Home > Articles > Certification > CompTIA

CompTIA A+ Exam Cram: Mobile Device Hardware and Operating Systems

As an A+ technician you need to know the basic hardware of mobile devices. This chapter covers Apple devices and Android-based devices, but also briefly discuss some of the other players in the market. This chapter covers CompTIA A+ 220-802 objectives 3.1 through 3.5.
This chapter is from the book

Mobile devices have simply exploded on to the mainstream scene. Especially since 2010, the amount of mobile devices in use has been growing exponentially. Now, it seems that everywhere you look there is someone tapping away on a tablet computer, smartphone, or other mobile device. As of 2012, half a million Android and Apple devices are activated daily—and that number is increasing! Because of this CompTIA has added an entire mobile devices section to the A+ 220-802 exam. As an A+ technician you need to know the basic hardware of these devices, the differences between the two main mobile operating systems, how to network and synchronize the devices, and how to secure them.

In this chapter we’ll pay the most attention to Apple devices and Android-based devices, but we’ll also briefly discuss some of the other players in the market. For this edition of the book I will refer to an Apple iPad2 tablet computer and an Android HTC Evo smartphone. I do this so that you can see some important configurations on the two most-used platforms in the mobile device market. So enough talk...let’s get mobile!

Mobile Hardware and Operating Systems

Mobile devices are computers, smaller and lighter than desktops and laptops, but computers nonetheless. There are similarities and differences in hardware between the two. You will find there are new players on the software side, and these too have similarities and differences compared to PCs and laptops. But remember that at their core, mobile devices are still computers, and many of the principles and rules that you have learned earlier in this book regarding hardware and software still apply.

Mobile Hardware Examples

A common device as of the writing of this book is the Apple iPad2. It is known as a tablet computer and is manufactured by Foxconn, who also constructs the iPhone, Kindle, Playstation 3, and Xbox 360. Table 17.1 gives a list of the hardware the iPad2 uses.

Table 17.1. Apple iPad2 Hardware

Hardware Component

Description

1 GHz ARM CPU

  • 32-bit Advanced RISC Machine Processor

  • Designed for simplicity and low-power

512 MB DDR2 RAM

  • Similar DDR standard to what PCs use

  • Smaller form factor

16 GB Flash Memory

  • Similar to solid-state flash memory in a USB flash drive

  • Used for permanent storage instead of an SATA or IDE hard drive

Multitouch touchscreen

  • Capacitive touchscreen that responds to fingers and stylus devices

Lithium-ion polymer battery

  • Similar to lithium-ion batteries in laptops

  • Can be made into any shape

  • Lasts for 10 hours on a full charge

As you can see from the table, the basic components of CPU, RAM, and so on are the same as desktop/laptop computers. But the types of components are different. The whole concept of this hardware configuration is based on portability and ease of use. Therefore, tablet computers will be less powerful than desktop computers and laptops; but, the hardware is matched to the type of applications the device will be used for.

Similar tablets (but with different software) include the Motorola Xoom, Samsung Galaxy, and Asus Transformer. These will often be less proprietary than an Apple device; for example, they might use Micro-USB ports for charging and synchronization of data, whereas the Apple iPad2 has a proprietary charging port. You might also see different names for the touch interface of a device. For example, the company HTC developed a user interface called TouchFLO for its smartphones that enabled the user to drag the screen up, left, or right. This has been replaced by HTC Sense, which is a multitouch-enabled touch screen similar to the Apple multitouch technology. As of 2012, most new smartphones and tablets feature multitouch touch screens.

Hardware Differences Between Tablets and Laptops

One of the big distinctions between tablets and laptops is the lack of field serviceable parts. Another difference is that tablets and other similar devices are usually not upgradeable. Some mobile devices, such as smartphones, can have upgraded memory cards and/or batteries, but that’s about it, and these are usually not serviceable in the field because it is difficult to protect yourself from ESD when working on these devices. (But that doesn’t mean it isn’t done.) Many organizations recommend you bring the device back to the lab for upgrades or parts swaps. Other devices such as the iPad2 are not user-serviceable whatsoever; and any attempt at doing so voids the warranty. If repair, upgrade, or replacement is necessary, most organizations utilize the warranties built in to these products, instead of trying to do the work in-house.

