LinuxSA Mailing list archives
From: Fraser Farrell <firstname.lastname@example.org>
To : <email@example.com>
Date: Fri, 13 Apr 2001 07:06:43 GMT
A cure to "no DRQ after issuing WRITE"
A message like this one appears on all of your
console displays (logged in or not), X terminals,
console applications, etc – disrupting anything
that happens to be on screen:
no DRQ after issuing WRITE
ide0 reset: success
Because That Message appears hundreds
of times per day; you're soon reduced to a
quivering wreck of frustration, desperately
reading HOW-TOS and manpages and DejaNews and
zillions of mail archives. But all you can
find is thousands of pleas from other poor
sods with the same problem, and hundreds of
replies saying "the hard disk is faulty".
But more often than not, your IDE hard disk
is either brand new, or it was running that
other popular operating system for months
or years before you rescued it.
SO WHY IS IT HAPPENING?
The kernel hackers reading this know the
answer already (and can probably recite
the relevant source code from memory ;-)
But in simple terms, this message is Linux's
way of telling you that it tried to WRITE to
a batch of disk sectors at once; but the drive
controller didn't respond with the IDE
"standard reply" to this multi-sector write.
Some newer drives – such as many Seagate
models – extend their capabilities by
providing extra info in their response to a
WRITE. Or they may be waiting for another
batch of data before actually doing the WRITE
and issuing the response.
An antique drive may also have trouble because
its controller doesn't respond in a "standard
IDE" way. This one probably won't affect you
unless you're a Linux minimalist trying to
run everything from a 20MB Conner... ;-)
Anyway, whenever Linux accesses these drives,
it detects what it thinks is a hardware glitch,
tries to reset the drive controller, and issues
Your drive ISN'T broken, but it's speaking
in an accent. Linux needs a bit of help to
understand what the drive controller is saying.
You need to use "hdparm" to interrogate the
disk controller, and then to tell Linux how to
access the drive in future. To save you from
reading the manpage (recommended, hdparm has
a ton of features...) here's the procedure that
gets rid of That Message in most cases:
(1) log in as root
(2) hdparm -i /dev/hda
This interrogates your first IDE hard disk,
and displays a pile of info about your disk
and its controller. The interesting bit is
the value of "MaxMultSect", which describes
your disk's multi-sector read/write capability.
You can do hdparm -i /dev/hdb to find out about
your second IDE hard disk, and so on.
As an example, my server's second drive
(a 2GB Seagate) returns a value of 32 for
(3) hdparm -mX /dev/hda
where X is the MaxMultSect value reported
in step (2). This tells Linux about your
disk's multi-sector read/write capability.
Using my second drive as an example again:
hdparm -m32 /dev/hdb
If this stops That Message from appearing, then
(4) Add the hdparm -mX... command to your startup
script (typically /etc/rc.local) so that this
cure is automatically applied if you reboot.
However, if That Message continues to appear,
you may need to specify other hdparm settings.
Or you may really have a faulty hard drive or
But for most sufferers, the above procedure
should alleviate much wailing and gnashing
of teeth. It's helped me on many occasions.
Fraser Farrell firstname.lastname@example.org
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