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Re: Disk Checking under MacOS X

On Tuesday, January 30, 2001, at 05:55 PM, Daniel J. Luke wrote:

> On Tue, Jan 30, 2001 at 05:03:45PM -0800, Dave Zarzycki wrote:
> > On Tue, 30 Jan 2001, Peter Bierman wrote:
> >
> > > >(HFS++? IBM JFS? ReiserFS? XFS? Beuller? Beuller? :)
> > >
> > > Are you offering to write it?
> > >
> > > IIRC,
> > > ReiserFS == GPL
> > > XFS == GPL
> >
> > IBM's JFS is GPL'ed too.
>
> Would it still be a problem for Apple to use a GPL'd filesystem (by default) if the OS could
> also run off of a non-GPL'd filesystem (UFS/HFS+)?
>

Some references:
http://oss.sgi.com/projects/xfs/license.html
http://oss.software.ibm.com/developerworks/opensource/jfs/
http://linuxberg.iol.it/x11html/preview/58475.html

Looking at the BSD sites, there seems to be a distinct lack of BSD licensed journaling
filesystems. I seem to remember one for FreeBSD, but it doesn't seem to be in there anywhere.

There's softupdates, which Louis Gerbarg's been working on, but is there any other way to
speed booting on a potentially corrupted disk up?

Is there any possibility of XFS or JFS being released by SGI or IBM under a BSD style
license (which would probably require prodding/monetary inducement by Apple)?

The only other possibility I could find on FreeBSD.org was
http://www.usenix.org/events/usenix99/full_papers/nightingale/nightingale_html/
which looked sort of interesting.

From the abstract:
... The driver also guarantees file system integrity in the events of system crashes
or failures. Moreover, unlike other approaches such as Log-structured File Systems
or Soft Updates, the DCD driver is completely transparent to the OS. It does not
require any changes to the OS or the on-disk data layout. As a result, it can be
used as a ``drop-in'' replacement for the traditional disk device driver in an
existing system to obtain immediate performance improvement. ...


Which, if I'm reading this right, implies that it could be "just" an extra layer in IOKit
just above the real device driver. There's no BSD code, so it'd be more complex than
porting something.
Their prototype is 3200 lines of C, and it seems like IOKit would reduce that...

--

Alan S. Blue
email@hidden



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