SYS V - What is Inode 1 ?

[Rick Adams]

>From an old mail conversation. "Guy" is Guy Harris.

>From research!dmr Sun Mar  1 18:40:52 1987
Date: Sun, 1 Mar 87 18:40:40 EST
From: research!dmr
Message-Id: <8703012340.AA08897 at seismo.CSS.GOV>
Subject: inumerology
Apparently-To: rick
Status: RO

Yes, v6 and previous had the root with i# 1, and v7 changed it to
2.  There were two reasons for the change: first, as Guy thought,
there was an idea of hiding bad blocks in the inode-1 file.
Since we never did that, a possibly stronger motivation was just
to prove that the system and the software were parameterized well
enough to make it possible to change.

Incidentally, years later I finally wrote a simple program that
hid bad blocks.  It doesn't use inode 1, though; you hand it
the name of an existing, empty file and a list of blocks, and
it fiddles the inode of the named file to put the blocks in it.
Now we tend to use disks with ECC and automatic revectoring,
but it still gets dusted off once in a while.