L01 - Fundamentals of IT

A modem is a device or a program 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 analogue waves. A modem converts between these two forms

Network interface card is a device that allows computers to be connected in a network, typically a LAN. It is the hardware connection between the computer and the network cable.

A terminal adapter is a hardware interface between a computer and an integrated services digital network (ISDN) line.

 A Wireless Router converts an internet signal into wireless signal which networked computers/ devices can be use to communicate with each other and the router. A hard- wired network is one that uses an Ethernet cable.

Wireless Network Card is the means by which the computer or device is able to send and recieve wireless communication. It is installed in a computer so it can connect radio-based computer networks. It uses an antenna to communicate through microwaves.

A hub is a common connection point for devices in a network. They allow multiple computers to communicate over a network. A USB hub allows multiple through a single USB port.

A Router allows messages to be sent between different types of networks, routers can have both cabled and wireless conncections.

A Switch is a device that connects devices to a LAN by cables. It sends the data only to the intended destination. This reduces network traffic because data is sent to the nodes where they are needed rather than the whole network. It can send and recieve information at the same time. It is more expensive than a hub and the number of ports may affect the performance.

A WAP has a number of dedicated radio channels that are available to a Wi-Fi computer can connect it. All data passing through the radio channel is then fed to the hard wired network that the WAP device is supporting.

Central Processing Unit (CPU)  records where all programs and instructions are located for future retrieval. It manages all of the hardware activities required to:

• Recieve instructions and data
• Actions them using the input data
• Outputs the results

The CPU has two main components:

Control Unit - which ensures that the instructions required to operate the computer are retrieved and interpreted in the correct order.

ALU - which undertakes the mathematical or logical operations required to complete the instructions.

Motherboards are the printed circuit of a personal computer. It connects thhe CPU to the memory and all other hardware. The CPU sits on the Motherboard.

Computer storage: Primary, Secondary. Where data and instructions are stored in a computer.

Primary storage is called Memory

• RAM, ROM, Cache, Virtual Memory, Registers

Secondary storage - Internal hard disks (HDD and SSD), Flash storage(USB, SD cards), Optical Media(CD, DVD, Blueray)

Register - high speed memory inside the CPU which stores the data that needs to be processed. Small amount of fast temporary memory within the processor or where the ALU/CPU can store and change values needed to execute instructions.

RAM - main place for storing instructions and data whilst a program is being executed. It does not retain its content without a supply of power. When a computer is turned off everything stored in its RAM is lost. (VOLATILE MEMORY)

ROM - is a flash memory chip that contains a small amount of NON VOLATILE MEMORY. This means that its content cannot be changed and it retains its memory after the computer is turned off.

Cache - is a small amount of memory which is a part of the CPU. It is closer to the CPU than RAM. It is used to temporarily to hold onto instructions and data that the CPU is likely to reuse.

Virtual Memory - it is a section of Volatile memory created temporarily on the storage device. It is created when a computer is running many processes at once and RAM is running low.

A physical interface on a computer to connect externals such as mice and keyboard

Over a network a port is a point where information is sent through, eg the http port.

• USB, Ethernet – connected straight, Fire wire (Camera, but being phased out), Network, HDMI, SATA

Expansion cards:

• Sound, Network, Graphics, Storage controller (RAID), Fibre channel.

Power supply:

• Receives electricity from the mains supply, Converts (AC to DC), Needs cooling system – usually a fan system, Very large computer may use water coolant systems.

USB port:

• Enables computer to connect with standalone devices like printers.

• Serial bus refers to the standard for digital data communication over short distances.

Fire wire:

• This type of port often connects devices which need high speed transfer of large amounts of data E.g. camera camcorder
• It conforms with IEEE1394 standard for the cabled devices to be connected.

SATA:

• This port allows devices such as optical and hard disk drives to link to a computer. 

• This port is linked to another port on the motherboard with a 7pin ribbon cable.

Network:

• The physical ports are those which connect computers to a modems, routers or local area networks (LAN).

