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RE: Another perspective on LiteOn drive modification - 7/25/2004 5:45:47 PM   
zebra


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Mmmk, its time for some technical information on the topic. Jackass's drive is fine. Others are not. Does damage occur as a direct result? Thats speculative I think. We cant mash it either way....

All that put to one side however...some facts

Write strategies relate to the positional laser timing, control and placement per block. All these drives and the structure of their firmwares contain inherent tables. The discs also contain parameters. Now, at time of calibration before lead in tables are indexed against the Media ID. In this respect, the tables are multidimensional.

The approach being used implemented to hack or change these tables is to cut and paste between media that share similar traits and then in some simple way, "tweak" if you will, table entries to obtain the desired effect. Now, an issue resides here as the process is:

* Being undertaken without complete and comprehensive understanding of the tables
* No real documentation officially from the hardware manufacturer or the chipset vendor/OPU fabricator
* No effective test equipment

NOW, as for DAMAGE perse...

It is very hard to say. Consider this however. Imagine if the table contents must obey rules and you break these afforementioned rules. An example might be if they define how the laser power is modulated over time, the increases and decreases should sum to zero. If you make them into a net positive then the object may run or loop away! It isnt me telling you that this is the case here, but subtle mistakes or misunderstandings will lead to problems!

This is the issue from a technical aspect. Think about it, what you will - there is always more to it. Unless you live on "the inside" and have access to certain pertinent technical information - these things might never become apparent.

Still, always more to know, more to research and learn!



< Message edited by zebra -- 7/25/2004 5:47:36 PM >


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RE: Another perspective on LiteOn drive modification - 7/25/2004 7:26:27 PM   
Laffin Assassin


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Thanx for going into great detail Zebra !!!


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RE: Another perspective on LiteOn drive modification - 7/25/2004 8:27:28 PM   
code65536


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Uh. That's NOT how strat switching is done on the LiteOns.

Maybe for the NEC where Herrie actually modifies the tables...

But for the LiteOn, it's a hook in the media code detection routine. The end result would be identical to someone changing the media code ID of the disc from one thing to the other, like Optodisc using a TY media code for their -R discs--the result is that they end up using the TY strat--would be identical to them using their own media code and doing a switch to TY.

And thus, since everything is nicely black-boxed by doing things at a higher level in the heirarchy, there is considerably reduced risk. You're right that as someone lacking the full specs of LiteOn's firmware, I don't know 100% of what is going, but emperical evidence of burns turning out much better--the difference between coastering with stock and not coastering--and also the lack of even one instance of something going terribly south, then I think that, even with the lack of perfect knowledge, the heuristic is sufficient.


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RE: Another perspective on LiteOn drive modification - 7/26/2004 3:33:00 AM   
zebra


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Hrrrrm, I guess black box theory can be argued for and against in that respect. Just going off the things that have been impressed upon me over the years. Seems to hold true for most hardware, i.e - the zero sum condition.

We shall see how it all pans out in time......


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RE: Another perspective on LiteOn drive modification - 7/29/2004 6:25:59 AM   
Halcyon

 

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What I find really odd about this "hacked firmware" thing is:

1) Change from single layer writing to dual layer writing requires re-focusing the laser to a different focal point. It is not just re-calibrating the power. This is a known fact if one reads the specifications for DL burning or any professional optical storage magazine article written by industry insiders.

It has not been proven (AFAIK) that this re-focusing can be implemented with firmware modifying (at least in all mfg drives).

It could be a hardware feature that's implemented on the construction level for all we know. I don't believe a single self-learned hardware hacker's claims, until I hear an explanation from a hardware design guy from inside some of the companies, the firmware of which they are hacking.

Of course, the hacked firmware may work, but as the only thing we have to support our thinking on these things are kProbe scans, there is not much proof either way.

2) I find it slightly odd that some people think that "let's change from strategy A to strategy B on disc X and get better kProbe scans" is a proof of better burn quality.

kProbe scans prove very little about general burn quality. They are a measure of how one drive (unit/model) sees the disc and how many causal errors are produced in the reading. Some of the upgrade hacks not only change the writing process, but also upgrade the reading process ACROSS different hardware parts (particularly PUH). I'm not all too convinced that they remaining readability results are accurate anymore, even for that one particular unit/model.

Furthermore, it has already been show by measurements by ODS magazine and others that different drives optimize the number of say DC jitter by optimizing different lower level measures.

In practise this means that one drive may be tolerant to different types of jitter. Some are more prone to land pit variations, due to slicer implementation, while others more tolerant of focus type problems. All of these factor into DC jitter, but do it differently. As such, it is impossible to say which disc measures (direct or indirect) are causing a rise in causal errors and more importantly, which drives will still be compatible with that disc.

The only way to assess "better burn" is to try out the various ready made strategies and then do a mass compatibility test of various burns on disc X using LiteOn, Samsung, LG, Pioneer, Nec, Plextor, BTC, MSI, CATS, Datarius, etc drives. In addition it requires scanning true low level disc characteristics and not only drive unit/model based causal indirect measures (i.e. PI/PIF).

