Gentoo Archives: gentoo-user

From: Jorge Peixoto de Morais Neto <please.no.spam.here@×××××.com>
To: gentoo-user@l.g.o
Subject: [gentoo-user] Accidentally issued hdparm -X /dev/hda on running system
Date: Tue, 31 Mar 2009 21:56:26
Message-Id: 38af3d670903311456u3b681e2ck91ee9f6b0e875f1c@mail.gmail.com
Hi. I wanted to know how was my HD set, and I was issuing
information-querying commands like hdparm /dev/hda,
hdparm -i /dev/hda when I accidentally issued hdparm -X /dev/hda (idiot me).
The hdparm man page does not tell what happens when the -X option is used
without an argument.
I suspect it is equal to using an argument of 0; the man page says
"Setting 00 restores the drive´s "default" PIO mode, and 01 disables IORDY"

The output of the hdparm -X /dev/hda command mentioned something
about IORDY.
I then issued hdparm -i /dev/hda and the output said the drive was still
in UDMA5. Good sign! Maybe the command did nothing. To be sure,
I issued hdparm -X 69 /dev/hda (to set the mode to UDMA5),
and issued another hdparm -i /dev/hda (the output seemed identical).
I checked dmesg, and I saw at the end one message saying that the mode
had been set to UDMA-100 (which is UDMA5 I believe). This is good:
this message was probably generated by the hdparm -X 69 /dev/hda
command, so the earlier hdparm -X /dev/hda command
must have generated no messages, which suggests it did nothing.

I then shut the computer down and I writing this from a liveCD.
I do not even want to access the disk read only without knowing I have
not messed up.

So: does anybody know if hdparm -X /dev/hda is safe (on a running system...)?

Thank you

-- 
Software is like sex: it is better when it is free - Linus Torvalds

Replies

Subject Author
[gentoo-user] Re: Accidentally issued hdparm -X /dev/hda on running system Nikos Chantziaras <realnc@×××××.de>