A laptop is actually just a smaller, portable version of a desktop computer. Like the desktop computer, it contains a similar processor, similar DDR RAM, and a hard drive that could possibly be solid-state, but regardless will most likely be plugged into an SATA port. It also has a keyboard, and a touchpad similar to a mouse. All this hardware is designed to make the best use of operating systems that you would normally find on a desktop computer. Tablets on the other hand use ARM-based processors and use nonvolatile flash memory hard-wired to the system instead of a magnetic or solid-state hard drive. So, as you can imagine, the tablet has a loss of performance when compared to a laptop. In addition, the tablet utilizes an on-screen keyboard and doesn’t require any type of mouse due to the touchscreen capability. All this hardware is designed to run mobile device software such as Android or iOS.

Mobile Operating Systems

Currently, mobile device software comes in one of two forms: open-source, which is effectively free to download and modify; and closed-source, otherwise known as vendor-specific, which cannot be modified without express permission and licensing. There are benefits and drawbacks to each type of system. Because you will see both in the field, you should know each one equally. Let’s go over these two systems.

Open-Source: Android

Android is an example of open source software. It is a Linux-based operating system used mostly on smartphones and tablet computers and is developed by the Open Handset Alliance, a group directed by Google. Google releases the Android OS code as open-source, allowing developers to modify it, and freely create applications for it. Google also commissioned the Android Open-Source Project (AOSP); its mission is to maintain and further develop Android. You’ll know when you are dealing with the Android open-source OS and related applications when you see the little robot caricature, usually in green.

Android OS versions are dubbed with names such as Cupcake, Gingerbread, and the two latest: Honeycomb (version 3) and Ice Cream Sandwich (version 4). To find out the version you are currently running, start at the Home screen; this is the main screen that boots up by default. Then tap the Menu button, and then tap Settings. (Settings is used often in this chapter as a starting point, so remember how to get there!) Scroll to the bottom and tap the About Phone (or just About) option. Then tap Software Information or similar option. This displays the version of Android. Figure 17.1 shows a smartphone using Android version 2.3.3 (Gingerbread)

Figure 17.1

Figure 17.1. Typical smartphone using Android version 2.3.3

Say a company wanted to create a custom version of the Android OS for a handheld computer that it was developing. According to the license, the company would be allowed to do this and customize the OS to its specific hardware. Some companies opt to use Android for this purpose, whereas others use Windows CE or Windows Mobile (for a fee), both designed for handheld computers.

Closed-Source: iOS

Apple’s iOS is an example of closed-source software. It is found on iPhones and iPads as well. It is based off Mac OS X (used on Mac desktops and laptops) and is Unix-based.

To find out the version of iOS you are running go to the Home screen, and then tap Settings. Tap General and then tap About. You see the Version number. For example, Figure 17.2 shows an iPad2 running Version 5.0 (9A334). 9A334 is the build number; this was the public release of version 5.0.

Figure 17.2

Figure 17.2. iPad2 using version 5.0 of iOS

Unlike Android, iOS is not open-source, and is not available for download to developers. Only Apple hardware uses this operating system. This is an example of vendor-specific software. However, if a developer wants to create an application for iOS, they can download the iOS software development kit (SDK). Apple license fees are required when a developer is ready to go live with the application.

Obtaining Applications

Mobile devices are nothing without applications. To this end, both Android and iOS have application sources where you can download free and paid applications (also known as apps).

Android users download applications from the Android Market (also accessible through Google Play.) This can be done directly from the mobile device. Or if a mobile device is connected via USB to a computer, the user can browse apps on the Google Play website while working on the computer and download directly from the site to the phone, passing through the computer.

iOS users download applications from the App Store. This was originally an update to the iTunes store, but on newer iOS mobile devices, it is now a separate icon on the Home screen. Apps can also be downloaded from a Mac or from a PC through the iTunes application.

Regardless of the OS, users would search for the name of the application they want, download it, start the installation process, agree to a license, and then finally make use of the app.

Some applications don’t work unless a person was to hack the OS and gain “superuser” privileges. In the Android world this is known as rooting the phone or other mobile device. In the iOS world it is jailbreaking. Note that performing either of these could be a breach of the user license agreement. It can also be dangerous. These types of hacks often require a person to wipe out the device completely, and install a special application that may or may not be trustworthy. Many phones are rendered useless or are compromised when attempting this procedure. Applications that have anything to do with rooting or jailbreaking should generally be avoided.