I'm not saying that changing the strategy may not work, but considering that there are hundreds of people working at LiteOn, with several decades of man work experience and plenty of lab grade equipment to assess quality, it does strike me a little odd that somehow they were not able to first build and then to choose the right strategy for a particular media, but some hacker with no knowledge of the hardware was able to do it by trial and error?

I'm sorry, but it's just a little bit too much to swallow in one gulp :)

Now, if the we actually had low level measures of the disc or a mass compatibility scan (using 10 most bought drives for example) to actually prove that the burns are better, then I would suspend my disbelief immediately.

However until that happens, I hope it's understandable that some may remain somewhat skeptical :)

And again, don't take this as an attack against the people who do the modifications. Of course I congratulate them for their curiousity, achievements and sharing of the results. Hell, I can say I'm a little bit envious I don't have the time nor the inclination (probably not even the skill) to even attempt the same myself :)

It's just that some people take these things (esp. too many users hanging around in forums) too literally and think that a couple of kProbe scans show how much better firmware hackers with LiteON drives can produce compared to the whole engineering team + bunch of pro test equipment of one whole optical drive company.

Just my two cents worth, don't take it personally as it's not meant as such. I'm just trying to poke holes where I see potential logical fallacies going around. Also, I don't claim to be infallible, so I could be wrong for all I know and I'm ready to admit it right out of the bat.

However, I just don't agree with the consensus opinion, because to me it defies common logic based on my current understanding of optical burning (which is far from being on even semi-neophyte level, I might add).

Food for thought.

regards,
halcyon


< Message edited by Halcyon -- 7/29/2004 1:26:57 PM >

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RE: Another perspective on LiteOn drive modification - 7/29/2004 7:20:58 AM   
zebra


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A scientific mind comes out from the shadows...


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RE: Another perspective on LiteOn drive modification - 7/29/2004 10:33:03 AM   
emperor


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I have many times explained why KProbe scans shouldn't be considered as safe to make assumptions about the writing quality of a single disc. Of course changing writing strategies may work for some discs better, but as Halcyon said, we need true measurements of the discs.

Also i am curious how come LiteON engineers haven't changed themselves the writing strategies with the 20 new CATS testing equipement...

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RE: Another perspective on LiteOn drive modification - 7/29/2004 10:40:53 AM   
S33K3R

 

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quote:

ORIGINAL: Halcyon

Food for thought.

regards,
halcyon


Wow, it sure is

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RE: Another perspective on LiteOn drive modification - 7/29/2004 12:27:07 PM   
Dolphinius_Rex


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quote:

ORIGINAL: emperor

I have many times explained why KProbe scans shouldn't be considered as safe to make assumptions about the writing quality of a single disc. Of course changing writing strategies may work for some discs better, but as Halcyon said, we need true measurements of the discs.

Also i am curious how come LiteON engineers haven't changed themselves the writing strategies with the 20 new CATS testing equipement...


Remember that up until they bought a WHOLE BUNCH of CATS technology, LiteON was using K-Probe for internal testing... we know this because of what is was originally created for. I'm sure LiteON will start doing a lot more PROPER research now that they've gotten equipment that works! Can you imagine how the poor LiteON techs must have been scratching their heads after getting good scan results on their LiteON DVD-ROMs and DVD-RW drives, and then hearing complaints from customers with OTHER LiteON drives getting bad scans?

One thing that I found VERY interesting is that I'm told it is possible for a LiteON drive to show a perfectly good scan result on a disc, that it is incapable of playing back 100% due to assymetry errors. This is something I'd like to see personally!

@Halcyon:
Thank you for your VERY well written post! As always, you continue to show that you possess the most important charactoristic for someone in any field of science, an open mind to possabilities outside those accepted as facts by the rest of the sheeple


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RE: Another perspective on LiteOn drive modification - 7/29/2004 12:41:52 PM   
emperor


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Well said Dolphy, i forgot that LiteON used KProbe for internal testing of writing quality, I hope with the new CATS, writing quality will eventually improved and we see LiteON competes with other manufacturers, not only at the earliest model shippment but also at writing quality.

What you describe about the assymetry problem could be true, we have said that only PI/PIF error won't show the true quality of the disc, its an indication.

That is why we have included a second drive (PX-712A) to get a second opinion, of course making all tests in CATS would be much more interesting

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RE: Another perspective on LiteOn drive modification - 7/29/2004 2:06:59 PM   
Dolphinius_Rex


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quote:

ORIGINAL: emperor

Well said Dolphy, i forgot that LiteON used KProbe for internal testing of writing quality, I hope with the new CATS, writing quality will eventually improved and we see LiteON competes with other manufacturers, not only at the earliest model shippment but also at writing quality.


I am betting that LiteON is very happy right now that they never officially supported K-Probe, since the results are so out of wack under many conditions with DVDR testing... I wonder if this is the whole reason why LiteON's DVD burners have been so horrible in comparison to their CD burners? that would actually explain quite a lot!!


