From mboxrd@z Thu Jan  1 00:00:00 1970
From: random832@fastmail.com (Random832)
Date: Sun, 21 Feb 2016 13:36:19 -0500
Subject: [TUHS] Unix v6 File System information
In-Reply-To: <20160221175008.13FB518C0ED@mercury.lcs.mit.edu>
References: <20160221175008.13FB518C0ED@mercury.lcs.mit.edu>
Message-ID: <1456079779.724937.527519010.4FC5154D@webmail.messagingengine.com>

On Sun, Feb 21, 2016, at 12:50, Noel Chiappa wrote:
>     > From: Random832 
> 
>     > They're 24 bits, aren't they?
> 
> Not according to the source:
> 
> 	typedef	long		daddr_t;
> 
> 	daddr_t	s_fsize;   	/* size in blocks of entire volume */
> 	short  	s_nfree;   	/* number of addresses in s_free */
> 	daddr_t	s_free[NICFREE];/* free block list */
> 
> (from param.h and filsys.h respectively).

That's the superblock. Look in ino.h.

/*
 * the 40 address bytes:
 *       39 used; 13 addresses
 *       of 3 bytes each.
 */

Which means you can't actually have a filesystem of more than 2^24-1
blocks.