Skip site navigation (1)Skip section navigation (2)
Date:      Sat, 1 Feb 1997 17:21:16 -0700 (MST)
From:      Terry Lambert <terry@lambert.org>
To:        BigDaddy@LiveNet.Net (Joseph I. Arias)
Cc:        hackers@FreeBSD.ORG
Subject:   Re: Subject: Re: Installing from DOS partition
Message-ID:  <199702020021.RAA07020@phaeton.artisoft.com>
In-Reply-To: <199702012131.QAA15986@Clifford.LiveNet.Net> from "Joseph I. Arias" at Feb 1, 97 04:27:00 pm

next in thread | previous in thread | raw e-mail | index | archive | help
> > ..because it's probably still a VFAT filesystem, i assume.
> > 
> > Install DOS 5. :)
> 
> So dos 6.22 is a VFAT system?  I was told different and that could be the
> only thing that it is? 

There is no difference between a FAT and a VFAT system.  They have the
same data layout.  The difference is in the use of the directory
layout.

FAT creates directory entries that, uniformly, never have all their
attribute bits set.  In FAT, a directory entry *is* the on disk inode
(this is why DOS can't do hard links).

VFAT creates additional directory entries for the "long names" for
files.  It does this by setting all the attribute bits on the entry,
and storing the long name data in the entry itself on the disk.  So
it tends to use up a lot of directory entries.

It turns out that every piece of software Microsoft tested ignores
entries with all attribute bits set.  Because of the way the DOS
findfirst/findnext operates, and the fact that one of the bits is
the "volume label" bit, software which uses the INT 21 DOS interfaces
never see these entries.


Other than reducing the number of real files that you can put in the
root directory by their very presence (the root has an existing hard
limit on the number of files, which dates back to before DOS knew
about directories), these additional entries will have ZERO, NONE,
ZILCH, NOTTA, *NO* EFFECT ON WHETHER OR NOT YOU CAN MOUNT THE DISK.


					Regards,
					Terry Lambert
					terry@lambert.org
---
Any opinions in this posting are my own and not those of my present
or previous employers.



Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?199702020021.RAA07020>