Comptia A+ Certification (Exams 220-901 & 220-902)

Easy Guide for Beginners

By Erwin Haas

Copyright©2017 by Erwin Haas

All Rights Reserved

Copyright © 2017 by Erwin Haas

All rights reserved. No part of this publication may be reproduced, distributed, or transmitted in any form or by any means, including photocopying, recording, or other electronic or mechanical methods, without the prior written permission of the author, except in the case of brief quotations embodied in critical reviews and certain other noncommercial uses permitted by copyright law.

Table of Contents

Introduction

Chapter 1- Hardware

Chapter 2- Networking

Chapter 3- Mobile Devices

Chapter 4- Windows Operating Systems

Conclusion

Disclaimer

While all attempts have been made to verify the information provided in this book, the author does assume any responsibility for errors, omissions, or contrary interpretations of the subject matter contained within. The information provided in this book is for educational and entertainment purposes only. The reader is responsible for his or her own actions and the author does not accept any responsibilities for any liabilities or damages, real or perceived, resulting from the use of this information.

The trademarks that are used are without any consent, and the publication of the trademark is without permission or backing by the trademark owner. All trademarks and brands within this book are for clarifying purposes only and are the owned by the owners themselves, not affiliated with this document. **

Introduction

The Comptia A+ Certification (Exams 220-901 & 220-902) exam tackles a number of topics. For you to pass this certification exam, you have to read these topics. This book is an exploration of the topics which are tested in this exam. Enjoy reading!

Chapter 1- Hardware

The Motherboard

The PC motherboard is made up of a mixture of hardware. The design of the motherboard may seem to be very standardized, but the fact is that its original design has evolved too much since the inception. In this exam, these are broken down based on their design, the form factor, as well as based on the standard governing them. The following are form factors which are important for the exam:

ATX

This forms the standard motherboard size. This forms the platform for the workstations and the gaming PCs. The form factor specification for this calls for a size which measures 12.0” by 9.6”. Note that the processor which is to be used is based on what fits in the socket for the motherboard which you have chosen.

Micro-ATX

For the overall size of the PCs to be reduced, the introduction of smaller form factors was done. The Micro-ATX was one of them, and it shaves a few inches off the length (9.6” by 9.6”). This one shares a similar power supply connections together with an Input/output back panel. It is capable of replacing the full size ATX motherboard. However, it may have an on-board audio. This type has at least a single expansion slot which a riser card can use.

Mini- ITX (ITX)

This is the best for those who are more interested in silence more than performance. However, note that we are not saying that the performance will generate noise, but what it does is that it generates heat which needs cooling, and this comes with noise. Also, due to its size, it will accommodate only fewer components.

The Expansion Slots

Let us discuss some of the expansion slots which are covered in the A+ 220-901 exam:

PCI

The 32 bit PCI (the Peripheral Component Interconnect) bus forms the oldest model of expansion slot which is covered in this exam. It is available in both 32 and 64 bit versions, and it is used for connecting the legacy hardware to a PC.

This PCI was then replaced by the PCI Express (PCI-e) that is the only one which you will practically use and see today.

PCI-X

PCI-X (in which X is for eXpress) has both the 32 and 64 bit slots which are designed so as to be backward compatible with the 32 bit PCI cards. The cards have been designed so that they can be used at 3.3 V. The voltage portion slot of this slot goes beyond what a 32 bit 3.3 V card is capable of reaching.

PCI-E

This is another variation of the PCI (where E is for Express). Note that the PCI–e and the PCI-X are currently not compatible with one another. When you are using the PCI-Express, you will have 16 lanes of communication available. The number of slots which it may utilize will be determined by the physixal size of the card. A good example of this is the x 16 slot which is capable of accommodating an x 1 card. When slots are used together, one will enjoy the increased bandwidth.

Mini-PCI

True computer portability was introduced in laptops after the introduction of a mini-PCI card. This can either be a modem or a wireless interface card. Some improvements have been implemented, but the real untethered portability was introduced by this standard.

RAM and CPU Sockets

The RAM slot is an integral component of the motherboard. In the case of the A+ exam, you should know the different types of RAM and its characteristics, and the best ones for high-performance servers and workstations.

DDR RAM

DDR (Double Data Rate) forms the standard RAM which is used in the majority of the PCs today. The DDR RAM comes in a number of versions which include the following:

DDR, which was first released at around 2000.

DDR2, which uses less power and doubled the DDR performance.

DDR3, which uses even less power and doubled the performance of the DDR2.

The DDR4 RAM is also available, and it is beginning to reach the consumer machines. It is expected that the next generation of the PCs which run the upcoming Skylake processors for Intel should offer a better support for the DDR4 RAM.

The type of RAM which is to be installed is determined by the type of the motherboard which is being used. Each DDR version has own unique and notched module shape, meaning the wrong version of the DDR RAM cannot be installed on the motherboard which does not support it.

DIMMs and SODIMMs

The DDR RAM has two primary physical sizes, that is, the DIMMs and the SODIMMs. DIMM is for Dual In-line Memory Module, while SODIMM is for Small Outline Dual In-line Memory Module. The DIMMS are widely  used in the desktop computers as well as in servers, while the SODIMMS are commonly used in the laptop computers.

RAM Characteristics

The following are the characteristics of RAM which you should know for the purpose of the exam:

Parity vs. Non-parity

The older versions of the RAM were available in either parity or non-parity types. A parity RAM is capable of detecting the memory-based data errors (without correcting them), while the non-parity RAM doesn’t have this kind of function.

The parity RAM was largely made obsolete by the ECC RAM.

ECC RAM

Error-Correcting Code (ECC) RAM is capable of doing both detection and correction of memory-based data errors. ECC RAM is commonly used in critical servers where data corruption cannot be tolerated. The ECC RAM is a bit expensive, and it needs ECC-supporting processors and motherboards that are more expensive too.