Ethernet - The Ethernet port is used for cable based network. This is linked directly to the computers network card.

Fibre channel port:

• A high-speed network technology primarily used to connect computer data storage to servers. Fibre channels typically run on optical fibre cables within and between data centres.

A motherboard has various expansion slots. A socket on the motherboard that is used to insert an expansion card (or circuit board). Which provides additional features to a computer such as video, sound, advanced graphics, Ethernet or memory.

Expansion cards - An electronic card that is used to add extra functionality to a computer.It is inserted into an expansion card slot on the motherboard of a computer. For example, video graphics cards are used to enhance the video quality on a computer.

Universal Serial Bus (USB)

• Enables the computer to connect with standalone devices such as printers

• Two uses of each port - Memory stick & Camera
• 2 Characteristics of each point -  Robust & Most common

Fire wire

• It links devices which need high speed transfer of large amount of data to computers using special cables.
• Two uses of each port -  Camcorders & External hard drives
• 2 Characteristics of each point - Allows data to be transferred very quickly. Can shift large amounts of data

SATA –Serial Advanced Technology Advancement

• It allows devices such as optical and other hard drives to link to a computer. The port is linked to another port on the motherboard with a 7pin ribbon cable
• 2 uses -Optical hard drives &External hard drives
• 2 Characteristics - Can easily link devices to a computer &Linked straight to the motherboard so can transfer quickly.

Network

• The physical port are those which connect computers to modems, routers or LANs.
• 2 uses - Connection to modem & Connection to routers and LAN
•  Characteristics - Allows you to connect quicker to a network than Wi-Fi

Fibre channel

• A high speed network technology primarily used to connect computer data storage to servers. It runs on optical fibre cables within and between data centres.
• 2 uses -Transfer large amounts of data to servers.Fibre optical cables used to transfer data on the internet.
• 2 Characterisitcs - Usually fast. Uses optical fibre cables. Transfer data quickly between one part of the world to another in seconds.Expensive

Expansion cards

• An electronic card that is used to add extra functionality to a computer.
• 2 uses -Video graphics card & Sound card
• 2 Characterisitcs - Enhance video quality &Smaller than the motherboard

Computer can be made up of individual components like screen, keyboard and mouse, with a case which contains the motherboard and CPU, power supply, hard drives, and expansion cards.

Computer can be made up of a single screen and case which combines the motherboard and everything else.

This type of PC reduces the space required to house the computer and the need for so many cables. They are easily moved. However, the ability to upgrade the hardware or repair it is limited compared with the traditional desktop.

Desktops allow the user to carry out a range activities such as data manipulation, document creation, game playing and design and communication facilities for personal or business purposes

Advantages- Lots of memory space. Easy to upgrade. Fast processors. No battery. Cheaper than laptops and tables. Disadvantages - Large footprint. Need keyboard, mouse and monitor. Big and heavy. Can be noisy. Requires a separate monitor. Not portable

Computer hardware is any physical component of a computer. 

An input device is a device that allows the user to give instructions or to provide data to the computer system. E.g. Keyboard, Mouse, Scanner, Sensors and Microphones.

An output device is a device that enables the computer system to provide information, data or instructions to another user which could be human or a computer. E.g. Printers, Speakers/Headphones, Visual display unit and Braille terminal. ·

• A mouse is a point and click device and it allows the user to communicate with the computer by placing a cursor at the particular point on the screen. The screen tracks the movement of the mouse and displays its location on the screen as the cursor. An advantage is that it is ideal for use with desktop computers. However, they need a flat space close to the computer. 
• A QWERTY keyboard has letters of the alphabet on each button, numbers and also some other symbols such as brackets and commas. The first six keys on the top row spell QWERTY. The advantage of the QWERTY keyboard layout is that it enables and increases the speed of typing. However, a disadvantage of the keyboard is RSI.

• A French keyboard is a keyboard that has the layout of AZERTY which is used for the accents of the French language. It has a specific layout for the characters of the Latin alphabet. The advantage is that you do not have to use a QWERTY keyboard and suffer the long process of adding in accents all the time. However, a disadvantage of the keyboard is RSI.

