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davidfor · 05-18-2013, 05:11 AM

While there isn't a limit on the books, there is a limit on the covers.

The user partition of the device is formatted as FAT32. This allows 64K files per directory. Or, more correctly, has 64K directory entries per directory. For the traditional short file names, that is 64K files. But, long files use multiple directory entries per file. So for a directory with files that have long names, the maximum number of files is a lot less.

The image file names used for sideloaded books is basically the full path for the file plus some extra characters. Because of that, it isn't hard to have an image file name that is 100 characters long. The device also creates three cover images per book. From previous discussions, this problem tends to start when you have 2000 or more books.

There are some things you can do to alleviate this, but there is no permanent fix. The simplest thing is to shorten the file paths used for your books. I use the default calibre save template of "{author_sort}/{title} - {authors}". If I dropped the {author} from that, it would shorten the name a lot.

In a discussion on this a while ago, I posted a set of suggestions of different ways to handle this. Except for shortening the file paths used, they all needed some changes made to the database on the device for each book. Unfortunately, I can't find that thread right now.

Last thing, the covers for books on the main memory and the SD card are handled differently and has changed with the firmware. At the moment, the covers for books on the SD card don't get saved, so they won't have this problem.

05-18-2013, 05:11 AM	#2
davidfor Grand Sorcerer Posts: 24,907 Karma: 47303748 Join Date: Jul 2011 Location: Sydney, Australia Device: Kobo:Touch,Glo, AuraH2O, GloHD,AuraONE, ClaraHD, Libra H2O; tolinoepos	While there isn't a limit on the books, there is a limit on the covers. The user partition of the device is formatted as FAT32. This allows 64K files per directory. Or, more correctly, has 64K directory entries per directory. For the traditional short file names, that is 64K files. But, long files use multiple directory entries per file. So for a directory with files that have long names, the maximum number of files is a lot less. The image file names used for sideloaded books is basically the full path for the file plus some extra characters. Because of that, it isn't hard to have an image file name that is 100 characters long. The device also creates three cover images per book. From previous discussions, this problem tends to start when you have 2000 or more books. There are some things you can do to alleviate this, but there is no permanent fix. The simplest thing is to shorten the file paths used for your books. I use the default calibre save template of "{author_sort}/{title} - {authors}". If I dropped the {author} from that, it would shorten the name a lot. In a discussion on this a while ago, I posted a set of suggestions of different ways to handle this. Except for shortening the file paths used, they all needed some changes made to the database on the device for each book. Unfortunately, I can't find that thread right now. Last thing, the covers for books on the main memory and the SD card are handled differently and has changed with the firmware. At the moment, the covers for books on the SD card don't get saved, so they won't have this problem.