What is the Difference between an E-Reader and a Tablet / Pad?
Nothing is simple, and certainly the use of the word ‘Tablet’ can cover a range of species from laptop-computers with keyboards and touch-screens, right through to a Smart-phone.
So lets deal with Tablets. A better name for the the sort we are talking about here is ‘Slate’ or even ‘Pad’. This consists of a self-contained portable device with a touchscreen, no physical keyboard and a build in rechargeable battery. In terms of processing power and RAM it is often less than an equivalent notebook computer, but more tham most Smart-phones. A Slate may only have a solid-state storage system (eg inbuilt, and plug-in flash memory) but not necessarily a file-system that allows the user the same kind of flexibility a PC would provide. Slates have a lot in common with smart-phones except they are larger and thus the screen is more usable. There are lots of application programs for slates which can make them appear to do most things a PC can do, but perhaps in a more vendor packaged/controlled way.
E-readers on the other hand share a similar form-factor to Slates, but conceptually are quite different in approach. Being designed primary for e-reading, they are designed for low power operation and high usability. So the battery lasts for weeks, even months, the screen only uses power when its changing (that’s right, the screen stays ‘on’ all the time, even when the device is off). They don’t get hot and can be read in bright ambient light, and don’t glare at the reader. At present the technology only gives monochrome displays with limited grey-scales, but colour displays are on the way. This low-power LCD technology, which presents remarkable clarity and contrast has been called ‘e-ink’ and there are at least two different implementations from major panel manufacturers. However, don’t expect the flash and glitter of highly responsive animated TFT LCD’s with capacitive touch screen overlays. Low power means slow changing and not terribly suitable for animations. Fine for reading, but not much use for playing action games.
The low-power design considerations of e-readers also can spill over into performance issues. Should you wish to view a 20MByte .pdf file, you might have to wait a few seconds for it to be rendered. Worse, because .pdf’s are dynamically constructed (or ‘rendered’) from instructions, scrolling through pages can be slow. Even worse still, certain e-readers have been known to ‘give up’ on complex or large .pdf’s altogether.
However, thankfully most e-book formats are not .pdf. The books themselves come in a variety of specialised formats that allow the e-book reader to maximize the potential to display it well. That said, a 6 or 7 inch ‘e-ink’ display might be fine to read a novel, but could be frustrating when displaying a two or three column article or a technical book containing tables and diagrams. A 9 or 10 inch display e-reader would do better for these jobs.
So, where does this leave us on e-readers and slates? Clearly compact e-readers win hands-down in the stakes of taking a novel to read around with us in our bag (or actually a whole library). The larger e-readers can better deal with wider formatted texts and can display ‘whole pages’ better, when as in .pdf a whole page is rendered at once, without resorting to zooming and scrolling around. For the more challenging technical .pdfs and books, then there is no getting away from the attributes of speed power and colour offered by slates.
As of right now, E-readers do not have touch screens like Tablets and Smart-Phones; as the new technology of e-ink doesn’t yet support it. But who knows what e-ink technology will be able to do in the future?