Buffered vs. Unbuffered

Buffered RAM puts less power load on the memory controller of the system. This becomes good when one has a lot of RAM already installed in the machine, as is the case with the high-performance servers. The regular workstations always have an unbuffered RAM installed.

Single-sided vs. Double-sided

If all the RAM chips are located on one side of your RAM module, then this is referred to as a single-sided RAM. If it has chips on both sides of the module, then it is referred to as a double-sided RAM. The single-sided RAM is a bit newer, and the older motherboards may encounter trouble when trying to recognize it.

RAM Channels

RAM channel is the communication level between the RAM modules and system’s memory controller. If there are a high number of channels, there will be more RAM modules which the memory controller will be able to access.

The majority of standard PCs are compatible with dual-channel, which means that the motherboard usually has not less than two RAM sockets, which are in need of two identical RAM modules already installed for the dual-channel to work.

Triple-channel motherboards usually have not less than three RAM sockets (or in multiples of three), and they usually need certain models of the CPUs, such as an Intel Core i7 or a Xeon processor. Quad-channel motherboards also exist with four RAM sockets, or in multiples of four. The triple and the quad-channel RAM systems are usually a bit expensive to build, and they mostly reserved to be used in high-performance servers as well as workstations.

CPU Sockets

For the Socket Types, there exist eleven individual sockets. However, these have been classified into two main categories. PGA (Pin Grid Array) consists of a socket on a motherboard which is made up of a pattern of small receptors which have been designed to accept some particular pin pattern for a chip only. There is also the LGA (Land Grid Array) type that reverses the design by putting small fragile pins in a socket where there is a greater protection from bending and breakage. This design is also good for providing a solid connection.

Cooling and Processor Speeds

The control of the processor speed is done by the use of the core speed of a processor multiplied by the speed of the Front Side Bus. It is possible for this speed to be manipulated. You can speed up or “Overclock” the speed by increasing the multiplier of the Front Side Bus. However, you should be aware that there is a danger as far as this is concerned. If the processor runs faster, then it will become hot. The normal use processors come with a 12 volt fan as well as a heatsink which has been attached to the processor by the use of clamps and thermal paste. This will provide adequate protection for general use, but it will prove inadequate when it comes to extreme situations such as overclocking. If you need to overclock your machine, you should consider upgrading the cooling system to some liquid based system, then add fans to your case, otherwise, the life of the processor will be shortened.

Passive Heat Sink

The passive (or the fanless) heatsink is made up of a small aluminum block having fins which stick up vertically for catching airflow and dissipating heat from the chip. It is a simple design which creates some enormous surface area which the device can use for the purpose of heat exchange.

Thermal Paste

The exchange occurs where the chip conducts the temperature through a layer of a thermally conductive paste so as to avoid an uneven thermal transfer.

Once you modify this design by attaching a fan to it, you will create a more familiar Active heatsink.

Active Heat Sink

The most modern approach to moving heat is by use of a liquid based cooler.

This design usually takes the elements which have been described up to this point and then adds a cooling liquid. A pile which is sealed and leak-proof is used for piping the liquid over chip, absorbing heat, and transferring it out to the “radiators” which are located in the cooler areas of machine, and this decreases the temperature. The cooled liquid is returned, and the process then repeats continuously.

When choosing a processor and a motherboard, the key features you should consider are the processor speed, the core number, and the amount of cache memory which is available. When calculating the processor speed, if you have four 2GHz cores, you should know that the resultant speed will not be additive. What you have are four cores which are capable of operating at 2.0 GHz simultaneously.

This is not equal to an 8GHz processor.   Having a look at the BIOS/UEFI will give you the rest of the information which is needed for you to satisfy the objective. On your Intel motherboards, is the hyper threading enabled? The hyper threading should be working since it enables the processor to work on your multiple tasks. It smoothes out operations and it allows multiple things to take place simultaneously.

You should also check the L1, L2, and the L3 cache. They are locations which are used as the temporary holding areas for the data which is in the process but not already complete. L1 forms the fastest and the expensive real estate on your machine. It is in multiples of 64 k of the fast memory on the processor chip.

The L2 is expected to follow that. In some cases, it is located on the chip, but in most cases, it is located on the motherboard. The L3 if it is available will be on the motherboard. These small storage areas are good in saving the PC from saving and retrieving the data to and then from the hard disk during the routine operations.

Virtualization

This topic is highly tested in this exam. Virtualization will enable you to run multiple instances of the complete machines on a single hardware platform. It is good for saving the resources, and to quite boost the productivity. Always remember to check the BIOS/UEFI first. 

When virtualization has been enabled, in the BIOS you will be able to install many virtual machines the way you like. Also, each of these has to be properly licensed. Once the installation has been done, it will be impossible for you to tell the virtual machine and the original.

Chipsets

The computers’ chipsets have been designed so as to enable the data to flow from PC components and memory and then to the processor. There exist small but very significant differences in the chip design, and you will notice that the chipsets make specific. This means that you have to find yourself CPU architecture support on the motherboard from one manufacturer rather than the other. They are classified as follows:

North Bridge

This is a bit faster of the two types of chipsets. It is used for connecting the main system memory, the AGP/PCIx, and the processor.

South Bridge

The PCI-E et al. forms the major connection here. It is made up of your hard disks USB connections, and these can be of any type.

The bus speed determines the overall speed of the machine. The speed of the chipset doesn’t matter, but the bus speeds forms the bottleneck. A machine which is capable of delivering data which is time sensitive becomes faster.

CMOS Battery

The CMOS/UEFI setting, which is the System Configuration Information, is being held safe in firmware. Such essential settings are usually maintained by a small watch battery. Signs of failure in this case are loss of PC date and the time, or loss of the hard disks. We should ensure that the configuration doesn’t get lost or maybe forgotten by simply keeping it electronically refreshed. The firmware is resistant to the data loss. For one to stay safe, it has to be electronically refreshed on a periodical basis by use of a tried as well as a true 2032 battery. This model has remained unchanged since 1985.