• An ergonomic keyboard is designed with ergonomic considerations to minimize muscle strain and a host of related problems. These keyboards are typically are for two handed typists and are V-shaped, to allow right and left hands to type at a slight angle which is at a slight angle which is more natural to the human form. However, a disadvantage of the keyboard is RSI.

•   A numeric keypad is use to add numeric data into the computer. The advantage is that it is small therefore making it easier to carry around. However, the keys are small and possibly hard to see and also, the keys are arranged differently on some of the devices. 

• A microphone records instructions from the user, or sounds that the user wishes to collect. The advantage of this, is that for people who are unable to use a traditional mouse or keyboard can use a microphone to input data.

• A scanner is a device that converts a document or photograph into a digital file that a computer can read or display. The scanner works by shinning a beam of light onto the surface pf the object that you are scanning. This light is then reflected back onto a sensor that detects the colour of the light. An advantage of scanners is that any image which is digitised by the scanner can then be included on electronic documents. However, the images can lose some quality in the scanning and digitising process.

• A sensor is a physical device that send signals to the computer. These signals enable the computer to decide whether an action must be triggered. For example, if a burglar alarm is set, any signal received from the motion sensors suggest that someone is in that room or building and the computer triggers the alarm. 

• A graphics tablet uses icons that you tap. It is useful for entering data, such as handwriting and drawings of objects which cannot be easily collected in other ways. The disadvantage is that it can be hard to control if the sensitivity is set too low or too high. An advantage of a graphics tablet is that it is much more natural to draw diagrams with a pencil type implement rather than with a mouse. 

(CRT monitor) Cathode Ray Tube monitor. It is a vacuum tube used as a display screen in a computer monitor. The viewing end of the tube is coated with phosphors, which emit light when struck by electrons. The benefits are that they have fast response times and no motion artefacts which is good for moving/changing images. The limitations are that the screen shape is a rounded spherical or cylindrical shape.

(TFT monitor) Thin Film Transistors. These transistors are used in high quality flat panel liquid crystal displays. TFT based displays have a transistor for each pixel on the screen. This allows the electrical current that illuminates the display to be turned on and off at a faster rate, which makes the display brighter and it shows motion smoother. The benefits are that they are very well known for their clear and vibrant colours but they usually has static resolution so the resolution of the monitor cannot be changed.

Inkjet printers use cartridges that contain the ink. They operate by heating the ink as it flows through a set of tiny nozzles. The heating process causes a small drop of ink to form and then is released as a single dot which then forms part of a letter or image. The disadvantage of these printers is that the colour printing can be extremely slow and it is nosier than a laser printer. However, the advantage is that they are cheap to buy and they produce a good quality printout better than a dot matrix printer.

A 3D printer is a machine that allows the creations of physical objects from a three dimensional digital model. Limitations of this printer are how dangerous they are since they can print items like guns and knives. However, it has many benefits, one being it creates more jobs and is cheaper to use in third world countries.

Plotters are much specialised types of printers because they are able to draw high quality images on large pieces of paper. The difference between a printer and a plotter is that a plotter draws the images using a pen that can be lowered, moved and raised across the paper to form continuous lines. The controlled pen is moved around the paper by computer controlled motors. A good thing about plotters is that the drawings are of the same quality, but they do not produce very high quality text printouts. 

Dot matrix printer are called impact printers. The print head contains a grid of pins and different combination pins are pushed out to from different characters. The print head hits a carbon ribbon leaving an imprint on the printer. This makes them fairly noisy since you can hear the pins striking the paper. These printers are ideal when you want carbon copies because the printer has enough force, when carbonised paper is used, to make an impact on the second copy. A benefit of the printers is that they can print on continuous stationary. But they cannot produce colour copies.

