UNIT 1. Introduction to the Personal Computer System.

UNIT 1. Introduction to the Personal Computer System.

Lesson 1. Personal computer.

Before reading the text, try to guess the meaning of the following words:

Nouns: Computer, machine, calculation, instruction, system, component, monitor, printer, program, function, reality, internet, information.

Adjectives: Electronic, original, physical, virtual.

Verbs: To base, to manage, to simulate.

 

Exercise 1. Read the text and translate it into Russian.

Personal computer.

A computer is an electronic machine that performs calculations based on a set of instructions. The first computers were huge, room-sized machines that took teams of people to build, manage, and maintain. The computer systems of today are exponentially faster and only a fraction of the size of those original computers.

A computer system consists of hardware and software components. Hardware is the physical equipment. It includes the case, keyboard, monitor, cables, storage drives, speakers, and printers. Software includes the operating system and programs. The operating system manages computer operations such as identifying, accessing, and processing information. Programs or applications perform different functions. Programs vary widely depending on the type of information that is accessed or generated. For example, instructions for balancing a check book are different from instructions for simulating a virtual reality world on the Internet.

Vocabulary:

To maintain – поддерживать, эксплуатировать

Exponentially – в геометрической прогрессии

Fraction – часть, фрагмент

Hardware – аппаратное обеспечение

Software – программное обеспечение

To include – включать, содержать

Case – системный блок

Keyboard – клавиатура

Storage drive – накопитель

Access – доступ

Process – обработка (n), обработать(v)

Application – приложение

To perform – выполнять

To vary – различаться

Exercise 2. Find in the text the English for:

  электронная машина, набор команд, в разы больше, физическое оборудование, широко варьироваться, моделирование виртуальной реальности.

 

Exercise 3. Find in the text the synonyms for:

Execute, number, enormous, group, construct, portion, various, kind, planet.

 

Exercise 4. Answer the following questions:

1. What is a computer?

2. What is the main function of a computer?

3. What are the components of a computer?

4. What is hardware?

5. What is software?

6. What is the function of an operation system?

 

Exercise 5. Try to retell the text using your answers.

Lesson 2. Case.

Exercise 1. Read the definitions and translate them into Russian.

Case (computer chassis, box, cabinet, tower) - enclosure that contains most of the components of a computer (usually excluding the display, keyboard and mouse).

 

Power supply - an electronic device that supplies electric energy to an electrical load.

 

Motherboard - a printed circuit board (PCB) that contains buses, or electrical pathways, that interconnect electronic components.

 

CPU (central processing unit) - the electronic circuitry within a computer that carries out the instructions of a computer program by performing the basic arithmetic, logical, control and input/output (I/O) operations specified by the instructions.

 

RAM (random access memory) - the temporary working storage for data and programs that are being accessed by the CPU.

 

ROM (read-only memory) - a type of non-volatile memory used in computers and other electronic devices.

 

Exercise 2. Read the text and translate it into Russian.

Cases.

The case of a desktop computer houses the internal components such as the power supply, motherboard, central processing unit (CPU), memory, disk drives, etc.

Cases are typically made of plastic, steel, or aluminum and provide the framework to support, protect, and cool the internal components.

A device form factor refers to its physical design and look. Desktop computers are available in a variety of form factors including:

· Horisontal case

· Full-size tower

· Compact tower

· All-in-one

Note: This list is not exhaustive, as many case manufacturers have their own naming conventions. These may include super tower, full tower, mid tower, mini tower, cube case, and more.

Computer components tend to generate a lot of heat; therefore, computer cases contain fans that move air through the case. As the air passes warm components, it absorbs heat and then exits the case. This process keeps the computer components from overheating. Cases are also designed to protect against static electricity damage. The computer’s internal components are grounded via attachment to the case.

Note: Computer cases are also referred to as the computer chassis, cabinet, tower, housing, or simply box.

Vocabulary:

To house – содержать, включать в     себя

Internal – внутренний

Steel – сталь

To provide – обеспечивать

To support – поддерживать

To protect – защищать

To be available – быть доступным

Tend to – как правило

To be grounded – заземлен

Attachment - присоединение

Power supplies.

Electricity from wall outlets is provided in alternating current (AC). However, all components inside a computer require direct current (DC) power. To obtain DC power, computers use a power supply to convert AC power into a lower voltage DC power.

A power supply includes several different connectors. These connectors are used to power various internal components such as the motherboard and disk drives. The connectors are “keyed” which means that they are designed to be inserted in only one orientation.

The different connectors also provide different voltages. The most common voltages supplied are 3.3 volts, 5 volts, and 12 volts. The 3.3 volt and 5 volt supplies are typically used by digital circuits, while the 12 volt supply is used to run motors in disk drives and fans.

Power supplies can also be single rail, dual rail, or multi rail. A rail is the printed circuit board (PCB) inside the power supply to which the external cables are connected. A single rail has all of the connectors connected to the same PCB while a multi rail PCB has separate PCBs for each connector.

A computer can tolerate slight fluctuations in power, but a significant deviation can cause the power supply to fail.

 

Motherboards.

The motherboard, also known as the system board or the main board, is the backbone of the computer. A motherboard is a printed circuit board (PCB) that contains buses, or electrical pathways, that interconnect electronic components.

These are some connections on the motherboard where computer components can be added:

· Central Processing Unit (CPU) - This is considered the brain of the computer.

· Random Access Memory (RAM) - This is a temporary location to store data and applications.

· Expansion slots - These provide locations to connect additional components.

