System

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A computer system is an integrated form of different components that work together to give a desirable result. It has different component and each works for a specific purpose; however, they generate a common result as required by the user.

Components of Computer System

Let us now understand the following basic components of a computer system.

• Hardware
• Software
• Humanware
• Firmware
• Bridgeware

Hardware

The physical components collectively form the hardware of a computer system. Hardware comprises of the equipment that helps in the working system of the computer.

Following are the different types of hardware components (which have specific functions) −

• Monitor − It displays (visual) the result.

• CPU − It is the Central Processing Unit that controls the computer’s functions and transmits data.

• Motherboard − It is mainly accountable to establish communication between components and transmission of information.

• RAM − It is the Random Access Memory and responsible for the storage of programs that are currently running and also stores data temporarily.

• Hard Disk Drive − It is a permanent memory storage device.

• Floppy Disk Drive − It is hardly being used in recent times.

• Optical disks − It is a device that also store data. For example, CD, DVD, etc.

Input & Output Device

The following table categorically lists down the input and output device −

Input Device	Output Device	Input Device	Output Device
Mouse	Monitor	Microphone	Speaker
Keyboard	Printer	Camera	Earphone
Scanner	Projector	Trackball	Monitor
Touchpad	Plotter	Joystick	Monitor

Software

The hardware components can only function when software components are added to the computer system. Software is a program that performs different commands given by a user.

Software is an intangible part of hardware and controls the sequence of operations.

Types of Software

Depending on the basic features and functionality, software can be categorized as −

• Operating Systems (OS)
• Application Software (AS)
• E-accessibility Software

Let us now discuss the software components in brief.

Operating System

This software helps to load the basic program automatically as soon as the computer is started. Following are the major types of operating system −

Operating Software	Examples
Microsoft Windows	XP, Vista, etc.
Mac OS X	Panther, Cheetah, Snow leopard, etc.
Linux	Debian, Ubuntu, Fedora, Knoppix, etc.

Application Software

The software, which can be used on an installed operating system, is known as application software. Following are the significant examples of application software −

Application Software	Examples
Office programs	Microsoft Office, OpenOffice, LibreOffice, etc.
Web browser	Internet Explorer, Mozilla Firefox, Google Chrome, Opera, Safari, etc.
Antivirus Program	Norton, McAfee, Quick Heal, Avira, Kaspersky, etc.

E-accessibility Software

The E-accessibility software components additional facilities to users such as −

• Voice recognition software
• Screen reader
• Magnifying tool
• On-screen keyboard
• Video games
• Learning software, etc.

Role of Computer in Today’s World

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In today’s world, for almost every activity whether personal (for example, operating personal savings bank account) or business-related (for example, selling any product or services); in some or the other way, we rely on the computer system.

Due to the growing dependency on computers, every small and big organizations and other business companies have started offering computer-based service. Furthermore, the advancement of communications, electronic service networks, and multimedia have opened a new door for corporates by providing an effective way of business processing, payment transfer, and service delivery.

Advantages of Computers in Business

Following are the major advantages of introducing computer system in business −

Independency

As computers help in making the business automated, the businesses are becoming more and more independent. No more, there is the need to put man-power for every work, as with the help of computer most of the works can be automated. Starting from ticket booking to a luxury car manufacturing, everything is automated.

Cost Cutting

A number of business are based online in recent times; therefore, there is no need to open business branch in every city, rather having one centralized inventory can make the business easier. There is no need to employ many man-power.

Marketing

With the use of computer system with Internet facility, it is very simple to make a business global in a given period of time. Website, email, social media websites, online advertisements, etc. are the important tools of online marketing.

Huge Transaction Capacity

A number of tasks are being done by computer including ticket booking to money transactions; this increases the transaction capacity.

Huge Storage Capacity

Normally, most of the businesses need to store and maintain huge data and other records; manually, it is very difficult to maintain, but the use of computer not only increases the storage capacity, but also facilitates the processing and retrieval of data anytime.

Improvement of Productivity & Efficiency

As most of the tasks in almost every industry has become automated, it has now become much easier to manufacture a huge bulk of products in very less time. Through computer technology, services also became faster and easier.

High Accuracy

There is hardly any scope of errors in an automated system; however, if any error occurs, it is largely a human error.

Ease of Data Sharing

Data sharing has now become very simple just the way it is simple to link one computer system to another.

Competition

The applicability of computer technology has increased competition; now, the customers can avail support 24x7.

Enhanced the Security System

Computer also helps keep the data of businesses secure. However, this security can face threats too. For instance, if someone hacks the system or there is a virus attack, it can have the potential to damage all the data that is secured.

