Format of .SAV savestate files

[Virtual Boxxy]

I have looked at the source code briefly, and it seems like a major task to document the file format of the .SAV files, so I'm wondering if somebody has already done it?

Sorry about cross posting, I posted in the wrong forum at first.

[mpack]

Documenting it would imply that it's fixed. It isn't. AFAIK the format could change completely, tomorrow. Even VDI format is not formally documented, but in that case we do at least expect the format to be backwards compatible.

[Virtual Boxxy]

Ok, I did see references to a version 1 and a version 2 of the "format" in the sources though, so it seems to be somewhat stable.

It doesn't matter though, I just want to make a diagnostics script, it would be ok if it breaks often on new versions.

[michaln]

The overall format has not changed in a while although there is certainly no guarantee it won't. But that's just a sort of container and individual devices manage the structure of their own saved data. That's something which is constantly changing.

The format is not formally documented because there are no external consumers. Then again the source code can be used to find out everything about it.

[Virtual Boxxy]

The format is not formally documented because there are no external consumers.

Or you could argue that there are no external consumers because the format is not documented

[mpack]

It's a private file. It isn't intended to exchange data with other software. It doesn't hold any user data, all it holds is the VirtualBox state. I can't think of any reason to make this a public format.

Incidentally, moving this topic to "Suggestions" since I can't see the relevance to "VirtualBox OSE".

[Virtual Boxxy]

For one thing, I can see no reason why it would not be useful to be able to move savestates between different machines, especially between your own machines with different configurations. One of my much-used savestates is no longer usable after changing the processor in the machine to a different type. It would not seem that far-fetched to make a script that converted the savestate of the processor VT-x registers to another processor (though maybe the technical obstacles are too great).

I get the feeling that you do not like and do not use savestates very much. They are extremely useful for a lot of people. For instance you can use them together with the debugging features for reverse engineering and malware analysis, where you really want a "freeze-frame" of the entire computer. Thus, the .SAV files do hold user data, an image of the virtual RAM memory.

In any case, the reason I want the file format is for a diagnostics script, which nulls the arguments that the files are private and that the format is not fixed.

The reason I think the thread belongs in OSE it that I'm not suggesting somebody documents the format, I'm asking if somebody already have done it, otherwise I might do it myself.