Chipset - This consists of the integrated circuits on the motherboard that control how system hardware interacts with the CPU and motherboard.

Basic input/output system (BIOS) chip and Unified Extensible Firmware Interface (UEFI) chip - BIOS is used to help boot the computer and manage the flow of data between the hard drive, video card, keyboard, mouse, and more.

Most chipsets consist of the following two types:

· Northbridge – Controls high speed access to the RAM and video card. It also controls the speed at which the CPU communicates with all of the other components in the computer. Video capability is sometimes integrated into the Northbridge.

· Southbridge – Allows the CPU to communicate with slower speed devices including hard drives, Universal Serial Bus (USB) ports, and expansion slots.

 

 

Exercise 3. Answer the following questions:

1. What types of current exist?

2. What is the main function of a power supply?

3. What are the most common voltages supplied?

4. What is a motherboard?

5. What computer components can be connected to a motherboard?

6. What is BIOS?

7. What is Northbridge and Southbridge?

 

Lesson 4. General safety.

General safety.

Safe working conditions help prevent injury to people and damage to computer equipment. A safe workspace is clean, organized, and properly lit. Everyone must understand and follow safety procedures.

Follow safety guidelines to prevent cuts, burns, electrical shock, and damage to eyesight. As a best practice, make sure that a fire extinguisher and first-aid kit are available. Poorly placed or unsecured cables can cause tripping hazards in a network installation. Cable management techniques such as installation of cables in conduit or cable trays help to prevent hazards.

This is a partial list of basic safety precautions to use when working on a computer:

· Remove your watch and jewelry and secure loose clothing.

· Turn off the power and unplug equipment before performing service.

· Cover sharp edges inside the computer case with tape.

· Never open a power supply or a monitor with a built-in power supply.

· Do not touch areas in printers that are hot or that use high voltage.

· Know where the fire extinguisher is located and how to use it.

· Keep food and drinks out of your workspace.

· Keep your workspace clean and free of clutter.

· Bend your knees when lifting heavy objects to avoid injuring your back.

· Wear safety goggles to prevent damage to eyesight

Before cleaning or repairing equipment, make sure that your tools are in good condition. Clean, repair, or replace items that are not functioning adequately.

Exercise 4. Imagine you are designing an ICT classroom with 16 networked PCs, Internet access and peripherals. What safety precautions should be taken into account? Use these notes to help you write four tips or suggestions.

·Room conditions (space, desks, chairs, lights and windows)

·Ergonomic devices

·Electrical safety (layout of cables and connectors, hotspots for a wireless network, etc.)

·Noticeboards and posters with health and safety recommendations.

 

Electrical safety.

Follow electrical safety guidelines to prevent electrical fires, injuries, and fatalities.

Some printer parts become hot during use, and other parts, such as power supplies, contain high voltage. Check the printer manual for the location of high-voltage components. Some components retain a high voltage even after the printer is turned off. Make sure that the printer has had time to cool before making the repair.

Electrical devices have certain power requirements. For example, AC adapters are manufactured for specific laptops. Exchanging AC adapters with a different type of laptop or device may cause damage to both the AC adapter and the laptop.

 

Fire safety.

Follow fire safety guidelines to protect lives, structures, and equipment. To avoid an electrical shock and to prevent damage to the computer, turn off and unplug the computer before beginning a repair.

Fire can spread rapidly and be very costly. Proper use of a fire extinguisher can prevent a small fire from getting out of control. Use the memory aid P-A-S-S to remember the basic rules of fire extinguisher operation:

P - Pull the pin.

A - Aim at the base of the fire, not at the flames.

S - Squeeze the lever.

S - Sweep the nozzle from side to side.

Be familiar with the types of fire extinguishers used in your country or region. Each type of fire extinguisher has specific chemicals to fight different types of fires:

· Paper, wood, plastics, cardboard

· Gasoline, kerosene, organic solvents

· Electrical equipment

· Combustible metals

When working with computer components, be alert for odors emitting from computers and electronic devices. When electronic components overheat or short out, they emit a burning smell. If there is a fire, follow these safety procedures:

· Never fight a fire that is out of control or not contained.

· Always have a planned fire escape route before beginning any work.

· Get out of the building quickly.

· Contact emergency services for help.

· Locate and read the instructions on the fire extinguishers in your workplace before you have to use them.

Exercise 3. Read the text.

Power fluctuation types

Voltage is a measure of energy required to move a charge from one location to another. The movement of electrons is called current. Computer circuits need voltage and current to operate electronic components. When the voltage in a computer is not accurate or steady, computer components might not operate correctly. Unsteady voltages are called power fluctuations.

The following types of AC power fluctuations can cause data loss or hardware failure:

· Blackout - Complete loss of AC power. A blown fuse, damaged transformer, or downed power line can cause a blackout.

· Brownout - Reduced voltage level of AC power that lasts for a period of time. Brownouts occur when the power line voltage drops below 80 percent of the normal voltage level and when electrical circuits are overloaded.

· Noise - Interference from generators and lightning. Noise results in poor quality power, which can cause errors in a computer system.

· Spike - Sudden increase in voltage that lasts for a short period and exceeds 100 percent of the normal voltage on a line. Spikes can be caused by lightning strikes, but can also occur when the electrical system comes back on after a blackout.

· Power surge - Dramatic increase in voltage above the normal flow of electrical current. A power surge lasts for a few nanoseconds, or one-billionth of a second.

Safety data sheet.

