System Concept : Data And Clock Speed Measurement

Data Measurement

KILOBYTE (KB)

In mathematics, 1 KB = 1000 bytes.

In computer, 1 KB = 1024 bytes or can be said as:

1 KB = 2¹⁰ bytes

This is how we get the calculation for 1024 bytes.

MEGABYTE (MB)

1 MB = 1 048 576 bytes or it can be said as:

1 MB = 2²⁰ bytes

GIGABYTE (GB)

1 GB = 1 073 741 824 bytes or it can be said as:

1 GB = 2³⁰ bytes

TERABYTE (TB)

1 TB = 1 099 511 627 776 bytes or it can be said as:

1 TB = 2⁴⁰ bytes


Clock Speed Measurement

HERTZ AND SECONDS

The clock speed unit is measured in hertz. A hertz is one cycle per second.

MEGAHERTZ (MHz)

Mega is a prefix that stands for million. Thus, megahertz (MHz) equals to one million cycles of the system clock. A computer that operates at 933 MHz (megahertz) has 933 million clock cycles in one second.

GIGAHERTZ (GHz)

Giga is a prefix that stands for billion.Gigahertz (GHz) equals to one billion cycles of the system clock.In relation with megahertz,1.0 GHz is equivalent to 1000 MHz.

For example, a microprocessor that runs at 200 GHz executes 200 billion cycles per second. This is what they are talking about if they say a computer is a 2.4 GHz machine. Its clock rate is 2.4 billion cycles per second.

GHz is most often used as a measurement of a PC processor chip and power, with bigger numbers meaning more speed and higher price.

PROCESSING SPEED

The system clock is one of the major factors that influence the computer speed. A CPU with a higher clock speed can process more instructions per second than a CPU with a lower clock speed. For example, a  1 GHz CPU is faster than a CPU operating at 800 MHz. The speed of the system clock affects only the CPU. It has no effect on peripherals such as a printer or disk drive.

MICROPROCESSOR SPEED

One way of comparing the performance of personal computers is by comparing their microprocessor speeds. Microprocessor speeds are determined by their clock speed and are usually expressed in gigahertz (GHz),  billion of machine cycles per second.

For example, a personal computer that is listed at 2.2 GHz has a processor capable of handling 2.2 billion machine cycles per second. A top speed personal computer can be much faster, with newer ones exceeding 3.0 GHz.

Direct comparison of clock is meaningful between identical microprocessor.

Thus, it is accurate to say that a Pentium 4 running at 2.4 GHz is approximately one-third faster than a Pentium 4 running at 1.8 GHz.

SPEED AND PATH

The combination of speed and number of paths determines the total processing speed or channel bandwidth. This is because different processors

often use different architectures. For this reason, a 1.4 GHz Pentium 4 performs better than a 1.4 GHz Pentium 3, but it is not as fast as a 1.4 GHz Power PC G4 processor.

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 Others Lesson : | click lesson to view |

• Overview Of Computer System
• Information Processing Cycle
• Data Representation
• Data and Clock Speed Measurement

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System Concept : Data Representation

BINARY DIGIT

Computers recognize only two discrete states: on and off. These states can be represented by two digits, 0 and 1. Each 0 or 1 is called a bit in the binary system.

Bit is the  smallest unit of data a computer can process. Bit is a short for binary digit. The binary system has a base of 2 with the two digits (0 and 1). Combinations of 0s and 1s represent larger numbers.

BIT

A bit is the smallest unit of data that the computer can process. Bit is a short for binary digit. A bit is represented by the numbers 1 and 0. These numbers represent the binary system. They correspond to the states of on and off, true and false, or yes and no.

All digital data use the binary system to process the information. This information include letters, digits or special character.

BYTE

Byte is a unit of information built from bits. One byte is equals to 8 bits. Eight bits that are grouped together as a unit. A byte provides enough different combinations of 0s and 1s to represent 256 individual characters.

One byte represents a single character such as the number 3, letter b

or a $ symbol. Bits and bytes are the basis for representing all meaningful information and programs on computers.