Laser printers  print a large number of sheets very quickly and print in the same way as photocopiers. They work by powdered ink being fused onto paper by heat and pressure. The benefits of a laser printer is the cost per page is low and they are cheaper than a dot matrix and ink jet. The disadvantage they are expensive to repair and it has lots of complex equipment and parts inside. 

Speakers

Computers can be fitted with a sound card which enables sound to be output through external speakers. The speakers usually produce a much higher quality sound then the internal speaker. This is good because everyone in the room can hear the output from the computer but the output can also disturb others who are trying to work.

Braille terminal is a specialist reader for visually impaired users. It displays the text through individual cells on the terminal, each of which has rounded plastic or metal pins that protrude above the surface of the cell. The user reads the text by interpreting the patterns of the pins. The benefits of this is that it is relatively easily learned and written/ printed. However, errors cannot be erased. 

Server is a computer that has been optimized to provide services to other computers over a network. Servers usually have powerful processors and a lot of memory and large hard drives. Severs in general are designed to be running 24/7. 

Smartphones can run applications, send and receive emails, take photographs and videos, record sound and act as a GPS system. They run apps, provide entertainment via your library and your latest game. You can create documents, manipulate data and set your alarm. Unfortunately, they hinder human interaction and reduce spatial awareness when in use.

An issue with smartphones is the security as if it is unlocked and the phone is left in public, it allows anyone to access your private life, passwords and usernames for your cloud storage if not logged out of apps properly. The malware[1] and security software available for smartphones is not yet as strong as those for PC’s and should take care when sensitive data is held on the smartphones.

[1] Malware is the malicious software that contains viruses, worms, Trojan horses, ransomware, spyware and adware. Which can harm the system for the computer or the user themselves. 

Advantages:

• Ability to browse full websites with large amount of data and it will appear the same way as it is in the desktop browser.
• Applications that can help you create and edit Microsoft office documents.
• Can synchronize personal and professional email account.

Disadvantages:

• Malware and security for smartphones is not yet as strong as those for PC’s.

Embedded system:

Cars have computes which monitor emissions from the engine and adjust the engine settings as required. Other computers check for problems with car systems and inform the driver.

An embedded system is a computer system with a dedicated within a larger mechanical or electrical system, often with real time computing constraints.  

The concept of the internet of things describes a global network of connected objects such as traditional computer networks but anything with RFID chips embedded within them. Since small and cheaper chips are becoming more available, connectivity now includes animals with microchips that identify their owners and GPS location. IoT devices require a rich set of wireless connectivity options and networking protocols. This allows them to store, transmit and integrate data.

Mainframes are huge machines designed to solve scientific and engineering problems that require complex calculations or the manipulation, collection and storage of large amounts of data. Mainframes are reliable and secure because they have rigorous backup capabilities and component redundancy, which means if one component fails, others take its place without stopping the processing or input/ output activities.

The components used in an all-in-one PC are found in a laptop or tablet, but in case of the laptop the mouse function is replaced by a touch pad and keyboard combined. Modern laptops can fold back, effectively turning them into a tablet with a virtual keyboard. A tablets screen size can be restrictive and loss or theft is easier. Storage within the tablet is by solid state flash memory.

A tablet is easily held in your hand and the screen view can be automatically changed from landscape to portrait by changing the orientation of the tablet. This sensor is called an accelerometer. A hybrid tablet is essentially a self-contained computer that exists in a tablet form. It expands on the tablet form factor though by offering a dock or keyboard that is designed to attach to the tablet and make it appear like a tablet. 

Advantages- Light weight, longer battery life, touch screen, portable, used as a GPS system, Better user experience and recognizes handwriting. 

Disadvantages- Expensive, smaller display and keybord, less ports, weak capability, input speed is slower on a virtual keyboard, cant handle large amounts of data.

Copper, Fibre, Wireless, Bluetooth, Wi-Fi, Microwave, Infrared, Laser, Satelitte, GSM, 3G/4G.

Copper wire cabling

• Twisted pair (TP) is a common cable usually used in telephone systems. Using cables is the traditional method for networking computers (Ethernet cables). Made up of copper wires with the data being transported via electrical signals.

