How PDAs Work

Traditional PDAs

Today's traditional PDAs are descendents of the original PalmPilot and Microsoft Handheld PC devices. Palm devices run the Palm OS (operating system), and Microsoft Pocket PCs run Windows Mobile. The differences between the two systems are fewer than in the past.

Palm PDAs

Most Palm devices are made by palmOne, which offers the Zire and Tungsten product lines. The company formed in 2003 when Palm Computing acquired Handspring, Inc. Sony, which produced the Palm-based CLIE, stopped producing PDAs in 2005.

Known for their ease of use, Palm OS PDAs have:

Pocket PCs

Pocket PC is the generic name for Windows Mobile PDAs. Their standard features include:

Smartphones

A smartphone is either a cell phone with PDA capabilities or a traditional PDA with added cell phone capabilities, depending on the form factor (style) and manufacturer. Characteristics of these devices include:

Well, it doesn't look like a PDA...

Related devices include ultraportable computers, smart watches and multimedia players. Ultraportable computers range in weight from less than a pound to about three pounds, come with a full desktop operating system (such as Windows XP), and include a small keyboard. Smart watches offer some PDA functions in a wristwatch form factor. Microsoft's SPOT (Smart Personal Objects Technology)-based watches, for example, can receive MSN Direct information such as weather and news. They can also receive calendar information and personal messages. Some multimedia players can combine the functions of a PDA with multimedia features, such as a digital camera, an MP3 player and a video player.

In the next section, we'll look at what PDAs do and how they do it.

Even the most basic PDAs handle standard personal information management (PIM) functions, run application software and synchronize with PCs. Here are some additional details about these basic features.

Handle Standard PIM Functions

All PDAs come with some kind of personal information management (PIM) software that typically handles the following tasks to keep you organized:

Run Application Software

PDAs can run specialized software applications:

Synchronize With PCs

Because PDAs are designed to complement your PC, they need to work with the same information in both places. If you make an appointment on your desktop computer, you need to transfer it to your PDA; if you jot down a phone number on your PDA, you should upload it later to your PC.

Synchronization software on the PDA works with companion software that you install on your PC. Microsoft Pocket PC devices use ActiveSync and Palm OS devices use HotSync synchronization software. On your computer, you also need an application like Microsoft Outlook or the Palm Desktop that holds PIM information on the PC side.

The beauty of synchronization is that you always have a backup copy of your data, which can be a lifesaver if your PDA is broken, stolen, or completely out of power.

Today, most PDAs incorporate wireless and multimedia functions of some type. Functions found on most (but not necessarily all) devices include:

Bells & Whistles

Bells & Whistles

High-end PDAs offer multimedia, security and add-on features not found on less expensive devices:

In the next section, we'll look at the computer that powers a PDA.

Microprocessors and Memory

Like standard desktop and laptop computers, PDAs are powered by microprocessors. The microprocessor is the brain of the PDA, and it coordinates all of the functions according to programmed instructions. Unlike desktop PCs and laptops, PDAs use smaller, cheaper microprocessors. Although these microprocessors tend to be slower than their PC counterparts, they're adequate for the tasks that PDAs perform. The benefits of small size and price outweigh the cost of slow speeds.

A PDA doesn't have a hard disk. It stores basic programs (address book, calendar, memo pad and operating system) in a read-only memory (ROM) chip, which remains intact even when the machine shuts down. Your data and any programs you add later are stored in the device's random-access memory (RAM). Information in RAM is only available when the device is on. Due to their design, PDAs keep data in RAM safe because they continue to draw a small amount of power from the batteries even when you turn the device off.

Less powerful PDAs have lower amounts of RAM. However, many application programs take up significant memory space, so most models have more memory. Also, Pocket PC devices generally require more resources and have even more RAM. To provide additional memory, many PDAs accept removable flash media add-on cards. These are handy for storing large files or multimedia content, such as digital photos.

Some newer PDAs, such as the Palm Tungsten E2, use flash memory instead of RAM. Flash memory is non-volatile, which means it preserves the data and applications it stores -- even when all battery power is depleted.