Computers and peripherals contain materials that can be harmful to the environment. Hazardous materials are sometimes called toxic waste. These materials can contain high concentrations of heavy metals such as cadmium, lead, or mercury. The regulations for the disposal of hazardous materials vary by state or country. Contact the local recycling or waste removal authorities in your community for information about disposal procedures and services.

A Safety Data Sheet (SDS) used to be known as a Material Safety and Data Sheet (MSDS). A Safety Data Sheet is a fact sheet that summarizes information about material identification, including hazardous ingredients that can affect personal health, fire hazards, and first-aid requirements. The SDS contains chemical reactivity and incompatibility information. It also includes protective measures for the safe handling and storage of materials and spill, leak, and disposal procedures.

To determine if a material is classified as hazardous, consult the manufacturer’s SDS. In the United States, the Occupational Safety and Health Administration (OSHA) requires that all hazardous materials be accompanied by an SDS when transferred to a new owner. The SDS information included with products purchased for computer repairs or maintenance can be relevant to computer technicians. OSHA also requires that employees be informed about the materials that they are working with and be provided with material safety information.

The SDS explains how to dispose of potentially hazardous materials in the safest manner. Always check local regulations concerning acceptable disposal methods before disposing of any electronic equipment.

The SDS contains valuable information:

· Name of the material

· Physical properties of the material

· Hazardous ingredients contained in the material

· Reactivity data, such as fire and explosion data

· Procedures for spills and leaks

· Special precautions

· Health hazards

· Special protection requirements

In the European Union, the regulation Registration, Evaluation, Authorisation and restriction of Chemicals (REACH) came into effect on June 1, 2007, replacing various directives and regulations with a single system.

 

Exercise 3. Using the internet resources try to find the information about safety disposal of:

Batteries, monitors, toner kits and cartridges, chemical solvents.

UNIT 3. Computer assembly.

Lesson 10. Start your PC.

BIOS and CMOS.

All motherboards need BIOS to operate. BIOS is a ROM chip on the motherboard that contains a small program. This program controls the communication between the operating system and the hardware.

Along with the POST, BIOS also identifies:

· Which drives are available

· Which drives are bootable

· How the memory is configured and when it can be used

· How PCIe and PCI expansion slots are configured

· How SATA and USB ports are configured

· Motherboard power management features

· The motherboard manufacturer saves the motherboard BIOS settings in a Complementary Metal Oxide Semiconductor (CMOS) memory chip.

When a computer boots, the BIOS software reads the configured settings stored in CMOS to determine how to configure the hardware.

Installation Tip: If the computer’s time and date is incorrect, it could indicate that the CMOS battery is bad or is getting very low.

 

BIOS setup program.

Default BIOS settings may need to be altered whenever hardware such as memory modules, storage devices, and adapter cards are added or changed. The BIOS setup program must be used to change settings.

To enter the BIOS setup program, press the proper key or key sequence during the POST. This key sequence varies between manufacturers but they commonly use the DEL key or a Function key to enter the BIOS setup program. For example, with an ASUS motherboard, use the DEL key or F2 function key during the POST to enter the BIOS program.

Note: Consult the motherboard documentation for the correct key or combination of keys for your computer.

Many motherboards display a graphic called a splash screen, while the computer goes through the POST process. The splash screen sometimes includes the manufacturer’s key combination to enter BIOS.

Although BIOS setup programs differ between manufacturers, they all provide access to similar menu items:

· Main - Basic system configuration

· Advanced - Advanced system settings

· Boot - Boot device options and boot order

· Security - Security settings

· Power - Advanced power management configurations

· JUSTw00t! - Advanced voltage and clock settings

· Exit - BIOS exit options and loading default settings

Note: The BIOS setup screens in this section are for reference only and most likely will not look the same as yours. Please consider them as a guide and refer to your motherboard manufacturer documents.

 

Hardware

Check the condition of the cables, components, and peripherals. Clean components to reduce the likelihood of overheating. Repair or replace any component that shows signs of damage or excess wear.

Use these tasks as a guide to creating a hardware maintenance plan:

· Remove dust from fans.

· Remove dust from the power supply.

· Remove dust from the components inside the computer and peripheral equipment, such as printers.

· Clean the mouse, keyboard, and display.

· Check for and secure any loose cables.

Software

Verify that installed software is current. Follow the policies of the organization when installing security updates, operating system updates, and program updates. Many organizations do not allow updates until extensive testing has been completed. This testing is done to confirm that the update will not cause problems with the operating system and software.

Use these tasks as a guide to creating a software maintenance schedule that fits your needs:

· Review and install the appropriate security updates.

· Review and install the appropriate software updates.

· Review and install the appropriate driver updates.

· Update the virus definition files.

· Scan for viruses and spyware.

· Remove unwanted or unused programs.

· Scan hard drives for errors.

· Optimize (defragment) hard drives.

 

Lesson 13. Troubleshooting.

Data Backup

A data backup is a copy of the data on a computer hard drive that is saved to another storage device or to cloud storage. Cloud storage is online storage that is accessed via the Internet. In an organization, backups may be performed on a daily, weekly, or monthly basis.

If you are unsure that a backup has been done, do not attempt any troubleshooting activities until you check with the customer. Here is a list of items to verify with the customer that a backup has been performed:

· Date of the last backup

· Contents of the backup

· Data integrity of the backup

· Availability of all backup media for a data restore

If the customer does not have a current backup and you are not able to create one, ask the customer to sign a liability release form. A liability release form contains at least the following information:

· Permission to work on the computer without a current backup available

· Release from liability if data is lost or corrupted

Description of the work to be performed

Exercise 3. Read the dialogue and complete it with the words below:

Checked, disconnected, found, go, switched, type, tight, unplugged, worked, working

 

Haider: Hello, IT Help Desk.

