CIS 1110A - Computer Operating Systems and Maintenance

Module 9

This chapter discusses supporting mobile devices. Objectives important to this lesson:

  1. Common types of mobile devices
  2. Mobile operating systems
  3. Wired and wireless mobile connections
  4. Synchronizing content
  5. Internet of Things devices
  6. Troubleshooting
  7. Current assignments


This is another long chapter with that Dr. Andrews summarizes in two pages, so there is hope of grasping the key points. The chapter begins with a list of devices you might be required to support in an enterprise environment that come in a new category. Some companies have a Bring Your Own Device (BYOD) policy for certain devices, which saves the company the expense of buying or leasing the device, but provides headaches to support staff who are charged to support devices that are not compliant with company standards.

  • Smartphones are cell phones, as the text says, but they are also computers that seem to be more capable each year. We had a Chief Technology Officer not long ago who pushed the envelope of what he required his smartphone to do. His goal was to be able to do all his work on it. As you might imagine, that goal is complicated by connectivity, bandwidth, screen size, memory size, and other issues.
  • Tablets and lightweight laptops, as a class, are less capable than heavier laptops. Reduced weight means a compromised set of features. Unlike smartphones, the screens are larger and the device may run some version of Windows instead of Linux. (Windows smartphones have never caught on.)
  • GPS tracking software is useful, especially for travel, either business or personal. This is still available in standalone devices, but it is often found in smartphones. In either case, it is a good idea to remind the user to download updates to stored maps.
  • The text mentions e-readers and fitness/health monitoring devices, which are nice to have, but neither serves a justifiable business purpose, except for the companies that sell them.

The text lists four operating systems that it says are the most popular.

  • Android by Google - This is an ever changing variant on Linux. Most smart device vendors have periodic updates for their software, once Google's new system has been tested on the vendor's devices. The text says that some version of Android is running on almost 80% of all smartphones. Dr. Andrews mentions that most new versions of Android have been named for a dessert, in alphabetical order from Cupcake through Pie. Google has apparently tired of this. 2019's version was just called Android 10, and 2020's version is called Android 11.
  • iOS by Apple - Apple does not usually mention it, but their OS is also a variant of Linux. Dr. Andrews says Apple has about 20% of the smartphone market
  • Windows 10 and Windows Mobile - Microsoft's smartphone OSs are only used by about .5% of smartphones. You can see why I said that they are not popular.
  • Chrome OS - If you have been doing the math so far, you should recognize that Chrome is not really used on smartphones, only on tablets and some other computers. It is a good system, but not much of a competitor for Android and iOS. It requires any program that will run on it must run through the Chrome browser.

Dr. Andrews discusses each of the operating systems listed above for a few pages. You should browse through any system you know well, and read the other sections to compare pluses and minuses.The text offers a major element of comparison on page 453.

  • Apple locks down its operating system, and strictly controls applications that are written for it. You don't download an application to run on an Apple phone unless Apple has approved it and marketed it through iTunes or Apple's App Store. 
  • Google is less strict about Android and Chrome, which makes it easier to create a program that will run on them. However, many vendors customize Android for their devices, making it less sure that an application will run on all current Android versions. You typically have a larger selection of apps and games on Google Play than you do on the Apple App Store.

The author recommends that you explore the settings app found in Android and in Apple smartphones when you need to configure anything about the device, such as turning Bluetooth, cell service, or Wi-Fi service on or off. She refers to "turning the antenna" on or off for each service, but I find it easier to think of them as separate services instead of antennas.

A mobile device that is connected to a cellular data service can be used as a Mobile Hotspot, if your contract for data allows that, and if you have a huge amount of data to share. This could be a nice feature if you are rich and have several poor friends. It is a bit like having my daughter attach to my WAP when she comes over, since I have no particular limit on data, and her contract frequently runs out. Cellular data is typically more expensive than cable data, and it comes with lower limits. The video below shows you how to set up a Mobile Hotspot on an Apple phone and on an Android phone. (It also reviews some of the ideas above.)

