Computer Advantages and Disadvantages
The Computer is an electronic device that is used to solve various problems according to a set of instruction given to it. The word computer is derived from a word compute, which means, To Calculate.
A computer has four Functions.
Input
Processing
Output
Storage
The information Processing Cycle
IPC
Many Advantages of the Computers
Explain some:
1. Computers are very helpful in education . Students can prepare their projects easily with the help of computers.
2. Medical science and Biotechnology are using computers to diagnose the diseases of a people .
3. Computers are helpful in offices, sciences , engineering and technology.
4. Computers are used to make good defense of a country.
5. A computer can store large amounts of data permanently. Users can use this data at any time . We can store any type of data in a computer.
6. A computer is reliable device .Failures are usually due to human error.
7. We can play games on a computer
8. We can watch movies on a Computer
9. We can send messages to our friends relatives and family anywhere in the word by connecting computers with Internet.
10. The computer is perfumes Speed, Storage , Efficiency , Accuracy, Reliability , etc
11. The computer rescores of Communications Channel
12. The computer is provide the online Education
13. The Computers are also used for research purposes .Internet provides many search websites.
Disadvantages of Computer
The big Disadvantage is Virus the virus is set of negative instruction.
1. The Virus is Damage all computer files and records
2. Computer perfumes after virus
26april virus
Chernobyl (CIH) Virus
Folder Virus
120,000 virus’s is introduced
In perverse years
3. Hacking means illegal activates different types of Hacking all types is wrong to the computer .
4. Key loggers are the illegal activates perfumes of the computer. TO send the repot of the computers and all password .
5. Waste the time in chatting and bade web pages.
6. Waste time in games and Movies .
7. Large time to used the computer bade effect in your eyes.
8. The computer is used very costly you purchased different software in different working .
9. Industry level the worker is not accepted it because poor education and this operate one person large worker is unemployed .
10. Your Hardware is dead all data is loss
Some Beginning Terms:
Hardware: The Physical parts of the computer are called
Computer Hardware: These are the things that can be seen and touched
Example the CPU. Monitor. Drivers. Mouse. Keyboard. Etc
Software: A set of computer instruction given to the computer to solve a problem is called software.
Default:
The original setting is called default for example Ms word when open you see the size of text is 12. Then you told this is original setting mean default.
Computer Characteristics
Speed: Computer works at a very high sped and are much faster than humans. A second is very large time period for computer. A computer can perform billions of calculation in a second. The time used by a computer to perform an operation is called processing speed. Computer speed is measured in Mega Hertz (MHz)
Reliability:
Failures are usually due to human error, one way or another.
A man to a calculation in billions digits may be suffer with some problem and mind error but computer is reliable machine.
Storage:
A computer can keep huge amounts of data.
Accuracy:
Accuracy means to provide results without any errors.
Recalling:
A computer can recall the stored data and information as and when required. The data stored in the computer can be used at a later.
The computer can recall the required data in a few seconds.
Classification of digital computer:
Computer is classified according to size, speed and memory capacity.
Computer is of different types.
1. Main frame computer
2. Mini computers
3. Micro computers
4. Super computers
5. Laptop
What is input?
Everything we tell the computer is input.
Types of input:
Data
Programs
Commands
User response
Data is the raw facts given to the computer.
Lowercase letter a.b.c ………………….z
Uppercase letter. A.B.C…………………Z
Digits 0.1…………………….9
Symbols +&*^%%^……………?
Programs:
Programs are the sets of instructions that direct the computer.
Commands:
Commands are special codes or key words that the user inputs to perform a task.
Commands
Key word
Special codes
Input Devices:
Key board
Mouse
Track ball
Glide pad
Game Devices
Multimedia
Scanner
Video Input
Sound Input
A digital camera or recorder
A video camera or recorder
Out put
The information of computer is called out put
• Printer
• Monitor
• Speaker
System software?
Operating system Utility software System software= (drivers ) Application software
System software:
System software is the operating system within the computer. Thus if you are using windows-based compute as ‘ system software
System software refer two categories:
Operating system = (live cycle for operating system)
Utilities programs
Operating system
Single-user Operating systems
A type of operating system in which only user can work at time is called single-user operating system. Dos. Windows 8x are example of single- user operating system. Dos work on command it is most sing-user operating system. Dos works on command it is most compatible with hardware
Multi- operating systems / (multi tasking operating systems)
A type of operating system in which more than one user can work at a time is called Multi- tasking operating system. Unix, Linux,
Windows NT/ 2000 are examples of single- user operating systems.