Fundamental Concept

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A computer is basically a programmable machine capable to perform arithmetic and logical operations automatically and sequentially. It is also known as a data processor, as it can store, process, and retrieve data as per the wish of the user.

Data processing involves the following three activities −

• Input of data
• Manipulation/processing of data
• Giving output (i.e. management of output result)
• In computer system, data is arranged orderly and systematically.

The term “computer” is derived from a Latin term “compute,” which means ‘to calculate.’ Initially, the computer system had been designed to calculate; it was intended to be a computing device. However, over a period of time, this device technically advanced; at present, it can perform a wide range of desirable works apart from data processing.

Major Functions of Computer System

Following are the core functions of a computer system −

• A computer accepts the command and/or data as input given by the user.

• A computer follows the instructions and stores the data given by the user.

• A computer processes the data as per the instructions given by the user.

• A computer gives the desirable results in the form of output.

Salient Features of Computer System

Following are the salient features of a Computer System −

• Automation − The operating system of a computer system is automatic, as no human intervention is required; simply you need to give the command and then it will do the work automatically.

• Speed − Depending upon the power of the computer, it can perform, it can take Millions of instructions per second.

• Storage − A computer system can store enormous quantity of data in different format. The storage capacity of a computer system is normally expressed in terms of Kilobytes (KB), Megabytes (MB), Gigabytes (GB), or Terabytes (TB).

• Accuracy − The accuracy of a computer system is very high.

• Versatility − A computer system is capable of performing a wide range of tasks.

• Diligence − A computer neither get tired nor lose concentration.

• Reliability − As a computer system always gives accurate result; therefore, its reliability is very high.

• Vast memory − A computer system can have a wide range of memory which can recall the desired data at any point of time.

Evolution of Computer System

The present Computer System has evolved after centuries of efforts from different intellectuals who contributed their works during different periods of time.

Abacus is (most likely) considered as the earlier counting device.

Let us now read about the innovators who contributed immensely in the development of a computer system.

John Napier

Napier was a Scottish mathematician who invented logarithms.

Further, Napier also invented a computing device, which consisted of sticks with numbers imprinted on them. Napier named sticks ‘bones,’ as they were made up of bones.

Blaise Pascal

Pascal was a French mathematician who invented a machine based on gear wheels, which helped greatly in calculation.

Charles Babbage

Babbage was an English Polymath, Mathematician, Mechanical Engineer, Philosopher, and Inventor. In 1822, he developed a machine capable to calculate the successive difference of expression and prepared a table which helped him in his calculations.

Lady Ada Lovelace

Lovelace was an English mathematician, who researched on Babbage’s work. She has given the concept that ‘computers can be programmed’. Her work helped a great deal in the advancement of computer system.

John Atanstoff

With the assistance of Berry, John Atanstoff developed the Atanstoff Berry Computer (more popular as ABC) in 1937. It marked the beginning of the development of electronic digital computer.

John Mauchly and Eckart

In 1947, John Mauchly and Eckart developed the first large scale Electronic Digital Computer. It was called the Electronic Numerical Integrator and Calculator (ENIAC).

Maurice V. Wilkes

In 1949, Wilkes (at Cambridge University) designed Electronic Delay Storage Automatic Calculator (EDSAC). It was the first computer that started its operating system on the stored program concept.

Input/Output Ports

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A connection point that acts as interface between the computer and external devices like mouse, printer, modem, etc. is called port. Ports are of two types −

• Internal port − It connects the motherboard to internal devices like hard disk drive, CD drive, internal modem, etc.

• External port − It connects the motherboard to external devices like modem, mouse, printer, flash drives, etc.

Let us look at some of the most commonly used ports.

Serial Port

Serial ports transmit data sequentially one bit at a time. So they need only one wire to transmit 8 bits. However it also makes them slower. Serial ports are usually 9-pin or 25-pin male connectors. They are also known as COM (communication) ports or RS323C ports.

Parallel Port

Parallel ports can send or receive 8 bits or 1 byte at a time. Parallel ports come in form of 25-pin female pins and are used to connect printer, scanner, external hard disk drive, etc.

USB Port

USB stands for Universal Serial Bus. It is the industry standard for short distance digital data connection. USB port is a standardized port to connect a variety of devices like printer, camera, keyboard, speaker, etc.

PS-2 Port

PS/2 stands for Personal System/2. It is a female 6-pin port standard that connects to the male mini-DIN cable. PS/2 was introduced by IBM to connect mouse and keyboard to personal computers. This port is now mostly obsolete, though some systems compatible with IBM may have this port.