Maryam: Hi, this is Maryam from Human Resources.

Haider: Hi, this is Haider. How can I help you, Maryam?

Maryam: I (1)_____ my computer off yesterday and today I can't t u r n it on.

Haider: What (2)________ of computer do you have?

Maryam: I'm not sure. It's a desktop computer. It (3) fine yesterday.

Haider: Don't worry. Have you (4)_______ the cable connections?

Maryam: No, I haven't. I can see some cables but I don't know which cable

goes where.

Haider: Make sure all cables are (5)______ and fully plugged in.

Maryam: Ok, give me a sec. Oh, I think I've (6)_____ the problem. I have one cable that is (7)________. It's the power cable. Where does it go?

Haider: The power cable should (8)_______ in the three-pronged port on the computer.

Maryam: OK, done. Let me t r y now. It's (9) _______fine. Sorry about that. Stupid of me.

Haider: Maybe the cleaners (10)________ your PC by mistake last night.

Maryam: Maybe. Good, we've solved the problem. Thank you, Haider.

Haider: You're welcome. Have a good day

Maryam: You too.

.

Conversation Etiquette

When you are talking to the customer, follow these guidelines:

· Ask direct questions to gather information.

· Do not use industry jargon.

· Do not talk down to the customer.

· Do not insult the customer.

· Do not accuse the customer of causing the problem.

Documenting Responses

Document the information from the customer in the work order, in the repair log, and in your repair journal. Write down anything that you think might be important for you or another technician. The small details often lead to the solution of a difficult or complicated problem.

Beep Codes

Each BIOS manufacturer has a unique beep sequence, a combination of long and short beeps, for hardware failures. When troubleshooting, power on the computer and listen. As the system proceeds through the POST, most computers emit one beep to indicate that the system is booting properly. If there is an error, you might hear multiple beeps. Document the beep code sequence, and research the code to determine the specific problem.

BIOS Information

If the computer boots and stops after the POST, investigate the BIOS settings. A device might not be detected or configured properly. Refer to the motherboard documentation to ensure that the BIOS settings are correct.

Event Viewer

When system, user, or software errors occur on a computer, the Event Viewer is updated with information about the errors. The Event Viewer application records the following information about the problem:

· What problem occurred

· Date and time of the problem

· Severity of the problem

· Source of the problem

· Event ID number

· Which user was logged in when the problem occurred

Although the Event Viewer lists details about the error, you might need to further research the problem to determine a solution.

Device Manager

The Device Manager displays all the devices that are configured on a computer. The operating system flags the devices that are not operating correctly with an error icon. A yellow circle with an exclamation point (!) indicates that the device is in a problem state. A red circle with an X means that the device is disabled. A yellow question mark (?) indicates that the system does not know which driver to install for the hardware.

Task Manager

The Task Manager displays the applications and background processes that are currently running. With the Task Manager, you can close applications that have stopped responding. You can also monitor the performance of the CPU and virtual memory; view all processes that are currently running, and view information about the network connections.

Diagnostic Tools

Conduct research to determine which software is available to help diagnose and solve problems. There are many programs to help you troubleshoot hardware. Manufacturers of system hardware usually provide diagnostic tools of their own. For instance, a hard drive manufacturer might provide a tool to boot the computer and diagnose why the hard drive does not start the operating system.

UNIT 5. Operating systems.

Terms.

An operating system (OS) has a number of functions. One of its main tasks is to act as an interface between the user and the hardware connected to the computer. The operating system also controls other functions:

· Software resources

· Memory allocation and all peripheral devices

· Common services to computer application software

From digital watches to computers, almost all computers require an operating system before they can be operated, hence the name.

To understand the capabilities of an operating system, it is important to first understand some basic terms. The following terms are often used when describing operating systems:

· Multi-user – Two or more users have individual accounts that allow them to work with programs and peripheral devices at the same time.

· Multitasking – The computer is capable of operating multiple applications at the same time.

· Multiprocessing – The operating system can support two or more CPUs.

· Multithreading – A program can be broken into smaller parts that are loaded as needed by the operating system. Multithreading allows different parts of a program to be run at the same time.

The OS boots the computer and manages the file system. Operating systems can support more than one user, task, or CPU.

Lesson 16. Storage drives.

Storage device types.

As a technician, you might have to perform a clean installation of an OS. Perform a clean install in the following situations:

· When a computer is passed from one employee to another

· When the OS is corrupt

· When the primary hard drive is replaced in a computer

The installation and initial booting of the OS is called the operating system setup. Although it is possible to install an OS over a network from a server or from a local hard drive, the most common installation method for a home or small business is through external media such as CDs, DVDs or USB drives. To install an OS from external media, configure the BIOS setup to boot the system from the media. Most modern BIOS should support booting from CD, DVD or USB.

Note: If the hardware is not supported by the OS, you may need to install third party drivers when performing a clean installation.

Before the operating system can be installed, a storage media device must be chosen and prepared. Several types of storage devices are available and can be used to receive the new operating system. The two most common types of data storage devices used today are hard disk drives and flash memory-based drives.

Hard Disk Drives

Although Hard Disk Drives (HDDs) are considered old technology, these drives are still common in modern computers and can be used for storing and retrieving data. HDDs contain a number of magnetic, spinning, rigid steel disks and magnetic heads mounted to a mobile arm. The magnetic head and is responsible for reading and writing data off the spinning disks.

