6 Nov
2024
6 Nov
'24
1:01 a.m.
On Tue, Nov 5, 2024 at 11:52 AM ron minnich <rminnich(a)gmail.com> wrote:
I keep wondering if this assertion of code difference
or lack thereof can
be tested. Are not all these sources available? Which bits are missing?
Yes. Great question.
https://people.freebsd.org/~imp/pmap/pmap.32v
https://people.freebsd.org/~imp/pmap/pmap.4.2
https://people.freebsd.org/~imp/pmap/pmap.4.3
https://people.freebsd.org/~imp/pmap/pmap.net.2
has the functions as I extracted them for the diff numbers I posted before.
The TUHS archive links
are at:
https://www.tuhs.org/cgi-bin/utree.pl?file=V7/usr/sys/sys/subr.c
https://www.tuhs.org/cgi-bin/utree.pl?file=4BSD/usr/src/sys/sys/subr.c
https://www.tuhs.org/cgi-bin/utree.pl?file=4.2BSD/usr/src/sys/sys/ufs_bmap.c
https://www.tuhs.org/cgi-bin/utree.pl?file=4.3BSD/usr/src/sys/sys/ufs_bmap.c
https://github.com/sergev/4.4BSD-Lite2/blob/master/usr/
src/sys/ufs/ufs/ufs_bmap.c
in case anybody wants to check my math or characterizations about the
differences.
Warner
On Tue, Nov 5, 2024 at 9:55 AM Noel Chiappa
<jnc(a)mercury.lcs.mit.edu>
wrote:
From:
Warner Losh
> On Mon, Nov 4, 2024 at 8:14PM Larry McVoy
wrote:
> The bmap implementations I saw were bit for
bit identical, same
code,
> same variables, same style, same indentation.
I'm 100% sure they
were
> not independent.
They are different in 4.3BSD. They are different
in 4.2BSD (but less
different). The underlying filesystems are different on disk, so
they
routines have to be different.
That last sentence points out something important that people need to
remember
in this discussion: in between 4.1 and 4.2 (technically, in 4.1B), BSD
switched to the BSD Fast File System, so I very much doubt that the
low-level
(i.e. logical file block to disk block) file system code in anything after
4.1A looks much like the AT+T low-level file system code. (I have no idea
how
the BSD code compares to the Linux file system code, but that's between
the
Linux people, and Berkeley.)
Noel