dvd drive hogging CPU?

  • Thread starter Thread starter peter
  • Start date Start date
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peter

When a dvd is inserted into a DVD drive, all apps stop responding to the
user (although the mouse still moves) for 10 seconds or so. This happens on
all computers running winXP, even on multi-core processor machines.

Is this some sort of bug?
 
peter said:
When a dvd is inserted into a DVD drive, all apps stop responding to the
user (although the mouse still moves) for 10 seconds or so. This happens on
all computers running winXP, even on multi-core processor machines.

Is this some sort of bug?
Click to expand...

There is an additional experiment you can try, just for fun.

Open up the Time/Date control panel, the one where they have the clock
with the second hand on it. Insert the DVD. Sure, the second hand will
stop, based on your description. But, does the system "lose" the 10
seconds, such that your time keeping is affected ? (I.e. The computer
and the wall clock are now off by 10 seconds.) Clock tick interrupts
have high priority, and if they are not being serviced, then chances
are you are stuck in the I/O driver for the DVD drive. Even on
a multi-core machine, there are limits to what you can do, if stuck
in the kernel. If the kernel is blocked, it won't take long before
all other processes will be blocked as well.

This is not normally how drivers are designed. In the distant past,
it would have been normal. But modern operating systems, intend
any expensive operations to run at non-interrupt level. If a
driver is waiting for a peripheral to respond, the driver should
exit, and either a timer or an interrupt can trigger the driver to
run at a more appropriate time, to check whether the DVD is ready
or not. By having the driver exit, it means the system can
continue to respond, tasks can be scheduled for the multicore
processor and so on.

I expect there is a mismatch of expectations here. Either the driver
writer doesn't know how DVDs work, or the DVD hardware designer doesn't
know he is supposed to respond instantly.

Just out of curiosity, is the driver the Microsoft default one,
or is the driver provided with the chipset drivers ? On my computer
here, with an Intel chipset, the Microsoft driver can be used. I
don't have to use an Intel provided driver, unless I'm doing RAID
or something. Maybe the response will differ, depending on which
driver option is being used ?

My best guess,
Paul
 
In the "Device Manager", "DVD/CD-ROM drives", find yours and double-click
it. In the "Properties" dialog box, select the "Driver" tab and click the
"Driver details" button.
In XP/2003-server you should have these driver files:
cdrom.sys, imapi.sys, redbook.sys, storprop.dll
All of them with the "signed" icon.

You may have others (probably unsigned) listed as well. They may have been
installed by some other applications like: Pinnacle, iTunes and many others
that use DVD/CD-burning features.
[
Such drivers cause a lot of pain, degraded performance... mostly trouble!

So your problem may be that one or all of this additional unsigned drivers,
like Paul said, does not exit and keeps waiting for the drive to become
ready. Poor design like always.

By the way Windows Explorer is also that stupid to freeze and wait for the
drive to become ready, even if there are no unsigned drivers installed.
Strange why Microsoft have not fixed this yet?
]


George Valkov


:
| peter wrote:
| > When a dvd is inserted into a DVD drive, all apps stop responding to the
| > user (although the mouse still moves) for 10 seconds or so. This happens
on
| > all computers running winXP, even on multi-core processor machines.
| >
| > Is this some sort of bug?
| >
|
| There is an additional experiment you can try, just for fun.
|
| Open up the Time/Date control panel, the one where they have the clock
| with the second hand on it. Insert the DVD. Sure, the second hand will
| stop, based on your description. But, does the system "lose" the 10
| seconds, such that your time keeping is affected ? (I.e. The computer
| and the wall clock are now off by 10 seconds.) Clock tick interrupts
| have high priority, and if they are not being serviced, then chances
| are you are stuck in the I/O driver for the DVD drive. Even on
| a multi-core machine, there are limits to what you can do, if stuck
| in the kernel. If the kernel is blocked, it won't take long before
| all other processes will be blocked as well.
|
| This is not normally how drivers are designed. In the distant past,
| it would have been normal. But modern operating systems, intend
| any expensive operations to run at non-interrupt level. If a
| driver is waiting for a peripheral to respond, the driver should
| exit, and either a timer or an interrupt can trigger the driver to
| run at a more appropriate time, to check whether the DVD is ready
| or not. By having the driver exit, it means the system can
| continue to respond, tasks can be scheduled for the multicore
| processor and so on.
|
| I expect there is a mismatch of expectations here. Either the driver
| writer doesn't know how DVDs work, or the DVD hardware designer doesn't
| know he is supposed to respond instantly.
|
| Just out of curiosity, is the driver the Microsoft default one,
| or is the driver provided with the chipset drivers ? On my computer
| here, with an Intel chipset, the Microsoft driver can be used. I
| don't have to use an Intel provided driver, unless I'm doing RAID
| or something. Maybe the response will differ, depending on which
| driver option is being used ?
|
| My best guess,
| Paul
 
George Valkov said:
In the "Device Manager", "DVD/CD-ROM drives", find yours and double-click
it. In the "Properties" dialog box, select the "Driver" tab and click the
"Driver details" button.
In XP/2003-server you should have these driver files:
cdrom.sys, imapi.sys, redbook.sys, storprop.dll
All of them with the "signed" icon.

You may have others (probably unsigned) listed as well. They may have been
installed by some other applications like: Pinnacle, iTunes and many
others
that use DVD/CD-burning features.
[
Such drivers cause a lot of pain, degraded performance... mostly trouble!
Click to expand...

Actually a good favourate here can be the drivers that some games add for
"copy" protection. Some of these can be a right pain in the hoop.
 
|
| | > In the "Device Manager", "DVD/CD-ROM drives", find yours and
double-click
| > it. In the "Properties" dialog box, select the "Driver" tab and click
the
| > "Driver details" button.
| > In XP/2003-server you should have these driver files:
| > cdrom.sys, imapi.sys, redbook.sys, storprop.dll
| > All of them with the "signed" icon.
| >
| > You may have others (probably unsigned) listed as well. They may have
been
| > installed by some other applications like: Pinnacle, iTunes and many
| > others
| > that use DVD/CD-burning features.
| > [
| > Such drivers cause a lot of pain, degraded performance... mostly
trouble!
|
| Actually a good favourate here can be the drivers that some games add for
| "copy" protection. Some of these can be a right pain in the hoop.

That's an interesting point! I didn't think of this! :-) Are the copy
protection drivers listed under Properties/Drivers for the CD/DVD device in
Device Manager? Or should I check all drivers (includding hidden -
set devmgr_show_nonpresent_devices=1
) one by one to find any suspects?
 
That's an interesting point! I didn't think of this! :-) Are the copy
protection drivers listed under Properties/Drivers for the CD/DVD device
in
Device Manager? Or should I check all drivers (includding hidden -
set devmgr_show_nonpresent_devices=1
) one by one to find any suspects?
Click to expand...

I've seen them attatched to the drives before when I've been in device
manager. Of course that doesn't mean that all of them will behave that way.
 
:
|
| |
| > That's an interesting point! I didn't think of this! :-) Are the copy
| > protection drivers listed under Properties/Drivers for the CD/DVD device
| > in
| > Device Manager? Or should I check all drivers (includding hidden -
| > set devmgr_show_nonpresent_devices=1
| > ) one by one to find any suspects?
|
| I've seen them attatched to the drives before when I've been in device
| manager. Of course that doesn't mean that all of them will behave that
way.

Thank You!


George Valkov
 
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