Infrared Port

Infrared port is a port that enables wireless exchange of data within a radius of 10m. Two devices that have infrared ports are placed facing each other so that beams of infrared lights can be used to share data.

Bluetooth Port

Bluetooth is a telecommunication specification that facilitates wireless connection between phones, computers and other digital devices over short range wireless connection. Bluetooth port enables synchronization between Bluetooth-enabled devices. There are two types of Bluetooth ports −

• Incoming − It is used to receive connection from Bluetooth devices.

• Outgoing − It is used to request connection to other Bluetooth devices.

FireWire Port

FireWire is Apple Computer’s interface standard for enabling high speed communication using serial bus. It is also called IEEE 1394 and used mostly for audio and video devices like digital camcorders.

Secondary Memory

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You know that processor memory, also known as primary memory, is expensive as well as limited. The faster primary memory are also volatile. If we need to store large amount of data or programs permanently, we need a cheaper and permanent memory. Such memory is called secondary memory. Here we will discuss secondary memory devices that can be used to store large amount of data, audio, video and multimedia files.

Characteristics of Secondary Memory

These are some characteristics of secondary memory, which distinguish it from primary memory −

• It is non-volatile, i.e. it retains data when power is switched off
• It is large capacities to the tune of terabytes
• It is cheaper as compared to primary memory

Depending on whether secondary memory device is part of CPU or not, there are two types of secondary memory – fixed and removable.

Let us look at some of the secondary memory devices available.

Hard Disk Drive

Hard disk drive is made up of a series of circular disks called plattersarranged one over the other almost ½ inches apart around a spindle. Disks are made of non-magnetic material like aluminum alloy and coated with 10-20 nm of magnetic material.

Standard diameter of these disks is 14 inches and they rotate with speeds varying from 4200 rpm (rotations per minute) for personal computers to 15000 rpm for servers. Data is stored by magnetizing or demagnetizing the magnetic coating. A magnetic reader arm is used to read data from and write data to the disks. A typical modern HDD has capacity in terabytes (TB).

CD Drive

CD stands for Compact Disk. CDs are circular disks that use optical rays, usually lasers, to read and write data. They are very cheap as you can get 700 MB of storage space for less than a dollar. CDs are inserted in CD drives built into CPU cabinet. They are portable as you can eject the drive, remove the CD and carry it with you. There are three types of CDs −

• CD-ROM (Compact Disk – Read Only Memory) − The data on these CDs are recorded by the manufacturer. Proprietary Software, audio or video are released on CD-ROMs.

• CD-R (Compact Disk – Recordable) − Data can be written by the user once on the CD-R. It cannot be deleted or modified later.

• CD-RW (Compact Disk – Rewritable) − Data can be written and deleted on these optical disks again and again.

DVD Drive

DVD stands for Digital Video Display. DVD are optical devices that can store 15 times the data held by CDs. They are usually used to store rich multimedia files that need high storage capacity. DVDs also come in three varieties – read only, recordable and rewritable.

Pen Drive

Pen drive is a portable memory device that uses solid state memory rather than magnetic fields or lasers to record data. It uses a technology similar to RAM, except that it is nonvolatile. It is also called USB drive, key drive or flash memory.

Blu Ray Disk

Blu Ray Disk (BD) is an optical storage media used to store high definition (HD) video and other multimedia filed. BD uses shorter wavelength laser as compared to CD/DVD. This enables writing arm to focus more tightly on the disk and hence pack in more data. BDs can store up to 128 GB data.

Primary Memory

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Memory is required in computers to store data and instructions. Memory is physically organized as a large number of cells that are capable of storing one bit each. Logically they are organized as groups of bits called words that are assigned an address. Data and instructions are accessed through these memory address. The speed with which these memory addresses can be accessed determines the cost of the memory. Faster the memory speed, higher the price.

Computer memory can be said to be organized in a hierarchical way where memory with the fastest access speeds and highest costs lies at the top whereas those with lowest speeds and hence lowest costs lie at the bottom. Based on this criteria memory is of two types – primary and secondary. Here we will look at primary memory in detail.

The main features of primary memory, which distinguish it from secondary memory are −

• It is accessed directly by the processor
• It is the fastest memory available
• Each word is stored as well as
• It is volatile, i.e. its contents are lost once power is switched off

As primary memory is expensive, technologies are developed to optimize its use. These are broad types of primary memory available.