Application software: / utility software
Application software is drivers and any other software mean Ms word and win boost, flash free hand. Drivers to hand. Drivers to handover in the hardware mean looking but application software is different work this to operating system . this under it to the operating system
+
Application software is the software that is used to perform tasks such as word- processing, a spreadsheet or database etc. it is importance to realize that the application software uses the operating system in order to function. You can think of the operating system as the ‘base’ software, with the application software running of top of the operating system software.
Types of RAM
There are two types of Ram
• Static RAM
• Dynamic (DRAM)
Static RAM
Static RAM is more expensive. It required more amount of space for a given amount of data that dynamic RAM. It does not need to be power-refreshed and is therefore faster to access.
Dynamic RAM;
DRAM is the least expensive kind of RAM. Dynamic RAM uses a kind of capacitor that should be recharged again and again. A power refresh is required after each read. DRAM must be refreshed many times in a second. That is why it is slow.
ROM (READ ONLY MEMORY)
Read only memory as the name suggests is a special type of memory chip that hold software that can be read but only written to. A good example is the ROM- BIOS chip, which contain read only software. Often network cards and video cards also contain ROM chip.
CD-ROM:-
CD –ROM stands for compact disk read only memory. The data on a CD-ROM can only be read and cannot be removed or changes. It is most commonly used type of optical disk. It has the storage capacity of up to 650 MB. It is used for storing large amounts of data and application programs.
DVD-ROM:-
DVD-ROM stands for Digital Video Disk Read Only Memory. A DVD operates similar to a CD-ROM disk. A DVD uses a laser with shorter wavelength. A laser with shorter wavelength can read smaller holes on a optical disk. Small size holes on the disk surface increases its data storage capacity. A DVD can store data up to 10 GB of data. Its storage capacity is seven times more than that of the CD-ROM.
What is processing?
1 bit = one on or off position
1 byte = 8 bits
So 1 byte can be one of 256 possible combinations of 0 and 1.
Numbers written with just 0 and 1, are called binary numbers.
Control unit
This is the part of the computer that controls the machine Cycle. It is takes numerous cycles to do even a simple addition of two numbers.
Fetch – get an instruction from main memory
Decode – translate it into computer commands
Execute- actually process the command
Store- writes the result to main memory
ALU
Stand for Arithmetic/logic unit
This is the part executes the computer’s commands.
A command must be either a basic arithmetic operation +-*/ or one of the logical comparisons.
Computer communication
Computer communication is the transmission of data information over a communications channel between two computers.
Communication between computers can be as simple as cabling two computers to the same printers. It can be as complex as a computer at NASA sending messages through an elaborate system of relays and satellites to tell a computer on Mars how to drive around without hitting the rocks.
Depending on the context, for computer communications you might use the terms:
Data communication for transmission of data and information over a communications channel
Telecommunication for any long- distance communication, especially television
Communications channel :
A communications channel , also called a communications line or link, is the path that the data follows as it is transmitted from one computer to another .
Transmission Media
Transmission media just means the physical materials that are used to transmit data between computers.
Cables :
Twisted wire : (Phone line)
Coaxial cable: (round insulated wire ) house cable
Fiber optic line ( glass fiber ) smaller cable Faster (speed of light)
Signals
Tow types of signals are used for data transmission
Digital and analog
digital
A Digital signal is a stream of 0’s and 1’s .
An analog signal :
It is particularly useful for wave data like sound waves .Analog signals are what your normal phone line and sound speakers use.
Modems
Communications between computers use the telephone system for at least part of the channel Such a device is the modem , which comes from Modulate / Demodulate , Which is what a modem s dose . It modulates a digital signal from the computer into an analog one to send data out over the phone line. Than for an incoming signal tit demodulates the analog signal into a digital one.
Downloading means to transfer a transfer a file to your computer
Uploading means to transfer a file to your computer to another .
Networks types
LAN , MAN
LAN: Local Area Network LANs would be within the same office, a single building , or several building s close as a LAN .
WAN Wide Area Network Which would be all networks too large to be LANs .WAN would be most useful for large companies like Microsoft, IBM etc.
TOPOLOGY:
The method of connecting different terminals for transmitting data from one computer to another is called network topology or network types or network technology.
Topology refers to how the computers in a network are configured in their connections with each other.
Physical layout of the computer network. The term topology is the way of connecting computers or nodes on a network. There are many ways in which computers can be connected together in a computer network. The way in which computers or other devices are connected in a network is called network topology.
There are following main types of topology.
1. ) BUS Network Topology.
2. ) STAR Network Topology.
3. ) RING Network Topology.
1= BUS (LINEAR) NETWORK TOPOLOGY:
In bus network topology, each terminal is connected to the central computer with one or two cables. A common bus is used in this type of network topology. If one cable has become defective, the terminals connected to that cable loses connection with the central computer, but other computers remains in connected. This topology is mostly used in business.
