MobileRead Forums - View Single Post - Jetbook's Hourglass of Death [Orig. & Lite]

infi · 02-03-2010, 02:46 AM

A bit more information I've just dug up. There is another thread here:
https://www.mobileread.com/forums/showthread.php?t=65048

... where sobkas has extracted the firmware for 0.33g, which relies upon FBReader (a multi-platform ebook reader) for book support for a number of formats (I think all except PDF).

It's possible that the caching issue might be in FBReader itself, rather than the system, so I pursued that a bit. I installed FBReader on my linux machine, and played around with it a bit. I noticed that the Recent Readings seems to be kept in FBReader itself, as it behaves the same (opening the most recently read book at the current page upon restarting FBReader), and even uses the same "Recent Readings" terminology.

Looking through FBReader's config files, it (currently) stores recent readings and some other details in ~/.FBReader/state.db, a SQLite database file, with fields for file, paragraph, character, etc. So it is perhaps entirely a bug with FBReader not restarting or going into a loop upon trying to reload files from cache.

It seems unlikely that the version on the JetBook is a recent version, so I did a bit of searching to find similar bugs with FBReader, instead of the JB, and ran across this:
http://groups.google.com/group/fbrea...4e7dc71ebdb669

And here are some previously fixed bugs which sound very similar to our freezes:
http://www.fbreader.org/obsolete/index.php

FBReader 0.10.5 is released (March 20, 2009).
An FBReader freeze has been fixed. -- process freeze on some book formats, must manually kill process
FBReader 0.10.4 is released (March 19, 2009).
Multiple fixes in the epub format support.
FBReader 0.8.17 is released (March 23, 2008).
# Fixed crash after removing a book from library.
FBReader 0.10.1 is released (January 16, 2009).
# Fixed an infinite loop in library building code.

So, my hypothesis is that JB's version of FBReader is an older version with some caching bugs. So far, on the newest FBReader version, I haven't been able to reproduce it, so I'm still working on setting up some tests of older versions, (if they will indeed show up on another platform), but it's difficult as FBReader relies upon several libraries, so I have to go mucking with LD_LIBRARY_PATH and so forth to get it to use the correct (old) ones.

Will report back if I find anything.

---

Tentatively, I think the FBReader version on 0.33g is 0.10.4. 0.12.2 is the newest (though newer doesn't always mean better, of course).

02-03-2010, 02:46 AM	#17
infi Member Posts: 10 Karma: 10 Join Date: Jan 2010 Device: JetBook	A bit more information I've just dug up. There is another thread here: https://www.mobileread.com/forums/showthread.php?t=65048 ... where sobkas has extracted the firmware for 0.33g, which relies upon FBReader (a multi-platform ebook reader) for book support for a number of formats (I think all except PDF). It's possible that the caching issue might be in FBReader itself, rather than the system, so I pursued that a bit. I installed FBReader on my linux machine, and played around with it a bit. I noticed that the Recent Readings seems to be kept in FBReader itself, as it behaves the same (opening the most recently read book at the current page upon restarting FBReader), and even uses the same "Recent Readings" terminology. Looking through FBReader's config files, it (currently) stores recent readings and some other details in ~/.FBReader/state.db, a SQLite database file, with fields for file, paragraph, character, etc. So it is perhaps entirely a bug with FBReader not restarting or going into a loop upon trying to reload files from cache. It seems unlikely that the version on the JetBook is a recent version, so I did a bit of searching to find similar bugs with FBReader, instead of the JB, and ran across this: http://groups.google.com/group/fbrea...4e7dc71ebdb669 And here are some previously fixed bugs which sound very similar to our freezes: http://www.fbreader.org/obsolete/index.php FBReader 0.10.5 is released (March 20, 2009). An FBReader freeze has been fixed. -- process freeze on some book formats, must manually kill process FBReader 0.10.4 is released (March 19, 2009). Multiple fixes in the epub format support. FBReader 0.8.17 is released (March 23, 2008). # Fixed crash after removing a book from library. FBReader 0.10.1 is released (January 16, 2009). # Fixed an infinite loop in library building code. So, my hypothesis is that JB's version of FBReader is an older version with some caching bugs. So far, on the newest FBReader version, I haven't been able to reproduce it, so I'm still working on setting up some tests of older versions, (if they will indeed show up on another platform), but it's difficult as FBReader relies upon several libraries, so I have to go mucking with LD_LIBRARY_PATH and so forth to get it to use the correct (old) ones. Will report back if I find anything. --- Tentatively, I think the FBReader version on 0.33g is 0.10.4. 0.12.2 is the newest (though newer doesn't always mean better, of course). Last edited by infi; 02-03-2010 at 03:52 AM.