Alternative to k3b? or why is everything soooooo slow?

Benjamin Scott dragonhawk at iname.com
Sun Nov 6 21:11:00 EST 2005


On Nov 6 at 1:58pm, Bruce Labitt wrote:
> I've got a Pioneer DVD-RW DVR-110D running in UltraDMA/66 mode.

   You might try "hdparm /dev/hdc" to check that.  I find IDE's performance 
settings are rather inconsistent in practice.  I know, in the past, I've had 
to use

 	hdparm -c1 -d1 -u1 /dev/hdc

on CD drives to get anything close to acceptable performance.

   You should also check your hard disks as well; if a hard disk bottleneck 
exists, that will kill your CD performance, too.  On hard disks, I use

 	hdparm -c1 -d1 -u1 -m16 /dev/hda

to boost performance.  Sometimes "-m16" needs to be "-m8".

   (It is at times like this that I am reminded why I prefer SCSI...)

   If you like to live dangerously, and/or have a UPS, you can add "-W1" to 
hdparm for hard disks, which will turn on cached (AKA delayed AKA deferred 
AKA lazy) writes.  That means writes from the OS will be cached in the 
drive's buffer RAM, returning control to the OS quicker.  While that can help 
response time, it does mean a system crash or power failure is far more 
likely to corrupt data on disk.  You have been warned.

> Worse than taking 2.5 hours to burn a potential coaster is the fact that my 
> system clock was more than 1 hour off [slow] after burning a full dvd!

   On the IBM-PC, that's a classic sign of "interrupt saturation".  The system 
clock (not the hardware clock) is advanced by IRQ0, the system timer.  If 
the system spends a lot of time servicing other interrupts, it misses too 
many of those timer ticks, and so the clock falls behind.  To fix the damage, 
update the system clock from the hardware clock:

 	hwclock --hctosys

   To fix the problem, you need to reduce the interrupt load the I/O is 
causing.  With IDE devices, this is usually a sign of programmed I/O (PIO) 
being used.  PIO is about the worst way possible to do I/O.  It's also the 
default for IDE.  See above about "hdparm" tuning.

   You should also check with the drive manufacturer for updated firmware and 
media compatibility.  High-speed drives tend to very particular when it comes 
to the media you feed them.  Using the "wrong" brand of media can really kill 
performance.  So the drive manufacturers will typically publish lists of media 
known to work well with their drives.  They will also publish updated 
firmware which adds adjustments and refinements for new and old media alike.

-- 
Ben <dragonhawk at iname.com>



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