Originally Posted by Ken Maltby
It is not as simple as file size. Other factors related to the book's construction and the
individual component files that define the display features. Because the different formats handle these factors differently, it does vary with format. It also varies by the
program used to create the file, and the options used, even within the same format.
For example; I also encountered the "File Too Large" message with an epub file made
from HTML using Calibre. This ebook had a great number of illustrations and did not
provide a separate directory for them.
But if I converted the HTML to pdb using Calibre first, then made an epub from the
pdb, no error message in the JBL. The new ebook was structured with a directory for
the images. Everything appears normally in the new ebook, including all the illustrations.
I appreciate that a spate of factors determines whether the JBL can open any given file, but I'm nonetheless interested in hard numbers. Just call me Philistene.
Still lacking those numbers, I conducted a small experiment. Starting with a 22.9 MB .mobi reference text that's chock-full of graphics, I converted it by means of Calibre to .epub, .pdf, .rtf, and .fb2 formats. Here are the sizes of each:
- .mobi 22.9 MB
- .epub 17.2 MB
- .pdf 33.3 MB
- .rtf 39.0 MB
- .fb2 26.2 MB
The only two that would open were those in .pdf and .fb2 format. They displayed reasonably well, but the .pdf had the appearance of graphical text, rather than character-based text. Also, each page had to be scrolled to see its entirety. The .fb2 didn't have these problems. It's ironic that two of the largest
files are the only ones that could be opened, huh?
The bottom line is that the conversion formatting errors, combined with lack of a search function, make the JBL a less-than-perfect choice for a large reference text, if you start with a .mobi file. That means it can't serve as a useful backup for my K2 in this role. Thus, I've abandoned the experiment.
I hasten to add that the JBL is a fine reader and I don't regret purchasing it for a moment. It displays all my DRM-free Kindle books (except those big pesky reference tomes) just fine. Moreover, the number of formats it can handle, together with its use of AA batteries and the presence of an SD slot, make it a pretty nifty little traveling companion.