Hello,

I am interested in learning about how data is structured on hard drives that use HFS+ file system. I can find resources that give a kind of general overview on the subject, but have not been able to find anything that gets into detailed nitty gritty. For example, if I were to start dumping bits from sector 2 (volume header), how is that data here organized, and how do I interpret it? etc. I have read through some of the faqs/stickys, but have not yet found what I am looking for.

If anyone can suggest some good technical resources, I would much appreciate it.

This newfound interest was spawned by the desire to troubleshoot an external HDD, questions for which I will post in the data recovery section.

Thanks,

Allasso

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You don't have to backup all of your files, just the ones you want to keep.

Thank you, that looks like a very good place to start.

Appreciate very much the quick and helpful reply.

another good page:

http://www.dubeyko.com/development/File ... splus.html

Amit Singh seems to be a good man to know for one interested in exploring HFS+ and Mac volumes. His book, "Mac OS X Internals: A Systems Approach", appears to be an excellent resource, from what I've found reading the excerpts on Google Books:

http://books.google.com/books?id=K8vUkp ... &q&f=false

Amit also has written some very helpful tools for analyzing HFS volumes, filexray, and its deprecated predecessor, hfsdebug (I'm using it now). hfsdebug is free, and only works on PPC (or supposedly intel with Rosetta - rules out using it on 10.7). filexray claims to be up to date with modern Macs and much superior, (and I am betting it is) and at this posting costs $79.

hfsdebug: http://mac.softpedia.com/get/System-Uti ... ebug.shtml
filexray: http://filexray.com/

note that these are read-only designed for analysis only.

I want to note that I have appreciated the input from the forum.

One little catch that the book helped me to see when I wasn't finding structures where I expected them, was the use of HFS wrappers.