Operating Systems

The operating system contains the pre-programmed instructions that tell the microprocessor what to do. The operating systems used by PDAs are not as complex as those used by PCs. They have fewer instructions, which require less memory.

PDAs and smartphones typically have one of two types of operating systems: Palm OS or Windows Mobile. However, RIM makes a specific OS for its BlackBerry devices, and the Symbian OS operates some smartphones.

In the next section, we'll look at the other parts that make up a PDA.

So far, we've looked at the PDA's microprocessor, memory and operating system. Now let's look at the other parts of a PDA.

Batteries

PDAs are powered by batteries. Some models use alkaline (AAA) batteries, while others use rechargeable batteries (lithium, nickel-cadmium or nickel-metal hydride). The battery life depends on what kind of PDA you have and how you use it. Here are some of the things that can drain batteries:

Battery life can vary from hours to months, depending upon the PDA model and its features. Most PDAs have power management systems in place to extend the battery life. Even if the batteries are so low that you can no longer turn the machine on (it will give you plenty of warning before this happens), there's usually enough power to keep the RAM refreshed.

If the batteries do run completely out of juice or if you remove them, most devices have an internal backup battery that provides short-term power (typically 30 minutes or less) until you install a replacement. If all power sources are depleted, PDAs lose all of the data in RAM. This makes backing up or synchronizing your PDA extremely important.

In addition to battery power, many PDAs come with AC adapters to run off household electric currents. A car adapter is also generally available as an accessory.

LCD Display

PDAs use an LCD (liquid-crystal display) screen. Unlike the LCD screens for desktop or laptop computers, which are used solely as output devices, PDAs use their screens for output and input. The LCD screens of PDAs are smaller than laptop screens, but vary in size. Almost all PDAs now offer color displays.

PDA displays have the following features:

Input Methods

PDAs vary in how you input data and commands. Some devices use a stylus and touch screen exclusively in combination with a handwriting recognition program. Using a plastic stylus, you draw characters on the device's display or dedicated writing area. Software inside the PDA converts the characters to letters and numbers. On Palm devices, the software that recognizes these letters is called Graffiti. Graffiti requires that each letter be recorded in a certain way, and you must use a specialized alphabet. For example, to write the letter "A," you draw an upside-down V. The letter "F" looks like an inverted L. To help Graffiti make more accurate guesses, you must draw letters on one part of the screen and numbers in another part.

Pocket PC PDAs offer three handwriting-recognition applications: Transcriber, Letter Recognizer and Block Recognizer. Letter Recognizer and Block Recognizer are similar to Graffiti and require specialized alphabets. By contrast, Transcriber recognizes your "regular" handwriting, as long as you write legibly. It is similar to the handwriting recognition capabilities found on Tablet PCs.

If you can't get the hang of PDA handwriting, you can use a miniature onscreen keyboard. It looks just like a regular keyboard, except you tap on the letters with the stylus. In addition, many devices now include a small (and usually cramped) QWERTY keyboard. Some of these require you to use your thumbs to type. And you can use a full-size keyboard by connecting it to the PDA via Bluetooth or a USB port. Each model also has a few buttons and navigation dials to bring up applications and scroll through files.

LCD Display

PDAs use an LCD (liquid-crystal display) screen. Unlike the LCD screens for desktop or laptop computers, which are used solely as output devices, PDAs use their screens for output and input. The LCD screens of PDAs are smaller than laptop screens, but vary in size. Almost all PDAs now offer color displays.

PDA displays have the following features:

Input Methods

PDAs vary in how you input data and commands. Some devices use a stylus and touch screen exclusively in combination with a handwriting recognition program. Using a plastic stylus, you draw characters on the device's display or dedicated writing area. Software inside the PDA converts the characters to letters and numbers. On Palm devices, the software that recognizes these letters is called Graffiti. Graffiti requires that each letter be recorded in a certain way, and you must use a specialized alphabet. For example, to write the letter "A," you draw an upside-down V. The letter "F" looks like an inverted L. To help Graffiti make more accurate guesses, you must draw letters on one part of the screen and numbers in another part.

