[davidfor]

Originally Posted by Rev. Bob

When you have the card inserted and turn on the Kobo, the following things happen in sequence:

1. Light beside power switch flashes to show that the unit is powering up.
2. Screen clears and shows boot animation.
3. 5 most recent books on the Kobo device show in the carousel.
4. Screen refreshes to show 5 most recent books on the device and card in the carousel.

Currently, there is no visible indication after step 3 that step 4 is coming, and the delay can take a while...long enough to make one wonder if the device is going to read the card at all. Sometimes it doesn't.

I haven't seen enough of a delay between 3 and 4 to make me concerned. And if 2 happens, I know that 4 will happen so I wait.

In theory, this is true. In reality, try removing the card while the device is on and you're at the home screen, loading a book or two on the card, then inserting the card. Sometimes the device will detect the insertion and trigger a scan, and sometimes it won't. Couple that with the above issue - that there's no way to tell whether the device is scanning the card unless it does so and finds new content to process, thus triggering the "processing" screen - and this is a problem.

The problem with that is the only reason a scan won't happen is if the device doesn't see the card. And if it doesn't see the card at all, how can it tell you that it isn't doing the scan? I have had circumstances where the scan didn't happen, but the device put up a prompt saying there was a problem with the card.

I almost never connect my device to my PC; that's why I have a card. Consider this sequence:

1. Book X exists on the card, and I've put it on a couple of shelves.
2. I edit the copy of X that's on my hard drive - say, to fix a cover or tweak the title.
3. With the device off, I pop the card from the device, insert it into the PC, and replace the old copy with the revised one - keeping the same filename and everything.
4. I eject the card, replace it in the device, and power the device on.

In every case so far, the updated X gets detected as a new book. Any reading progress goes away, all shelving data is erased, it shows up in the Most Recent carousel - it's a new book. The old X doesn't show up in the library or on any shelves, having been replaced.

I see. I normally connect the device and maintain the card or device from the PC. I'll have a play and see what happens.

Furthermore, over time, it takes the device longer and longer to scan the card. (It's taken my device over 20 minutes before, with maybe 150 books on the card and only a few of those having been changed.) Doing a factory reset (or just wiping the database) and scanning the card from scratch takes a fraction of the scan time, but naturally that has the drawback of losing all the shelf/progress information the database had.

My theory is that instead of old-X getting either updated in or properly removed from the database, it's getting hidden (supplanted by new-X) and is still taking up space...thus adding to processing time, as observed. There needs to be some way of streamlining the database and/or speeding up scan time.

All that is surprising. I've spent a lot of time looking at the database after just about any operation. I haven't done the checks with 2.4.0, but with the previous few firmware versions, the database was kept clean. But, records for the SD card stay there until the books are removed. Ejecting the card and inserting it again should not change the database. But ejecting and inserting a new card will remove all the books from the first card and add all the books from the second card. The same happens if you eject the card, delete a few books and add different ones. And I have never found duplicates for a book unless the file name or path of the book changed.

As for whether this only happens on the SD card - no, it also happens if I connect the device to the PC and manually replace standard EPUBs (not kepubs) stored in the internal memory. (Again, manually - as in, not through sync software but through Windows Explorer file copying.)

I haven't done that for an SD card, so I don't completely know what will happen. I assumed it was the same as for the main memory, but I will have to test. It might be different depending on whether it is done through the device or when the card is ejected.

For the main memory, what happens depends on the firmware. With the current firmware, if you replace a book (exact same name and path), if the file size changes, the device removes the book completely during the processing. Then you have to add the book again. That means it is treated as brand new book. This is a defence mechanism on Kobo's part. It doesn't know what changed, so it doesn't know if it is safe to accept. Because the most likely changes are style or text changes, the calibre driver updates the file size in the database so that the files are not rejected. But, if structure of the epub file changes, these aren't handled. The most likely problem is that the TOC doesn't work, but it has caused the device to reboot on older firmware.