Character

8 bits = 1 byte

One byte represents one character such as A, 7, 9 and +.Eight bits that are grouped together as a unit. A byte provides enough different combinations of 0s and 1s to represent 256 individual characters.

For example, the capital letter F is represented by the binary code 01000110 that can be understood by the computer system. Eight bits grouped together as a unit are called a byte. A byte represents a single character in the

computer.

CHARACTER CODES

There are three character codes to represent characters which are ASCII, EBCDIC and Unicode. Each byte contains eight bits. A byte provides enough different combination of 0s and 1s to represent 256 characters.

The combinations of 0s and 1s are defined by patterns. These patterns are called coding scheme. The 256-character capability of ASCII and EBCDIC is too small to handle the characters that are used by other languages such as

Arabic, Japanese and Chinese.

The Unicode coding scheme is designed to solve this problem. It uses two bytes (16 bits) to represent one character. Unicode will have more than 65,000 different characters. This can

cover all the world’s languages.

WHAT IS ASCII ?

ASCII pronounced as "ask-key" stands for the American Standard Code for Information Interchange and was proposed by ASA (American Standard Association) in 963 and was finalised in 1968.ASCII is a standard of 7-bit code used to represent characters, which include letters, numbers and punctuation marks.

7 bits allow the computer to encode a total of 128 characters for the numbers 0-9, uppercase and lowercase letters A-Z and a few punctuation symbols. However this 128 bit  code only suitable for english language speaking users.

IBM and Apple expanded the amount of space reserved for the character codes to 8-bits, equivalent to 1 byte.

FUNCTIONS OF ASCII

ASCII was established to achieve compatibility between various types of data processing equipment making it possible for the components to communicate with each other successfully.

ASCII enables manufacturers to produce components that are assured to operate correctly in a computer.

ASCII makes it possible for humans to interact with a computer. It also enables users to purchase components that are compatible with their computer configurations.

HOW ASCII WORKS IN A COMPUTER SYSTEM?

When you press a key, for example the letter D on your keyboard, the electronic signal is sent to the CPU for the computer to process and store in memory. Every character is converted to its corresponding binary form. The computer the processes the letter as a byte., which actually a series of on and off of electrical states. When the computer is finished processing the byte, the software installed in the system convert the byte back which is then displayed in the screen.  In this example, the letter D is converted to 01000100.

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 Others Lesson : | click lesson to view |

• Overview Of Computer System
• Information Processing Cycle
• Data Representation
• Data and Clock Speed Measurement

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System Concept : Information Processing Cycle

COMPUTER HARDWARE BLOCK DIAGRAM

An Input device feed raw data to the processor. A processor processes raw data and turns it into useful information. A storage device keeps or stores both process and unprocess data for later usage.  An output device shows or display the processed data.

INPUT DEVICES

When data is entered into the computer system, it is called an input. Input comes in various forms; texts, graphics, audio and video. Input devices are needed to input data into the computer system.

Keyboard, mouse, scanner, barcode reader and digital camera are some example of input devices.

Input is any data or instructions that we enter into the computer system for processing.

There are some common ways of feeding input data into the system, which are:

   •   typing on a keyboard

   •   pointing with a mouse

CPU accepts instruction from the user and translates the instruction into readable information (decode).

OUTPUT DEVICES

 Output is the result of raw input data that has been processed by the central processing unit into meaningful information. Common forms of output are texts, numbers, graphics, sounds, animations and videos.The most common output devices are computer screens, speakers and printers.

Output is data that has been processed into a useful form, called information. There are four types of output, which are texts, graphics, audio and video.

The text consists of characters that are used to create texts, sentences and paragraphs.

Graphics are digital representations of non text information such as drawings, charts and photographs.

Audio is music, speech or any other sound. Video consists of images that

provide the appearance of full motion.

STORAGE DEVICES

The system’s primary storage, Random Access Memory (RAM) can only hold data temporarily. Thus, secondary storage is needed to provide additional storage. The data stored in the secondary storage is considered permanent until it is deleted or removed.

Secondary storage can be magnetic disks and optical disks. Examples of secondary storage are hard disks, rewritable CDs and DVDs as well as removable disks such as pen drives.

