(Fwd) Re: DOSFS bug fixes, IDE drivers and sample released

[Brett Swimley]

Does a similar situation exist if you are creating or removing a directory entry?

Regards,

Brett Swimley

Quoting "Eugeny S. Mints" <Eugeny.Mints at oktet.ru>:

> On Wed, 16 Apr 2003, Joel Sherrill wrote:
> 
> >
> >
> > "Eugeny S. Mints" wrote:
> > >
> > > On Wed, 16 Apr 2003, Joel Sherrill wrote:
> > >
> > > > Chris Caudle wrote:
> > > >
> > > > >>I have found that listing the directory after closing the file
> > > > >>seems to do the trick. It must purge the buffers to the disk.
> > > > >>
> > > > >>
> > > > >
> > > > >I haven't looked at the DOSFS code yet, does it have a sync() or
> fsync() function?
> > > > >If the file system keeps the allocation table cached in memory, you
> may need to flush the allocation table to the storage device, especially if
> you are shutting down power on the RTEMS system and moving the storage device
> to a different machine (or just re-booting into Windows, Linux, MacOS etc. on
> the same machine).
> > > > >
> > > > >
> > > > Or at least a flush() on the file itself?
> > >
> > > Sorry, that I was silent for a long time but I was away from
> > > my  mail box.
> > >
> > > As to sync/fsync/flush - sync call is implemented in DOSFS.
> > > I suppose that Angelo needs UNmount the volume to achieve
> > > his  goals. During 'unmount' a volume is automatically
> > > syncronized.
> >
> > I understand that it has to sync when unmounting but shouldn't
> > sync work even with it staying mounted?  I think the issue here
> > was simply that he was surprised it wasn't written until he closed.
> > [NOTE: This is standard behavior for many systems so is not unexpected.]
> >
> > So the question is.. if I have an open file and want to ensure its
> > contents are written to disk, is it sufficient to sync() or should
> > it flush() and sync() and what?  I think unmounting is a bit too
> > heavy handed because it potentially impacts other tasks.
> 
> If you have an open file and want to ensure its
> contents are written to disk you shoul sync() it - and this
> sync call is implemented in DOSFS.
> 
> >
> > > >
> > > > Not to get me started on a tangent but my disertation included some
> > > > thought on the idea
> > > > that different embedded systems needed different disk caching and
> > > > scheduling algorithms.
> > > > Ideally those should be selectable on a per-file basis but at a
> > > > partition level would be
> > > > acceptable.  For example, a write-only log file should have data kept
> > > > only long enough to
> > > > get it to disk but a sequentially read file could use read-ahead and
> > > > discard as soon as
> > > > the application read the data.  With some (intelligent) hints from the
> > > > application,
> > > > the algorithms could be better selected.
> > > >
> > > > >-- Chris Caudle
> > > > >
> > > > >
> > > > >
> > > >
> > > >
> > > >
> > >
> > > --
> > > Eugeny S. Mints
> > > OKTET Ltd.
> > > 1 Ulianovskaya st., Petergof, St.Petersburg, 198904 Russia
> > > Phone: +7(812)428-4384 Fax: +7(812)327-2246
> > > mailto:Eugeny.Mints at oktet.ru
> >
> 
> --
> Eugeny S. Mints
> OKTET Ltd.
> 1 Ulianovskaya st., Petergof, St.Petersburg, 198904 Russia
> Phone: +7(812)428-4384 Fax: +7(812)327-2246
> mailto:Eugeny.Mints at oktet.ru
> 


-- 
Brett Swimley
Advanced Electronic Designs
406-585-8892 / 406-585-8893 (fax)
brett.swimley at aedinc.net