Power connections

The AT P8-P9 has been long used to power most legacy machines. P8 and P9 have been widely used for powering the IBM XT, after the original PC was released in the 80s.

The ATX20+4 was introduced later, but it has been around for a long time now. After the need for power increased, manufacturers responded by releasing the ATX. It is a platform which supplied advanced features such as power saving fan controls and energy saving sleep modes. Today, it is the ATX 20 or the 24 pin design of 20 and 24 pin ATX connection which areused for providing power connections to modern motherboards.

Fan connectors

Most fans have a voltage which ranges between 5 to 19 volts. It is always good for you to ensure that you get the one with the right voltage. Front panel connections have also been introduced for a number of configurable connectors. With combination of the USB devices to nearly anything, there is an incredible ease of connectivity. The options for this are given below:

Power light

USB

Power button

Drive activity lights

Audio

button

Chapter 2- Networking

For you to be able to understand network security, it is good for you to first understand the basics of computer networks. Network security is a term used to describe all activities which are designed for protection of the network. Such activities include the usability, integrity, reliability, and safety of the data and network.

A good network security mechanism is one which targets a number of threats, and it targets securing your network from such threats. Let us discuss some of the basics of computer networks.

Cables and Connectors. Fiber Optic

The fiber optic transmissions involve the use of light pulses for signals which are sent over glass or plastic strands. The glass medium (the fiber) can break or lose a signal once it is bent over some particular radius,and this is based on its thickness. This calculation of the radius is done based on the thickness of fiber and cable that should not be coiled tightly.

The protection of the fiber core is done by cladding, and a plastic sheath is wrapped in the synthetic strength fibers so as to give this cable some resistance to breakage. The outer part is made of a plastic outer sheath. In case you are concerned about the moisture seeping into cable, a synthetic gel has to be used for filling any gaps and for protecting the fiber.

The benefits associated with the use of fiber optic cable to the copper are many. It is possible for each of the connectors to be configured so as to make use of a single-mode or multimode. The following are some of the benefits of using fiber optic compared to copper cables:

The fiber has broader bandwidth, which makes it possible for it to handle more discrete channels at a higher speed. It is also immune to electromagnetic interference which makes it less from less signal degradation.

Fiber has less signal loss (or attenuation) over a distance.

It is impossible to “tap” fiber, which provides an increased security over a copper cable.

The Straight Tip (ST) connector is one of longstanding connector types. It will be easy for you to recognize it once you find it on the field. This is shown below:

The Subscriber Connector (SC) has been in use for a long time, and is a very reliable and stable snap-in connector which offers a low signal loss together with ease of use. Sometimes, this connector is referred to as a standard connector or square connector due to its shape.

The LC connector is somehow a newer design when compared to the others. Sometimes, it is known as a Lucent connector, Local Connector, or a Little Connector. Its main advantage is the size. It is about half the size of a SC connector and completely comparable.

Twisted Pair Connectors

The 802.3 cables are still widely used in networking, despite the rise in the use of fiber optic cables. The implementation of the twisted pair connectors is done in two, which include the RJ-11 and RJ-45.

RJ-11 

This connector used to support early 10BASE-T networks and the Voice Grade telephone connections which had a 6-pin capability. It is still used in the telephone implementations, and it has been overrun in the networking by RJ-45 which will be described later. The RJ-11 is in support of speeds of 10 Mbps, and it is sufficient for voice but inefficient for networking, which can attain speeds of about 1000Mbps.

RJ-45

This connector is the successor to the RJ-11 connector for network use. It makes use of four twisted pairs of wire which have been configured so as to reduce cross-talk and the other problems which are associated with cables. At the initial configuration, this connector was in a position to match the RJ-11 speeds of 10Mbps, which formed the standard during that time. You should know how the wiring is done in the RJ-45 connectors. The two dominant wiring pinouts for this include T-568A and the T-568B.

Changes made in the other network hardware have made it possible for the connector to reach a speed of 100Mbps. With the advancement in technology, greater speeds were attained by enhancing the internal configuration of the connector and the cable, while the original size and shape of the connector were left unchanged.

Coaxial

The Thinnet or the RG-58 is also another variant of a cable.

The 10BASE2 connector and the cable were a bit hard to manage, compared with the closely related 10BASET. It made use of BNC connectors and a shielded copper core cable which is less manageable. It had a speed of 10Mbps, and a longer range implementation of the required bus topology was a bit hard, and a T connection was needed at each host and at the termination at cable ends for the purpose of preventing signal reflection.

F- Connector

The Home Media Center PC usually needs this connector for connecting the cable or the antenna system to your PC.

By use of a RG-6 cable, such a connection becomes an F-type connector. This one is the same as BNC, with the difference being the F connector usually screws on to a component by use of multiple rotations of a connector to unit as a connection which is more likely to fail in cable than at the connection point. This connection is strong and not easy to pull out.

Characteristics of Cabling and Connectors

It is good for you to learn the characteristics of the cables and connectors, as well as compare and then contrast between the various types of these. The following are the characteristics and the types of various cablings:

Fiber:

The types are single-mode and multi-mode.

There are limitations in speed and transmission.

Twisted pair:

The types are STP, CAT3, CAT5, UTP, CAT5e, CAT6e, CAT7, CAT6, plenum, and PVC.

There are limitations in speed and transmission.

Effects and splitters on signal quality.

Coaxial:

The types are RG-6, and RG-59.

Fiber Optic

We need to debug the misconception of the single mode fiber versus the multimode. Whenever you come across a fiber connector which has two cables on the same connector that will be a Duplex connector, with one cable for transmitting and the other one for receiving, which is not the case with a single connector (simplex).

The multimode/ single-mode distinction is cable color with a yellow cable which signifies single mode cable. If this was in a perfect world, then there would have been a yellow cable for the single mode, and then black, gray, or orange for the multimode. Below is a picture for the orange multimode:

If you don’t observe what the cable color standard is, the marking will be done clearly on the cable jacket. The advantage in this case is that a single mode cable has the capability of transmitting over longer distances with no attenuation or signal loss. The multimode cable is capable of carrying multiple signal modes in the fiber. It has multiple benefits, but this is paid for in the pricing which in our case becomes loss of quality and distance.