ADVANTAGES:-
Easy to connect a computer or peripheral devices.
Requires less cable length.
Inexpensive hardware devices.
Adding additional computer easily.
Easy to extend a bus, two cables can be joined with a connector.
DISAVANTAGES:-
Entire network shuts down if there is a break in the main cable.
Terminators are required at both ends of main cable.
Difficult to identify the problem if the entire network shuts down.
Heavy network traffic can slow a bus considerably.
Each connector reduces the strength of the electrical signal
As the number of computer increases, the speed of the network slows down.
(BUS NETWORK TOPOLOGY)
2= STAR NETWORK TOPOLOGY:
In star network topology, each computer or terminal is directly connected to the Central controller Unit (HUB) through an individual cable and Hub is connected to the central computer (file server or main computer).If one of computers has become defective, than there is no any effect on star network topology .This type of networking most expensive because each computer has a separate cable for connection.
(STAR NETWORK TOPOLOGY)
ADVANTAGES:-
Easy to install, modify and add new computers without disturbing the rest of the network computers.
Easy to detect faults and to remove parts.
Hub can accommodate multiple cable types.
It is more flexible among the remaining topology.
DISADVANTAGES:-
Requires more cable length than a linear topology.
If the hub or central computer fails, the entire network breaks down.
More expensive than bus topology.
3= RING (TOKEN )NETWORK TOPOLOGY:
in a ring topology , computers are connected on a single of cable .Each computer repeats and keeps the signal strong .No terminator is required. Each node most determines whether or not any received data is for its use and if not, it passes the data on to its neighbor.
ADVANTAGES:-
All connected computer have equal. access and has the same opportunity to transmit.
Adding additional nodes easily.
DISADVANTAGES:-
It is difficult to configure.
Media failure can stop all communication.
Problem detection and solving is difficult.
Adding or removing computers disrupts the network.
ANALOG DATD TRANSMISSION
The transfer of data from one place to another in continuous wave from is called analog data transmission .The analog signal consists of continuous electrical wave or signals constantly very in one or more values and these changes in values can be used to represent data. The light waves, sound wave or radio waves are examples of analog signas.The transmission through telephone lines, microwave system or satellite is the example of analog data transmission.
Examples:
Measurement of Temperature, Volume, Vocal Waave, Waves, Analog Clock, Pressure, Fan Dimmer. Etc.
DIGITAL DATA TRANSMISSION
Digital data transmission system is the transmission of data from one location to another location in the from of digital signal. A digital signal consists of individual electrical pulses that represent two values like “0” for off and “1” for on.
Computer accepts the data in digital forms.
Digital Form;
01010101010
Examples:
(Only two values exist.)
On/Off switch, Day/Night concept, Digital Clock, etc.
INTER-NET:
The network of networks is called internet:
Explanation:
Internet stands for International Networking.
In this case , a central computer is used as server machine and this system is attached with other server machines through satellites. All of the Internet users are attached to their own server using telephone line with using Modem. The local server machine keeps all the accounts of all its users.-
In July-2000, 180-Billions of internet users and increasing rate of
Internet users are 10% p.a.
E-MAIL:
E-MAIL stand for Electronic Mail. It is a communication system in which data is sent and received through computer from one location to another.
In this case, a central computer is used as Post Office, and this system is attached with other Post office Machines through satellite. All of the e-mail users are attached to their own fax machine and post office using telephone lines and modem.
WEB-BROWSING:
The process of digging out information any specific subject is called web browsing.
E-COMMERCE:-
E0-Commerce stand for Electronic commerce: the need for electronic commerce stand from the demand within business and government to make better use of computing and to better apply computer technology to improve customer interacton, vusiness processes, corner)enterprises.
"Computer technology" redirects here. For the corporate, see technology restricted.
Computer
A pc may be a programmable machine designed to mechanically perform a sequence of arithmetic or logical operations. the actual sequence of operations will be modified pronto, permitting the pc to unravel quite one reasonably drawback. a crucial category of pc operations on some computing platforms is that the acceptive of input from human operators and also the output of results formatted for human consumption. The interface between the pc and also the human operator is understood because the program.
Conventionally a pc consists of some kind of memory, a minimum of one component that carries out arithmetic and logic operations, and a sequencing and management unit which will amendment the order of operations supported the data that's hold on. Peripheral devices enable info to be entered from Associate in Nursing external supply, and permit the results of operations to be sent out.
A computer's process unit executes series of directions that build it browse, manipulate and so store knowledge. Conditional directions amendment the sequence of directions as a operate of the present state of the machine or its surroundings.