Screen Configurations

Mobile device displays rotate by default if the user turns the device, allowing the screen to be viewed vertically or horizontally. This aids when looking at pictures, movies, or viewing websites. But in some cases, a user might want to lock the rotation of the device so that it stays as either vertical or horizontal, without moving. On an Android device this can be done by accessing Settings, then tapping Display, and then deselecting Auto-rotate screen. On an iOS device (version 4 or 5) this can be done by double-tapping the Home button (which brings up the multitasking bar on the bottom) and then swiping the bar all the way to the right. Finally, a circular arrow is shown to the far left; tap this, and rotation will be locked. Some iPads (such as the iPad2) also have a side switch that can be configured to enable/disable rotation lock; this feature can be turned on in Settings > General > Use side switch to: Lock Rotation.

Screen orientation is a simple concept to understand and use. But it can be more complicated when it comes to applications. For example, Apple mobile devices make use of the Accelerometer: a combination of hardware and software that measure velocity; they detect rotation, shaking of the device and so on. It’s the accelerometer that enables a mobile device to automatically adjust from portrait (vertical) to landscape (horizontal) mode using the three axes: the X-axis (left to right), the Y-axis (up and down), and the Z-axis (back to front). These are manipulated by developers for applications and games so that the program can recognize particular movements of the device and translate them to specific application functions. Newer Apple devices include a gyroscope, which adds the measurements of pitch, roll, and yaw, just like in the concept of flight dynamics. You won’t need a pilot’s license to use an iPad, but this additional measurement of movement has a great impact on the development of newer applications and especially games. Of course, if the accelerometers or gyroscope of the mobile device fail and a reset of the device doesn’t fix the problem, it must be repaired at an authorized service center.

Android devices have a screen calibration utility called G-Sensor calibration. It is found in Settings > Display. To make sure that the three axes are calibrated properly, this program is run while the mobile device is laid on a flat surface. You can tell if the surface is level by the horizontal and vertical leveling bubbles on the display. Then press the Calibrate button to reset the G-sensor, as shown in Figure 17.3.

Figure 17.3

Figure 17.3. G-Sensor calibration on a typical smartphone

Other mobile devices’ calibration programs show a crosshair or similar image in the center of the screen. You need to tap with a stylus as close to the center of the display as possible. If a stylus is not available, use the pointed end of a pen cap.

A reset can also fix problems with calibration (as well as other types of problems). There are two types of resets: soft and hard. A soft reset is usually performed simply by powering the device off and then powering it back on again. This can fix temporary problems quickly and easily. It is similar to rebooting a PC. However, more advanced problems require a hard reset. Warning! A hard reset may remove all data and applications and return the device to its original factory state. Do not perform a hard reset without backing up the contents of the memory card in the mobile device, and any additional settings you require. You can find more information on resets in the section titled “Mobile Security.”

Today’s Apple devices do not offer a calibration utility. Sometimes, issues that appear to be calibration problems are actually something else with an easy fix. For example, cheaper screen protectors can bubble and otherwise cause problems when tapping on the screen. Removing the protector and installing a new one properly can fix this problem. When installing a screen protector, use a long, flat surface to squeeze all the bubbles out; there are shims that can be purchased for just this purpose. Use a decent screen protector such as Ghost Armor or something similar. Good quality screen protectors will not only protect the display, but they will also reduce glare, smudging, and fingerprints, without reducing sensitivity. Dirty screens can also be a culprit when a user is having difficulty tapping on icons or smaller items. Clean the display with a lint-free cloth. If the screen is very dirty, mix 50% isopropyl alcohol and 50% water, apply conservatively to the cloth, and then clean the display with the cloth. Make sure all traces of liquid are removed when you are done. If none of these steps work, the device needs to be brought in to an authorized service center for repair.

GPS and Geotracking

The Global Positioning System (GPS), developed by the U.S. DoD is a worldwide system of satellites that provide location information for anything with a GPS receiver. Any mobile device with a GPS receiver can use this system to identify its location and utilize mapping programs and any other applications that rely on GPS. Some mobile devices do not have a GPS receiver, and instead use cell tower triangulation, or Location Services that uses crowd-sourced Wi-Fi locations to determine the approximate location of the device.

