware or BIOS code on an occasional basis

Secondary Memory Types

• Hard Disk Drives

• Solid State Drives
• Optical Drives
• Tape Drives

 

 

Output Devices

There are several output devices that are as follows:

Monitor

This is the most common computer output device. It creates a visual display by the use of which users can view processed data.  Monitors come in various sizes and resolutions.

Common Types of Monitors

• Cathode Ray Tube – this uses phosphorescent dots to generate the pixels that constitute displayed images.
• Flat Panel Screen – this makes use of liquid crystals or plasma to produce output. Light is passed through the liquid crystals in order to generate pixels.

Printer

This device generates a hard copy version of processed data, like documents and photographs. The computer transmits the image data to the printer, which then physically recreates the image, typically on paper.

Types of Printers

• Ink Jet – this kind of printer sprays tiny dots of ink onto a surface to form an image.
• Laser – this type utilises toner drums that roll through magnetized pigment, and then transfers the pigment onto a surface.
• Dot Matrix – dot matrix printers utilise a print head to set images on a surface, using an ink ribbon.

Speakers

speakers are attached to computers to facilitate the output of sound; sound cards are required in the computer for speakers to function. The different kinds of speakers range from simple, two-speaker output devices right the way up to surround-sound multi-channel units.

Headset

This is a combination of speakers and microphone.  It is mostly used by gamers, and is also a great tool for communicating with family and friends over the internet using some VOIP program or other.

Projector

 This is a display device that projects a computer-created image onto another surface: usually some sort of whiteboard or wall. The computer transmits the image data to its video card, which then sends the video image to the projector. It is most often used for presentations, or for viewing videos.

 

Input Devices

There are several input devices that are as follows:

Keyboard

one of the primary input devices used to input data and commands. It has function keys, control keys, arrow keys, keypad and the keyboard itself with the letters, numbers and commands.  Keyboards are connected to the computer through USB or Bluetooth.  A laptop keyboard is more compact than a desktop keyboard to make the laptop smaller and lighter.  Smartphones and tablets use on-screen keyboard to input messages and select commands.

Mouse

It is an input device used to control the cursor and coordinates. It can be wired or wireless.  It allows the user to do the following:

• Move the mouse cursor
• Select
• Scroll
• Open or execute a program
• Drag-and-drop
• Hover
• Perform other functions with the use of additional buttons
• A laptop uses a touchpad as the mouse.  A smartphone and tablet use a touchscreen as primary input device and the user’s finger is used as the mouse.

Microphone

It is an input device that allows users to input audio into their computers. Here are some uses of the microphone:

• Audio for video
• Computer gaming
• Online chatting
• Recording musical instruments
• Recording voice for dictation, singing and podcasts
• Voice recorder
• Voice recognition
• VoIP – Voice over Internet Protocol

Digital Camera

It is an input device that takes pictures digitally. Images are stored as data on memory cards.  It has an LCD screen that allows users to preview and review images.  Digital cameras have become popular over film cameras because of the following features:

• LCD screen – allows users to view the photos and videos immediately
• Storage – can store thousands of pictures
• Picture development – allows users to choose and pick which pictures to develop
• Size – takes up less space and can be easily carried

Scanner

It is an input device that reads an image and converts it into a digital file. A scanner is connected to a computer through USB.  There are different types of scanners:

• Flatbed scanner – uses a flat surface to scan documents
• Sheetfed scanner – like a laser printer where paper is fed into the scanner
• Handheld scanner – the scanner is dragged over the page to be scanned
• Card scanner – for scanning business card

Touch Screen

It is an input device that allows users to interact with a computer using their fingers. It is used widely in laptop monitors, smartphones, tablets, cash registers and information kiosks.  Most common functions of touchscreens are as follows:

• Tap
• Double-tap
• Touch and hold
• Drag
• Swipe
• Pinch

Barcode Reader

It is also known as barcode scanner or point of sale (POS) scanner, is an input device capable of reading barcodes.

Webcam

It is an input device connected to the computer and the internet that captures still picture or motion video.

Biometric Devices

It is an input device used to input biometric data into a computer. Here are the types of biometric devices:

• Face scanner
• Hand scanner
• Finger scanner
• Voice scanner

Stylus

 It is a pen-shaped input device used to write or draw on the screen of a graphic tablet or device. Initially it was just used for graphic tablets and PDAs, but now, it has become popular on mobile devices as a replacement for the user’s fingers.  It’s used for more accurate navigation and to keep oils from user’s fingers off the device screen.

