I am writing this on my Sylvania netbook. It is a computer, regardless of what the box says. If I so choose, I could replace the operating system, add or remove software, do pretty much everything that you can do with other small computers (with the understanding that, by its nature, it is somewhat limited).
Still, it meets the qualification; it is a computer.
The term computer, though, is being used and misused in interesting ways these days, especially where mobile devices are concerned. Much of this goes back to the early days of these devices and the divergent evolutionary courses they took. One of the best examples is the Apple Newton. Quite a ways into its development, the deliberate corporate decision was made to cut back on its capabilities; it had the potential to cut into Apple's flagship, the Macintosh computer line. In 1992, then Apple CEO John Sculley coined the phrase "PDA" to describe the Newton. With that, a whole new genre was born, satellites for your main computer. Now, a device that held much promise as a stand alone unit is relegated to secondary.
The first Newtons were amazingly powerful little devices, though they could hardly be considered satellites (even though they were). The first Message Pads were as powerful as the early Macintosh computers and has as many features. The problem was that they were too powerful for their size.
They were also too big. The original Message Pads could not fit easily in shirt pockets, unlike similar devices of the day (the Tandy Zoomer, for instance; we'll cover that shortly). It needed a case. In the early and mid 1990's, it was not unusual to see professionals with Newton cases hanging from their belts.
The Newton was, in fact, a tablet computer.
Not so the first true PDA's, though like the Newton they were not originally named such. Various companies had in fact been making digital assistants in various forms since the early 1980's. There was software that would allow some of the early notebook computers such as the Tandy Model 100 series to even act as large digital organizers. The first devices that truly fit the name PDA, even in function, were much smaller though in no way less powerful. One such line was the Tandy Zoomer.
The Zoomer was developed in the early 1990's, partly by the team that would go on to release the even more successful Palm line. When the Zoomer was being developed, the term PDA didn't exist; it was a handheld computer that relied on pen or stylus input. The operating system it ran was a variation of the PC-GEOS desktop running on top of a very lightweight DOS. While it was not as powerful as the Newton, it was in many ways a kindred spirit.
It was also a commercial flop.
And sadly the Newton did not do much better. It's biggest problem was that it was orphaned. It was not a "PDA", even if Apple's CEO coined the term. But it had been deliberately crippled so as not to interfere with their flagship Macintosh line. It never really fit either category.
In reality, the Newton wasn't a PDA. It was a tablet computer, more or less.
So, for that matter, are almost all PDA's.
For instance, I have a GoType keyboard for my Palm IIIxe that turns it into a more powerful computer than my old Macintosh Plus. The Palm OS, though, is interesting in that it really is just a fancy GUI on top of a database, and aside from some fancy applications, doesn't really have a file system like most other operating systems. It's still a computer, as it fits all the classic definitions of one. It's just a small one.
When Microsoft came up with the Windows CE and the Pocket PC concept, they didn't hide behind fancy terms; they were computers, are computers. Some are PDA-like, some are clamshell, some are regular computers, laptop and otherwise.
So you see this becomes a real mess in a hurry.
Okay, we can safely assume that they are all computers. Then why can't we just say that they are all computers? We're letting the corporate powers that be decide? Of course we are! That makes it easier for us to pigeon hole the devices, and it certainly makes it easier to dispose of them when the time comes. After all, they aren't computers.
But they are computers. and capable of a lot more than they want us to think. All of the essentials are there; processors, RAM, storage, methods of input, displays.
You can call it a wireless tablet, sure, go ahead. That little Windows CE laptop can be called an Internet device. And the thing in your pocket? Sure, it's a PDA.
Rest assured, though, they have all the power found in computers that we coveted just a few years back.