Flash Memory-Based Drives

Flash memory is a type of non-volatile data storage medium that can be electrically erased and re-written. It became popular over the last decade as the flash technology evolved and became more reliable. Different types of flash memory are used in different applications:

· USB Flash Drives - USB flash drives are a good solution for storing operating system installation images. They are fast, reliable, resilient and inexpensive. USB flash drives are comprised of flash memory and a small control board to govern data transfer. They are most commonly used to store operating system installation images, but they can also be used to store a full installation of an OS if space allows.

· Solid State Drives (SSD) - Another popular application for flash memory is the SSD. An alternative to hard disks, SSDs are disks that employ high performance flash memory technology to achieve fast data storage without the moving parts of HDDs. SSDs are faster and less prone to physical problems. Due the high performance type of flash memory used, SSDs tend to be more efficient than USB flash drives and are a great choice for OS hosting.

· Solid State Hybrid Disks (SSHDs) - A popular and less expensive option than SSDs, SSHD devices combine the speed of SSDs with the lower price of HDDs by packing both technologies in the same enclosure. In SSHDs, data is stored in an HDD, but a small flash memory is used to cache frequently used data. This allows for frequently used data to be accessed by the operating system at SSD speeds, while other data is transferred at HDD speeds. SSHDs are a good option for storing operating systems.

· Embedded MultiMediaCard (eMMC) - Although slower and less expensive than SSD, eMMC is very popular in cell phones, PDAs and digital cameras.

Regardless of the application, flash memory-based storage devices can be used to store entire installations of operating systems. With different levels of performance, flash-memory based drives allow for flexibility when designing modern computer hardware.

A few different standards govern the connection between computers. Hot swapping is a technique used in servers that allows devices such as hard drives to be connected or disconnected without powering down the computer. While the entire computer hardware and OS must be designed to support this feature, it is very useful in servers as it allows for part replacement without interrupting service.

When the storage device type has been chosen, it must be prepared to receive the new operating system. Modern operating systems ship with an installer program. Installers usually prepare the disk to receive the operating system, but it is crucial for a technician to understand the terms and methods involved in this preparation.

 

Hard drive partitioning.

A hard drive is divided into areas called partitions. Each partition is a logical storage that can be formatted to store information, such as data files or applications. If you imagine a hard drive as a wooden cabinet, the partitions would be the shelves. During the installation process, most operating systems automatically partition and format available hard drive space.

Partitioning a drive is a simple a process, but to ensure a successful boot, the firmware must know what disk and partition on that disk has an operating system installed.

The partition scheme has direct influence in the location of the operating systems on a disk. Finding and launching the operating system is one of the responsibilities of a computer firmware. The partition scheme is very important to the firmware. Two of the most popular partition scheme standards are MBR and GPT.

Master Boot Record

Publicly introduced in 1983, the master boot record (MBR) contains information on how the hard drive partitions are organized. The MBR is 512 bytes long and contains the boot loader, an executable program that allows a user to choose from multiple operating systems. MBR has become the de facto standard but has limitations that had to be addressed. MBR is commonly used in computers with BIOS-based firmware.

GUID Partition Table

Also designed as a partition table scheme standard for hard drives, the globally unique identifier (GUID) partition table (GPT) makes use of a number of modern techniques to expand on the older MBR partitioning scheme. GPT is commonly used in computers with UEFI firmware. Most modern operating systems now support GPT.

A technician should understand the process and terms relating to hard drive setup:

· Primary partition - The primary partition contains the operating system files and is usually the first partition. A primary partition cannot be subdivided into smaller sections. On a GPT partitioned disk, all partitions are primary partitions. On an MBR partitioned disk, there can be a maximum of four partitions.

· Active partition – In MBR disks, the active partition is the partition used to store and boot an operating system. Notice that only primary partitions can be marked active in MBR disks. Another limitation is that only one primary partition per disk can be marked active at one time. In most cases, the C: drive is the active partition and contains the boot and system files. Some users create additional partitions to organize files or to be able to dual-boot the computer. Active partitions are only found on drives with MBR partition tables.

· Extended partition – If more than 4 partitions are required on an MBR partitioned disk, one of the primary partitions can be designated an extended partition. After the extended partition is created, up to 23 logical drives (or logical partitions) can be created within this extended partition. A common setup is to create a primary partition for the OS (drive C:) and allow an extended partition to occupy the remaining free space on a hard drive, right after a primary partition. Any extra partitions can be created within the extended partition (drives D:, E: and so on). While the logical drives can’t be used to boot an OS, they are perfect for storing user data. Notice that there can be only one extended partition per MBR hard drive and that extended partitions are only found on drives with MBR partition tables.

· Logical drive - A logical drive is a section of an extended partition. It can be used to separate information for administrative purposes. Because GPT partitioned drives cannot have an extended partitions, they do not have logical drives.

· Basic disk - A basic disk (the default) contains partitions such as primary and extended as well as logical drives which are formatted for data storage. More space can be added to a partition by extending it into adjacent, unallocated space, as long as it is contiguous. Either MBR or GPT can be used as the underlying partition scheme of basic disks.

· Dynamic disk - Dynamic disks provide features not supported by basic disks. A dynamic disk has the ability to create volumes that span across more than one disk. The size of the partitions can be changed after they have been set, even if the unallocated space is non-contiguous. Free space can be added from the same disk or a different disk, allowing a user to efficiently store large files. After a partition has been extended, it cannot be shrunk without deleting the entire partition. Either MBR or GPT can be used as the partition scheme of dynamic disks.

· Formatting - This process creates a file system in a partition for files to be stored.