Central Processing Unit (CPU)

The central processing unit (CPU) or processor, is the unit which performs most of the processing inside a computer. It processes all instructions received by software running on the PC and by other hardware components, and acts as a powerful calculator.

The CPU is placed into a specific square-shaped socket found on all motherboards by inserting its metallic connectors or pins found on the underside. Each socket is built with a specific pin layout to support only a specific type of processor.

The CPU is the heart and brain of a computer. It receives data input, executes instructions, and processes information. It communicates with input/output (I/O) devices, which send and receive data to and from the CPU.

The central processing unit (CPU) has two components

Control Unit

The control unit extracts instructions from memory and decodes and executes them.

The control unit acts as an intermediary that decodes the instructions sent to the processor, tells the other units such as the Arithmetic Logic Unit (below) what to do by providing control signals, and then sends back the processed data back to memory.

Arithmetic Logic Unit (ALU)

An arithmetic logic unit (ALU) is a digital circuit inside the processor that handles arithmetic and logical operations by loading data from input registers.

After the control unit provides the ALU with the instruction on the operations that must be performed, the ALU completes them by connecting multiple transistors, and then stores the results in an output register.

The control unit will then move this data to memory.

To function properly, the CPU relies on the system clock, memory, secondary storage, and data and address buses.

Smaller devices like mobile phones, calculators, held gaming systems, and tablets use smaller-sized processors known as ARM CPUs to accommodate their reduced size and space.

Components of a Computer System

Every computer system has the following three basic components:

• Input unit
• Central processing unit
• Output unit

Input Unit

These components help users enter data and commands into a computer system. Data can be in the form of numbers, words, actions, commands, etc. The main function of input devices is to direct commands and data into computers. Computers then use their CPU to process this data and produce output.

Another example of input devices is touch-screens. Users can simply touch these screens without using any other device to enter commands. From smartphones to ATM machines, these input devices are becoming very popular these days.

Central Processing Unit

After receiving data and commands from users, a computer system now has to process it according to the instructions provided. Here, it has to rely on a component called the central processing unit. The CPU further uses these three elements:

Memory Unit

Once a user enters data using input devices, the computer system stores this data in its memory unit. This data will now remain here until other components of CPU process it. The memory unit uses a set of pre-programmed instructions to further transmit this data to other parts of the CPU.

Arithmetic and Logic Unit

This part of the CPU performs arithmetic operations. It does basic mathematical calculations like addition, subtraction, division, multiplication, etc. Further, it can even perform logical functions like the comparison of data.

Control Unit

This unit is the backbone of computers. It is responsible for coordinating tasks between all components of a computer system. The control unit collects data from input units and sends it to processing units depending on its nature. Finally, it also further transmits processed data to output units for users.

Output Unit

The third and final component of a computer system is the output unit. After processing of data, it is converted into a format which humans can understand. After conversion, the output units displays this data to users. Examples of output devices include monitors, screens, printers and speakers. Thus, output units basically reproduce the data formatted by the computer for users’ benefit.

 

 

 

Types of Computer

 Computer sizes and power

Computers can be generally classified by size and power as follows, though there is considerable overlap:

• Personal computer: A small, single-user computer based on a microprocessor.

• Workstation: A powerful, single-user computer. A workstation is like a personal computer, but it has a more powerful microprocessor and, in general, a higher-quality monitor.

• Minicomputer: A multi-user computer capable of supporting up to hundreds of users simultaneously.

• Mainframe: A powerful multi-user computer capable of supporting many hundreds or thousands of users simultaneously
• Supercomputer: An extremely fast computer that can perform hundreds of millions of instructions per second.

Supercomputer and Mainframe

Supercomputer is a broad term for one of the fastest computers currently available. Supercomputers are very expensive and are employed for specialized applications that require immense amounts of mathematical calculations (number crunching). For example, weather forecasting requires a supercomputer. Other uses of supercomputers scientific simulations, (animated) graphics, fluid dynamic calculations, nuclear energy research, electronic design, and analysis of geological data (e.g. in petrochemical prospecting). Perhaps the best known supercomputer manufacturer is Cray Research.

