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From: robert@cheviot.UUCP (Robert Stroud)
Newsgroups: net.unix-wizards
Subject: Re: inode numbers
Message-ID: <358@cheviot.UUCP>
Date: Sat, 15-Jun-85 00:38:48 EDT
Article-I.D.: cheviot.358
Posted: Sat Jun 15 00:38:48 1985
Date-Received: Sun, 16-Jun-85 05:44:51 EDT
References: <1725@aecom.UUCP> <44700005@gypsy.UUCP>
Reply-To: robert@cheviot.UUCP (Robert Stroud)
Organization: U. of Newcastle upon Tyne, U.K.
Lines: 32

In article <44700005@gypsy.UUCP> lrr@gypsy.UUCP writes:
>
>Inode number 1 is ``reserved'' and (to the best of my knowledge) it is not
>used. 
>
>Larry Rogers
>Siemens Research and Technology Laboratories
>princeton!siemens!jaguar!lrr

On at least some European V7 systems, inode 1 is used for a list of bad
blocks. Basically mkfs has been extended to include a secret undocumented
option (in the true Unix tradition!) which scans the whole device and puts
any funny blocks in inode 1 out of harms way. As far as I know, nothing else
pays any attention to the list - it is just a device for keeping blocks off
the free list without upsetting fsck.

Such modified versions of mkfs take 5 arguments. The first two are as normal,
the next two are the m/n ratio (something to do with the initial spacing of
the free list I think), and the fifth indicates whether the bad block check
is required.

I have no idea whether this feature is standard (but undocumented), or a
local hack, but I have seen it on more than one system.

Robert Stroud,
Computing Laboratory,
University of Newcastle upon Tyne.

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