Sometimes there isn't an easy way to connect to another devices service wirelessly. In that case, you may be able to tether two devices together. Page 456 shows a picture of a laptop that has no data service, connected by a USB cable to a cell phone whose owner is willing to share his/hers. (In a few pages, the author mentions that such cables often have micro USB, mini USB, or USB-C connectors for Android devices. Apple devices have used Lightning connectors for a while, but some now use USB-C connectors.) When using a shared connection, the text points out that you may need to supply one or more of three identifiers.

  • IMEI - International Mobile Equipment Identity, an ID that identifies mobile phones and tablets
  • IMSI - International Mobile Subscriber Identity, an ID that identifies a subscription to a service or a subscriber; it includes data on home country and mobile network information; if your device has a SIM (Subscriber Identity Module) card, it will be stored there, otherwise it will be stored by your carrier and can be found with the IMEI
  • ICCID- Integrated Circuit Card ID, identifies a SIM card; it will be found under Settings, About or Settings, System, About, if your device has a SIM card.

Regarding SIM cards, the author points out that if you are upgrading from a device that uses a SIM card to another, you can transfer credentials by moving the card to the new device. If your carrier does not use SIM cards, or if you are changing to a device that does not use them, you will have to have your account moved to the new device by the carrier. In either case, contact the carrier for the correct procedure.

The text discusses how to set up email on a mobile device. This should be familiar to anyone who has used mail on a mobile device. The text points out that email can typically be accessed by a browser (web interface) or by a client (program interface), You should be aware of POP3 and IMAP, the two main protocols that are used for email, as well as SMTP.

  • SMTP protocol uses port 25 on a TCP/IP stack, and is used for mail being sent to mail servers. This includes traffic from the user to a server, and from server to server.
  • POP3 protocol uses port 110 to retrieve mail from a server. It pulls the mail to your local device.
  • IMAP4 protocol is like POP3 in that it is used for mail retrieval, but different in that it uses port 143, and it leaves the mail in your server mailbox for access from other devices.

Basic facts: outgoing email is typically sent across the Internet using Simple Mail Transfer Protocol (SMTP, port 25). This is what your post office uses to send email to another post office. This does require an SMTP server on each of the networks involved. The receiving SMTP server delivers your email to your mailbox, which you can think of as a set of records in a database. Your email client may pull the mail from the mailbox with Post Office Protocol 3 (POP3, port 110), or just read it with Internet Message Access Protocol (IMAP, port 143). There is no specific POP3 or IMAP server involved with those requests to your mailbox, only a service that your client's request activates in the post office.

The text presents a short section on synchronizing data from a mobile device. It begins by telling us that synchronizing is about making a copy of your data in another place. Making a back up is more extensive, because that concept include making a copy of your OS and programs. In either case, you are encouraged to consider storing in the related cloud service, Google storage for Android, and iCloud for Apple. There is also a discussion of synchronizing with a desktop, to allow continuation of work on that device. This makes it necessary to synchronize back to the phone, if you intend to continue on a file that you changed on the PC. General rule: if you change a file, synch to the other device ASAP. A way to manage such things would be to use Microsoft's OneDrive or Dropbox.

The video below is kind of long, but it addresses the concepts of the Internet of Things and the lack of security on them.

All devices need security, especially those that use wireless technology. The text discusses several ways to increase security:

  • device access - devices need to be locked to prevent physical access
  • encryption - a strong password should be required to pass by the encryption used on mobile devices
  • multifactor authentication - identification is who you claim to be, authentication is proving who you are; Most security is based on one or more of three types of things: something you have (like a key or an ID card), something you know (like a PIN or a password), or something you are (like a fingerprint or the shape of your face). Some devices also allow you to use something you do, like drawing a pattern on a touchscreen.
  • apply security patches
  • use firewalls
  • install software to locate misplaced or stolen devices
  • install software to remotely wipe the device (typically seen in enterprise environments)

The text turns to diagnosing and removing malware. What you do can depend greatly on the tools available to you. I recommend reviewing slides 70 through 82 of the PowerPoint file for this chapter.


  1. Read the chapter, and the next one for next week.
  2. Complete the assignments and class discussion made in this module, which are due by 6pm next week.