Mainframe was a term originally referring to the cabinet containing the central processor unit or "main frame" of a room-filling Stone Age batch machine. After the emergence of smaller "minicomputer" designs in the early 1970s, the traditional big iron machines were described as "mainframe computers" and eventually just as mainframes. Nowadays a Mainframe is a very large and expensive computer capable of supporting hundreds, or even thousands, of users simultaneously. The chief difference between a supercomputer and a mainframe is that a supercomputer channels all its power into executing a few programs as fast as possible, whereas a mainframe uses its power to execute many programs concurrently. In some ways, mainframes are more powerful than supercomputers because they support more simultaneous programs. But supercomputers can execute a single program faster than a mainframe. The distinction between small mainframes and minicomputers is vague, depending really on how the manufacturer wants to market its machines.

Minicomputer

It is a midsize computer. In the past decade, the distinction between large minicomputers and small mainframes has blurred, however, as has the distinction between small minicomputers and workstations. But in general, a minicomputer is a multiprocessing system capable of supporting from up to 200 users simultaneously.

Workstation

It is a type of computer used for engineering applications (CAD/CAM), desktop publishing, software development, and other types of applications that require a moderate amount of computing power and relatively high quality graphics capabilities. Workstations generally come with a large, high-resolution graphics screen, at large amount of RAM, built-in network support, and a graphical user interface. Most workstations also have a mass storage device such as a disk drive, but a special type of workstation, called a diskless workstation, comes without a disk drive. The most common operating systems for workstations are UNIX and Windows NT. Like personal computers, most workstations are single-user computers. However, workstations are typically linked together to form a local-area network, although they can also be used as stand-alone systems.

Personal computer:

It can be defined as a small, relatively inexpensive computer designed for an individual user. In price, personal computers range anywhere from a few hundred pounds to over five thousand pounds. All are based on the microprocessor technology that enables manufacturers to put an entire CPU on one chip. Businesses use personal computers for word processing, accounting, desktop publishing, and for running spreadsheet and database management applications. At home, the most popular use for personal computers is for playing games and recently for surfing the Internet.

Personal computers first appeared in the late 1970s. One of the first and most popular personal computers was the Apple II, introduced in 1977 by Apple Computer. During the late 1970s and early 1980s, new models and competing operating systems seemed to appear daily. Then, in 1981, IBM entered the fray with its first personal computer, known as the IBM PC. The IBM PC quickly became the personal computer of choice, and most other personal computer manufacturers fell by the wayside. P.C. is short for personal computer or IBM PC. One of the few companies to survive IBM's onslaught was Apple Computer, which remains a major player in the personal computer marketplace. Other companies adjusted to IBM's dominance by building IBM clones, computers that were internally almost the same as the IBM PC, but that cost less. Because IBM clones used the same microprocessors as IBM PCs, they were capable of running the same software. Over the years, IBM has lost much of its influence in directing the evolution of PCs. Therefore after the release of the first PC by IBM the term PC increasingly came to mean IBM or IBM-compatible personal computers, to the exclusion of other types of personal computers, such as Macintoshes. In recent years, the term PC has become more and more difficult to pin down. In general, though, it applies to any personal computer based on an Intel microprocessor, or on an Intel-compatible microprocessor. For nearly every other component, including the operating system, there are several options, all of which fall under the rubric of PC

Desktop model

A computer designed to fit comfortably on top of a desk, typically with the monitor sitting on top of the computer. Desktop model computers are broad and low, whereas tower model computers are narrow and tall. Because of their shape, desktop model computers are generally limited to three internal mass storage devices. Desktop models designed to be very small are sometimes referred to as slimline models.

Notebook computer

An extremely lightweight personal computer. Notebook computers typically weigh less than 6 pounds and are small enough to fit easily in a briefcase. Aside from size, the principal difference between a notebook computer and a personal computer is the display screen. Notebook computers use a variety of techniques, known as flat-panel technologies, to produce a lightweight and non-bulky display screen. The quality of notebook display screens varies considerably. In terms of computing power, modern notebook computers are nearly equivalent to personal computers. They have the same CPUs, memory capacity, and disk drives. However, all this power in a small package is expensive. Notebook computers cost about twice as much as equivalent regular-sized computers. Notebook computers come with battery packs that enable you to run them without plugging them in. However, the batteries need to be recharged every few hours.

Laptop computer

A small, portable computer -- small enough that it can sit on your lap. Nowadays, laptop computers are more frequently called notebook computers.

Subnotebook computer

A portable computer that is slightly lighter and smaller than a full-sized notebook computer. Typically, subnotebook computers have a smaller keyboard and screen, but are otherwise equivalent to notebook computers.

