[ale] ALE NW: Fine-Grain Directions

Jeff Hubbs hbbs at comcast.net
Thu Aug 19 17:34:28 EDT 2004


The Web site has directions to get me in the general vicinity of
tonight's ALE meeting, but how can I find the right building/room?

- Jeff

On Thu, 2004-08-19 at 17:21, Danny Cox wrote:
> Mike,
> 
> On Wed, 2004-08-18 at 07:30, Mike Panetta wrote:
> > I am messing around with some (brute force) hot swap, and I can get the swapping done
> > and it re reads the ptable correctly if I force it to, but it will not re read the geometry
> > which is causing some (maybe harmless) error messages saying its trying to access
> > a non existant block when it rereads the partition table.  Does anyone know of a way
> > to force linux to re read an IDE drives C,H,S (geometry)?  I have tried all the obvious
> > hdparm commands...  I wish it would just do it when a bus reset occured, that would
> > make things easy.  Anyone know why this is not done?
> 
> 	The easy answer: because they didn't have to.
> 
> 	Seriously, the IDE drivers have 10+ years of cruft in 'em.  When it was
> first written, hot-swap obviously wasn't even considered possible (with
> IDE).
> 
> 	In a previous life I got to implement IDE hot swap for the 2.4 kernel. 
> We had ACPI tell us when something happened (drive N just
> (dis)appeared), and I wrote a routine to handle it via the
> ide_register() and ide_unregister() functions.  Since ide_register()
> assumes (bad function!) many things (like: the drive is in PIO mode), I
> had to make sure that the assumptions were valid.  Specifically, upon
> removal, I had to reset the chipset to PIO speed, and such.  Thus, when
> ide_register() was called, it was just as if the machine was performing
> "drive discovery" during boot, with all that it implies (re-reading the
> geometry, partition table, etc.)
> 
> 	Okay before this becomes a novel or even a short story...whoops!
> 
> 	If you're masochistic enough to want still more info, feel free to
> contact me off-list.
> 
> 	By the way, the IDE driver is getting a major face-lift from Alan Cox
> and Bart (something).  Apparently, Alan is appalled (with two Ps ;-) at
> the locking therein, some of which is totally broken, racey, etc.
> 
> 	There I go again.  Bye!



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