The first electronic digital computers were developed within the mid-20th century (1940–1945). Originally, they were the dimensions of an oversized area, overwhelming the maximum amount power as many hundred fashionable personal computers (PCs).[1] during this era mechanical analog computers were used for military applications.
First all-purpose computers
In 1801, Joseph Marie Jacquard created Associate in Nursing improvement to the textile loom by introducing a series of punched paper cards as a templet that allowed his loom to weave convoluted patterns mechanically. The ensuing loom was a crucial step within the development of computers as a result of the employment of punched cards to outline woven patterns will be viewed as Associate in Nursing early, albeit restricted, kind of programmability.
It was the fusion of automatic calculation with programmability that created the primary recognizable computers. In 1837, Charles Babbage was the primary to create by mental act and style a totally programmable mechanical pc, his analytical engine.[20] restricted finances and Babbage's inability to resist tinkering with the planning meant that the device was ne'er completed ; all the same his son, Henry Babbage, completed a simplified version of the analytical engine's computing unit (the mill) in 1888. He gave a undefeated demonstration of its use in computing tables in 1906. This machine was given to the museum in South Kensington in 1910.
A succession of steady a lot of powerful and versatile computing devices were created within the Nineteen Thirties and Nineteen Forties, step by step adding the key options that ar seen in fashionable computers. the employment of digital natural philosophy (largely fabricated by applied scientist in 1937) and a lot of versatile programmability were vitally necessary steps, however process one purpose on this road as "the 1st digital electronic computer" is troublesome.Shannon 1940 Notable achievements embrace.
Computers exploitation vacuum tubes as their electronic parts were in use throughout the Fifties, however by the Nineteen Sixties had been mostly replaced by semiconductor transistor-based machines, that were smaller, faster, cheaper to supply, needed less power, and were a lot of reliable. the primary transistorized pc was incontestable at the University of Manchester in 1953.[31] within the Seventies, computer circuit technology and also the sequent creation of microprocessors, like the Intel 4004, more slashed size and price and more inflated speed and responsibleness of computers. By the late Seventies, several merchandise like video recorders contained dedicated computers referred to as microcontrollers, and that they began to seem as a replacement to mechanical controls in domestic appliances like laundry machines. The Nineteen Eighties witnessed home computers and also the currently omnipresent pc. With the evolution of the web, personal computers have become as common because the tv and also the phonephone within the house
Bugs
Main article: software package bug
The actual 1st pc bug, a lepidopterous insect found cornered on a relay of the Harvard Mark II pc
Errors in pc programs ar referred to as "bugs". they'll be benign and not have an effect on the utility of the program, or have solely refined effects. however in some cases they'll cause the program or the whole system to "hang" – become unresponsive to input like mouse clicks or keystrokes – to utterly fail, or to crash. Otherwise benign bugs might generally be controlled for malicious intent by Associate in Nursing unscrupulous user writing Associate in Nursing exploit, code designed to require advantage of a bug and disrupt a computer's correct execution. Bugs ar typically not the fault of the pc. Since computers simply execute the directions they're given, bugs ar nearly forever the results of computer user error or Associate in Nursing oversight created within the program's style.[33]
Rear Admiral Grace Hopper is attributable for having 1st used the term "bugs" in computing when a dead lepidopterous insect was found shorting a relay within the Harvard Mark II pc in September 1947.[3
Machine code
In most computers, individual directions ar hold on as computer code with every instruction being given a singular variety (its code or opcode for short). The command to feature 2 numbers along would have one opcode, the command to multiply them would have a distinct opcode then on. the only computers ar ready to perform any of a couple of various instructions; the a lot of advanced computers have many hundred to settle on from, every with a singular numerical code. Since the computer's memory is ready to store numbers, it may store the instruction codes. This results in the necessary incontrovertible fact that entire programs (which ar simply lists of those instructions) will be diagrammatic as lists of numbers and may themselves be manipulated within the pc within the same means as numeric knowledge. the elemental construct of storing programs within the computer's memory aboard the info they treat is that the crux of the von Neumann, or hold on program, design. In some cases, a pc may store some or all of its program in memory that's unbroken break free the info it operates on. this is often referred to as the Harvard design when the Harvard Mark I pc. fashionable von Neumann computers show some traits of the Harvard design in their styles, like in processor caches
While it's attainable to jot down pc programs as long lists of numbers (machine language) and whereas this method was used with several early computers,[35] it's extraordinarily tedious and doubtless erring to try to to thus in apply, particularly for sophisticated programs. Instead, every basic instruction will be given a brief name that's indicative of its operate and straightforward to recollect – a mnemotechnical like ADD, SUB, MULT or JUMP. These method ar together referred to as a computer's programing language. changing programs written in programing language into one thing the pc will truly perceive (machine language) is typically done by a worm referred to as Associate in Nursing computer programme.