Storage is a location which data, instruction and information are held for future use. Every computer uses storage to hold system software and application software.

When we issue a command to start the application software, the operating system locates the program in storage and loads it into memory.

A storage medium, also called secondary storage is the physical material in the computer that keeps data, instruction and information.

A storage device is the computer hardware that records or retrieves items to and from storage media.

THE CENTRAL PROCESSING UNIT

The central processing unit or the CPU is the brain of the computer.

All processing activities are done in the CPU. It utilises the computer memory to execute instructions from the application software and accomplish a task. For example: editing a letter, drawing a picture and sorting numbers. The processor must be connected to input devices, output devices and storage devices to carry out the above mentioned tasks.

 The processing unit controls all activities within the system. For every instruction, the control unit repeats a set of four basic operations called the machine cycle: 

 

Fetching

the process of obtaining a program instructions or data item from memory.

Decoding

the process of translating a program instruction into signals that the computer can execute.

Executing

the process of implementing the instructions in a program.

Storing

the process of writing the result to the storage or memory.

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 Others Lesson : | click lesson to view |

• Overview Of Computer System
• Information Processing Cycle
• Data Representation
• Data and Clock Speed Measurement

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System Concept : Overview Of Computer System

Computer System

A computer system is defined as combination of components designed to process data and store files. A computer system consists of four major hardware components; input devices, output devices, processor and storage devices.

A computer system requires hardware, software and a user to fully function.

Software refers to set of instructions that tell the hardware what to do. Software can also have various other functions such as performing computation, communication with other software and human interaction.

User refers to a person who uses the computer for any purposes such as work, business and entertainment.

Computer Hardware

Computer hardware consists of:

input devices

processor

output devices

storage devices

Input Devices

 

Input devices feed data or commands in a form that the computer can use. Example of input devices are:

• Keyboard
• Light Pen
• Joystick
• Microphone
• Mouse
• Video
• Digital camera.

Processor

 

The CPU is an example of a processor. It has the same important as the brain to human being.

Output Devices

Output devices such as the monitor shows people the process data or information. This type of information can be understood and use by computer user. Other example of output devices are:

• Printer
• Plotter
• Speaker

Storage Devices

Storage usually means secondary storage. It consists secondary storage devices such as hardisk, Floppy Disk, diskette, CD ROM and DVD ROM.

Software

There a 2 types of computer software, system software and application software. System software is any computer software that helps to run computer system. System software controls, integrate and manages the individual component of a computer system.

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 Others Lesson : | click lesson to view |

• Overview Of Computer System
• Information Processing Cycle
• Data Representation
• Data and Clock Speed Measurement

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Software Requirement : Cliect Software

FUNCTIONS OF WEB BROWSER

A web browser is a software application that enables a user to display and interact with HTML documents hosted by web servers or held in a file system. Text and images on a web page can contain hyperlinks to other web pages at the same or to different websites.

Web browser allow a user to quickly and easily access information provided on many web pages at many websites by surfing these links.

Web browsers available for personal computer include Microsoft Internet Explorer, Safari, Netscape and Opera.Web browsers are the most commonly used type of Hypertext Transfer Protocol (HTTP) user agent.

Although browsers are typically used to access the World Wide Web, they can also be used to access information provided by web servers in private networks or content in file systems.

FUNCTIONS OF EMAIL CLIENT

An email client is a computer program that is used to read and send email.

FUNCTIONS OF FILE TRANSFER PROTOCOL (FTP)

File Transfer Protocol (FTP) is used to connect two computers over the Internet so that the user of one computer can transfer files and perform file commands on the other computer.

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• Server Software
• Client Software

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Sofware Requirement : Server Software

Software such as Windows Server 2003, Windows NT and Red Hat Linux are some of the examples of server software. All of these software fall under the Network Operating System.

DEFINITION OF NETWORK OPERATING SYSTEMS

An operating system is the program that first loads when a computer boots and manages any other software or hardware on the computer.

A Network Operating System or known as NOS, has additional functionality that allows it to connect computers and peripherals to a network.

