EPUB 3 : 300kb HTML file size limit

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Does the 300kb file size limit for individual HTML file is recommended for EPUB 3 formats? My understanding is that this limitation has been set as a good practice considering the e-ink readers for EPUB 2 and not part of IDPF specification.

Is it fine to ignore this file size limit in EPUB 3 as these formats are at present read in tablets and smartphone devices where the hardware specifications are superior than e-ink readers?

The 300KB implementation limit on individual HTML files existed only in some of the first EPUB 2 reading systems using Adobe technology (known as Reader Mobile SDK aka RMSDK), such as the original Sony Reader PRS-500. It was in order to guarantee functionality and performance despite limited device HW memory and CPU. By 2009 Adobe had enhanced the RMSDK SW to work around the limit and so the restriction was no longer "hard" (see discussion of this here: http://www.mobileread.com/forums/showthread.php?t=50992 ). But even on the latest implementations, exceptionally long "chunks" may lead to performance issues, for example linking deep into a different chunk will usually require the reading system to paginate all the pages up until the page that's the link destination, which can lead to a substantial pause. 

So I would consider at this point 300KB chunk size to be not a hard limit but only a best practice for best practices to achieve good performance, and secondarily to ensure content works on very old reading systems such as original Sony Reader.

As Barbossa said about the Pirate's Code, it's "more what you'd call 'guidelines' than actual rules...". Arrgh.

Thanks bill for the response. It is wise to have the limitation as best practice for EPUB 2 considering the e-ink based readers.

Whereas for EPUB 3 which are at present read by devices having higher hardware configuration (more RAM+ faster processors), i wish that the limit should be increased.

Myself at present not sure whether to consider this 300Kb limit for EPUB 3 formats as well.

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