Quote:
Originally Posted by Sergi
Is incredible this limitation. In this days, when you explain to someone that there's a limitation of 300kb in a new device, it's like if you were talking of something of the past.
I can understand the 300k as a recommendation, not as obligation. They can recommend no to use big files for performance questions.
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Unfortunately I understand the constraint all too well. These ebook readers have a very limited CPU to conserve power. I've never noticed an ebook reader getting warm in my hands due to the CPU running. Whenever you load an ebook it has to process the entire "flow" before it can render a single page. If you have a book that has nothing but 290KB xhtml documents you will notice it takes a lot longer to load than one that has only 30KB documents.
These CPUs are typically running in the 200 to 500MHz and are much simpler than a similar processor used in a home computer. A 400 MHz Pentium III processor can compute more and faster than these CPUs, but they also take a lot more power. They have an L2 cache 512KB compared to the 16KB used in the ARM920T for the Pocketbook 302. A Pentium III can do 1,083 MIPS (Million Instructions Per Second) at 400 MHz. The ARM920T can do 555 MIPS at 400 MHz. And just to show an extreme, the Intel Core i7 Extreme Edition i980EE is rated at 147,600 MIPS at 3.3 GHz. The PRS-505 used the ARM920T at 200 MHZ so it would be around 222 MIPS.
I should also mention that the xhtml document may only be 290KB, but it takes a lot more RAM to render the document. You also need to consider that most of these devices only have 64MB to 128MB of RAM. Most modern computers come with at least 2GB.
I should say that I understand the constraint because I have run up against long delays in Windows while manipulating XML documents with my own programs. If you've been following the development of Sigil, you'll see he has had to give up treating entire books as a single flow for the same reason. This is on modern computers that you see a large delay. Admittedly editing has a lot more overhead than simply rendering the file, but it is magnified on these underpowered CPUs.
I agree that the limit is annoying, but this is due to the target CPU and not a limit of programming. CPUs have gotten better since Adobe started their Mobile Edition. You would think that they could at least double the limit by now.
Etienne66