02-03-2021, 07:51 AM | #1 |
Junior Member
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Device: Kindle App for Android
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Long gap between record 0 and record 1
Hello, Has anyone figured out the reason for the long gap between record 0 and record 1 in kindle formats?
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02-04-2021, 08:12 AM | #2 |
Grand Sorcerer
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I remember seeing speculation that it is unused space left there to allow changes to be made to the book's metadata in place by only rewriting record zero, avoiding the need to rewrite the whole file.
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02-04-2021, 04:28 PM | #3 |
Sigil Developer
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FWIW, besides extra metadata that was where local user and device specific DRM info was stored. That way there was room for multiple user keys. In actuality only a single key per book was used for text encryption but that key was encrypted so that only a device or user key could get decrypt it to access it And all of that took space. But that was a long time ago, so things have probably changed considerably.
It was actually quite smart as the book's text could be encrypted once independently of user or device but that key was itself encrypted by user specific keys that could be written on the fly as the book was downloaded very very quickly. |
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kindle, mobi, prc |
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