To enable/disable GPS on an Android-based device go to Settings > Location, and select Use GPS satellites. To enable/disable GPS on an Apple device such as an iPad, go to Settings > Location Services.

Geotracking is the practice of tracking and recording the location of a mobile device over time. This location tracking is done by Apple and Google as well as other organizations and governments. Privacy issues aside, this practice is being done, so if a user doesn’t want their location known, simply disable the GPS setting.

Cram Quiz

Answer these questions. The answers follow the last question. If you cannot answer these questions correctly, consider reading this section again until you can.

220-802 Questions

  1. A user is having difficulty tapping on icons. What should you do to help the user? (Select the two best answers.)

    circle.jpg

    A.

    Clean the display.

    circle.jpg

    B.

    Tap the Home button.

    circle.jpg

    C.

    Install a screen protector.

    circle.jpg

    D.

    Initiate a soft reset.

    circle.jpg

    E.

    Initiate a hard reset.

  2. Which of the following can aid a mobile user in finding the nearest coffee shop? (Select the best answer.)

    circle.jpg

    A.

    Geotracking

    circle.jpg

    B.

    iOS

    circle.jpg

    C.

    GPS

    circle.jpg

    D.

    GSM

  3. A user wants to stop his tablet from shifting horizontally when he turns it. Which of the following should you enable?

    circle.jpg

    A.

    Lock Rotation

    circle.jpg

    B.

    Accelerometer

    circle.jpg

    C.

    Gyroscope

    circle.jpg

    D.

    Screen Calibration

  4. What kind of display would an iPad2 use?

    circle.jpg

    A.

    CRT

    circle.jpg

    B.

    Multitouch

    circle.jpg

    C.

    Tap screen

    circle.jpg

    D.

    Singletouch

  5. What are two common operating systems used by mobile devices? (Select the two best answers.)

    circle.jpg

    A.

    Blueberry OS

    circle.jpg

    B.

    iOS

    circle.jpg

    C.

    Google OS

    circle.jpg

    D.

    Android OS

  6. What type of CPU do mobile devices use?

    circle.jpg

    A.

    Core i7

    circle.jpg

    B.

    Phenom II

    circle.jpg

    C.

    ARM

    circle.jpg

    D.

    Pentium

  7. Which OS is considered to be closed-source?

    circle.jpg

    A.

    Android OS

    circle.jpg

    B.

    Bluetooth

    circle.jpg

    C.

    Linux

    circle.jpg

    D.

    iOS

  8. What are a couple of differences between a tablet computer and a laptop? (Select the two best answers.)

    circle.jpg

    A.

    Tablets have little or no field serviceable parts.

    circle.jpg

    B.

    Tablets are upgradeable.

    circle.jpg

    C.

    Laptops don’t use touch screens.

    circle.jpg

    D.

    Tablets use flash memory as the hard drive.

    circle.jpg

    E.

    Tablets use RAM.