Multimode is good for “moderate” distances, which is an indication that after some point, these modes will lose their distinction by a process known as “modal dispersion.”  You can view it as distortion. It becomes advantageous to the implementations which make use of a number of modes on the LAN, most probably the backbone. Some more discrete signals are also supported.

Contrary to expectations, any cable company which is transmitting hundreds of channels has to use a single mode fiber due to the distance limitations. The fiber cable size measurements are written as XX/YYY, which refers to the relationship of thecore to the cladding. It is measured in microns, and you will observe sizes such as 50/125 which means a 50 micron core and a 125 micron cladding, and such sizes will handle the multimode transmissions. Cores of 9 microns may also be available for the single mode implementations which would support the practically infinite bandwidth. In a Fiber Distributed Data Interface (FDDI) case, you may see even four cores, while in general use; you may only have a single core.

Twisted Pair

All of the cables given below use a form of the twisted pair cable. This cable can be grouped into two classes despite an unshielded twisted pair (UTP) or the deployment Shielded twisted pair (STP).

UTP vs STP

The difference comes in internal construction of your cable, probably the insulation amount or the shielding which surrounds each of the internal cable pair. Every internal pair has been twisted at different twists per inch to reduce the possibility of pairs being parallel to one another and allow for crosstalk.

Types

CAT3

This is used in early implementations of the twisted pair, and it makes use of up to 6 conductors or wires. The type is commonly used in a telephone that has two pairs for every phone. This is an indication that the cable will be supporting two phone lines.

CAT5

The cable rating has four pairs, and it is capable of supporting transmission speeds of up to 100Mbps, with the maximum cable length being 100 meters (or 328 feet). The real world applications can provide you with higher speeds, but this is the specification in the A+.

CAT5e

This is simply the CAT5 which has been enhanced. The enhancement of this has been reduced crosstalk. This may not be a big deal to you until when you have a look at numbers. CAT5e is in support for gigabit Ethernet 1000Mbps. This can be attributed to the stricter attention to the number of twists in the pairs. The hardware must be able to support this speed. It provides 1Gbps, with the maximum cable length being 90 meters (or 295 feet).

CAT6

This one supports 10Gbps with the frequency being of 250 Mhz. This is a way of reducing the crosstalk. With the maintenance of a form for the external RJ-45, the connector and the cable were developed so as to further isolate cables from one another, which explain the source of the higher throughput.

CAT6e

This has an enhancement which doubles transmission frequency up to 500 MHz, and then restores traditional segment length up to 100 meters (or 328 feet). It is not a standard, but it is recognized and widely observed.

CAT7

This performance standard has increased the performance up to 600 MHz, and it has provided a more durable and reliable cable compared to its predecessors. It has some additional shielding layer by wrapping of entire insulated pair with an additional layer wrapping of a whole cable bundle.

Coaxial

Radio Grade-6 (RG-6) cables usually have a number of uses in communication. The construction may vary by the manufacturer, but all will have a solid copper core which has been encased in a plastic insulating sleeve which has been covered by a wire mesh (or a foil) which insulates this cable from noise and it provides grounding. All of this will be contained inside a plastic jacket. It is terminated with an F-type connector which is used on a RG-6 and the RG-59 cables. The RG-6 is now becoming the preferred type of cable for the installation of cable television.

Radio Grade-59 (RG-59) Coaxial cables were sometimes used in the heavily CATV installations.  The process of construction is similar to RG-6 with the difference being that the RG-59 makes use of a thinner core. The RG numbering system utilizes increasing numbers so as to represent the thicker cores, and the RG-6 is made thicker than the RG-59. Both of these cable types make use of the F-type terminators.

Splitters

In most cases, you will be called on to add workstations in a wired building which has no open outlets in a reasonable distance. A host can be added to the Ethernet network outlet by use of a splitter. The splitter is a simple device which plugs into the wall jack or the other suitable jack, and it provides two connections when  there was once one.

Cable Jackets

These are used for ensuring safety when you are using the network.  The outer sheath of these cables is made up of either PVC (PolyVinylChloride) or Plenum grade. The PVC is cheaper and good for the patch cables.

The TCP/IP

TCP/IP is a robust protocol which is used for management of networks from the smallest of LANs to the World Wide Web.

IP Addresses

This is the IP protocol, and it is used for identifying hosts. The twomain types of IP addresses which are actively used are the IPv4 and IPv6.

The TCP/IP protocol stack forms the base for the World Wide Web and a number of local networks. Each host or client which connects to a network such as the Web needs a unique address. If addresses are duplicated, then a failure will occur in either one or two hosts. IP protocol is utilized for identification of hosts. IPV4 was the first original addressing organization, and it is still used today. In 1999, the Internet Assigned Numbers Authority (IANA) began to deploy the IPv6 protocol due to the depletion of IP addresses.

IPv4

An IP address is made up of 32-bits which are separated in dotted decimal notation to give four octets which are separated by dots. The numbers are usually assigned in the binary form. The maximum value per octet is 255.

IPv6

This was introduced in 1999 so as to solve the problem of depleting IP addresses. It uses 128 bits per address which are written in decimal format. An IPv6 address is made up of eight groups of hexadecimal values. The hexadecimal numbering will allow up to 16 values which are case sensitive (0-9 and A-F) to be expressed rather than the decimal system with 10 numbers.

Unicast

Unicast addresses are used for the purpose of sending information to a single node on the network. The unicast address types are usually unique local, link-local, and global.

Multicast

Muticast addresses are used for sending to multiple groups or targets. It is good in supporting broadcast streams.

Anycast

Anycast addresses are used to deliver content to the closest destination only as determined by the router.