RAM

RAM stands for Random Access Memory. The processor accesses all memory addresses directly, irrespective of word length, making storage and retrieval fast. RAM is the fastest memory available and hence most expensive. These two factors imply that RAM is available in very small quantities of up to 1GB. RAM is volatile but my be of any of these two types

DRAM (Dynamic RAM)

Each memory cell in a DRAM is made of one transistor and one capacitor, which store one bit of data. However, this cell starts losing its charge and hence data stored in less than thousandth of a second. So it needs to be refreshed thousand times a second, which takes up processor time. However, due to small size of each cell, one DRAM can have large number of cells. Primary memory of most of the personal computers is made of DRAM.

SRAM (SRAM)

Each cell in SRAM is made of a flip flop that stores one bit. It retains its bit till the power supply is on and doesn’t need to be refreshed like DRAM. It also has shorter read-write cycles as compared to DRAM. SRAM is used in specialized applications.

ROM

ROM stands for Read Only Memory. As the name suggests, ROM can only be read by the processor. New data cannot be written into ROM. Data to be stored into ROM is written during the manufacturing phase itself. They contain data that does not need to be altered, like booting sequence of a computer or algorithmic tables for mathematical applications. ROM is slower and hence cheaper than RAM. It retains its data even when power is switched off, i.e. it is non-volatile. ROM cannot be altered the way RAM can be but technologies are available to program these types of ROMs −

PROM (Programmable ROM)

PROM can be programmed using a special hardware device called PROM programmer or PROM burner.

EPROM (Erasable Programmable ROM)

EPROM can be erased and then programmed using special electrical signals or UV rays. EPROMs that can be erased using UV rays are called UVEPROM and those that can be erased using electrical signals are called EEPROM. However, handling electric signals is easier and safer than UV rays.

Cache Memory

Small piece of high speed volatile memory available to the processor for fast processing is called cache memory. Cache may be a reserved portion of main memory, another chip on CPU or an independent high speed storage device. Cache memory is made of fast speed SRAMs. The process of keeping some data and instructions in cache memory for faster access is called caching. Caching is done when a set of data or instructions is accesses again and again.

Whenever the processor needs any piece of data or instructions, it checks the cache first. If it is unavailable there, then the main memory and finally secondary memory is accessed. As cache has very high speed, time spent in accessing it every time is negligible as compared to time saved if data indeed is in the cache. Finding data or instruction in cache is called cache hit.

Evaluation of Microprocessor

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The first microprocessor introduced in 1971 was a 4-bit microprocessor with 4m5KB memory and had a set of 45 instructions. In the past 5 decades microprocessor speed has doubled every two years, as predicted by Gordon Moore, Intel co-founder. Current microprocessors can access 64 GB memory. Depending on width of data microprocessors can process, they are of these categories−

• 8-bit
• 16-bit
• 32-bit
• 64-bit

Size of instruction set is another important consideration while categorizing microprocessors. Initially, microprocessors had very small instructions sets because complex hardware was expensive as well as difficult to build.

As technology developed to overcome these issues, more and more complex instructions were added to increase functionality of the microprocessor. However, soon it was realized that having large instruction sets was counterproductive as many instructions that were rarely used sat idle on precious memory space. So the old school of thought that supported smaller instruction sets gained popularity.

Let us learn more about the two types of microprocessors based on their instruction set.

RISC

RISC stands for Reduced Instruction Set Computers. It has a small set of highly optimized instructions. Complex instruction are also implemented using simpler instructions, reducing the size of instruction set. The designing philosophy for RISC incorporates these salient points −

• Number of instructions should be minimum.
• Instructions should be of same length.
• Simple addressing modes should be used
• Reduce memory references to retrieve operands by adding registers

Some of the techniques used by RISC architecture include −

• Pipelining− A sequence of instructions is fetched even if it means overlapping of instructions in fetching and execution.

• Single cycle execution − Most of RISC instructions take one CPU cycle to execute.

Examples of RISC processors are Intel P6, Pentium4, AMD K6 and K7, etc.

CISC

CISC stands for Complex Instruction Set Computers. It supports hundreds of instructions. Computers supporting CISC can accomplish wide variety of tasks, making them ideal for personal computers. These are some characteristics of CISC architecture −

• Larger set of instructions
• Instructions are of variable length
• Complex addressing modes
• Instructions take more than one clock cycle
• Work well with simpler compilers

Examples of CISC processors are Intel 386 & 486, Pentium, Pentium II and III, Motorola 68000, etc.

EPIC

EPIC stands for Explicitly Parallel Instruction Computing. It is a computer architecture that is a cross between RISC and CISC, trying to provide the best of both. Its important features include −

• Parallel instructions rather than fixed width
• Mechanism to communication compiler’s execution plan to hardware
• Programs must have sequential semantics

Some EPIC processors are Intel IA-64, Itanium, etc.