Pocket PC PDAs offer three handwriting-recognition applications: Transcriber, Letter Recognizer and Block Recognizer. Letter Recognizer and Block Recognizer are similar to Graffiti and require specialized alphabets. By contrast, Transcriber recognizes your "regular" handwriting, as long as you write legibly. It is similar to the handwriting recognition capabilities found on Tablet PCs.

If you can't get the hang of PDA handwriting, you can use a miniature onscreen keyboard. It looks just like a regular keyboard, except you tap on the letters with the stylus. In addition, many devices now include a small (and usually cramped) QWERTY keyboard. Some of these require you to use your thumbs to type. And you can use a full-size keyboard by connecting it to the PDA via Bluetooth or a USB port. Each model also has a few buttons and navigation dials to bring up applications and scroll through files.

If you're in the market for a PDA, the main question you should consider is, "What will I be using this for most of the time?" If you're looking for basic PIM functions and organization, you probably don't need wireless connectivity. On the other hand, if you travel frequently and want to stay in touch via e-mail, you need Wi-Fi capability or a smartphone with cellular data service.

Because most people use a PDA as a PC accessory, synchronization is an important consideration. Look for a device that easily synchronizes with the PIM software you use on your computer. For example, if you have a Macintosh computer or you don't use Microsoft Outlook, a Palm OS device may be more to your liking.

The device's data entry method is another important consideration. If you plan to use your PDA for e-mail or other text-heavy applications, consider a built-in keyboard. If you can, try out the keyboard before you buy.

The size and shape of the device and its display are also important considerations. The device should be comfortable to hold. The display size and clarity should also meet your expectations. As with the keyboard, it's best to make a trip to a store that sells the devices you're interested in so you can try it out before you buy.

If you are interested in a multipurpose device that combines features such as GPS, an MP3 player, or digital camera, look for a device that has these features integrated. Alternatively, you can opt for a device with an SDIO slot and use compatible SDIO peripherals. If you plan to use numerous applications or store large files, look for a device that accepts flash memory media cards.

Accessories to consider include an additional battery, a car or travel charger, headphones, a carrying case, a plastic screen protector and add-on keyboards.

If you're interested in a smartphone, many of the considerations for purchasing a cell phone apply. Some of the most important things to check include service providers' coverage area, the additional cost for cellular data service (if any), and the length of the service contract. For more information, see How Buying a Cell Phone Works. You should also consider the capabilities of the different smartphone operating systems, such as Symbian, BlackBerry , Palm OS and Windows Mobile Pocket PC Phone edition.

The Future of PDAs

Traditional PDAs appear to be less popular than they have been in the past. Several manufacturers have exited the PDA market, including Sony and Toshiba. Sales of traditional PDAs have declined in recent years, according to IDC's Worldwide Handheld QView press release dated February 2, 2005.

For the future, PDAs need to continue to add to their core PIM functions in order to survive. The emergence and gaining popularity of smart phones and devices that combine other features such as wireless Internet, GPS and multimedia capabilities seem to back this trend.

For answers to frequently asked questions about PDAs, check out the FAQ on the following page.

Here are answers to some frequently asked questions about PDAs.

Why would I need a PDA?

A PDA might be helpful if you:

How much do PDAs cost?

PDAs range in cost from about $150 to $1,000, depending on the features you decide to buy. Most are in the range of $300 to $500.

Can my PDA work with my desktop or laptop?

PDAs are designed to work with desktops or laptops and to make the information in your bigger computers portable. So you need to keep the information up-to-date. PDAs have features that make this easier for you. The communication between PDA and PC is referred to as data synchronization or syncing. This is typically done through a serial or USB port on the PDA. Some PDAs have a cradle that they sit in while hooked up to the PC. Many PDAs also have an infrared communications port that uses infrared (IR) light to beam information to a PC or another PDA. Some PDAs also offer wireless methods to transfer data to and from a PC/PC network through a wireless e-mail /Internet service provider like those available on new models of cell phones. Finally, some PDAs offer telephone modem accessories to transfer files to and from a PC/PC network.