A Network Operating System is most frequently used with Local Area Networks and Wide Area Networks, but could also have application to larger network systems.

A NOS is not the same as the networking tools provided by some existing operating systems, Windows XP for instance.

NOS is an operating system that has been specifically written to keep networks running at optimal performance.

EXAMPLES OF NETWORK OPERATING SYSTEMS

Some popular Network Operating Systems include:

• Windows NT
• Windows 2000 Server
• Windows Server 2003
• Red Hat Linux

Windows NT is a family of operating systems produced by Microsoft, the first version of which was released in July 2003.

It was the first 23-bit version of Windows. Windows XP and Windows Server 2003 are the latest versions of Windows NT.

Windows 2000 (also referred to as Win2K or W2K) is graphical and business-oriented operating system. It is part of the Microsoft NT line of operating systems and was released on February 17, 2000.

Windows 2000 comes in four versions which are Professional, Server, Advanced Server and Datacenter Server.

Additionally, Microsoft offers Windows 2000 Advanced Server-Limited edition, which was released in 2001 and runs on 64-bit Intel Itanium Microprocessor.

Windows Server 2003 is the name of Microsoft’s line of server operating systems. It was introduced in April 2003 as the successor to Windows 2000 Server.

It is considered by Microsoft to be the cornerstone of their Windows Server System line of business server products.

Red Hat Linux was one of the most popular Linux distributions, assembled by Red Hat. It is one of the “middle-aged” Linux distributions; 1.0 was released in November 3^rd, 1994.

Since 2003, Red Hat has discontinued the Red Hat Linux line in favour of its new Red Hat Enterprise Linux.

Red Hat Linux 9, the final release, ended on April 30^th, 2004, although the Fedora Legacy project continues to publish updates.

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• Server Software
• Client Software

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Hardware Requirements : Transmission Medium

Transmission media can be divided into two broad categories.  

• Physical transmission media
• Wireless transmission media 

The twisted-pair cable, coaxial cable and fibre optic cable are examples of physical transmission media.

Wireless transmission medium or unguided medium is through air.

PHYSICAL TRANSMISSION MEDIUM

In physical transmission medium, waves are guided along a solid transmission medium. Wireless transmission medium waves are unguided and the transmission and reception are by means of antennas.

Twisted-Pair Cable 

    Two insulated copper wires that  are twisted around each other. Each connection on twisted-pair requires both wires.  

   The twisted-pair cable is generally a common form of transmission medium. It consists of two wires or conductors twisted together, each with its own plastic insulation. The twisted wires cancel out electromagnetic interference that can cause crosstalk , the noise generated by adjacent pairs

Coaxial Cable  

A cable consisting of a conducting outer metal tube that encloses and is insulated from a central conducting core, used primarily for the transmission of high-frequency signals

The coaxial cable, often referred to as ‘coax’, consists of a single copper wire surrounded by at least three layers.They are an insulating material, a woven or braided metal and a plastic outer coating.

This cable is often used as cable television (CATV) network wiring because it can be cabled over longer distances in comparison to the twisted-pair cable.

Fibre Optic Cable  

Glass fibre used for laser transmission of video, audio and/or data.

The fibre optic cable is a networking medium that uses light for data transmission.

The intensity of light is increased and decreased to represent binary one and zero.

Its core consists of dozens or hundreds of thin strands of glass or plastic which uses light to transmit signals.

Each strand, called an optical fibre, is as thin as a human hair

WIRELESS TRANSMISSION MEDIA

Wireless is a method of communication that uses electromagnetic waves rather than wire conductors to transmit data between devices.Wireless networks are telephone or computer networks that use radio frequencies and infrared waves as their carrier.

Wireless transmission can be categorised into three broad groups:

• Radio Waves
• Microwaves
• Infrared

Radio Waves

There is no clear difference between radio waves and microwaves. Electromagnetic waves ranging in frequencies between 3 KHz and 1 GHz are

normally called radio waves. Waves ranging in frequencies between 1 and 300 GHz are normally called microwaves.