Hand-held computer

A portable computer that is small enough to be held in one’s hand. Although extremely convenient to carry, handheld computers have not replaced notebook computers because of their small keyboards and screens. The most popular hand-held computers are those that are specifically designed to provide PIM (personal information manager) functions, such as a calendar and address book. Some manufacturers are trying to solve the small keyboard problem by replacing the keyboard with an electronic pen. However, these pen-based devices rely on handwriting recognition technologies, which are still in their infancy. Hand-held computers are also called PDAs, palmtops and pocket computers.

Palmtop

A small computer that literally fits in your palm. Compared to full-size computers, palmtops are severely limited, but they are practical for certain functions such as phone books and calendars. Palmtops that use a pen rather than a keyboard for input are often called hand-held computers or PDAs. Because of their small size, most palmtop computers do not include disk drives. However, many contain PCMCIA slots in which you can insert disk drives, modems, memory, and other devices. Palmtops are also called PDAs, hand-held computers and pocket computers.

 

 

Generations Of Computers

There are five generations of computer:

• FIRST GENERATION: VACUUM TUBES (1940-1956)

• SECOND GENERATION: TRANSISTORS (1956-1963)

• THIRD GENERATION: INTEGRATED CIRCUITS (1964-1971)

• FOURTH GENERATION: MICROPROCESSORS (1971-PRESENT)

• FIFTH GENERATION: ARTIFICIAL INTELLIGENCE (PRESENT AND BEYOND)

FIRST GENERATION: VACUUM TUBES (1940-1956)

The first computer systems used vacuum tubes for circuitry and magnetic drums for memory, and were often enormous, taking up entire rooms. These computers were very expensive to operate and in addition to using a great deal of electricity, the first computers generated a lot of heat, which was often the cause of malfunctions.

First generation computers relied on machine language, the lowest-level programming language understood by computers, to perform operations, and they could only solve one problem at a time. It would take operators days or even weeks to set-up a new problem. Input was based on punched cards and paper tape, and output was displayed on printouts.

The UNIVAC and ENIAC computers are examples of first-generation computing devices. The UNIVAC was the first commercial computer delivered to a business client, the U.S. Census Bureau in 1951.

SECOND GENERATION: TRANSISTORS (1956-1963)

The world would see transistors replace vacuum tubes in the second generation of computers. The transistor was invented at Bell Labs in 1947 but did not see widespread use in computers until the late 1950s.

The transistor was far superior to the vacuum tube, allowing computers to become smaller, faster, cheaper, more energy-efficient and more reliable than their first-generation predecessors. Though the transistor still generated a great deal of heat that subjected the computer to damage, it was a vast improvement over the vacuum tube. Second-generation computers still relied on punched cards for input and printouts for output.

THIRD GENERATION: INTEGRATED CIRCUITS (1964-1971)

The development of the integrated circuit was the hallmark of the third generation of computers. Transistors were miniaturized and placed on silicon chips, called semiconductors, which drastically increased the speed and efficiency of computers.

Instead of punched cards and printouts, users interacted with third generation computers through keyboard and monitors and interfaced with an operating system, which allowed the device to run many different applications at one time with a central program that monitored the memory. Computers for the first time became accessible to a mass audience because they were smaller and cheaper than their predecessors.

FOURTH GENERATION: MICROPROCESSORS (1971-PRESENT)

The microprocessor brought the fourth generation of computers, as thousands of integrated circuits were built onto a single silicon chip. What in the first generation filled an entire room could now fit in the palm of the hand. The Intel 4004 chip, developed in 1971, located all the components of the computer from the central processing unit and memory to input/output controls on a single chip.

In 1981 IBM introduced its first computer for the home user, and in 1984 Apple introduced the Macintosh. Microprocessors also moved out of the realm of desktop computers and into many areas of life as more and more everyday products began to use microprocessors.

As these small computers became more powerful, they could be linked together to form networks, which eventually led to the development of the Internet. Fourth generation computers also saw the development of GUI's, the mouse and handheld devices.

FIFTH GENERATION: ARTIFICIAL INTELLIGENCE (PRESENT AND BEYOND)

Fifth generation computing devices, based on artificial intelligence, are still in development, though there are some applications, such as voice recognition, that are being used today. The use of parallel processing and superconductors is helping to make artificial intelligence a reality.

Quantum computation and molecular and nanotechnology will radically change the face of computers in years to come. The goal of fifth-generation computing is to develop devices that respond to natural language input and are capable of learning and self-organization.