Public and Private Addresses

In both the IPV4 and the IPv6 systems, there are some addresses which have been reserved for private use. These include the following:

IPV4:

10.0.0.0 – 10.255.255.255

172.16.0.0 – 172.31.255.255

192.168.0.0 – 192.168.255.255

IPV6:

This is the address block address block of fc00::/7.

APIPA/link local

This is well known as the Zero configuration network. The APIPA and the link local addresses are usually assigned to the hosts when there isn’t a DHCP server which is reachable and there isn’t manual address assignment. IPv4 makes use the address range 169.254.1.0 to 169.254.254.255, while IPv6 is assigned the block of fe80:/64, which means that address fe80 and zeroes will make 64 bits.

Static Addressing vs. Client-side DHCP

The Dynamic Host Configuration Protocol (DHCP) is the most common addressing method for both IPV4 and IPV6. This work is assigned to the DHCP server. DHCP works by assigning a unique IP address to each host in the network. The server has a pool of addresses which it will use to assign any host which attempts to establish a connection to the network.

Gateways and DNS

Network clients are able to access computers located on local network or the Internet by use of its IP address if it is known. The Internet access would have been based on configuration of the Gateway on a network. This is simply a device which handles off the network requests and then forwards them to the Internet. The address for the device becomes part of the client configuration as it is the address of the DNS server.

The Domain Name Server or the DNS resolves the IP addresses into the host names. The DNS server keeps a list of IP addresses of machines known to this and domain name. If the server does not know the name, then it will have to request it from the DNS servers which have it. Once a device has successfully connected, such information has to be cached locally. Always be aware that the Default Gateway and the DNS Server have to be configured for the settings to work properly.

Subnet mask vs. CIDR

Subnet Masks

Subnet masks were introduced so as to allow more 32-bit addresses for use in identifying networks. It is an addressing scheme which allows a second set for numbers to identify the number of bits of address which should be used for identifying the network in the eight bit blocks which were commonly known as classes. The subnet mask is 32-bits long, and it is formatted in a similar manner as an IP address. With this, we are allowed to use either 16 bits or more for a network address.

CIDR

Classless Inter-Domain Routing (CIDR) was introduced as a granular way to assign the network addresses. It is a method which allowed for any number of the bits to be used as a subnet.

WiFi Networking

The various WiFi networking standards, as well as the encryption types, are tested in the exam. Let us discuss these:

Standards

The WiFi networking standards belong to the 802.11 a/b/g/n/ac family. Let us discuss these standards individually:

802.11a

This is a standard which is capable of supporting a transmission speed of 54Mbps for about 50 meters in a 5GHz band. The standard is essentially deprecated.

802.11b

This forms the first Wi-Fi standard to be widely adopted. It provides a speed of 11Mbps with the distance being 100 meters and direct line of sight in the 2.4 GHz band which is more crowded. It suffers interference from the household devices such as cordless phones and the microwave ovens.

802.11g

This is a standard which is capable of transmitting at a speed of 54 MHz with a distance of about 100 meters outdoors in a 2.4GHz band.

802.11n

This is a standard which is capable of transmitting at a speed of 600Mbps while making use of up to 4 emulated full-duplex MIMO (Multi In Multi Out)  antennae which can send and then receive virtually simultaneously by use of Time Division Multiplexing (TDM) to slice the transmissions into chunks which are imperceptible so as to create an impression of full-duplex. The 802.11 family standards are all half-duplex.

802.11ac

To date the latest standard, 802.11ac, is capable of reaching speeds of 7 Gbps theoretically using even eight antennae. The additional antennae will allow the 802.11ac standard to use some theoretical channel bandwidth of between 80 to 160 MHz.

Encryption Types

The very nature of wireless signals makes them insecure. It is possible for any third party to intercept and read them. This calls for us to encrypt them. The following are some of the encryption types which can be used for this:

Networking Protocols

WEP

The WEP (Wired Equivalent Protocol) was known to be “go to” encryption in the early wireless environment, since it provided an equivalent security of hard wired connection. Currently, it is known to be less than secure due to the sophistication of the wireless eavesdropping and the key is static, never changing, which makes it shareable for evildoers.

WPA

The WPA (Wired Equivalent Protocol) provides keys which are constantly changing together with a stronger encryption method. It marked the best encryption practical during the time, and it is seen as a replacement for the WEP. It is also known as TKIP (Temporal Key Integrity Protocol), and it generates changing keys. This protocol is used together with the other encryption protocols so as to improve their effectiveness.

WPA2

The WPA2 (Wi-Fi Protected Access 2) is the best protection at the moment, and it was developed based on AES (Advanced Encryption Standard), which is the government standard for the encryption of the classified communication and documentation.

TKIP

The TKIP (Temporal Key Integrity Protocol) is a replacement for WEP, and it generates authentication keys which change frequently by adding a additional security layer.

AES

All wireless networking devices which were manufactured from 2006 must have support for AES (Advanced Encryption Standard) so that they can be allowed to make use of the Wi-Fi logo. AES will improve the method which is used by the TKIP for generation of the encryption keys.

When you are setting up a wireless “n” router, you should know the devices which will be in a position to access it. The AES is the fastest and strongest method of encryption. Once a packet has been received, it must be acknowledged. Any packets which fail will be retransmitted.

TCP and UDP

The Transmission Control Protocol (TCP) is simply a protocol which is used to address the reliability issues which are related to the IP. TCP is tasked with establishing a connection and ensuring continuity, which is necessary for reliable communication on a network and the Internet.

The User Datagram Protocol (UDP) is an unreliable connectionless delivery system which facilitates communication. In this protocol, there is no inter-packet relationship. Due to the lack of acknowledgement, this protocol is faster. Below are the protocols, together with their respective ports:

FPT- port 21

The protocol is used for transferring files in a client /server configuration. Its operation can either be in active or passive mode, and makes use of TCP for controlling the connection. In the active mode, the client has to initiate the connection simply by informing a server on the port it intends to be using so as to receive data. In the active mode, port 21 is used to command and control data which is to be sent out on  port 20, which will serve as the FTP server’s data port. The passive mode is commonly used in situations in which the inbound client TCP connections cannot be possible.

