Application Images (app.bin Files) Guide

[CrashX]

Application images (or app.bin files) are a disk with a filesystem in a file. So instead of formatting your HDD you format the file and copy files into it. There are two major file systems that make sense to be used for the app.bin files: ext3 and cramfs.

ext3 is a widely used Linux filesystem that should be used for app.bin files where the application must write to the app.bin file, e.g. to cache downloaded files. cramfs (compressed ROM file system (don't ask me why is ram instead of rom)) on the other hand is a filesystem that is readonly, so ideally for themes because they are a fixed set of files.

In general it doesn't matter which one you use when you don't need write access to the app.bin file, but the cramfs has the advantage that it does not take damage in case of a crash due to power loss of the WDTV. Its an unlikely event, but can happen and in this case the app.bin file must be replaced with a fresh copy.

http://sourceforge.net/apps/trac/wdtvtools/wiki/Tutorials/CreateApplicationImage

Is this what we should follow to create app.bin ?
Anyone have a guide on how to compile app.bin ?

[recliq]

The guide for ext3 is correct.
You should also have a look here -> http://wiki.wdlxtv.com/Creating_an_app_bin

Another tip: Try using binaries instead of trying to compile it yourself at first.
You can find a lot of binaries running on wdtv live in debian squeeze repository (arch: mipsel).
On a debian linux you can download the mipsel .deb file and extract it with

Code: Select all

dpkg -x <mipsel_package>.deb <mipsel_package>
dpkg -e <mipsel_package>.deb <mipsel_package>/DEBIAN


to ./<mipsel_package>

The second command extracts the control files for setup (sometimes quite usefull when building in app.bin ;P).
Copying all files to wdtvlive will most likely not be the end. You then have to satisfy dependencies and eventually install additional libaries (ldd is your friend!)...

[derlinuxer]

Moin,

little improvement extracting a deb package:

Code: Select all

ar p mypackage.deb data.tar.gz | tar zx


This will unpack the content in one step.

[cornet]

Hi there

I'm new here and need your help.

I would like to replace the default samba server on my WDLXTV with new one from debian squeeze repository (DSR). What I already did:

1. set up the squeez image and installed there all needed packages
2. got the samba.mipsel.deb from DSR and extracted it into a new folder.
3. placed binaries into bin/ (not usr/bin), libs into lib/ (not usr/lib) and created the folder structure like in Creating_an_app_bin guide.

What happens to the files from DEBIAN folder?
Do I need to uninstall/stop the old server?
Do I need to edit files in etc/init.d/?
Should be anything else done before creating the app.bin?
Which image is better ext3 or cramfs?

Thank you for your help

Regards, Denis

[recliq]

First off, i think it's not that simple to replace samba since as far as I remember the samba code in wdtv is modified by wd.

Anyways the files in DEBIAN dir don't need to be copied to the app, but you should have a look at them. They are control files for debian setup, so you will find information what is done to install the app.

You need an etc/init.d/Sxx script if you want to start an application on boot up.

As for ext3 vs. cramfs: If you don't need any write access to your app.bin use cramfs since it produces much smaller images, otherwise go for ext2/3.

[cornet]

Thank you recliq

It was very helpful for me. As you said it's not easy to replace samba I didn't try it. But I managed to replace the default dropbear ssh server with openssh one. It's much faster. It was my first successful app.bin for wdtv