On Tue, Dec 11, 2001 at 06:28:56PM +1030, Greg Lehey wrote:
> On Monday, 10 December 2001 at 22:45:22 -0800, Terry Lambert wrote:
> > Hiten Pandya wrote:
> >> i wanted to ask if there were any _plans_ to port
> >> JFS (Journaled File System) to FreeBSD...
> >
> > Not unless you have plans.  When I was an IBM employee, they would
> > not change the license, and so it's impossible to ship a CDROM
> > where it's the boot FS, or boxes on which it is the boot FS, and
> > still have it be legal, because of the license conflicts.
> >
> > I fought this for about a year within IBM, before I gave up.
> Since then, it has become possible for the loader to load modules
> before booting the kernel.  This means that, theoretically, it would
> be possible to have a JFS root file system.  Given the strong
> opposition to the GPL in some factions of the FreeBSD project, I don't
> see this happening any time soon, especially since we still don't know
> if it will buy us anything.
> >> It is used on IBM MainFrames and Enterprise servers
> >> for high performance and maximum throughput...
> >
> > No, it's not.  The Linux JFS is derived from the OS/2 JFS code, not
> > the good AIX JFS code.
> That's correct, but note that AIX is moving to this code base too, so
> it's not as if it's second-rate.  From what I've seen of the
> structures, JFS2 is *much* better than JFS1.  I haven't compared
> performance.

I happened to be with IBM working on AIX (I was the AIX architecture
manager at the time) during the development of the original JFS (for
AIX 3.1 on the first RS/6000s). Its design and implementation were
largely the result of the efforts of a single person (Al Chang) from
IBM research, who was also the primary designer/developer for the
VM system for AIX 3.1. Consequently, the JFS code was designed to
take advantage of the specific VM implementation (and the underlying
RS/6000 VM hardware). This resulted in a rather unportable code base.
Additionally, since it was derived from AT&T (and BSD) filesystem
code, there were some licensing issues. As I recall, these two issues
(portability and license) were what lead to the reimplementation for
OS/2 (I wasn't involved or even very familiar with that effort though).


Bob Willcox             Boucher's Observation:
[EMAIL PROTECTED]               He who blows his own horn always plays the music
Austin, TX                 several octaves higher than originally written.

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