SSH- port 22

The SSH (Secure Shell) usually opens up a secure network channel which provides integrity and confidentiality for network services over an unsecured network by use of a public key cryptography which makes it a cryptographic network protocol. This protocol is used for securing remote network logins as well as other confidential data. The passwords can’t be intercepted, since encryption is established before login is required.

Telnet- port 23

Telnet was developed to support remote logins, as well as communication between the computers in networks. Telnet doesn’t encrypt data, which explains why SSH has replaced Telnet for secure connections.

SMTP- Port 25

Simple Mail Transfer Protocol is used for the transmission of emails over the Internet via port 25.

Pop 3- port 110

The Post Office Protocol, with its latest version being pop3, is used for the management of messages on the server.

IMAP- port 143

Today, the users of mail are capable of using mail services from many devices of different types.  With IMAP (Internet Message Access Protocol), the message is left on the server independent of its delivery status. Any device which tries to check will find the message. However, due to filling up of the available space, you have to configure the mechanism for trashing the messages.

DNS- port 53

The DNS (Domain Name System) is responsible for the work of translating domain names such as www.facebook.com to their corresponding IP address, which are less readable to humans so as to facilitate communication.

HTTP- port 80

HTTP (Hyper Text Transfer Protocol) is the foundation for the Internet, and it is used by web browsers for communication purposes. A client/server method is used in this case, whereby a URL (uniform resource locator) locates and requests information from the target server of the resource.

Internet Connection Types

With the POTS dial-up connection, the Internet connectivity has become a routine in our daily existence. Here is how it is broken down.

Cable

This is a broadband Internet connection of high speed which is always on. It uses a cable modem for communicating over a line which carries the cable television signal. Based on a service agreement, it can support high speeds.

DSL

Digital Subscriber Line (DSL) makes use of the common copper telephone lines. When operating under the basic configuration, it provides 3 signals to and from the DSL modem.

In SDSL (Symmetric Digital Subscriber Line), both the upload and download speed are the same, but in ADSL (Asymmetric Digital Subscriber Line), these are not the same.

Dial-up

This makes use of the POTS lines, but there is no persistent communication. A modem is required so as to modulate a digital signal from a PC to an analog waveform which is being used by the phone lines, and once it has reached the receiving end, the signal will have to be demodulated or converted back to digital. 

Fiber

Currently, the fiber optic is providing the highest bandwidth of about 43 terabytes per second, and this is determined by the provider. The capacity of the media, as well as being on a dedicated line, makes this possible.

Satellite

This uses a satellite which is orbiting round the earth in an orbit, which means that at any point, the satellite will be at a relative location from your point. Over 400 satellites keep on orbiting in this manner. The majority of these are communication satellites which deliver data, voice, Internet, and video. You have to use a satellite mounted at the roof.

Cellular

This was introduced as a way of replacing career sense multiple accesses (CSMA). 2G cellular networks are slower, and you should expect a speed of over 50kbps. The 2G Edge or 2G E followed this with a speed of 384Kbps. The 3G then came with a higher speed of 200K to 4Mbps. Now, with the 4G cellular network, you can get a speed of 1Gbps.

Network Types

There are a number of factors which can be considered for the classification of networks. The following are some of the types of networks:

LAN

A LAN (Local Area Network) is when one or more wireless devices or PCs are connected so as to share services and resources with each other. Examples of such a network type include a business which can interconnect either one or more buildings to users (hosts) within. Each floor might have a printer which each user will be in a position to access.

WAN

A WAN (Wide Area Network) is the opposite of a LAN. The WAN can have several users and networks which are small. These will be spread over a large geographical area. The Internet is an example of a WAN network.

PAN

A PAN (Personal Area Network) is a short range network which consists of personal devices. This is simply a Bluetooth configuration made up of activity monitors and personal heart which are connected to a cell phone. This cell phone can then connect to a laptop‘s Bluetooth to create another PAN.

MAN

A MAN (Metropolitan Area Network) covers a large geographical area, such as   a city or a metropolis. The MANs are made by cities and municipalities so as to provide the essential connectivity during  power outages or any other catastrophic events which would interrupt the traditional WAN.

Network Tools

Let us discuss the tools which are used in networking:

Crimper

The same crimping can be used for both CAT 5 and CAT 6. You only have to ensure that the cable ends are matched against each other, and adhere to the wiring standards. The crimper can then be used for terminating the RJ cables.

Cable Stripper

For most cables to be terminated, the cable coatings have to be removed. A good example of this is the coaxial cable. The outer sheath should be cut away so as to expose the mesh shielding and the core protection will be removed.

Multimeter

These can be either analog or digital. The analog meters are used for testing continuity positive AC, resistance and negative voltages. The display is a needle placed over a gradient background with a needle resting on a value which is being measured. The analog Multimeters are damaged when they are extremely under voltage or the overvoltage which can damage delicate internal windings. 

Digital Multimeters solve this problem by just auto-ranging themselves into volt/amp range, which would provide the relevant output or by displaying some error message.

Cable tester

This is used for diagnosing any problems with your cables such as breakages, crossed pairs to lose wires. It operates well, and it can help you greatly when it comes to troubleshooting.

Patch Panel

This is where the cables which go to the wall jack terminate. In some cases, you are only expected to connect a RJ-45 port to the numbered port. In some other cases, you have to run some 8 wires into the patch channel.

Network Architecture Devices

It is good for you to be aware of the various network devices, and the differences between them.

Hub

The smallest kind of network one can have is a peer-to-peer network. The purpose of a hub is to distribute signals to many hosts, and the Career Sense Multiple Access (CSMA) is responsible for managing the communication whereby the cable has to be checked before transmission.

Router/ Access Point

This can be seen as the traffic cop in the network. It is responsible for determining the traffic which gets into the network and the one which does not. It is responsible for finding the shortest path to the destination of your traffic.

Bridge

Obtains a digital signal from a wireless environment, and then this is converted for use in a wired environment.