Cram Quiz Answers

220-802 Answers

  1. A and D. A dirty display can cause issues when trying to manipulate a multitouch screen. By cleaning it, the user might find that is it easier to use. A soft reset (turning the device off and on) can sometimes fix the problem as well. Tapping the Home button simply brings the person to the Home screen. Screen protectors are a good idea, but if installed incorrectly, they could actually be the reason that a user has issues tapping icons. After the screen is cleaned, a decent quality screen protector should be installed. Hard resets often initiate a complete wipe of the system. Use this only as a last resort.
  2. C. GPS is used to locate the mobile user. From that information, one of several programs can locate that all-important nearest coffee shop. Geotracking is the practice of tracking and recording the location of a mobile device. However, geotracking is done by organizations, whereas GPS is something installed to the mobile device. iOS is the operating system used by Apple mobile devices. GSM is a cellular standard.
  3. A. Enable Lock Rotation on Apple devices. On Android devices disable Auto-rotate. The Accelerometer is a term used by Apple to describe the hardware/software that controls the three axes of movement. The Gyroscope is another term used by Apple to describe the device that measures the additional three movements (pitch, roll, and yaw) of newer Apple devices. Screen calibration is used to reset the device that measures the three axes.
  4. B. iPad2 devices use multitouch screens, which allow more than one contact point. Cathode ray tube (CRT) is an older technology monitor used by desktop computers. You would “tap” the screen, but it is known as a touchscreen. Singletouch screens are an older technology; you won’t see much of that in the field.
  5. B and D. Two common operating systems used by mobile devices are iOS and Android OS. Blackberry OS is the OS used on Blackberry devices. Android is effectively controlled by Google. There is a Google Chrome OS designed to work with web applications that is also open-source.
  6. C. Most commonly, mobile devices use ARM (Advanced RISC Machine) CPUs. Core i7, Phenom II and the older Pentium are used by desktop and laptop computers.
  7. D. The Apple iOS is a closed-source vendor specific operating system. Android is a type of Linux that is open-source. Bluetooth is a wireless standard, not an operating system.
  8. A and D. Unlike laptops, tablets are not field-serviceable. They use flash memory instead of an SATA hard drive. Tablets are for the most part not upgradeable. Some laptops do come with touchscreens. Both tablets and laptops use RAM.

InformIT Promotional Mailings & Special Offers

I would like to receive exclusive offers and hear about products from InformIT and its family of brands. I can unsubscribe at any time.

Overview


Pearson Education, Inc., 221 River Street, Hoboken, New Jersey 07030, (Pearson) presents this site to provide information about products and services that can be purchased through this site.

This privacy notice provides an overview of our commitment to privacy and describes how we collect, protect, use and share personal information collected through this site. Please note that other Pearson websites and online products and services have their own separate privacy policies.

Collection and Use of Information


To conduct business and deliver products and services, Pearson collects and uses personal information in several ways in connection with this site, including:

Questions and Inquiries

For inquiries and questions, we collect the inquiry or question, together with name, contact details (email address, phone number and mailing address) and any other additional information voluntarily submitted to us through a Contact Us form or an email. We use this information to address the inquiry and respond to the question.

Online Store

For orders and purchases placed through our online store on this site, we collect order details, name, institution name and address (if applicable), email address, phone number, shipping and billing addresses, credit/debit card information, shipping options and any instructions. We use this information to complete transactions, fulfill orders, communicate with individuals placing orders or visiting the online store, and for related purposes.

Surveys

Pearson may offer opportunities to provide feedback or participate in surveys, including surveys evaluating Pearson products, services or sites. Participation is voluntary. Pearson collects information requested in the survey questions and uses the information to evaluate, support, maintain and improve products, services or sites, develop new products and services, conduct educational research and for other purposes specified in the survey.

Contests and Drawings

Occasionally, we may sponsor a contest or drawing. Participation is optional. Pearson collects name, contact information and other information specified on the entry form for the contest or drawing to conduct the contest or drawing. Pearson may collect additional personal information from the winners of a contest or drawing in order to award the prize and for tax reporting purposes, as required by law.

Newsletters

If you have elected to receive email newsletters or promotional mailings and special offers but want to unsubscribe, simply email information@informit.com.

Service Announcements

On rare occasions it is necessary to send out a strictly service related announcement. For instance, if our service is temporarily suspended for maintenance we might send users an email. Generally, users may not opt-out of these communications, though they can deactivate their account information. However, these communications are not promotional in nature.

Customer Service

We communicate with users on a regular basis to provide requested services and in regard to issues relating to their account we reply via email or phone in accordance with the users' wishes when a user submits their information through our Contact Us form.

Other Collection and Use of Information


Application and System Logs

Pearson automatically collects log data to help ensure the delivery, availability and security of this site. Log data may include technical information about how a user or visitor connected to this site, such as browser type, type of computer/device, operating system, internet service provider and IP address. We use this information for support purposes and to monitor the health of the site, identify problems, improve service, detect unauthorized access and fraudulent activity, prevent and respond to security incidents and appropriately scale computing resources.

Web Analytics

Pearson may use third party web trend analytical services, including Google Analytics, to collect visitor information, such as IP addresses, browser types, referring pages, pages visited and time spent on a particular site. While these analytical services collect and report information on an anonymous basis, they may use cookies to gather web trend information. The information gathered may enable Pearson (but not the third party web trend services) to link information with application and system log data. Pearson uses this information for system administration and to identify problems, improve service, detect unauthorized access and fraudulent activity, prevent and respond to security incidents, appropriately scale computing resources and otherwise support and deliver this site and its services.