Programming language
Main article: artificial language
Programming languages offer numerous ways that of specifying programs for computers to run. in contrast to natural languages, programming languages ar designed to allow no ambiguity and to be curt. {they ar|they're} strictly written languages and are typically troublesome to browse aloud. they're usually either translated into computer code by a compiler or Associate in Nursing computer programme before being run, or translated directly at run time by Associate in Nursing interpreter. generally programs ar dead by a hybrid technique of the 2 techniques.
Program style
Program style of little programs is comparatively easy and involves the analysis of the matter, assortment of inputs, exploitation the programming constructs inside languages, production or exploitation established procedures and algorithms, providing knowledge for output devices and solutions to the matter as applicable. As issues become larger and a lot of advanced, options like subprograms, modules, formal documentation, and new paradigms like object-oriented programming ar encountered. giant programs involving thousands of line of code and a lot of need formal software package methodologies. The task of developing giant software package systems presents a big intellectual challenge. manufacturing software package with Associate in Nursing tolerably high responsibleness inside a foreseeable schedule and budget has traditionally been difficult; the tutorial and skilled discipline of software package engineering concentrates specifically on this challenge.
Components
Main articles: Central process unit and micro chip
A general purpose pc has four main components: the arithmetic logic unit (ALU), the management unit, the memory, and also the input and output devices (collectively termed I/O). These components ar interconnected by busses, typically product of teams of wires.
Inside every of those components ar thousands to trillions of little electrical circuits which might be turned off or on by suggests that of Associate in Nursing electronic switch. every circuit represents a trifle (binary digit) of knowledge so once the circuit is on that represents a "1", and once off it represents a "0" (in positive logic representation). The circuits ar organized in logic gates so one or a lot of of the circuits might management the state of 1 or a lot of of the opposite circuits.
The management unit, ALU, registers, and basic I/O (and typically different hardware closely joined with these) ar together referred to as a central process unit (CPU). Early CPUs were composed of the many separate elements however since the mid-1970s CPUs have generally been created on one computer circuit referred to as a micro chip.
Control unit
Main articles: processor style and management unit
Diagram showing however a selected MIPS design instruction would be decoded by the system.
The management unit (often referred to as an effect system or central controller) manages the computer's numerous components; it reads and interprets (decodes) the program directions, reworking them into a series of management signals that activate different components of the pc.[38] management systems in advanced computers might amendment the order of thusme directions so on improve performance.
A key part common to all or any CPUs is that the program counter, a special memory cell (a register) that keeps track of that location in memory consecutive instruction is to be browse from.[39]
The management system's operate is as follows—note that this is often a simplified description, and a few of those steps could also be performed at the same time or in a very completely different order reckoning on the kind of CPU:
1. browse the code for consecutive instruction from the cell indicated by the program counter.
2. decrypt the numerical code for the instruction into a group of commands or signals for every of the opposite systems.
3. Increment the program counter thus it points to consecutive instruction.
4. browse no matter knowledge the instruction needs from cells in memory (or maybe from Associate in Nursing input device). the situation of this needed knowledge is often hold on inside the instruction code.
5. offer the mandatory knowledge to Associate in Nursing ALU or register.
6. If the instruction needs Associate in Nursing ALU or specialised hardware to finish, instruct the hardware to perform the requested operation.
7. Write the result from the ALU back to a memory location or to a register or maybe Associate in Nursing output device.
8. Jump back to step (1).
Since the program counter is (conceptually) simply another set of memory cells, it will be modified by calculations worn out the ALU. Adding a hundred to the program counter would cause consecutive instruction to be browse from an area a hundred locations more down the program. directions that modify the program counter ar typically referred to as "jumps" and permit for loops (instructions that ar continual by the computer) and sometimes conditional process (both samples of management flow).
The sequence of operations that the management unit goes through to method Associate in Nursing instruction is in itself sort of a short worm, and indeed, in some a lot of advanced processor styles, there's another nevertheless smaller pc referred to as a microsequencer, that runs a code program that causes all of those events to happen.
Arithmetic logic unit (ALU)
Main article: Arithmetic logic unit
The ALU is capable of playing 2 categories of operations: arithmetic and logic.[40]
The set of arithmetic operations that a selected ALU supports could also be restricted to addition and subtraction, or may embrace multiplication, division, pure mathematics functions like trigonometric function, cosine, etc., and sq. roots. Some will solely treat whole numbers (integers) while others use floating purpose to represent real numbers, albeit with restricted exactitude. However, any pc that's capable of playing simply {the easyst|the only|the best} operations will be programmed to interrupt down the a lot of advanced operations into simple steps that it will perform. Therefore, any pc will be programmed to perform any arithmetic operation—although it'll take longer to try to to thus if its ALU doesn't directly support the operation. Associate in Nursing ALU may additionally compare numbers and come Boolean truth values (true or false) reckoning on whether or not one is capable, bigger than or but the opposite ("is sixty four bigger than 65?").