 

Computer Applications

computers are used in various fields, such as homes, businesses, government offices, research organizations, educational institutions, medical, entertainment, etc. Computers have taken industries and businesses to a whole new level. In this article, we have elaborated the most common uses of computers in different fields:

Business

Currently, computers can be seen in almost every business. Computers are almost part of a business setup because they increase productivity and help race in a competitive environment. In businesses, computers are primarily used to store and manage accounts and personal data, maintain projects, track inventory status, and make reports and presentations. Besides, computers are best suited for transaction processing because they are more accurate and faster than humans. Computers also help people analyze their investment, expenses, profits, sales and many other aspects of the business.

Science

Scientists are amongst one of those people who use computers as their primary work tool. In science, research and engineering, computers are best suited for collecting, analyzing, categorizing, and storing the data. They also help scientists to exchange data with each other both internally and internationally. Computers enable scientists from different locations (such as different countries) to work together on the same project with cloud support. Besides, computers play a crucial role in launching, maintaining, controlling spacecraft, and operating many other technologies.

Government

In the government sector, computers are beneficial. They are getting used to performing various functions in different departments and improving their services' quality, efficiency, and productivity. Some examples of such services are city planning, traffic control, law enforcement, infrastructure developments, and tourism. In most cases, the primary purposes of using computers are performing data processing tasks, maintaining citizens' database, and promoting a paperless environment. Apart from this, computers are playing a crucial role in the country's defense system. They are helping in missile development, rocket, satellite launches, etc.

Health and Medical

Computers are radically changing the methods of diagnosis in hospitals. They are used for maintaining patients' information, records, live monitoring of patients, X-rays, and more. Everything is being digitized with the help of computers. Computers help configure lab-tools, monitor heart rate, and blood pressure, etc. Doctors get extra advantages in treating patients with proper drugs and medicines. Additionally, computers enable doctors to exchange patient's data easily with other medical specialists. Besides, advanced surgical devices are based on robotics that helping surgeons to conduct complex operations and surgeries remotely.

Education

Computers are broadly getting used in the education field. They help people get different educational materials (such as images, videos, e-books, etc.) in one place. All such information can be accessed through the Internet. Additionally, computers are best suited for online classes, online tutoring, online examinations, and creating assignments and projects. Apart from this, they can also be used to maintain and monitor student performance and other information.

Industry

Computers are used in industries to perform various tasks, such as maintaining inventory, interior designing, designing samples or virtual products, communicating over video conferencing, and more. Online marketing has made it easier for people to buy products in rural areas. Online trading in stock markets has also seen a significant revolution due to its easy participation potential. Computers have enabled people from different levels of different locations to participate easily in stock marketing.

Banking

Banking has become so advanced in the past few years. Most countries use online banking systems where customers can access their data directly using computers and the Internet. People can check their account balance, transfer money, and pay online bills, including credit cards. Besides, Banks use computers to perform transactions and store customer data, transaction records, etc. Banks have reduced the number of manual errors, number of employees, and costs to a great extent by using computers. ATMs are the best example of computers that are helping people to withdraw and deposit the money themselves.

Entertainment

Computers nowadays are one of the best mediums for entertainment. Computers can be used to watch movies, play games, listen to music, etc. Computers combined with MIDI instruments can be used to record audio through artificial instruments. Besides, people can also enjoy recording their videos with webcam and apply several entertaining AI effects. Several Photo editor programs are also available with fabulous powerful features.

Training

Most companies use computers to provide training to their employees. Computer-based training helps companies save their time, money, and increase productivity. Also, computer-based training can be used to train employees for large distances in various locations. This will eliminate travel time and costs, making the training process much more comfortable and smoother.

Arts

Computers have become part of art, photography, dance, and culture. Computers with advanced features allow users to draw their projects directly on it. Besides, people can use computers to digitize their photos. There are several photo editor software that can help people edit and customize their photos. Apart from this, the dance's movements and steps can be shown live with animations' help.

Sports

In today's technologically developed world, computers are being used in almost every sport. There are many sports activities where computers are making things possible. In sports, computers are mainly used to maintain scoreboards, records, and other statistics. Furthermore, they are used to analyze player movements and make various in-game decisions. Computers help make complex in-game decisions (especially in umpiring), which cannot be seen by human eyes.

Robotics

Robotics is one of the emerging fields of technology that uses computers for science and engineering as well as designing machines. These machines can be virtual (such as software bots) and physical ones that can reduce or eliminate human workload. Additionally, some machines can perform heavy tasks that humans cannot complete, or that may take a long time to complete. Car manufacturing was one of the first examples where robots helped to assemble car parts and perform many other heavy tasks. However, nowadays, robots are beneficial in many fields, such as exploring areas where conditions are difficult for humans, helping the military, helping law enforcement and helping health professionals, etc.

