Casey Ransberger | 2 Jun 2011 21:26
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Re: Getting information from broken image

Hi,

On Jun 2, 2011, at 3:12 AM, Mateusz Grotek <unoduetre <at> poczta.onet.pl> wrote:

(big snip)

I donno how the image
is organized, but if it's like a filesystem maybe it would be possible
to create some tool to extract objects from it. I wondered if there is
such a tool. (I suppose the answer is no). Thanks.

So it's a big heap of objects, which are comprised mostly of references to other objects. 

I struggled quite a bit at first to map the persistent object memory onto something that I could really recognize, like a filesystem. 

I'm not sure how useful this metaphor is, but here's a try: it's almost like a filesystem in which almost everything is a symbolic link to something else, if you envision the objects as analogous to directories. Oh, and there are cyclical references going on, I don't think the weak metaphor I'm using here can hold that part up very well:)

I can't say anything of real use WRT extracting stuff from a completely hosed image; I've needed at least a recovery console to open in order to make it back to a state that I can recover objects from. Basically the image format is currently beyond my experience, but if I wanted to find out how it works, the first thing I would try is pulling down VMMaker and looking at the Slang code for the object memory itself. This could be terrible advice though, so I'd go for a second opinion if I was you:)

If just you want to move some objects between two images, you might want to check out SmartRefStream. 

I've also longed to see some tools for image exploration/visualization. I'm really excited about the work of Craig Latta in this area. I would strongly recommend that you check out Spoon when you can. 
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