UTP (Unshielded twisted pair) - 4 sets of twisted pairs with an outer case. 

Pros: Realatively cheap and has a fast data transmission rate (1000Mbps).

Cons: Interference and needs many repeaters,

Coaxial Cable - Solid copper cable covered in an insulating with plastic cable. The case is then covered with a copper mesh which is all encased with another plastic sleeve,

Pros: Less interference than UTP and data transmission rates: (1000Mbps)

Cons: more expensive than UTP, bulkier and harder to install. 

Fibre optic cabling -These are made up of glass fibres with the data being transported via light signals. 

The light is pulsed down hollow glass or plastic tubes. The internal reflection keeps signal loss to a minimum. 

Pros: No electrical interference, Fast data transmission rates: 14000Gbps, Very fast and can transmit over long distances without repeaters (Record 160Km). 

Cons: Expensive over short distances, difficult to install and prone to damage, 

 Fibre optic cables should be considered for the business because it is very fast and can transmit data over very long distances without repeaters. This means it will enable the business to stream videos and download large files from websites. Making it less expensive since the business would need a large quantity of the cable.

Whereas Copper offers a very limited bandwidth meaning it would place heavy demands on the internet access therefore slowing everything and everyone down.  So the use of fibre would be more suitable since it enhances performance reliability alongside with offering the use of both phones and internet service on the same fibre. 

Hardware faults: Power surges,  Poor maintenance, Accidental damage, Malware,  Intentional damage, Electricity interruptions and failures. 

Troubleshooting often involves the process of elimination, where a technician will follow a set of steps to determine the problem or resolve the problem.

Tips for troubleshooting

• Log issue on a fault log sheet. This should include:  Machine,Owner or users, Fault, Date, Symptoms, Problem history – Has this happened before? Is this similar problem to other machines? Is this a temporary fault?  Back up documentation –What has been backed up and to which location?

IT technicians will be able to remember exactly what they have done and can avoid making the same mistakes again. If they ask someone else for help it will be easier since they already know what they have tried.

• Take notes about error messages. If your computer gives you an error message, be sure to write down as much information as you can.

IT technicians will be able to use this information later to find out if people are having the same error. Using the internet can help since there are millions of sites and documents relating to error messages.

•   Always check cables. Sometimes faults may occur as a result of cables not connecting properly. This could be as easy as checking cables for monitor or keyboard. Firstly, make sure all related cables are properly connected.

•  Restart the computer. This can solve a lot of basic issues IT technicians may experience with the computer. 

Always look for the simplest explanations first.  

• If the computer doesn’t power up. Check if cable is unplugged. If it is a laptop it may need to be charged.

Record the steps you take to identify the faults.

• Log steps which you have taken to identify the fault. Confirm you have completed the test before starting the next one.

State the tools used to identify the fault.

• Log tools used to identify faults.

Record actions taken to resolve issue - Log actions, Replaced hard disc, Updated drivers, Reinstalled software, Replaced motherboard.

Note the product specification

• Take note of product specification of any hardware or software.

Always record the time taken and costs arising from the fault findings and repairs.

It is necessary to carry out this action as it analyses:

• Maintenance requirements
• The robustness of particular hardware
• Trends and patterns that identifies which particular sets of actions result in failures and their time scales
• “What If” scenarios

Hardware or software tools that can quickly find the required solution to repair failed products or processes on a machine or a system. An example of this is Event viewer, Self-test programs and Diagnostic software.

Event Viewer is a tool that displays detailed information about significant events and allows you to monitor events in your system. 

Where is Windows System event log?

• Open Event Viewer by clicking the start button.
•  Click control panel
• Clicking system and security.
•  Clicking administrative tools, and then double click Event Viewer.
•  If you’re prompted for an administrator password or confirmation, type the password or provide confirmation.
• Click an event log in the left pane.

How do I find the application event log?