Uses of Computer

Computers are playing a vital role in almost every field and making our day-to-day tasks more manageable. Computers were only used to perform complex numerical calculations in a previous time, but they have reached too far and now perform many different roles. They are now performing diverse set functions from complicated calculations to generating business reports, bill generation to education, programming or development to entertainment, etc.

 

Computer Overview

Today’s world is an information-rich world and it has become a necessity for everyone to know about computers. A computer is an electronic data processing device, which accepts and stores data input, processes the data input, and generates the output in a required format.

A computer system has three main components: hardware, software, and people. The equipment associated with a computer system is called hardware. Software is a set of instructions that tells the hardware what to do. People, however, are the most important component of a computer system - people use the power of the computer for some purpose. In fact, this course will show you that the computer can be a tool for just about anyone from a business person, to an artist, to a housekeeper, to a student - an incredibly powerful and flexible tool.

The purpose of this tutorial is to introduce you to Computers and its fundamentals.

Functionalities of a Computer

If we look at it in a very broad sense, any digital computer carries out the following five functions −

Step 1 − Takes data as input.

Step 2 − Stores the data/instructions in its memory and uses them as required.

Step 3 − Processes the data and converts it into useful information.

Step 4 − Generates the output.

Step 5 − Controls all the above four steps.

Characteristics of Computer

• Speed 
• Storage
• Accuracy 
• Diligence
• Cost Effectiveness 
• Flexibility

Advantages of computer

Multitasking

Multitasking is one of the major advantage of computer. Person can perform multiple task, multiple operation, calculate numerical problems within few seconds. Computer can perform trillion of instructions per second.

Speed

Now computer is not just a calculating device. Now a day’s computer has very important role in human life. One of the main advantages of computer is its incredible speed, which helps human to complete their task in few seconds. All the operations can be performed very fast just because of its speed elsewise it takes a long time to perform the task.

Cost/ Stores huge amount of data

It is a low cost solution. Person can save huge data within a low budget. Centralized database of storing information is the major advantage that can reduce cost.

Accuracy

One of the root advantage of computer is that can perform not only calculations but also with accuracy.

Data Security

Protecting digital data is known as data security. Computer provide security from destructive forces and from unwanted action from unauthorized users like cyber attack or access attack.

 

Disadvantage of Computer

As we know advantage comes with disadvantage.

Virus and hacking attacks

Virus is a worm and hacking is simply an unauthorized access over computer for some illicit purpose. Virus is being transferred from email attachment, viewing an infected website advertisement, through removable device like USB etc. once virus is transferred in host computer it can infect file, overwrite the file etc.
For example: Huge portion of internet  was going down including Twitter, Netflix, Reddit and CNN in October 2016 because the largest DDoS attack was launched on service provider DYN using IoT Botnet.

Online Cyber Crimes

Online cyber-crime means computer and network may have used in order to commit crime. Cyberstalking and Identity theft are the points which comes under online cyber-crimes. For example: one may get the access of the access to your shopping account like amazon account now that person will be able to know your personal details like debit card or credit card number which can be than misused.

Reduction in employment opportunity

Mainly past generation was not used of the computer or they have the knowledge of computer they faced a big problem when computer came in field. As we have seen in banking sector senior bank employees faced this problem when computer came to the banking sector.
Above were the main disadvantage of computer, no IQ, Dependency, No feeling, Break down are the basic disadvantages of computer.

 

 

Logic Gates

A logic gate is a device that acts as a building block for digital circuits. They perform basic logical functions that are fundamental to digital circuits. Most electronic devices we use today will have some form of logic gates in them. For example, logic gates can be used in technologies such as smartphones, tablets or within memory devices.

In a circuit, logic gates will make decisions based on a combination of digital signals coming from its inputs. Most logic gates have two inputs and one output. Logic gates are based on Boolean algebra. At any given moment, every terminal is in one of the two binary conditions, false or true. False represents 0, and true represents 1. Depending on the type of logic gate being used and the combination of inputs, the binary output will differ. A logic gate can be thought of like a light switch, wherein one position the output is off -- 0, and in another, it is on -- 1. Logic gates are commonly used in integrated circuits (IC).

Basic logic gates

There are seven basic logic gates: AND, OR, XOR, NOT, NAND, NOR, and XNOR.