Repeater/Extender

This is a device used for refreshing a signal and restoring it back to its original state in terms of strength. Of course, the strength of a signal degrades as one move away from an access point. A repeater helps to solve this problem.

Chapter 3- Mobile Devices

Laptop Hardware and Components

The laptop components are tested in the exam. You should familiarize yourself with these:

Expansion options

In the early days of laptops, expansion cards were the most effective way  to expand the capability of a laptop. These later evolved to CardBus technology and then ExpressCard. These technologies have nowbeen replaced by the USB.

SODIMM

These are now known to be volatile memory, since they have a charge which can retain the content. They were designed due to the need to have extra memory locations which can fit in the available small space.

Flash

This was originally designed so as to help in holding non-volatile memory in the PCs. It is now highly used as a way of storing portable data.

Thumb Drive

Devices should be write-protected to stay safe against the risk of data loss and virus infection. As technology advanced, the packaging and the capacity also advanced. Slots for solid state memory packages were then built into the laptops due to their small size, and they don’t take much space on a laptop and then offered a safe and efficient portability of the data.

Hardware/Device Replacement

In the case of laptops and other portable devices, there is the repair vs. replace cost as well as the convenience balance which is always a factor. What is the cost of the replacement? How much better, faster is your new device? What will be the cost of repair? You can do a backup before you can go to bed.

During the replacement or repair, the device should not be powered. You should also have the device manual with you to act as a guide. This is because the process of repair or replacement will be different based on the model and the manufacturer.

Keyboard

This is one of the easiest components for you to replace, and you may be expected to remove the components so as to get at screws.

The aim should be to keep the metal edges from a direct contact with easily damaged plastic. Slip the tool into a crevice between faceplate and then pry upwards gently. Move to a different position. You should consult the documentation so as to be sure that there aren’t any screws involved. After you begin to separate, work on pieces at the edge of the faceplate until it can be lifted up. Before you can move it too far, just check whether there are some ribbon cables or some other connectors which have been connected to it.

2 to 4 screws should be exposed, so remove them and then lift your keyboard up until you are able to see the ribbon cable which connects it to the motherboard.

Observe the orientation, and you will see one side of your ribbon being striped. The connectors are the Zero Insertion Force (ZIF) type, and they are released by lifting tabs at both ends of a connector. Get a replacement keyboard, and then insert your ribbon cable in a connector which you removed the original from ensuring that there are no unwanted twists in your ribbon.

This should slip right to the socket. Insert the cable until it stops, and then push down on the connector ends so as to secure it. Reverse the process to the point in which the face plate comes into a position but it isn’t snapped in. Power up, and then test your keyboard. In case it works, just power down your machine and then replace the face plate.

Hard Drive

It is good for you to check the website of the manufacturer so as to be sure of the exact type which you should use. 

To access the hard drive, you have to remove the service panel on the bottom part of the laptop. The panel can be identified since in most cases, it covers the memory and the drive and maybe the wireless card.

There can also be a panel which covers only your hard drive. Remove your panel by loosening screws which secure it, and then prying it up. These screws are designed to stay on the panel. Once the panel has been removed, you will be able to see the hard drive.

There will be two or four screws holding the drive in a mounting assembly. Remove your drive carefully, and then disconnect its SATA connector.

Mount your new drive into the assembly, and reconnect its SATA connector, then replace the drive in your laptop by screwing. Replace its service panel. If you need to check whether the drive is seen, just power up and then access UEFI/BIOS, and look for your disk. The operating system will not show it until the time you have initialized it.

Memory

For you to install the memory, you have to remove the service panel as we did previously. The SO-DIMMS pairs are held by some metal clips on the sides of every module. Move these clips outward at the same time, and its module will then pop up slightly, which will be enough for you so as to grasp then remove.

This should be done for both modules. Remove the new memory from the packaging, and install it carefully in by sliding this into memory slots and then pushing down so as to engage the clips. Take note of the silver retaining clips as well as the notch in the memory module which has been aligned perfectly in the socket. Remember the palm rest and the touchpad were removed so as to access the memory.

CPU

You have to choose the best CPU for replacement, based on the options for the manufacturer.  Choose the best match based on cost and performance. Once you have removed the keyboard and the bezel assembly, you should be able to see the heat sink.

Since the height isn’t available as it would have been in a conventional PC, you will notice that the heat exchange assembly is occupying about one fourth of the surface area of your system board, by use of copper piping so as to get processor heat to the fan in a single long flat package.

After removing this, you will see that your processor is visible. Both the processor and the heat exchanger will be visible. Remember that the old thermal paste is still stuck to the processor, and the rest of this is on the bottom of the heat exchanger. Just clean it off.

Remove the old processor, and then replace it. Ensure that you have the thermal compound or a thermal pad between the new processor and the heat sink for distribution of heat evenly.

Chapter 4- Windows Operating Systems

The following are the tools which are used in the Windows operating system.

Aero

This tool was introduced for the first time in Windows Vista, and it introduced transparency and animation features to the desktop. Windows 7 added some enhancements to the Aero tool, such as the Aero peek which clears all the open windows.  Once the mouse is placed over so as to show the button for Show Desktop, the Aero Shake will allow to just holding the title bar of a window. Aero Glass was replaced in Windows 8/8.1 with a solid color scheme for supporting the Metro UI.  Windows 10 introduced back Aero features for particular items such as Action Center and the Start menu.

Gadgets

Gadgets and Sidebar were developed with Windows Vista all the way to Windows 7, and they provided applets which would be placed on the sidebar for displaying things such as weather, clock, currency converter, and system details. This is usually shown vertically along the right-hand side of display.

User account control

This feature was introduced in Windows Vista, and it is part of Windows to-date.

It was developed so that it can help you prevent any unauthorized changes to your system.

BitLocker

This was also introduced in Windows Vista, and it is available today as a way of encrypting the whole drive.  It can be used for encrypting the removable devices and all the volumes. A passphrase or passcode can be created for unlocking the drive once it has been moved to another computer.

