[geekmaster]

Originally Posted by Jessica Lares

The Kindle Touch has 256MB of DRAM memory according to the teardowns and specifications of that part. The Kindles before the third/keyboard have 128MB. The Kindle OS probably takes about 20-50 of it on its own, the rest for the reading, browsing, etc "apps" if you call them.

That estimate is not accurate for modern kindles. The kindle OS consists of the linux kernel, and the framework (the GUI) and all supporting device drivers and background processes. On the K5 (touch), this includes a very large Xorg graphics layer. I did very thorough memory testing when the K5 was first released. It uses MOST of the RAM just for itself, leaving little left for apps and books. Your 20-50MB estimate is extremely short of reality, especially on the newer kindles.

Originally Posted by Jessica Lares

The Kindle storage on the other hand varies from 2-4GB depending on the model. That is where your books and whatever else you keep in there is. However, as you note, when they tell you it's 2GB, and it's only 1.4GB, it's not just because of the fancy number explanations they give you about the bytes and rounding, etc, it's because they've allocated the remaining 600MB for the OS, drivers, firmware updates, and virtual memory (which the Kindles must have very little of). So when you open up that 50MB PDF file, it uses a little bit of your RAM just to open it, and a little bit of virtual memory/that allocated hard drive space to store those images until you either turn off the Kindle completely or it expires (depending on how Amazon handles that anyway). Think of it as your internet browser cache which saves most of the GUI of websites so it can render them faster as you navigate and go back to pages the next day.

I disagree. What you call "storage" is actually the "USB Drive" partition (/dev/mmcblk0p4 on the K4 and K5) of the onboard mmc memory storage device. The kindle does not even contain the hard drive that you mention above. Nor does it contain "virtual memory", which in linux exists in a swap file or swap partition. The kindle has neither of these, because virtual memory swap files are very hard on mmc devices and wear them out prematurely. That means that the very small amount of RAM not already occupied by the OS is all there is.

Originally Posted by Jessica Lares

So when you get that error that your Kindle doesn't have enough memory to render the rest of the pages, it's because there is not enough space VIRTUALLY to handle the images and embedded text in that PDF. It's not a problem with Amazon bought ebooks because they have guidelines in place that don't let authors use images bigger than 127KB in size.

First, there is no virtual memory in the kindles. Second, the 127KB limit you refer to is the maximum image size allowed in "the Kindle File Format" (.mobi), which has nothing to do with the PDF files being discussed here. It would be helpful and much less confusing if you supplied supporting evidence, references, or links, instead of just claiming that I am "wrong". I would like to examine your evidence so that I can update my own personal knowledge base, if your information is true.

I have read the technical manuals from amazon, and the reference manuals from the chipset manufacturers, and the source code for all of the kindle models that I own (DX,DXG,K3,K4,K5). I have also written a significant base of original code that works on ALL of the eink kindle models, and is being used by other developers as well. I have also discovered jailbreak methods that are in reserve (shared with other developers) that will be published when existing known methods no longer work. I do not see any evidence that your information is better than mine (or even correct). Sorry.