 

UNIT 6. Networks.

Lesson 18.

Network definition.

Networks are systems that are formed by links. For example, roads that connect groups of people together create a physical network. Connections with your friends create your personal network. Websites that allow individuals to link to each other’s pages are called social networking sites.

People use the following networks every day:

· Mail delivery system

· Telephone system

· Public transportation system

· Corporate computer network

· The Internet

The public transportation system shown in the figure is similar to a computer network. The cars, trucks, and other vehicles are like the messages that travel within the network. Each driver defines a starting point (source computer) and an ending point (destination computer). Within this system there are rules, similar to stop signs and traffic lights, which control the flow from the source to the destination.

 

Network media.

Communication across a network is carried on a medium. The medium provides the channel over which the message travels from source to destination. The plural for medium is media.

Network devices are linked together using a variety of media. These media are:

· Copper cabling - Uses electrical signals to transmit data between devices

· Fiber-optic cabling - Uses glass or plastic fiber to carry information as light pulses

· Wireless connection - Uses radio signals, infrared technology, or satellite transmissions

 

Bandwidth and latency.

Bandwidth on a network is like a highway. The number of lanes on the highway represents the amount of cars that could travel on the highway at the same time. An eight-lane highway can handle four times the number of cars that a two-lane highway can hold. In the highway example, the cars and trucks represent the data.

When data is sent over a computer network, it is broken up into small chunks called packets. Each packet contains source and destination address information. Packets are sent across a network one bit at a time. Bandwidth is measured in the number of bits that can be sent every second. The following are examples of bandwidth measurements:

· b/s - bits per second

· kb/s - kilobits per second

· Mb/s - megabits per second

· Gb/s - gigabits per second

Note: 1 byte is equal to 8 bits, and is abbreviated with a capital letter B. The capital letter B is normally used when describing size or storage capacity, such as a file (2.5 MB) or disk drive (2 TB).

The amount of time it takes data to travel from source to destination is called latency. Like a car traveling across town that encounters stop lights or detours, data is delayed by network devices and cable length. Network devices add latency when processing and forwarding data. When surfing the Web or downloading a file, latency does not normally cause problems. Time critical applications, such as Internet telephone calls, video, and gaming, can be significantly affected by latency.

 

Exercise 3. Give the definitions to the next types of networks:

WLAN, WAN, LAN, PAN, MAN, Peer-to-peer network, Client-server network.

 

Wireless security.

The best way to secure a wireless network is to use authentication and encryption. Two types of authentication were introduced with the original 802.11 standard, as shown in the figure:

· Open system authentication - Any wireless device can connect to the wireless network. This should only be used in situations where security is of no concern.

· Shared key authentication - Provides mechanisms to authenticate and encrypt data between a wireless client and AP or wireless router.

The three shared key authentication techniques for WLANs are as follows:

· Wired Equivalent Privacy (WEP) - This was the original 802.11 specification securing WLANs. However, the encryption key never changes when exchanging packets, making it easy to hack.

· Wi-Fi Protected Access (WPA) - This standard uses WEP, but secures the data with the much stronger Temporal Key Integrity Protocol (TKIP) encryption algorithm. TKIP changes the key for each packet, making it much more difficult to hack.

· IEEE 802.11i/WPA2 - IEEE 802.11i is now the industry standard for securing WLANs. The Wi-Fi alliance version is called WPA2. 802.11i and WPA2 both use the Advanced Encryption Standard (AES) for encryption. AES is currently considered the strongest encryption protocol.

Since 2006, any device that bears the Wi-Fi Certified logo is WPA2 certified. Therefore, modern WLANs should always use the 802.11i/WPA2 standard.

 

Exercise 2. Give the definitions to the next terms:

Router, Modem, Firewall, Switch, Patch panel, Wireless access point, Repeater, Hub, PoE switch

 

Analog Telephone

Analog telephone, also called plain old telephone service (POTS), transmits over standard voice telephone lines. This type of service uses an analog modem to place a telephone call to another modem at a remote site, such as an Internet service provider. The modem uses the telephone line to transmit and receive data. This method of connection is known as dialup.

Broadband

Broadband is a technology that is used to transmit and receive multiple signals using different frequencies over one cable. For example, the cable used to bring cable television to your home can carry computer network transmissions at the same time. Because the two transmission types use different frequencies, they do not interfere with each other.

Broadband uses a wide range of frequencies that can be further divided into channels. In networking, the term broadband describes communication methods that transmit two or more signals at the same time. Sending two or more signals simultaneously increases the rate of transmission. Some common broadband network connections include cable, DSL, ISDN, and satellite. The figure shows equipment used to connect to or transmit broadband signals.

 

POTS

A POTS connection is extremely slow, but it is available wherever there is a landline telephone. There are two major disadvantages of using the phone line with an analog modem. The first is that the telephone line cannot be used for voice calls while the modem is in use. The second is the limited bandwidth provided by analog phone service. The maximum bandwidth using an analog modem is 56 Kb/s, but in reality, it is usually much lower than that. An analog modem is not a good solution for the demands of busy networks.

ISDN

ISDN is very reliable because it uses POTS lines. ISDN is available in most places where the telephone company supports digital signaling to carry the data. Because it uses digital technology, ISDN offers faster connection times, faster speeds, and higher quality voice than traditional analog telephone service. It also allows multiple devices to share a single telephone line.

DSL

DSL allows multiple devices to share a single telephone line. DSL speeds are generally higher than ISDN. DSL allows the use of high-bandwidth applications or multiple users to share the same connection to the Internet. In most cases, the copper wires already in your home or business are capable of carrying the signals needed for DSL communication.

