How Pdas Work

Learn how Personal Digital Assistants, or PDAs, works to help you organize your personal information.

Personal Digital Assistants, or PDAs, have replaced the traditional desk organizer as today's new personal information manager. The two types of PDAs on the market are the handheld computer and the palm-sized computer. These popular gadgets have taken over the organizer's basic duties of storing, accessing, and organizing addresses, phone numbers, calendars, and to-do lists. The advanced models now have wireless internet capabilities, mp3 music playback, digital photography, and cell phone capabilities.

PDAs are a recent technological development. The 1990s saw the advent of the handheld computer with the introduction of the Apple Newton Message Pad, the first popular handheld. The Palm Pilot PC was introduced to the world in 1996 and immediately became popular with users as it was smaller than the Newton, easier to navigate, and lighter to carry - all factors that eventually led to the discontinuation of the Newton in 1998. Microsoft decided to jump onto the bandwagon and launched an operating system designed for handhelds called Windows CE. The devices currently on the market include the larger and heavier handheld, and the smaller, lighter, and simpler to use palm-sized PCs. 3COM no longer has the monopoly on the PDA: Casio, Hewlett Packard, Compaq, and Sony now have comparable products. This has driven the price for a palm-sized PC down considerably.

PDAs are like miniature computers; they are priced to sell depending on the features and options selected by the user. All PDAs come with the same basic components. There is the brain to the PDA called a microprocessor. All PDAs have a display screen, called a liquid crystal display screen, or LCD. There is also RAM, which stores the programs and data currently in use. Input devices in the form of a touch screen allow the user to interact with the machine itself. Depending on the size of the unit, there will either be a stylus or keyboard for input as well. A battery unit powers the PDA. Finally, there are built-in ports on the PDA that allow it to connect to a computer through a special cable.

The display screens come in a variety of sizes and resolutions. LCDs can be black and white or colored, and they can be passive matrix screens or active matrix screens. A passive matrix display uses less power than the active matrix display. An active matrix display provides a faster screen resolution, and is easier to view. The LCDs serve as the output and input points for the PDA.

The methods of input for the PDA depend on the type of PDA used. On handhelds, the device receives input from the user through the use of a keyboard or a touch screen. A palm-sized device such as the Palm Pilot PC receives input from the user using a pen-like stylus and touch screen. A user "writes" on the LCD screen with the stylus. Electrical signals generated by the motion of the stylus on the LCD screen create characters that are recognized by handwriting recognition software preloaded onto the PDA. Writing on a PDA is a special art form; the characters must be shaped in a certain way that allows recognition by the software. Not all writing is accurately translated by the software. When recognition fails, information can be entered by touching buttons on the screen using the stylus.

Batteries provide power to the PDAs. Alkaline or rechargeable battery sources can be used, depending on the PDA model. Power requirements are dictated by the overall features and programs contained on the PDA. PDAs with advanced software and color monitor capabilities will use more power than simple PDAs, so the battery life is shorter. The life of a battery runs anywhere from 2 hours to 2 months depending on the usage. Most PDAs today come with power management features.



PDAs require an operating system to communicate with other hardware components. There are two major operating systems (OS) on the market: the Palm OS, by 3COM, and Microsoft Windows CE, or Pocket PC. The Palm OS exchanges information with a personal computer using a proprietary program called the Palm Desktop. The Pocket PC OS exchanges calendar and contact information with Microsoft Outlook. The Pocket PC OS can handle color displays and support Microsoft Office-based applications. The Palm OS uses less memory and may be faster and more intuitive to the user than the Pocket PC. Recent upgrades to the Palm OS now allow it to share and exchange data with Microsoft Outlook.

The process by which a PDA exchanges information with a personal computer is called data synchronization, or syncing for short. To sync with a computer, a cable must be connected to the PC from the PDA using the computer's serial or USB port. The Palm Pilot comes with a cradle that connects to the personal computer using the cable. The PDA can recharge and facilitate information exchanges while it sits in the cradle. Recent PDA models have infrared ports which allow wireless data transfers between the computer and the PDA.

PDAs don't store their programs and data on hard drives as computers do, but on smaller capacity chips called ROM, or read-only memory. The ROM chip loads the programs and data into temporary storage called RAM when the PDA is turned on. As long as the PDA is powered on, any information that the PDA uses is stored in RAM.

The memory configurations of a PDA vary from 2 megabytes to 64 megabytes. Again, the more features and options a PDA has, the more memory and power is needed to ensure smooth functioning. Luckily, recent models can handle memory expansion using flash or secure digital media cards.

Continuing improvement in technological innovations has made the PDA a more complete personal information manager. Users can store and retrieve names, addresses, phone numbers, and task lists, and schedules on a PDA using a stylus and touch screen. By syncing the PDA with the computer, PDAs can update existing calendar and contact information that is stored on the computer. Certain models of the PDA, such as the Sony Clie model, now carry support for digital photography and music. Some models offer cell-phone support and wireless internet capabilities. Word processing, spreadsheets, and expense tracking are also available on these models. Keep in mind, though, that the extra features usually mean a higher price tag. As with most technologies, you get what you pay for.

With all the bells and whistles these new PDAs have to offer, it is a marked improvement over the bulky, post-it note filled organizers of the past. With continuing innovations and technology improvements, we may be able to one day replace the personal computer entirely with this portable gadget.

© High Speed Ventures 2011