Digital Devices

Mobile Computing Devices

Mobile computing is a generic term describing one's ability to use technology while moving, as opposed to portable computers, which are only practical for use while deployed in a stationary configuration. (Wikipedia, 2009)

Types of Devices

There are many mobile computing devices on the market:

Cell phones

Cell phones feature traditional phone services such as call waiting and voice mail, calendars, contact databases, text messaging, e-mail capabilities as well as digital image and video capture. Most cell phones also feature voice-activated dialing, which is important for hands-free operation.

When you speak into a cell phone, the sound enters the microphone as a sound wave. Because analog sound waves need to be digitized, an analog-to-digital converter chip converts your voice's sound waves into digital signals. The digital data is then compressed into the smallest possible space so that it will transmit more quickly to another phone. The processor cannot perform the mathematical operations required at this stage quickly enough, so a specialized chip, called the digital signal processor, is included in a cell phone to handle the compression work. Finally, the digital data is transmitted as a radio wave through the cellular network to the destination phone. When you receive an incoming call, the digital signal processor decompresses the incoming message and a digital-to-analog converter changes the message to sound waves so that you can hear it.

Just as you pay an Internet service provider (ISP) for Internet access for your desktop or notebook computer, connecting your cell phone to the Internet requires that you have a wireless Internet service provider. Phone companies that provide cell phone calling plans (such as Rogers, Telus and Bell Canada) usually double as wireless ISPs. Internet connectivity plans, and often text messaging plans, are usually known as data plans. It is often difficult to display Web pages on cell phones without a great deal of horizontal scrolling to view content.

Personal digital assistants (PDA)

A personal digital assistant (PDA) is a small device that allows you to carry digital information. Often called palm computers or handhelds, PDAs are about the size of your hand and usually weigh less than 5 ounces. Although small, PDAs are quite powerful and can carry all sorts of information, from calendars to contact lists to specially designed personal productivity software programs (such as Excel and Word), to songs, photos, and games. And you can easily "synchronize" your PDA and your home computer so that the changes you make to your schedules and files on your PDA are made on your home or office computer files as well.

All current PDAs feature touch-sensitive screens that allow you to enter data directly with a pen like device called a stylus. To make selections, you simply tap or write on the screen with the stylus. Other PDAs include integrated keyboards or support small, portable, folding keyboards. With a touch screen and stylus, you can use either handwritten text or special notation systems to enter data into your PDA. One of the more popular notation systems is the Graffiti text system.

When comparing PDA processors, one consideration to keep in mind is processor speed, which is measured in hertz and is the number of operations the processor completes each second. Processor speed is not the only aspect of the processor that affects performance. To measure performance, PDA reviewers often run the same task on competing PDAs and then compare the time it takes to complete the task. This process is called benchmarking and gives a good indication of the unit’s overall system performance. When comparing PDAs, also look for the expected operating time on one battery charge.

Most PDAs contain internal hard drives. Modern PDAs only use RAM for running applications. User data is stored in flash ROM.

You can also transfer your data from your PDA to a desktop by using a device called a cradle or a sync cable. You can also use the PDA cradle to synchronize your PDA with your computer. The process of updating your data so the files on your PDA and computer are the same is called synchronizing. To synchronize your desktop and PDA, you place the PDA in its cradle or connect the cable and touch a hot sync button. Microsoft has recognized the vast increase in portable computing devices by integrating synchronization into Windows Vista. This feature is known as Sync Center. Many PDAs include an IrDA port that transmits data signals using infrared light waves. Another type of wireless connection available for PDAs is Bluetooth, which uses radio waves to transmit data signals over short distances (up to about 30 feet).

Portable media players (MP3 players)

Portable media players (PMPs) are small portable devices that enable playing of MP3 files anywhere. MP3 is a format for efficiently storing music as digital files. Digital files (using special data formats such as AVI or MPEG-4) can hold video, audio, or images. Many companies are now manufacturing PMPs that handle video and still images as well as music files.

The number of songs a PMP can hold depends on how much storage space it has. Inexpensive PMPs use built-in flash memory, a type of nonvolatile memory, to store files. Some of the PMPs that use flash memory allow you to add storage capacity by purchasing removable flash memory cards. Other PMPs use a hard disk drive and can store a much larger amounts of music. Another factor that determines how much music a player can hold is the quality of the MP3 music files.

Flash memory cards are noiseless, very light, use very little power, and slide into a special slot in the player. Because flash memory is nonvolatile, when you store data on a flash memory card, you won't lose it when you turn off the player. In addition, flash memory can be erased and rewritten with new data.

Ethical issues are important when dealing with PMP's. The fundamental right of an artist to own his or her own material has come under significant pressure due to the ease of downloading and sharing MP3 files. However, it is a double-edged sword, for musicians need an audience first and a paying audience second. Those with a paying audience want to keep it that way and those with no audience want to find one. So a musician trying to get noticed sees the Internet and MP3 as a way to distribute music with little cost, and if the music is good enough, develop a following who might pay in the future.

The very same technology works against a musician who is able to sell music, for now it can gotten easily for free. Existing schemes try to work both ways, with thousands of samples available so a person can listen before the purchase. On the other hand, any musician can distribute music for free. Music is also being distributed between people directly on the Internet. Using "peer-to-peer" services, people share their files directly. In some jurisdictions this is illegal.

Smartphones

Smartphones are a result of the convergence (or combination of features) of various portable devices such as PMPs, PDAs, and cellular phones. These devices attempt to provide a single solution for your portable computing needs.

Flash Memory

We store and transfer all kinds of files on our computers — digital photographs, music files, word processing documents, PDFs and countless other forms of media. But sometimes your computer's hard drive isn't exactly where you want your information. Whether you want to make backup copies of files that live off of your systems or if you worry about your security, portable storage devices that use a type of electronic memory called flash memory may be the right solution.

Several different types of flash cards are used with different models of MP3 players. One popular type is Compact Flash cards. These are about the size of a matchbook and can hold between 64 MB and 8 GB of data. Multimedia cards and SmartMedia cards are about the same size as CompactFlash cards but are thinner and less rugged. Sony devices use a special format of flash memory called the Memory Stick.

Tablet PC's

A tablet PC is a portable computer that is lightweight, features advanced handwriting recognition, and can be rotated into a clipboard style. Tablet PCs are available from a variety of manufacturers, come in a variety of designs, and are about the same size as a clipboard. Tablet PCs are named such because the monitor can be used either in a traditional notebook mode or in "tablet mode", much like an electronic clipboard. Tablet PCs also can be connected to a full-size keyboard and monitor.

Notebook Computers

The most powerful mobile computing solution is a notebook computer. Notebooks offer large displays and all of the computing power of a full desktop system. Most notebooks weigh more than tablets.

Notebooks use the same operating systems that run on desktop systems. Notebook operating systems have some special settings, such as power management profiles. A power management profile contains recommended power-saving settings, such as turning off your hard drive after 15 minutes of no use, shutting down the monitor after 20 minutes of no movement, and switching the machine to standby or hibernation mode after a certain length of time. Most notebooks have integrated support for wireless connectivity.

Netbook

Something similar to a Notebook computer is a Netbook computer. A netbook is a laptop computer designed for wireless communication and access to the Internet.

Review

Digital media and devices are all around us. Their popularity has turned into necessity. How many of us do not have cell phones. Of those that do how many do not have the ability to gather our data such as e-mails and the internet? These questions were answered either directly or indirectly in the unit.

Next we will look at security and how important it is in our daily lives.