There are limitations to DSL technology:

· DSL service is not available everywhere, and it works better and faster the closer the installation is to the telephone provider's central office (CO).

· In some cases, installed telephone lines will not qualify to carry all DSL signals.

· The voice information and data carried by DSL must be separated at the customer site. A device called a filter prevents data signals from interfering with voice signals.

Cable

Most homes that have cable television have the option to install high-speed Internet service using that same cable. Many cable companies offer telephone service as well.

Satellite

People who live in rural areas often use satellite broadband because they need a faster connection than dialup, and no other broadband connection is available. The cost of installation and the monthly service fees are generally much higher than those of DSL and cable. Heavy storm conditions can degrade the quality of the connection slowing down or even disconnecting the connection.

Cellular

Many types of wireless Internet services are available. The same companies that offer cellular service may offer Internet service. PC Card/ExpressBus, USB, or PCI and PCIe cards are used to connect a computer to the Internet. Service providers may offer wireless Internet service using microwave technology in limited areas.

Type	Advantages	Disadvantages	Speed

Data center.

As organizations evolve, they require increasing amounts of computing power and hard drive storage space. If left unaddressed, this will impact an organization’s ability to provide vital services. The loss of vital services means lower customer satisfaction, lower revenue, and, in some situations, loss of property or life.

Large enterprises typically own a data center to manage the storage and data access needs of the organization. In these single tenant data centers, the enterprise is the only customer or tenant using the data center services. However, as the amount of data continues to expand, even large enterprises are expanding their data storage capacity by utilizing the services of third-party data centers.

Lesson 22. Mobile devices.

Laptops and mobile devices.

The first laptops were used primarily by business people who needed to access and enter data when they were away from the office. The use of laptops was limited due to expense, weight, and limited capabilities compared to less expensive desktops.

Improvements in technology have allowed the laptop to become lightweight, powerful, and much more affordable. Because of this, laptops are found in just about every setting today.

Laptops run the same operating systems as desktop computers and most come with built in Wi-Fi, webcam, microphone, speakers, and ports to attach external components.

A mobile device is any device that is hand-held, lightweight, and typically has a touchscreen for input. Like a desktop or laptop computer, mobile devices use an operating system to run applications (apps), games, and play movies and music. Mobile device also have different CPU architecture, designed to have a reduced instruction set when compared to laptop and desktop processors.

With the increase in demand for mobility, the popularity of laptops and other mobile devices continues to grow. This chapter focuses on many features of laptops, mobile devices, and their capabilities.

 

Connection types.

Mobile devices can connect to other devices to use shared peripherals or other resources. They can be wired or wireless connections.

Wired Connections

· Micro/Mini universal serial bus (USB) connectors – These USB connectors can charge a device and transfer data between devices.

· Lightning connector – allows Apple mobile devices to connect to host computers and other peripherals, such as USB battery chargers, monitors, and cameras.

· Proprietary vendor specific ports – Proprietary vendor specific ports can be found on some mobile devices. These ports are not compatible with other vendors, but often compatibles with other products from the same vendor. These ports are used to charge the device and communicate with other devices.

Wireless Connections

Besides Wi-Fi, mobile devices also use the following wireless connections:

· Near field communication (NFC) – NFC enables mobile devices to establish radio communications with other devices by placing the devices close together or by touching them together.

· Infrared (IR) – If a mobile device is IR enabled, it can be used to control other IR controlled devices remotely, such as a TV, set top box, or audio equipment.

· Bluetooth – This wireless technology allows data exchange over a short distance between two Bluetooth-enabled devices or connect to other Bluetooth-enabled peripheral devices, such as speakers or headphones.

Shared Internet Connections

A smartphone’s Internet connection can be shared with other devices. There are two ways to share the smartphone’s Internet connection: tethering and mobile hotspot. The ability to share the connection depends on the cellular carrier and the plan with the carrier.

· Tether – This uses your cellular phone as a modem for another device, such as a tablet or laptop. The connection is made over a USB cable or Bluetooth.

· Mobile hotspot – A hotspot is where devices connect using WiFi to share a cellular data connection.

Lesson 24.

Scheduling maintenance.

Because laptops and mobile devices are portable, they are used in different types of environments. As a result, they are more likely than desktop computers to be exposed to these harmful materials and situations:

· Dirt and contamination

· Spills

· Drops

· Excessive heat or cold

· Excessive moisture

In a laptop, many components are placed in a very small area directly beneath the keyboard. Spilling liquid onto the keyboard can result in severe internal damage. It is important to keep a laptop clean. Proper care and maintenance can help laptop components run more efficiently and extend the life of the equipment.

Cellular communications.

When people began to use cell phones, there were few industry-wide standards for cell phone technology. Without standards, it was difficult and expensive to make calls to people who were on another network. Today, cell phone providers use industry standards, making it less expensive to use cell phones to make calls.

Cellular standards have not been adopted uniformly around the world. Some cell phones are capable of using multiple standards, whereas others can use only one standard. As a result, some cell phones can operate in many countries, and other cell phones can only be used locally.

The first generation (1G) of cell phones began service in the 1980s. First-generation phones primarily used analog standards. With analog, interference and noise cannot easily be separated from the voice in the signal. This factor limits the usefulness of analog systems. Few 1G devices are in use today.

In the 1990s, the second generation (2G) of mobile devices was marked by a switch from analog to digital standards. Digital standards provide higher call quality.

As 3G cell phone standards were being developed, extensions to the existing 2G standards were added. These transitional standards are known as 2.5G standards.

