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Re: New problem with an hp CD5750

Le lundi 02 avril 2007 à 09:59 -0400, Lennart Sorensen a écrit :
> On Sat, Mar 31, 2007 at 12:35:01PM +0200, storm66@club-internet.fr wrote:
> > I have always some problems with the HP dc5750. After installing
> > "wildly" the system (by copying a Knoppix 32 bits CD on the HD).
> > The system runs, slowly..., even X and KDE are OK, but I encounter a new
> > problem.
> > Ths disk is deadly slow :
> > hdparm -t gives 1.43 Mo/s !!!!
> > on an 23 years old Amiga 2000 running Linux I get 3.4 Mo/s
> > so 1.43 Mo/s is quite a pain.
> > I want to compile a new kernel with only the needed modules , eg a
> > better disk driver, and no unused modules. The problem is that I can't
> > get a working kernel on the machine, the kernel does not boot with a
> > panic "does not find the disk ... append a correct root=... ".
> > I try with a 2.6.20 kernel, take the 2.6.19 config found in the Knoppix
> > install and a make oldconfig. The kernel compile is OK but panics while
> > booting not finding the boot disk. 
> > 
> > There is something which does not work properly with the disk
> > driver  ... 
> > Any help will be appreciated.
> Usually less than 2MB/s means you don't have DMA enabled, which usually
> means you are using the wrong ide driver or have a bad configuration
> somewhere.  You can check the settings in /proc/ide/hda/settings or
> whatever your HD is.
> As for installing knoppix that way, I have no idea.  knoppix is a
> tolerable live cd but I would hate to have it as my normal use system.


Somebody on the list give me an advice to switch (in the BIOS) IDE
emulation from "Legacy IDE" to "Native" I noticed that when I select
"Legacy IDE" the access turns to UDMA 100 with no other choice.
When I try it I get a kernel panic at boot ... not syncing ... please
append a correct "root=".
So it is a misfit between the drivers and the system or with the way the
SATA drivers works.
Are the SATA hd devices always called HDx with the SATA driver working
or are they called SDx like the Scsi hd ?
On one of my home systems I lost an SCSI disk and replace it by a
standard IDE one and the disk is seen as SDE after the SCSI disks
(kernel 2.6.20).

Knoppix is Debian based, so the system seems to be OK, and I update it
with apt-get set to etch.
I recompile the last 2.6.19 with SATA set to "Off" and the machine boots
(Legacy IDE) with the same bad disk performance. A simple "vi" on a file
is looooong as on the venerable Amiga which I used as reference.
(Yes an Amiga 2000 works with Linux, this one has known its firts kernel
before the 2.0 and runs with a Debian since 2.0.x, I think x was 10 to
12 many years ago, it runs now 2.6.18 with full success). 
On my "big" (2x AMD 2Ghz) system the same "hdparm -t /dev/sde1" gives
66.46 Mo/s on the IDE disk.

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