The AND gate is so named because, if 0 is called "false" and 1 is called "true," the gate acts in the same way as the logical "and" operator. The following illustration and table show the circuit symbol and logic combinations for an AND gate. (In the symbol, the input terminals are at left and the output terminal is at right.) The output is "true" when both inputs are "true." Otherwise, the output is "false." In other words, the output is 1 only when both inputs one AND two are 1.

 

AND gate

Input 1	Input 2	Output
	1
1
1	1	1

The OR gate gets its name from the fact that it behaves after the fashion of the logical inclusive "or." The output is "true" if either or both of the inputs are "true." If both inputs are "false," then the output is "false." In other words, for the output to be 1, at least input one OR two must be 1.

 

OR gate

Input 1	Input 2	Output
	1	1
1		1
1	1	1

 

The XOR ( exclusive-OR ) gate acts in the same way as the logical "either/or." The output is "true" if either, but not both, of the inputs are "true." The output is "false" if both inputs are "false" or if both inputs are "true." Another way of looking at this circuit is to observe that the output is 1 if the inputs are different, but 0 if the inputs are the same. 

 

 

XOR gate

Input 1	Input 2	Output
	1	1
1		1
1	1

 

A logical inverter, sometimes called a NOT gate to differentiate it from other types of electronic inverter devices, has only one input. It reverses the logic state. If the input is 1, then the output is 0. If the input is 0, then the output is 1.  

 

 

 

Inverter or NOT gate

Input	Output
1
	1

 

The NAND gate operates as an AND gate followed by a NOT gate. It acts in the manner of the logical operation "and" followed by negation. The output is "false" if both inputs are "true." Otherwise, the output is "true."

 

NAND gate

Input 1	Input 2	Output
		1
	1	1
1		1
1	1

 

The NOR gate is a combination OR gate followed by an inverter. Its output is "true" if both inputs are "false." Otherwise, the output is "false."

NOR gate

Input 1	Input 2	Output
		1
	1
1
1	1

 

The XNOR (exclusive-NOR) gate is a combination XOR gate followed by an inverter. Its output is "true" if the inputs are the same, and "false" if the inputs are different.

 

XNOR gate

Input 1	Input 2	Output
		1
	1
1
1	1	1

Complex operations can be performed using combinations of these logic gates. In theory, there is no limit to the number of gates that can be arrayed together in a single device. But in practice, there is a limit to the number of gates that can be packed into a given physical space. Arrays of logic gates are found in digital ICs. As IC technology advances, the required physical volume for each individual logic gate decreases and digital devices of the same or smaller size become capable of performing ever-more-complicated operations at ever-increasing speeds.

Composition of logic gates

High or low binary conditions are represented by different voltage levels. The logic state of a terminal can, and generally does, often change as the circuit processes data. In most logic gates, the low state is approximately zero volts (0 V), while the high state is approximately five volts positive (+5 V).

Logic gates can be made of resistors and transistors or diodes. A resistor can commonly be used as a pull-up or pull-down resistor. Pull-up and pull-down resistors are used when there are any unused logic gate inputs to connect to a logic level 1 or 0. This prevents any false switching of the gate. Pull-up resistors are connected to Vcc (+5V), and pull-down resistors are connected to ground (0 V).

Commonly used logic gates are TTL and CMOS. TTL, or Transistor-Transistor Logic, ICs will use NPN and PNP type Bipolar Junction Transistors. CMOS, or Complementary Metal-Oxide-Silicon, ICs are constructed from MOSFET or JFET type Field Effect Transistors. TTL IC's may commonly be labeled as the 7400 series of chips, while CMOS ICs may often be marked as a 4000 series of chips.

 

Memory

Memory is the electronic holding place for the instructions and data a computer needs to reach quickly. It's where information is stored for immediate use. Memory is one of the basic functions of a computer, because without it, a computer would not be able to function properly. Memory is also used by a computer's operating system, hardware and software.

There are technically two types of computer memory: primary and secondary. The term memory is used as a synonym for primary memory or as an abbreviation for a specific type of primary memory called random access memory (RAM). This type of memory is located on microchips that are physically close to a computer's microprocessor.

If a computer's central processer (CPU) had to only use a secondary storage device, computers would become much slower. In general, the more memory (primary memory) a computing device has, the less frequently the computer must access instructions and data from slower (secondary) forms of storage.

Memory vs. storage

The concept of memory and strorage can be easily conflated as the same concept; however, there are some distinct and important differences. Put succinctly, memory is primary memory, while storage is secondary memory. Memory refers to the location of short-term data, while storage refers to the location of data stored on a long-term basis.