Which operating system is best for PDAs?

Each operating system has its advantages. The Palm OS is the market leader, so there is a lot of software written and being developed for it. But developers are working on software for the PocketPC systems, too. Palm OS takes up less memory and runs faster, and users say it is easier to use. PocketPC easily supports color displays, graphics, standard Windows packages (Word, Excel), and other devices (such as built-in MP3 players or MPEG movie players). PocketPC takes up more memory and is slower, and users say it is more complicated.

If my PDA is stolen, which seems possible since they are so small, is there anything I can do to protect my personal data?

If you keep your PDA data synchronized with your desktop computer, you'll always have a back-up copy. So if you lose your PDA, you'll still have the data. You can also do several things to lock up your PDA's information. In most models, you can use password protection. There are security programs available, too, that can keep someone from getting to your data. And some applications provide encryption.

How does a PDA work with the Internet?

One thing that PDA makers have done to make their devices work better for Internet access is a process called Web Clipping. Instead of downloading whole Web pages, Web Clipping slices out bits of text information and sends it through the airwaves to your PDA. News headlines, phone numbers, e-mail and other information can be transmitted this way.

Can handheld computers get viruses?

Viruses have infected some PDA models. The Phage virus, for example, overwrites some of Palm's executable files. Several companies have devised anti-virus software for PDAs. If you download programs from the Internet, you can be vulnerable to viruses. You have to watch out for the same things that you would if you downloaded a file to your desktop computer. Be cautious about downloading a file or program that comes from a source you don't know. To find out more about computer viruses, read How Computer Viruses Work.

How quickly will a PDA run out of memory?

The data commonly stored on PDAs doesn't take up much memory -- it's mostly text without images, so you can store a lot before you run out of room. Some PDAs need more memory for their operating systems; and if you use your PDA for e-mail or accessing the Internet, you'll need more memory. If you worry about having enough, you could choose a model that has expandable memory.

If I buy a PDA today, how soon will it be outdated?

PDA development, like the rest of the computing world, moves very quickly. The models available today have more functions and can be less expensive than the models available a few years ago. Eventually, PDAs will merge with cell phones and use a cellular network to communicate via voice as well as text. It is also likely that PDAs will become faster and have more memory as computer technology advances. The key to buying a PDA that suits you is to consider what you will use it for, then buy the model that will fill that need. Think of the function rather than the form. For example, if your primary need is for an organizer to keep your appointments and contacts, you will be able to use any good PDA for years to come. If you are the kind of person who develops "computer envy," then you might look for an upgradeable model and watch for the latest software.

On the next page, you'll find out about PDA software programs that'll make your job simpler and easier.

Most PDAs come with a sync program that synchronizes and updates information on both your computer and your PDA. Microsoft Pocket PCs use software called ActiveSync; Palm OS products use HotSync; and BlackBerry has Desktop Software.

For all PDAs, the process of downloading and installing new software is more or less the same:

PDAs have always been an essential tool for the busy executive. Today's PDA software allows professionals to say organized as well as connected. They can work no matter where they are.

Most PDAs come standard with an office application suite (word processor, spreadsheet, etc.), a Web browser and an e-mail program. Traveling executives can open e-mail attachments with their PDA, edit documents and send them back to associates while on the road.

Now that most PDAs have Internet connectivity, PDA software applications allow access to real-time online data.

Some of the professionals using PDA software applications are:

[Sources: Handango, Sage Software, CollectiveMed and Orbitron Technologies]

But PDAs aren't used just for business. The same software can be used to download and play games like chess, Sudoku and backgammon.

There's also PDA software that allows you to record DVDs for playback on your handheld device, and other programs that turn your PDA into a portable photo album, MP3 player or eBook reader.

So, if you use your PDA for business or pleasure, just remember that there's software working behind the scenes to make it all possible.

For more information about PDA software and related topics, check out the links on the next page.