•  Click start
• Click control panel
• Click performance and maintenance
• Click administrative tools
• Double click computer management
• In the console tree, click event viewer
• The application, security and system logs are displayed in the event viewer window.

Event Viewer is a tool that displays detailed information about significant events and allows you to monitor events in your system. Such as, programs that don’t start as expected or updates that are downloaded automatically on your computer.It maintains logs about program, security, and system events on your computer.

When an error occurs the Event viewer is updated with the following information:

• What the problem is
• When it occurred (Date and Time)
•   The seriousness of the problem
•   What cause the problem
• An even ID number
• Who was logged into the machine at the time?

Event viewer can be helpful when troubleshooting problems and errors with Windows and other programs.

Diagnostic software:

A diagnostic program is a program written for the purpose of locating problems with the software, hardware or any combination thereof in a system, or a network of systems. Diagnostic programs provide solutions to the user to solve issues.

They are programs that are available from third parties. Some are free and others require payments.

Self-Test programs:

 They are often provided by the hardware manufacturer. They are often embedded systems in the hardware in which carries out hardware diagnostics to check the health of the hardware. The diagnostics are used to confirm a fault that might have been detected during normal operations.

Power on Self-Test (POST), Ping Tests, IP (internet protocol) configuration /IF (interface) configuration, Nslookup

Power on Self-Test are just run after the board powers up. POST run diagnostics on the hardware components on the board. POST checks memory, power supply, hardware, CPU, BIOS and heating and cooling.

POST is a function of the BIOS (basic input and output system). There are 2 types of post diagnostic information:

1.      Beep codes –One beep /motherboard and CPU are function well. More than one beep /error has been detected.

 2.  POST codes are visual errors.

IP (internet protocol) configuration /IF (interface) configuration: IPC is a Windows console application that has the ability to gather all the data regarding current Transmission Control Protocol/ IP configuration values and then display this data on screen.

IF configuration: Files control the software interfaces for individual network devices. As the system boots, it uses these files to determine what interfaces to bring up and how to configure them.

Nslookup: Name server lookup is a network utility program used to obtain information about internet servers.  It finds name server information for domains by querying the Domain Name system (DMS).

Solving more difficult problems:(Ask someone for help) 

• Search the Web. It's possible that other users have had similar problems, and solutions to these problems are often posted online.
• If you have a friend or family member who knows a lot about computers, they may be able to help you.
•  For difficult problems, a more drastic solution may be required, like reformatting your hard drive or reinstalling your operating system. If you think you might need a solution like this, we recommend consulting a professional first. 

Hexadecimal numbers are base 16 numbers used to simplify how binary is represented. Hexadecimal has 16 digits rather than 10 as its base. The hex numbers are 0-9 and then use the letters A-F.

The 16 digits of the Hex are: 0 1 2 3 4 5 6 7 8 9 A B C D E F. Each hex digit reflects a 4-bit binary sequence. 

Hex is much easier for humans to read hexadecimal numbers than binary numbers. It is used by programmers to describe locations in memory because it can be represented every byte. Hex is commonly used to describe colours on web pages. Hex codes are used to simplify binary codes. Hexadecimal is translated into binary for computer use.  

Bit = 1 zero or 1 one

Byte = 8 bits

Nibble = 4 bits 

To convert denary numbers to hex, you need to remember:

• The place values for binary digits
• The equivalent binary numbers for the first 16 hex digits.

Example 1:  To convert a 4-bit (nibble) binary number “1100” to hex: 

Example 2: To convert an 8bits (1 byte) binary number “10111001” to hex: 

Let’s work out an Example 1 - What is the denary value of hex value 2D?

1. Separate the hex digits (2) an (D)
2. Find the equivalent  of each in binary
   1. 2 = 0010
   2. D

• First convert to “D” to Denary  = 13

• Then convert  13 to binary = 1101

• Equivalent binary numbers (2 = 0010; D = 1101).

• Piece them together to get 00101101

A number system is a way to represent numbers.

Decimal or Denary –Base 10-Number system which humans work with.

Binary –Base 2 –Number system – use by computers to understand and manipulate data.

