What is a PDA?
What does PDA stand for? Personal Digital Assistant. A PDA is a computer that fits in the palm of your hand. Its main purpose is to carry your PIM (person information manager) applications and data: address book, calendar, notes and tasks. PDAs have been around for quite a few years now, and they can do much more than PIM functions these days. There are two major breeds: Palm OS and Pocket PCs. Palm OS PDAs are made by Palm, Sony and Handspring, though Handspring is leaving the PDA market and concentrating on Palm OS smartphones these days. Pocket PCs are made by many companies, including HP, Toshiba, Dell and ViewSonic. They have touch screen LCDs which respond both to the stylus and your finger, and most are color these days. All have a stylus which you can use to navigate the screen and enter information using handwriting recognition (HWR). Several now have built-in thumb keyboards in addition, which have become popular in the last year. Unlike PCs, they don't have hard drives, which is generally a good thing since hard drives don't like to be bounced around in your pocket or purse. Instead they have RAM and ROM memory, a portion of which is used to store programs and data. Palm OS PDAs generally come with 16 megs of RAM, while Pocket PCs have 32 or 64 megs. The ROM area is non-volatile, which means it isn't erased even if you wipe out the PDA via a hard reset. ROM is where the operating system and basic programs that come with the unit are installed. If you install add-in commercial and shareware programs, they'll go in RAM. PDAs have a CPU, aka processor, just as your PC does, and speeds range from 33 MHz to 400 MHz. Generally Pocket PCs have faster processors and more memory because the Pocket PC operating system (OS) requires more horsepower than does Palm OS.

Expansion Slots
Most all current PDAs have expansion slots that can access storage/memory cards and IO cards such as modem and networking cards. Pocket PCs usually have SD slots and sometimes CF slots. Palm brand PDAs and the Handspring Treo have SD slots. Sony Cliés have Memory Stick slots and the NX series and NZ90 also have a CF slot that accepts Sony's WiFi network card and storage cards with a 3rd party driver that sells for $28. Right now there are storage cards and Palm's Bluetooth SD card (Palm OS only) for SD slots with more Bluetooth cards and WiFi cards coming soon. CF slots on Pocket PCs can accept storage cards, CF digital camera modules, CF modems, wired Ethernet Cards and WiFi cards. For the Clié, you can get Memory Stick storage cards, a digicam Memory Stick and overseas, a Bluetooth Memory Stick.

Syncing
Since the Pocket PC OS is made by Microsoft, Pocket PCs sync with MS Outlook for PIM information and email. Outlook 2000 is included with Pocket PCs. They can also sync with and read/edit MS Word and Excel files. Advanced formatting is not supported by Pocket Word and Excel, but the basic stuff is supported.
Palm OS PDAs can sync to Palm Desktop, which is a full-featured desktop PIM application or Outlook. Note that syncing to Outlook is provided via bundled 3rd party software: Palm and Handspring brands come with PocketMirror, and Sony Clié PDAs come with Intellisync Lite. Many Palm OS PDAs come with Documents To Go, which is a very capable Office suite for Palm OS that allows you to work with Word, Excel and even PowerPoint files. Docs To Go supports more advanced formatting than does Microsoft's own Pocket Word and Excel! You can buy Documents To Go or one of the other Office suites for Palm separately if your PDA doesn't come with it.

Screens
Both current Pocket PCs and Palm OS PDAs have color screens (there are a few exceptions, such as the $99 Palm Zire). Pocket PC screens are 320 x 240 pixels. Palm OS PDA screens come in a variety of resolutions: from the basic 160 x 160 pixel screen, all the way up to 320 x 480 on the Sony Clie NX series and NZ90 All current Sonys have either 320 x 320 or 320 x 480 pixel displays, and Sony pioneered higher resolution displays on Palm OS. All Handsprings including Treos, have 160 x 160 screens. Palm brand PDAs have 160 x 160 screens or 320 x 320 for Tungsten models and the Palm Zire 71. Several Palm and Pocket PC models have transflective displays, and these are brighter with richer colors (see individual reviews for screen type). All current PDA screens are viewable indoors and outdoors, though they do look best indoors.

Mobile Phone and Wireless Integration, Internet Access for Email and Web
In recent years, we've seen several Palm OS Smartphones and Pocket PC Phone Edition units hit the market (see this page for those reviewed on our site). These units marry a mobile phone with a PDA, which means you can have all the benefits of a PDA and make phone calls and surf the web using one device. These convergence units are starting to catch on now that they've become less bulky and prices have dropped to £250- £500 (or less, depending on mobile network provider rebates and specials). The good points are having all your info in one device and wide coverage for data access (email and web surfing). The drawbacks include: if you're a geek and like to upgrade your PDA frequently, you'll have to deal with the added complexity of changing phones with your network provider and you can ring up a big bill if you spend a lot of time on the Net.

Accessories
There is a huge range of software and hardware accessories for your PDA. From Add on Video or Digital cameras, to MP3 Players and beyond. Some PDAs can now double up a in car satelite navigational systems. Make sure when you purchase that you can upgrade or purchase the addins you require.