Windows Defender

This has been in use for defending systems since the release of Windows 98. To be secure, ensure that it is updated on a regular basis.

Windows Firewall

This is a very effective way to ensure that your PC is secure. It is built-in, and it works by filtering traffic to and from the PC. It can be configured so as to allow some programs and deny others from communicating to your network.

Event Viewer

This can be accessed from the control panel. It gives you detailed information about any errors which it encounters in your system.

Easy transfer

This is a useful tool which can be accessed from the control panel. It will allow you to migrate the settings of a particular file to another file. This can be accessed through Getting Started and then the Welcome screen under “Transfer files and settings from another computer” and then clicking on the Easy transfer link which is displayed. You can then use the method to be used for doing the transfer such as a Flash disk, network, or a specialized cable.

System and Security

The category view gives you the PC settings which have an effect on the security of your system. You should use the best way for classifying or grouping the available icons.

Boot Methods

Internal hard drive (partition)

This involves allowing the computer to boot to its internal storage, or a partition on a hard disk or a solid state drive (SSD).

CD-ROM / DVD

Most desktops and laptops are made with internal optical drives The media in this can be bootable. This method requires you to check UEFI or the BIOS firmware and then you’re Optical Drive before other bootable devices, even the USB.

Netboot

Netboot is Apple’s version of the PXE, and it uses most of same startup initialization routines.

PXE

This helps you to get the result you expect on multiple PCs. If you need to work at high volumes, then a high volume server will be needed. The UEFI and the BIOS should be set so that it can access the Preboot eXecution Environment (PXE), and this will help UEFI/BIOS to make use of the network so as to look for the installation files.

Type of Installations

All the devices from Microsoft are in need of an operating system so as to work. The following are the available types of installations:

Clean install

All the current versions of the Microsoft Windows and variants are available for download, and they can be used for burning physical copies of installation media (such as a DVD 4GB). It is good for you to download and then run Upgrade Assistant and you will ensure that everything is compatible. Also, ensure that you have the right version, either 32-bit or a 64-bit. If you install a 32-bit version on a 64-bit machine, then you will experience decreased memory availability, limitations of the storage media, and a less than a perfect experience.

Upgrade

Similar methods apply for the clean install, but it is impossible for you to Upgrade from a 32-bit Operating system to 64-bit. The process needs a clean install only due to the massive number of changes required for the basic architecture and the core files which are affected. The 32-bit programs should work in a 64 bit environment since the provisions were made to support this. The upgrade install should be supported in the same bit depth as well as in OS versions which are currently supported. Just know that it is possible for you to upgrade OS 7 to 8. However, note that there are circumstances which might make you pay for this.

Refresh/restore

In this method of installation, you need  to create some restore points before any problems may arise. This means that you will be in a position to revert your system back to its original state in case a problem occurs.

Repair installation – Recovery partition

This involves setting up a backup or a restore set. With the recovery installation, it will be possible for you to get your system back to normal even after occurrence of a failure. The tools can be accessed by hitting a  specific key and this is based on the manufacturer.

Multiboot

The systems of today have large enough storage capacity and memory. This gives them the ability to support multiple operating systems. This involves the technology of virtualization.

Image deployment

This is a good way of reducing anomalies which may arise between the installations. A single image can also be used as the foundation for the multiple installs.

Partitioning

Now that you have learned the types of installations, you should know the partitions on which the installation has been done. You should know the devices and how the data is stored on them.

Basic

After an installation of a new hard drive on the Windows system, it has to be configured to be a basic disk. This type of disk is independent of the other disks, and it can be formatted to a compatible portioning system such as MBR or GPT.

Primary

After installation of a new drive, it has to to be initialized and then formatted. In case there are no other options selected, then one primary partition will have to be created, and you will format this to get the file system which you desire. This is the point when we begin to refer to it as a volume.

Extended

A disk may only have one extended partition. The contents of the disk may be resized so as to contain a smaller primary partition which has been resized so as to provide the unallocated space which can then be dedicated to each partition. An extended partition can be further divided.

Logical

The extended partition may be sub-divided so as to get many logical partitions. The dimensions for the logical partitions can be found at the first part of the extended partition, but not in MBR. The logical partitions are not expected to fill your entire extended partition. The empty space may be retained in an extended partition which then may be carved up into additional logical partitions in the future if there is a need.

Dynamic

This type of disk is not limited to a single disk or volume. All the volumes which are used on the dynamic disks are referred to as the dynamic volumes.

GPT

This one is capable of supporting the large hard disks up to a tune of 18 Exabytes.

File System Types

The following are some of the available file system types:

NFS (Network File System)

This is the oldest file system. It has a string security system, and is capable of supporting files with large sizes.

SMB

This forms the basis of the Windows network file sharing protocol.

CDFS

This file system was initially introduced in the Linux operating system, and it allows us to export boot images onto a CD. With this file system, any data which has been placed on a CD can be treated just like a normal file from the command line.

FAT32

This was introduced so that it can address the complexities found in Windows 95 such as the long filenames.

NTFS

This stands for the New Technology File System, and it allows our servers as well as other systems to support the current technologies.

ExFAT

This is a good file system for use in the USB and Flash drives. It has a large support for files and other enhancements.

ext3, ext4

These two are Linux file systems. The ext3 was replaced by the ext4 since the latter can support large files and other systems.

Quick format vs. full format

A quick format will remove all the files on a volume without scanning your drive for problems. A full format will remove all the files, and then scan your disk for any bad sectors.

Workgroup vs. Domain setup

When it comes to Workgroups and Domains, you have to determine whether it will be a home network or a business? Also, the size and the scale, do you have skills or the personnel for handling the administrative tasks?

Conclusion

We have come to the end of this guide. For you to pass the Comptia A+ Certification (Exams 220-901 & 220-902),, there are a number of chapters which you have to master. You have to identify the chapters which are tested in the exam, and then study them. These topics have been discussed in this book!