Hexadecimal –Base 16- Number system – commonly used in computer programming.

Denary number systems is also known as decimal. Denary numbers are number combinations of the digits between 0 and 9. Denary is known as base 10. Each number in the denary number system has a place value. Each column is a power of ten in the base 10 system. All denary numbers have a binary equivalent and it is possible to convert between denary and binary. 

Computers use binary to translate sets of instructions into machine codes which the computer can understand and store data. Binary can only contain two digits (0 and 1). A binary digit, or bit, is the smallest unit of data. Each binary digit must be assigned a place value.  

One way to convert a denary number to binary is to divide it by two and note the remainder. If you keep dividing by two and noting the remainders until you have nothing left.

You will end up with a line of ones and zeros. Then flip those numbers, you will have the binary number for 83.

Bits and Bytes groupings:

A group of 8 bits is called a byte.

0 or 1                     =             1 Bit (Binary Digit)

8 Bits                    =             1 Byte (equivalent to 1 Character of text)

1024 Bytes           =             1 Kilobyte (Kb)

1024 Kb               =             1 Megabyte (Mb)

1024 Mb              =             1 Gigabyte (GB)

1024 GB              =             1 Terabyte (Tb)

RAM – Random Access Memory.  It is the temporary store that the CPU uses for data and instructions. It is typically measures in gigabytes.  If a computer loses power, all data stored in the RAM is lost, this is why it is known as volatile memory. Both data and instructions are binary numbers, usually in bytes (8 bits).

 Volatility:

Describes what happens to them memory stored when the power is turned off. If it is volatile the memory is erased when the power is lost- all contents are lost. If it is non- volatile the memory is not lost when the power is turned off. 

ROM –Read Only Memory.It can be read but not changed by a program or user. ROM is used to store the instructions for the computer to start up when it is turned on, BIOS (Basic Input Output System). The data in the ROM is saved even if the computer is switched off and this is known as non- volatile memory. 

The rules of the BIOS software are:

• Loading the operating the system. Checking the hardware devices and their configuration. and remembers the settings (Clock, HDD)

ROM  examples:

•  In printers storing the type of fonts used, and in washing machines storing different washing programs and settings

RAM can be changed as you can read and write the contents, ROM cannot be changed by a program or a user but it can be read. 

Cache Memory: is a small amount of memory which is a part of the CPU. It is closer to the CPU than RAM. It is used to temporarily hold instructions and data that the CPU is likely to refuse. Cache memory in computer systems is used to improve system performance.A small amount of fast, costly memory that is used in between two devices that communicate at different speeds.In CPU cache, frequently used code or data is loaded in chunks from the slower RAM into the cache. The CPU accesses the Cache memory at its own faster speed.This means the CPU isn’t slowed down by having to wait for data from RAM. 

Ping Tests: it is a method of checking if the computer is connected to a network. It determines the latency or delay between two computers. Ping tests the connectivity between requesting host and destination hosts.

• 1. It works by sending a packet to the specific address and waiting for a reply.
• 2.   A response shows that the host can be reached.
• 3.  This procedure is repeated with different hosts until the problem is identified. 
• A ping test is run for troubleshooting to know connectivity as well as response time. 

Open softwareis free an openly available to everyone. People who create the open software publish the code and allow others to use and modify it. Open software is usually tested in public by online contributors. For example, the BBC makes use of MySQL and it creates open source software, such as the program to improve the compatibility of iPlayer on smart TVs.

Closed Softwareis also known as Proprietary software. Closed software legally remains the property of the organisation, group, or individual who created it. The organisation that owns the rights to the product usually does not release the source code, and may insist that only those who have purchased a special license key can use it. If a user purchases the closed software, he/she is purchasing a right to use it but do not own it. 

Off the shelf software is also referred to as COTS (Commercial Off the shelf software). Off the shelf software are already developed and available for sale to the general public. For example, Microsoft Office is a COTS software product that is a packaged software solution for businesses.