Cookies and Related Technologies

This site uses cookies and similar technologies to personalize content, measure traffic patterns, control security, track use and access of information on this site, and provide interest-based messages and advertising. Users can manage and block the use of cookies through their browser. Disabling or blocking certain cookies may limit the functionality of this site.

Do Not Track

This site currently does not respond to Do Not Track signals.

Security


Pearson uses appropriate physical, administrative and technical security measures to protect personal information from unauthorized access, use and disclosure.

Children


This site is not directed to children under the age of 13.

Marketing


Pearson may send or direct marketing communications to users, provided that

  • Pearson will not use personal information collected or processed as a K-12 school service provider for the purpose of directed or targeted advertising.
  • Such marketing is consistent with applicable law and Pearson's legal obligations.
  • Pearson will not knowingly direct or send marketing communications to an individual who has expressed a preference not to receive marketing.
  • Where required by applicable law, express or implied consent to marketing exists and has not been withdrawn.

Pearson may provide personal information to a third party service provider on a restricted basis to provide marketing solely on behalf of Pearson or an affiliate or customer for whom Pearson is a service provider. Marketing preferences may be changed at any time.

Correcting/Updating Personal Information


If a user's personally identifiable information changes (such as your postal address or email address), we provide a way to correct or update that user's personal data provided to us. This can be done on the Account page. If a user no longer desires our service and desires to delete his or her account, please contact us at customer-service@informit.com and we will process the deletion of a user's account.

Choice/Opt-out


Users can always make an informed choice as to whether they should proceed with certain services offered by InformIT. If you choose to remove yourself from our mailing list(s) simply visit the following page and uncheck any communication you no longer want to receive: www.informit.com/u.aspx.

Sale of Personal Information


Pearson does not rent or sell personal information in exchange for any payment of money.

While Pearson does not sell personal information, as defined in Nevada law, Nevada residents may email a request for no sale of their personal information to NevadaDesignatedRequest@pearson.com.

Supplemental Privacy Statement for California Residents


California residents should read our Supplemental privacy statement for California residents in conjunction with this Privacy Notice. The Supplemental privacy statement for California residents explains Pearson's commitment to comply with California law and applies to personal information of California residents collected in connection with this site and the Services.

Sharing and Disclosure


Pearson may disclose personal information, as follows:

  • As required by law.
  • With the consent of the individual (or their parent, if the individual is a minor)
  • In response to a subpoena, court order or legal process, to the extent permitted or required by law
  • To protect the security and safety of individuals, data, assets and systems, consistent with applicable law
  • In connection the sale, joint venture or other transfer of some or all of its company or assets, subject to the provisions of this Privacy Notice
  • To investigate or address actual or suspected fraud or other illegal activities
  • To exercise its legal rights, including enforcement of the Terms of Use for this site or another contract
  • To affiliated Pearson companies and other companies and organizations who perform work for Pearson and are obligated to protect the privacy of personal information consistent with this Privacy Notice
  • To a school, organization, company or government agency, where Pearson collects or processes the personal information in a school setting or on behalf of such organization, company or government agency.

Links


This web site contains links to other sites. Please be aware that we are not responsible for the privacy practices of such other sites. We encourage our users to be aware when they leave our site and to read the privacy statements of each and every web site that collects Personal Information. This privacy statement applies solely to information collected by this web site.

Requests and Contact


Please contact us about this Privacy Notice or if you have any requests or questions relating to the privacy of your personal information.

Changes to this Privacy Notice


We may revise this Privacy Notice through an updated posting. We will identify the effective date of the revision in the posting. Often, updates are made to provide greater clarity or to comply with changes in regulatory requirements. If the updates involve material changes to the collection, protection, use or disclosure of Personal Information, Pearson will provide notice of the change through a conspicuous notice on this site or other appropriate way. Continued use of the site after the effective date of a posted revision evidences acceptance. Please contact us if you have questions or concerns about the Privacy Notice or any objection to any revisions.

Last Update: November 17, 2020