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davidfor · 07-22-2013, 02:39 AM

GeoffR is right about what is happening. There is a workaround to this that calibre uses when sending a new copy of the book. The way the device tells that the book has changed is the file size. The internal database records the file size, and if the size of the book on the disk doesn't match this, the book get removed from the disk and the database. The Kobo driver in calibre updates the file size when it resends a book if it changes. You can easily do this yourself.

But, if you keep the book on the SD card, it is handled differently. In that case, the database details of the book are removed, but the book is not. In fact, the book is added to the database as a new book.

There is another but. Firmware 2.8.1 changes the handling for books in the main memory. This will now match the handling for the SD card. The book gets removed from the database and then added as a new book. This means you lose the reading position, shelves and bookmarks, but you don't lose the book.

Oh, the reason Kobo has been doing this is the because of the way they handle books. The first time they see them, the book is processed to extract the metadata and TOC. This is loaded into the internal database. The stored TOC is used for navigation. If the book is replace, the stored TOC could be out of sync with the book and that will cause problems. Recent firmware handles this better than older firmware.

07-22-2013, 02:39 AM	#5
davidfor Grand Sorcerer Posts: 24,905 Karma: 47303824 Join Date: Jul 2011 Location: Sydney, Australia Device: Kobo:Touch,Glo, AuraH2O, GloHD,AuraONE, ClaraHD, Libra H2O; tolinoepos	GeoffR is right about what is happening. There is a workaround to this that calibre uses when sending a new copy of the book. The way the device tells that the book has changed is the file size. The internal database records the file size, and if the size of the book on the disk doesn't match this, the book get removed from the disk and the database. The Kobo driver in calibre updates the file size when it resends a book if it changes. You can easily do this yourself. But, if you keep the book on the SD card, it is handled differently. In that case, the database details of the book are removed, but the book is not. In fact, the book is added to the database as a new book. There is another but. Firmware 2.8.1 changes the handling for books in the main memory. This will now match the handling for the SD card. The book gets removed from the database and then added as a new book. This means you lose the reading position, shelves and bookmarks, but you don't lose the book. Oh, the reason Kobo has been doing this is the because of the way they handle books. The first time they see them, the book is processed to extract the metadata and TOC. This is loaded into the internal database. The stored TOC is used for navigation. If the book is replace, the stored TOC could be out of sync with the book and that will cause problems. Recent firmware handles this better than older firmware.