Radio waves are normally omnidirectional. When an antenna transmits radio waves, they are propagated in all directions. This means that the sending and receiving antennas do not have to be aligned.

The omnidirectional characteristics of radio waves make them useful for multicasting, in which there is one sender but many receivers.

Our AM and FM radio stations, cordless phones and televisions are examples of multicasting

Microwave

Electronic waves with frequencies between 1 GHz to 300 GHz are normally called microwaves.

Unlike radio waves, microwaves are unidirectional, in which the sending and receiving antennas need to be aligned. Microwaves propagation is    

line-of-sight therefore towers with mounted antennas need to be in direct sight of each other.

Two types of antenna are used for microwave communications. They are the parabolic dish antenna and the horn antenna.

The parabolic dish antenna receives ingoing transmissions by reflecting the signal to a common point called the focus.

Outgoing transmissions are broadcasted through a horn antenna by deflecting signals outward in a series of narrow parallel beams.

High-frequency microwaves cannot penetrate walls. This is why receiving antennas cannot be placed inside buildings.

Infrared

Infrared is used in devices such as the mouse, wireless keyboard and printers. Some manufacturers provide a special port called the IrDA port that allows a wireless keyboard to communicate with a PC. 

Infrared signals have frequencies between 300 GHz to 400 THz. They are used for short-range communication.

Infrared signals have high frequencies and cannot penetrate walls. Due to its short-range communication system, the use of an infrared communication 

system in one room will not be affected by the use of another system in the next room.

This is why using an infrared TV remote control in our home will not interfere with the  use of our neighbour’s infrared TV remote control.

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Hardware Requirements : Devices

Communication devices are hardware components that enable a computer to send or receive data, instructions and information to and from one or more computers.

Examples of communication devices are:

• Network Interface Card (NIC)
• Wireless Network Interface Card (WNIC)
• internal and external modem
• hub or switch
• router
• wireless access point

NETWORK INTERFACE CARD

A network card, sometimes pronounced as NICK, is an adapter card or PC card  that enables the computer to access the network.

A Network Interface Card is a piece of computer hardware designed to allow computers to communicate over a computer network. The card implements the electronic circuitry required to communicate using a specific physical layer and data link layer standard such as ethernet or token ring

WIRELESS NETWORK  INTERFACE CARD

 

Wireless Network Interface Card is a network card that provides wireless  data transmission.

A Wireless Network Interface Card or WNIC is a network card which connects to a radio-based computer network.

WNIC is an essential component for wireless desktop computer. This card uses an antenna to communicate through microwaves.

WNICs are designed around the IEEE 802.11 standard which sets out low-level specifications on how all wireless networks operate and can operate in two modes known as infrastructure mode and ad hoc mode.

NETWORK COMMUNICATION CHANNELS

There are two types of modem, internal modem and external modem. An internal modem only works in stand-alone computers. It is built into the computer.

An external modem is separated from the computer and is also mobile.

A modem is a device that enables a computer to transmit data over telephone or cable lines.

Computer information is stored digitally, whereas information transmitted over telephone lines is transmitted in the form of analog waves. A modem converts between these two forms.

HUB/SWITCH 

Hub or switch is a common connection point for devices in a network. Hubs are commonly used to connect segments of a LAN.

Hubs are commonly used to connect segments of a LAN. A hub contains multiple ports.

When a packet arrives at one port, it is copied to the other ports so that all segments of the LAN can see all the packets.

A hub connects all the devices on its ports together. A switch understands when two devices want to talk to each other, and gives them a switched connection.

ROUTER

A router is a communications device that connects multiple computers or other routers together and transmits data to the correct destination.

A router is a computer networking device that forwards data packets across a network toward their destinations, through a process known as routing.

A router acts as a junction between two or more networks to transfer data packets among them. In order to route packets, a router communicates with other routers using routing protocols.

WIRELESS ACCESS POINT

A wireless access point is a device that connects wireless communication devices together to form a wireless network.

Wireless access point (or Wireless AP) usually connects to a wired network and can relay data between wireless devices and wired devices.

Several Wireless APs can link together to form a larger network that allows "roaming". Wireless access points have IP addresses for configuration.

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