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RE: Another perspective on LiteOn drive modification - 7/29/2004 6:28:53 PM   
emperor


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Heh, LiteON should release better products instead of semi-final-will-fixed-with-firmware-upgrades

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RE: Another perspective on LiteOn drive modification - 7/29/2004 8:15:13 PM   
Laffin Assassin


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That will be a first if they do !!!


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RE: Another perspective on LiteOn drive modification - 7/30/2004 1:43:45 AM   
zebra


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Sadly, I have to agree with that sentiment from Emperor - it would be nice to see a product that works wonderfully from the word 'go'.

Having said this and in LiteOn's defence, they are a company of phenominal volume and expenditure. Their engineering strategy is one of first-to-market prototyping (i.e, an iterative model). For this reason, we see stream of model after model with a flurry of developmental effort here and there in "waves". This begs the question - is this the nature of the third tier manufacturer?

Company strategy is not something we can change in a hurry, ultimately, it is not CD/DVD enthusiasts and certainly not the modding community that make these decisions.

However, again, I agree with Emperor and Assassin here, it would be a nice, fresh, welcome change for the better!


< Message edited by zebra -- 7/30/2004 1:44:59 AM >


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RE: Another perspective on LiteOn drive modification - 7/30/2004 12:41:13 PM   
Halcyon

 

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Thanks for all the additional info!

I find it odd, if not a little hard to believe, that LiteOn would not have had any professional DVD measurement equipment before their big AudioDev CATS purchase a few weeks ago.

Of course, I'm not a dvd developer, but the amount of variables to play with is quite different from cd drive production, so I would have imagined them to have some sort of equipment in addition to kProbe and their own drives under development.

If there was a single design spec to which to design to, I'm sure they could have done more easily without pro equipment, but as dvd specification gives so much more leeway to designers (based on my understanding), I think they really need something else to verify their own designs.

Anyway, let the situation be what it is, I'm glad also that they bought more equipment to test with.

Also, I must clarify that I don't mean this as a veiled attempt against anyone, especially the vocal people in various forums, who have for long been saying the same things that I am now slowly trying to understand.

I wanted to add this little disclaimer here, because I've noticed that there still seems to be some "bad blood" between some forum actives and I do not want to add to that. I do not have qualms with anyone and if somebody has with me, I hope they take it up with me, because I usually see the error of my ways and apologize :)

Still after writing all that, I'm a little unsure why the hacked firmware are so openly recommended by so many with very little disclaimers. I've tried to read many test threads, I claim not to know it all, but I have not found conclusive proof that many of the hacked firmware (esp. the "speed hack burns") really produce any better quality burns.

Personally I would just want to buy a dvd drive that is specified at 4x DVD+R/DVD-R and it would burn ANY DISC on the market within specifications and it would be usable in almost any reader (dvd-rom, combo, burner, set top box, xbox, you name it) with 99% likelihood.

After all, that is something which the normal consumers (not us active hobbyists) expect.

They buy a 4x certified drive and 4x certified disc and they expect it to work.

I don't think this is a such an unfair requirement after all.

If there were some discs that didn't work at all (in any burners), they obviously should not be sold at all and the manufacturers should be sued to kingdom come.

As this is already a reality in the cd-r burner & media market with some selected high quality drives, I hope we are going to see it in the future with dvd burners and media too.

I'm just not convinced it's going to happen if we are as an active community content with speed hacked firmware, few kProbe scans and speed as the main criteria of what is "good".

I still don't know how to achieve this perfectly (better understanding of quality with stock and hacked firmware), but I know that the work that many of you do (buying various writers, testing various media with various burners/readers/software) is the right way to go (imho).

The problem is that much of the good work get's lost amongst the "me too" postings in forums from beginners who I cannot of course expect to know better (I was even more a beginner myself at one time).

But is there a solution to this?

Can we give back useful, consistent, accurate and applicable feedback to manufacturers and firmware hackers alike?

What does it require (sans buying Pulsetec based analyzers)?

Scanning with various chipsets/puhs/transport designs?

Combining averages and other statistical data about various scans together?

Making one big central database, where kProbe, CD Speed and DVD Info Pro scan data results can be uploaded, analyzed and published?

Is there a way?

What say you?

cheers,
halcyon


< Message edited by Halcyon -- 7/30/2004 7:42:21 PM >

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RE: Another perspective on LiteOn drive modification - 7/30/2004 1:08:09 PM   
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Halcyon, as always your posts are huge and you ask too many questions which no-one can answer with a definantly answer.

Using CATS could give more or less "safe" results, of course we have already heard many opinions that CATS are useless etc, which simply aren't true. Standing beside the KProbe mythology is good for keeping users close to your tests and methods, saying the truth on the other hand is the only way to go.

From our side we are working on many things to improve this situation, and providing several suggestions to software authors, how can give us better and safer results.

When our projects come up, we will have much to discuss

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