Bespoke software is developed for a specific purpose. Bespoke software is specifically developed when a company requires a piece of software to perform a very specific task or function and there's no existing software that does what they need. Bespoke software can be very expensive. 

Shareware software is also known as Trial software. This software gives the user a few days to try the software before he/she buys the program. After the trial time expires, the user will be asked to enter a code or to register the product before he/she can continue to use it. With the shareware software, all intellectual property rights and copyright remains the property of the author

Freeware software is distributed free of charge and never requires payment as long as there no modifications such as upgrades and it comes with no warranty. Some examples are, Acrobat Reader, iTunes, MSN Messenger. 

Embedded software is computer software embedded in the computer or devices developed to control these machines or devices. The software is embedded or in-built. The software controls functions of various hardware devices and systems. Some examples of devices/machines which uses this type of software are, Traditional PCs, Microwaves Ovens, GPS Systems, and Smart Watches.

Open source – Free to use, can open most documents and files created by Proprietary software.

Closed source – When purchasing closed software, you buy the right to own the copy but not the property.

Off the shelf – Can be customised and has a wide support from a large user base. Upgrades and compatibility.

Bespoke – The Company will get the exact software that they need and the software will work exactly how they want it to work.

Shareware –It is free, it can be copied and is covered by copyright.

Freeware – It usually licensed at no cost or an optional fee. It is covered by copyright.

Embedded – Small size and faster to load, Easy to manage and a low cost.

Open source – May not contain as many features as the equivalent commercial application.

Closed source – Smaller number of versions commonly used software since companies are the only ones with the rights to build and develop the software.

Off the shelf – Large memory footprint and may not meet all of the client’s needs.

Bespoke – It takes a long term to develop such a system, between a few months to a year, it also costs a great deal of money to develop such a system.

Shareware – It cannot be modified and may be a cut down or a temporary version.

Freeware – You cannot sell freeware software.

Embedded – Difficult to upgrade, hardware is limited and difficult to transfer data from one system to another.

Wireless technologies do not used cables but instead use radio frequency signals to transmit data or instructions between devices, including computers, printers and certain credit/ debit card payment terminals using electromagnetic radiation.

Copper wire connections. A cheaper cable to use when connecting network devices. It is used for a voice signal in a telephone system. Traditional method for networking in computers which transport data via electrical signals. 

Fibre Cables. To transfer data over a long distance with a greater user experience due to the lack of electrical interference it has. Made up of glass fibres with the data being transported via light signals.  It is a very fast method of transmitting data over long distances without repeaters.  

Bluetooth. It is used for exchanging data over short distances within 10 metres from fixed and mobile devices. It is a high speed, low-power microwave wireless link technology used in small devices.                           Wi-Fi. It allows devices to communicate with one another. It is mainly used to connect internet routers to devices like computers and phones.It uses radio waves to allow devices to connect with each other. It is a low-power wireless communication. 

Microwave.An effective type of wireless data transmission that transfers information using two separate methods.

Infrared. A media transmission system that transmits data signals through light emitting diodes or lasers.the point to point system in which transmission is possible between two points limited to a range and line of sight. This means devices must be within range, only a few metres apart and must be in line of sight. 

Laser. Wireless LANs user laser transmission technique for transmitting data. Any person or thing or object that breaks the laser beam will block the transmission.

Satellite.Allows users to stay connected virtually anywhere on the Earth. You can communicate directly with the orbiting satellites via radio signals.

GSM.Is a digital technology and is a second-generation (2G) cell phone system. A GSM modem is a specialized type of modem which accepts a SIM card. It operates over a subscription to a mobile operator, just like a mobile phone. 

3Gmobile networks were designed mainly for phone calls (voice) but with improved internet access speeds when compared to the earlier 2G standard.A 3G mobile phone can make voice calls, and also access the Internet using a data channel. Internet access speeds will vary depending on technology and location.

4G mobile networks are designed primary for carrying data using the IP protocol. 4G networks are expected eventually to offer faster internet download speeds compared to 3G.