Performace/speed problem with K3b

[Germanbear]

Hi buddies!

First i have to plead guilty for being a Knoppix newbie, but finally
it has attracted my interest. I meanwhile managed to successfully
boot fromhd=/dev... which runs without any error messages and
fairly quick, too.
Starting to explore the numerous applications, i selected K3b,
but what a disappointment! On my PII, 400 MHz, 128 MB it burns
DVDs (on the fly) with lame 0.5x ! Running Win98 on the same hardware,
i typically slow down burning speed to 4x due to quality considerations,
while the DVD drive would be capable of 16x.
To me, it appears unlikely that limited memory or the location of the files
to burn (on an ext. USB 2.0 ext. drive) is the bottleneck.

Any ideas?


Regards and compliments for the (so far) quite impressive OS!

[Cuddles]

Germanbear,

First of all, welcome to Knoppix

From what I "jest" from your post, you are wondering "why" k3b may be running slower on your hardware, than say, Windows98 does????

From what I can see, you have a Pentium II, running @ 400 MHZ, booted off the hard drive, instead of the CD, you have 128 MB RAM, and your media you are burning the files from is coming from a USB 2.0 connected external drive. Further, I guess you feel burning at 4x speed, versus the 16x speed that your DVD burner device can handle is a problem. Am I correct on my assumptions here???

From what I can see, and from what I know, I can see many "bottle-necks", possibly, and, with some assuptions and guessing, involved...

How fast is your hard drive? Speed in both "burst" rate, as well as "sustain" rate, and even the "through-put" speed...

How good is the media you are using to burn with? Poor quality DVD R media may be detected in the burner, and rates are adjusted accordingly...

How much swap space do you have? This in combination with the physical memory can have better results. The more physical memory, the more the system, and k3b, can use without having to use external storage, temp files, and swaping in and out of memory, files destined to the burning device...

How fast is the USB device? How fast is the "burst", "sustain" and through-put rates of that device, and the connection that it is going through???

As a test, have you tried to move the files from the external USB device to the local connected hard drive you are booted from, and try a burn that way? Does the speed increase, decrease, or same, results???

Just some ideas

I burn, mostly, around 4x speed as well, as you said, for quality considerations, some of the Distro ISO files prefer the slower speeds, or they create nice coasters. I have been up to as high as 8x speed, and, yes, my burners (x2) can attain rates as high as 32x speed. I have not worked with my DVD burner yet, it is the newest of my hardware, and havent had the chance to use it yet, but, I do have a CD-RW, and have used cheap media in it, for one time burning, and rewrittable media, better quality, in it... Burn rates have NEVER been at full speed, though... Good media, R ONLY, and with the CD-RW device, I have not been able to burn, successfully, a good CD without it being a coaster, at speeds it "should" be able to do, that being 32x...

I have two systems, both running hard drive installed Kanotix, which is an "off-shoot" of Knoppix, i.e. a close relation to Knoppix. Both these systems have CD-RW burners in them, a DVD player in one, the other system has a DVD-R+R+RW device. One system is a AMD (32 bit) XP Atholon, running around .5 GHZ, the other system is a AMD (64 bit) 64, running at 2.x GHZ. One system has 512 MB physical RAM with a 512 MB swap, the other system, has 1 GB of physical RAM with a 512 MB swap. All the hard drives are connected via IDE internal, are "somewhat" new drives, possibly within a year, but, they are not rated for "video speeds", thus, the "burst" and "sustain" rates are not capable of access / sending the amount of data required to output 24 FPS video, without some buffers or temp files to handle the delays. Then again, the cost of "video" hard drives is a lot more than I am willing to pay for, too.

So, not that I have all the answers, or, that I have "your" answers, but, simply, I do not acquire the speeds that my burners are capable of either, with k3b, and, with systems that are more "capable" of possibly doing them, then the system you are describing. Dont know what to tell you? I just live with it...

Ms. Cuddles
-=- Come to the Dark Side - We have penguins! -=-

[DirkS]

Hi Germanbear!

My suggestion: Try to find a knoppix 3.7, boot that and try another burn with k3b. I observed weird speed penalties lately, also with burning (4x max. speed) with a faster system than yours. Right now I suspect unionfs to be the culprit. Knoppix 3.7 didn't use unionfs yet, so if I'm right, you get what you need

Alternatively, you could use a different life CD/DVD that does not use unionfs. But not Kanotix, at least the latest one seems to have the same problem as the actual knoppix.

Good Luck!
Dirk

[DirkS]

Harry Kuhman pointed me to the dma-cheat. A new test made clear that my speed problem was indeed caused by dma being off. 3.7 had it on by default, 4.0.2 had not. Therefore, my new suggestion is:
With Knoppix 4.0.2, at the boot prompt type "knoppix dma" and try burning again. Please post the result, I'm very interested in it.

More Good Luck
Dirk