Logic operations involve Boolean logic: AND, OR, XOR and NOT. These will be helpful for making sophisticated conditional statements and process mathematical logic.
Superscalar computers might contain multiple ALUs, permitting them to method many directions at the same time.[41] Graphics processors and computers with SIMD and MIMD options typically contain ALUs which will perform arithmetic on vectors and matrices.
Memory
Main article: pc knowledge storage
Magnetic core memory was the pc memory of alternative throughout the Nineteen Sixties, till it absolutely was replaced by semiconductor memory.
A computer's memory will be viewed as a listing of cells into that numbers will be placed or browse. every cell incorporates a varietyed "address" and may store one number. the pc will be taught to "put the quantity 123 into the cell numbered 1357" or to "add the quantity that's in cell 1357 to the quantity that's in cell 2468 and place the solution into cell 1595". the data hold on in memory might represent much something. Letters, numbers, even pc directions will be placed into memory with equal ease. Since the processor doesn't differentiate between differing types of knowledge, it's the software's responsibility to offer significance to what the memory sees as nothing however a series of numbers.
In most fashionable computers, every memory cell is about up to store binary numbers in teams of eight bits (called a byte). every computer memory unit is ready to represent 256 completely different numbers (2^8 = 256); either from zero to 255 or −128 to +127. To store larger numbers, many consecutive bytes could also be used (typically, two, four or eight). once negative numbers ar needed, they're typically hold on in two's complement notation. different arrangements ar attainable, however ar typically not seen outside of specialised applications or historical contexts. A pc will store any reasonably info in memory if it will be diagrammatic numerically. fashionable computers have billions or maybe trillions of bytes of memory.
The processor contains a special set of memory cells referred to as registers which will be browse and written to rather more apace than the most memory space. There ar generally between 2 and 100 registers reckoning on the kind of processor. Registers ar used for the foremost often required knowledge things to avoid having to access main memory whenever knowledge is required. As knowledge is continually being worked on, reducing the requirement to access main memory (which is commonly slow compared to the ALU and management units) greatly will increase the computer's speed.
Computer main memory comes in 2 principal varieties: random-access memory or RAM and ROM or fixed storage. RAM will be browse and written to anytime the processor commands it, however fixed storage is pre-loaded with knowledge and software package that ne'er changes, thus the processor will solely browse from it. fixed storage is often accustomed store the computer's initial start-up directions. In general, the contents of RAM ar erased once the facility to the pc is turned off, however fixed storage retains its knowledge indefinitely. In a PC, the fixed storage contains a specialised program referred to as the BIOS that orchestrates loading {the pc|the pc}'s software package from the magnetic disk drive into RAM whenever the computer is turned on or reset. In embedded computers, which regularly don't have disk drives, all of the desired software package could also be hold on in fixed storage. software package hold on in fixed storage is commonly referred to as computer code, as a result of it's notionally a lot of like hardware than software package. non-volatile storage blurs the excellence between fixed storage and RAM, because it retains its knowledge once turned off however is additionally rewritable. it's generally abundant slower than typical fixed storage and RAM but, thus its use is restricted to applications wherever high speed is mindless.[42]
In a lot of refined computers there could also be one or more RAM cache reminiscences, that ar slower than registers however quicker than main memory. usually computers with this kind of cache ar designed to maneuver often required knowledge into the cache mechanically, typically while not the requirement for any intervention on the programmer's half.
Input/output (I/O)
Main article: Input/output
Hard disk drives ar common storage devices used with computers.
I/O is that the suggests that by that a pc exchanges info with the skin world.[43] Devices that offer input or output to the pc ar referred to as peripherals.[44] On a typical pc, peripherals embrace input devices just like the keyboard and mouse, and output devices like the show and printer. magnetic disk drives, diskette drives and memory device drives function each input and output devices. pc networking is another kind of I/O.
I/O devices ar typically advanced computers in their claim, with their own processor and memory. A graphics process unit may contain fifty or a lot of small computers that perform the calculations necessary to show 3D graphics[citation needed]. fashionable desktop computers contain several smaller computers that assist the most processor in playing I/O.