Memory is most often referred to as the primary storage on a computer, such as RAM. Memory is also where information is processed. It enables users to access data that is stored for a short time. The data is only stored for a short time because primary memory is volatile, meaning it isn't retained when the computer is turned off.

The term storage refers to secondary memory and is where data in a computer is kept. An example of storage is a hard drive or a hard disk drive (HDD). Storage is nonvolatile, meaning the information is still there after the computer is turned off and then back on. A running program may be in a computer's primary memory when in use -- for fast retrieval of information -- but when that program is closed, it resides in secondary memory or storage.

How much space is available in memory and storage differs as well. In general, a computer will have more storage space than memory. For example, a laptop may have 8 GB of RAM while having 250 GB of storage. The difference in space is there because a computer will not need fast access to all the information stored on it at once, so allocating approximately 8 GB of space to run programs will suffice.

The terms memory and storage can be confusing because their usage today is not always consistent. For example, RAM can be referred to as primary storage -- and types of secondary storage can include flash memory. To avoid confusion, it can be easier to talk about memory in terms of whether it is volatile or nonvolatile -- and storage in terms of whether it is primary or secondary.

How does computer memory work?

When a program is open, it is loaded from secondary memory to primary memory. Because there are different types of memory and storage, an example of this could be a program being moved from a solid-state drive (SSD) to RAM. Because primary storage is accessed faster, the opened program will be able to communicate with the computer's processor at quicker speeds. The primary memory can be accessed immediately from temporary memory slots or other storage locations.

Memory is volatile, which means that data in memory is stored temporarily. Once a computing device is turned off, data stored in volatile memory will automatically be deleted. When a file is saved, it will be sent to secondary memory for storage.

There are multiple types of memory available to a computer. It will operate differently depending on the type of primary memory used, but in general, semiconductor-based memory is most associated with memory. Semiconductor memory will be made of integrated circuits with silicon-based metal-oxide-semiconductor (MOS) transistors.

Types of computer memory

In general, memory can be divided into primary and secondary memory; moreover, there are numerous types of memory when discussing just primary memory. Some types of primary memory include the following

• Cache Memory. This temporary storage area, known as a cache read as "cash" is more readily available to the processor than the computer's main memory source. It is also called CPU memory because it is typically integrated directly into the CPU chip or placed on a separate chip with a bus interconnect with the CPU.

• RAM. The term is based on the fact that any storage location can be accessed directly by the processor.

• Dynamic RAM. DRAM is a type of semiconductor memory that is typically used by the data or program code needed by a computer processor to function.

• Static RAM. SRAM retains data bits in its memory for as long as power is supplied to it. Unlike DRAM, which stores bits in cells consisting of a capacitor and a transistor, SRAM does not have to be periodically refreshed.

• Double Data Rate SDRAM. DDR SRAM is SDRAM that can theoretically improve memory clock speed to at least 200 MHz.

• Double Data Rate 4 Synchronous Dynamic RAM. DDR4 RAM is a type of DRAM that has a high-bandwidth interface and is the successor to its previous DDR2 and DDR3 versions. DDR4 RAM allows for lower voltage requirements and higher module density. It is coupled with higher data rate transfer speeds and allows for dual in-line memory modules (DIMMS) up to 64 GB.

• Rambus Dynamic RAM. DRDRAM is a memory subsystem that promised to transfer up to 1.6 billion bytes per second. The subsystem consists of RAM, the RAM controller, the bus that connects RAM to the microprocessor and devices in the computer that use it.

• Read-only memory. ROM is a type of computer storage containing nonvolatile, permanent data that, normally, can only be read and not written to. ROM contains the programming that enables a computer to start up or regenerate each time it is turned on.

• Programmable ROM. PROM is ROM that can be modified once by a user. It enables a user to tailor a microcode program using a special machine called a PROM programmer.

• Erasable PROM. EPROM is programmable read-only memory PROM that can be erased and re-used. Erasure is caused by shining an intense ultraviolet light through a window designed into the memory chip.

• Electrically erasable PROM. EEPROM is a user-modifiable ROM that can be erased and reprogrammed repeatedly through the application of higher than normal electrical voltage. Unlike EPROM chips, EEPROMs do not need to be removed from the computer to be modified. However, an EEPROM chip must be erased and reprogrammed in its entirety, not selectively.

• Virtual Memory. A memory management technique where secondary memory can be used as if it were a part of the main memory. Virtual memory uses hardware and software to enable a computer to compensate for physical memory shortages by temporarily transferring data from RAM to disk storage