Third-generation (3G) standards enable mobile devices to go beyond simple voice and data communications. It is now common for mobile devices to send and receive text, photos, audio, and video. 3G even provides enough bandwidth for video conferencing. 3G mobile devices are also able to access the Internet to browse, play games, listen to music, and watch video.

Fourth-generation (4G) standards provide ultra-broadband Internet access. Higher data rates allow users to download files much faster, perform video conferencing, or watch high-definition television. These are some common 4G standards:

· Mobile WiMAX

· Long Term Evolution (LTE)

The specification for 4G devices sets peak speed requirements at 100 Mb/s for highly mobile devices (devices in cars or trains) and 1 Gb/s for devices being used by people moving slowly or standing still.

Mobile WiMAX and LTE

Even though Mobile WiMAX and LTE fall short of the data rate to be compliant with 4G (128 Mb/s and 100 Mb/s, respectively), they are still considered 4G standards, because they offer so much improvement over the performance of 3G. WiMAX and LTE are also forerunners to versions that will be compliant with the full specification of 4G.

Technologies that add multimedia and networking functionality can be bundled with cellular standards. The two most common are Short Message Service (SMS), used for text messaging, and Multimedia Message Service (MMS), used for sending and receiving photos and videos. Most cellular providers charge extra for adding these features.

As a mobile device moves from an area of 4G coverage to 3G coverage, the 4G radio shuts off and turns on the 3G radio. Connections are not lost during this transition.

Hotspot

A hotspot is a physical location where an Internet connection is shared among wireless users. A personal hotspot can be created using a mobile device with a cellular data connection. The mobile device with hotspot enabled can offer Internet connection to other devices in the wireless LAN.

Airplane Mode

Most mobile devices also have a setting called Airplane Mode that turns off all cellular, Wi-Fi, and Bluetooth radios. Airplane Mode is useful when traveling on an airplane or when located where accessing data is prohibited or expensive. Most mobile device functions are still usable, but communication is not possible.

There are apps available for mobile devices that can display available networks, signal strength of access points and towers, and even locations of networks. A WiFi analyzer can be used to display information about wireless networks, while a cell tower analyzer can be used on cellular networks. These can be very useful tools to start with when diagnosing mobile device radio problems.

 

Introduction to E-mail.

The email structure relies on servers and clients. Email servers are responsible for forwarding email messages sent by their users. Users utilize email clients to compose, read and manage their messages. Email clients can be web-based or standalone applications. Standalone email clients are platform dependent. This section focuses on email clients for mobile devices.

The following information is required when setting up an email account:

· Display name

· Email address

· Email protocols used by the incoming mail server

· Incoming and outgoing mail server names

· Username

· Account password

 

The protocols used in email include the following:

· Post Office Protocol version 3 (POP3)

· Internet Message Access Protocol (IMAP)

· Simple Mail Transfer Protocol (SMTP)

· Multipurpose Internet Mail Extensions (MIME)

· Secure Socket Layer (SSL)

You need to know how to configure a device to accept the correct incoming mail format. You can configure the email client software using a wizard.

POP3

Post Office Protocol 3 (POP3) retrieves emails from a remote server over TCP/IP. POP3 does not leave a copy of the email on the server; however, some implementations allow users to specify that mail be saved for some period of time. POP3 supports end users that have intermittent connections, such as dialup. A POP3 user can connect, download email from the server, and then disconnect. POP3 usually uses port 110.

IMAP

Internet Mail Access Protocol (IMAP) allows local email clients to retrieve email from a server. Like POP3, IMAP allows you to download email from an email server using an email client. The difference is that IMAP allows the user to organize email on the network email server, and to download copies of email. The original email remains on the network email server. Unlike POP3, IMAP typically leaves the original email on the server until you move the email to a personal folder in your email application. IMAP synchronizes email folders between the server and client. IMAP is faster than POP3, but IMAP requires more disk space on the server and more CPU resources. The most recent version of IMAP is IMAP4. IMAP4 is often used in large networks, such as a university campus. IMAP usually uses port 143.

SMTP

Simple Mail Transfer Protocol (SMTP) is a text-based protocol that transmits emails across a TCP/IP network. It is an email format for text that uses only ASCII encoding. SMTP must be implemented to send email. SMTP sends email from an email client to an email server or from one email server to another. A message is sent after recipients are identified and verified. SMTP usually uses port 25.

MIME

Multipurpose Internet Mail Extension (MIME) extends the email format to include text in ASCII standard as well as other formats, such as pictures and word processor documents. MIME is normally used in conjunction with SMTP.

SSL

Secure Sockets Layer (SSL) was developed to transmit files securely. All data exchanged between the email client and the email server is encrypted. When configuring an email client to use SSL, make sure to use the correct port number for the email server.

Exchange

Exchange is an email server, contact manager, and calendaring software created by Microsoft. Exchange uses a proprietary messaging architecture called Messaging Application Programming Interface (MAPI). MAPI is used by Microsoft Office Outlook to connect to Exchange servers, to provide email, calendar, and contact management.

Laser printing process.

The laser printer process involves seven steps to print information onto a single sheet of paper.

1. Processing - The data from the source must be converted into a printable form. The printer converts data from common languages, such as Adobe PostScript (PS) or HP Printer Command Language (PCL), to a bitmap image stored in the printer’s memory. Some laser printers have built in Graphical Device Interface (GDI) support. GDI is used by Windows applications to display printed images on a monitor so there is no need to convert the output to another format such as PostScript or PCL.