Multitasking
Main article: pc multitasking
While a pc could also be viewed as running one mammoth program hold on in its main memory, in some systems it's necessary to offer the looks of running many programs at the same time. this is often achieved by multitasking i.e. having the pc switch apace between running every program successively.[45]
One suggests that by that this is often done is with a special signal referred to as Associate in Nursing interrupt, which might sporadically cause the pc to prevent execution directions wherever it absolutely was and do one thing else instead. By memory wherever it absolutely was execution before the interrupt, the pc will come thereto task later. If many programs ar running "at an equivalent time", then the interrupt generator may well be inflicting many hundred interrupts per second, inflicting a program switch anytime. Since fashionable computers generally execute directions many orders of magnitude quicker than human perception, it should seem that a lot of programs ar running at an equivalent time although just one is ever execution in any given instant. This technique of multitasking is usually termed "time-sharing" since every program is allotted a "slice" of your time successively.[46]
Before the time of low-cost computers, the principal use for multitasking was to permit many of us to share an equivalent pc.
Seemingly, multitasking would cause a pc that's switch between many programs to run a lot of slowly, in direct proportion to the quantity of programs it's running, however most programs pay abundant of their time looking forward to slow input/output devices to finish their tasks. If a program is looking forward to the user to click on the mouse or press a key on the keyboard, then it'll not take a "time slice" till the event it's looking forward to has occurred. This frees up time for different programs to execute so several programs could also be run at the same time while not unacceptable speed loss.
Multiprocessing
Main article: parallel processing
Cray designed several supercomputers that used parallel processing heavily.
Some computers ar designed to distribute their work across many CPUs in a very parallel processing configuration, a method once utilized solely in giant and powerful machines like supercomputers, mainframe computers and servers. digital computer and multi-core (multiple CPUs on one integrated circuit) personal and portable computer computers ar currently wide on the market, and ar being more and more utilized in lower-end markets as a result.
Supercomputers above all typically have extremely distinctive designs that dissent considerably from the fundamental stored-program architecture and from general purpose computers.[47] They typically feature thousands of CPUs, made-to-order high-speed interconnects, and specialised computing hardware. Such styles tend to be helpful just for specialised tasks thanks to the big scale of program organization needed to with success utilize most of the on the market resources directly. Supercomputers typically see usage in large-scale simulation, graphics rendering, and cryptography applications, additionally like different supposed "embarrassingly parallel" tasks.
Networking and also the net
Main articles: pc networking and net
Visualization of some of the routes on the web.
Computers are accustomed coordinate info between multiple locations since the Fifties. The U.S. military's SAGE system was the primary large-scale example of such a system, that crystal rectifier to variety of special-purpose industrial systems like Sabre.[48]
In the Seventies, pc engineers at analysis establishments throughout the us began to link their computers along exploitation telecommunications technology. the trouble was funded by ARPA (now DARPA), and also the electronic network that resulted was referred to as the ARPANET.[49] The technologies that created the Arpanet attainable unfold and evolved.
In time, the network unfold on the far side educational and military establishments and have become referred to as the web. The emergence of networking concerned a definition of the character and bounds of the pc. pc operational systems and applications were changed to incorporate the power to outline and access the resources of different computers on the network, like peripheral devices, hold on info, and also the like, as extensions of the resources of a personal pc. ab initio these facilities were on the market primarily to individuals operating in hi-tech environments, however within the Nineteen Nineties the unfold of applications like e-mail and also the World Wide internet, combined with the event of low-cost, quick networking technologies like local area network and ADSL saw pc networking become virtually omnipresent. In fact, the quantity of computers that ar networked is growing phenomenally. a really giant proportion of private computers often hook up with the web to speak and receive info. "Wireless" networking, typically utilizing portable networks, has meant networking is turning into more and more omnipresent even in mobile computing environments.
Hardware
See also: History of computing hardware
The term hardware covers all of these components of a pc that ar tangible objects. Circuits, displays, power provides, cables, keyboards, printers and mice ar all hardware.
