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Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!ukma!rutgers!bpa!manta!brant
From: brant@manta.pha.pa.us (Brant Cheikes)
Newsgroups: comp.sys.att,unix-pc.general
Subject: Re: From blocks to files (on a UNIXpc)
Summary: This is the right idea.
Message-ID: <464@manta.pha.pa.us>
Date: 10 Feb 89 05:13:15 GMT
References: <462@manta.pha.pa.us> <848@ttrde.UUCP>
Reply-To: brant@manta.pha.pa.us (Brant Cheikes)
Organization: Soul of the Gnu Machine, Philadelphia
Lines: 31

You all know the question.

In article <848@ttrde.UUCP> pfales@ttrde.UUCP (Peter Fales) writes:
>As it turns out, I am working on a program that does exactly this.
[...]
>My program is a few weeks
>(months?) away from being a useable product, but I can post it if there
>is enough interest.

I'm interested, so either post it or mail it to me, thanks.

>The way I am doing it - the only way so far as I know - is to search 
>through the inode list, and look the list of blocks that belong to
>each inode.  Then you can do a find -inum to find the file with that
>inode.

This is correct, though you should not overlook the freelist.

>There are a few other things to consider.  For example, the bad block
>may be in the swap area, or (shudder) the inode list.

I believe these are easy computations given knowledge of the sizes of
partitions 0, 1, and 2, and the total number of inodes.  My
understanding of the Unix filesystem is that the inode blocks are the
first blocks of partition 2.  So given 800 total inodes, and 8 inodes
per block, the first 100 blocks of partition 2 are reserved for the
inodes.
-- 
Brant Cheikes
University of Pennsylvania, Department of Computer and Information Science
brant@manta.pha.pa.us, brant@linc.cis.upenn.edu, bpa!manta!brant