Hardware
First Generation (Mechanical/Electromechanical) Calculators Antikythera mechanism, distinction engine, Norden sight
Programmable Devices Jacquard loom, Analytical engine, Harvard Mark I, Z3
Second Generation (Vacuum Tubes) Calculators Atanasoff–Berry pc, IBM 604, UNIVAC 60, UNIVAC 120
Programmable Devices
Colossus, ENIAC, Manchester Small-Scale Experimental Machine, EDSAC, Manchester Mark one, Ferranti Pegasus, Ferranti Mercury, CSIRAC, EDVAC, UNIVAC I, IBM 701, IBM 702, IBM 650, Z22
Third Generation (Discrete transistors and SSI, MSI, LSI Integrated circuits)
Mainframes
IBM 7090, IBM 7080, IBM System/360, BUNCH
Minicomputer
PDP-8, PDP-11, IBM System/32, IBM System/36
Fourth Generation (VLSI integrated circuits) Minicomputer VAX, IBM System i
4-bit PC
Intel 4004, Intel 4040
8-bit PC
Intel 8008, Intel 8080, Motorola 6800, Motorola 6809, MOS Technology 6502, Zilog Z80
16-bit PC
Intel 8088, Zilog Z8000, WDC 65816/65802
32-bit PC
Intel 80386, Pentium, Motorola 68000, ARM design
64-bit microcomputer[52]
Alpha, MIPS, PA-RISC, PowerPC, SPARC, x86-64
Embedded pc
Intel 8048, Intel 8051
Personal pc
Desktop pc, information processing system, laptop computer, Personal digital assistant (PDA), personal computer, Tablet PC, wearable pc
Theoretical/experimental Quantum pc, Chemical pc, desoxyribonucleic acid computing, Optical pc, Spintronics primarily based pc
Other Hardware Topics
Peripheral device (Input/output)
Input Mouse, Keyboard, Joystick, scanner, Webcam, Graphics pill, Microphone
Output Monitor, Printer, speaker system
Both Floppy Winchester drive, magnetic disk drive, memory device drive, character printer
Computer busses
Short range RS-232, SCSI, PCI, USB
Long vary (Computer networking)
Ethernet, ATM, FDDI
Software
Main article: pc software package
Software refers to components of the pc that don't have a cloth kind, like programs, data, protocols, etc. once software package is hold on in hardware that can't simply be changed (such as BIOS fixed storage in Associate in Nursing IBM laptop compatible), it's generally referred to as "firmware" to point that it falls into Associate in Nursing unsure space somewhere between hardware and software package.
Computer software package
Operating system
Unix and BSD
UNIX System V, IBM AIX, HP-UX, Solaris (SunOS), IRIX, List of BSD operational systems
GNU/Linux
List of Linux distributions, Comparison of Linux distributions
Microsoft Windows
Windows 95, Windows 98, Windows NT, Windows 2000, Windows Me, Windows XP, Windows view, Windows 7
DOS
86-DOS (QDOS), PC-DOS, MS-DOS, DR-DOS, FreeDOS
Mac OS
Mac OS classic, Mac OS X
Embedded and time period
List of embedded operational systems
Experimental Amoeba, Oberon/Bluebottle, set up nine from Bell Labs
Library
Multimedia
DirectX, OpenGL, OpenAL
Programming library C customary library, customary templet Library
Data
Protocol
TCP/IP, Kermit, FTP, HTTP, SMTP
File format
HTML, XML, JPEG, MPEG, PNG
User interface
Graphical program (WIMP)
Microsoft Windows, GNOME, KDE, QNX Photon, CDE, GEM, Aqua
Text-based program
Command-line interface, Text program
Application
Office suite
Word process, publishing, Presentation program, direction system, programming & Time management, program, Accounting software package
net Access
Browser, E-mail consumer, Web server, Mail agency, Instant electronic messaging
style and manufacturing Computer-aided style, Computer-aided producing, Plant management, Robotic producing, provide chain management
Graphics
Raster graphics editor, Vector graphics editor, 3D modeler, Animation editor, 3D lighting tricks, Video piece of writing, Image process
Audio
Digital audio editor, Audio playback, Mixing, Audio synthesis, pc music
software package engineering
Compiler, Assembler, Interpreter, Debugger, Text editor, Integrated development surroundings, software package performance analysis, Revision management, software package configuration management
Educational Edutainment, instructional game, Serious game, trainer
Games
Strategy, Arcade, Puzzle, Simulation, First-person shooter, Platform, Massively multiplayer, Interactive fiction
Misc Artificial intelligence, Antivirus software package, Malware scanner, Installer/Package management systems, File manager
Languages
There ar thousands of various programming languages—some supposed to be general purpose, others helpful just for extremely specialised applications.
Programming languages
Lists of programming languages Timeline of programming languages, List of programming languages by class, people list of programming languages, List of programming languages, Non-English-based programming languages
Commonly used Assembly languages
ARM, MIPS, x86
Commonly used high-level programming languages
Ada, BASIC, C, C++, C#, COBOL, Fortran, Java, Lisp, Pascal, Object Pascal
Commonly used Scripting languages
Bourne script, JavaScript, Python, Ruby, PHP, Perl
Professions and organizations
As the use of computers has unfold throughout society, there ar Associate in Nursing increasing variety of careers involving computers.
Computer-related professions
Hardware-related Electrical engineering, Electronic engineering, pc engineering, Telecommunications engineering, Optical engineering, Nanoengineering
Software-related Computer science, publishing, Human–computer interaction, info technology, info systems, procedure science, software package engineering, computer game trade, Web design
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