"Widow Twankey" <Widow.Twankey@Aladdin.com> wrote in message
news:94C0755D4808FCE1@130.133.1.4...
i read somewhere that for cds burning at 52x the disc is rotating at 10,800
rpm
and that 16x is the limit for dvd because at this speed the disc would be
rotating at 10,800 rpm

can anyone confirm this?

"GTAUK" <nospamgtauk@bigfoot.com> wrote in message
news:c4m5pk$2jpb1t$1@ID-7934.news.uni-berlin.de...
Thats basically rubbish, albeit with an element of truth.... getting a cd
or dvd to spin faster in a drive isnt really a problem (faster motor=more
rpm's from the disk) the problems come when it comes to the laser being
able to read and write to the disk when its going that fast, in theory a cd
could reach and perform reliably at around 80x speed, the trouble then of
course becomes reliability of the data transfer between your H.D or other
cd/dvd drive to the drive your are writing to...the average home owners
equipment just couldnt keep up. Getting the disk to spin quicker is an
easy task, getting it to spin quicker and read/write reliably with other
3rd party elements is another ball game altogether.
The only real limits on speed at the moment is the laser itself in the
drive, and the mechanism that moves the laser head back and forth, solve
those 2 problems and you can go as fast as you like, again the biggest
problem though currently with the way a cd/dvd drive functions is its only
possible to make the laser move back and forth at a certain speed and still
function reliably and correctly...hence the reason why cd drives have been
stuck at the 52x speed limit for a while. Once someone can make that cd
head move quicker and more reliably then its basically just a case of
writing firmware to deal with it and shoving a faster drive motor in the
drive, sounds easy, but in practice is very difficult.

"Dave" <Fake@NGGGGGGG.com> wrote in message
news:c4mde6$mae$1@newsg3.svr.pol.co.uk
Well there does seem to be a very real possibility of CDs disintegrating
in 52x CD readers.

What about that?

--

Brian Gregory (In the UK).
ng@bgdsv.co.uk
To email me remove the letter vee.

GTAUK wrote:

Correct on both scores, give or take a few hundred RPMs. Mechanical stresses
on both the motor and media, are limiting factors.
Plextor will ship their 12x DVD burner shortly. Expect others to follow
suit.

Dave wrote:
This IS a problem. Otherwise, performance cars would all rev at
100,000rpm or so.

There are physical limits to the amount of centrifugal force a DVD will
handle.

Odie

"GTAUK" <nospamgtauk@bigfoot.com> wrote in
news:c4m5pk$2jpb1t$1@ID-7934.news.uni-berlin.de:

I once had a DVD burner that burned at 300x (a little known device from a
strange compnay out of Haiti that mysteriously disapeared). The problem
was, everytime one burned a DVD they actually went back in time, and when
it was finsihed, the resultant product was an 8-track tape.

di

"Dave" <Fake@NGGGGGGG.com> wrote

... which is mostly ignorant nonsense. The limit is mostly defined by the
disks themselves. See
http://www.research.philips.com/Info...cleDetail.asp?
lArticleId=2848
and
http://www.research.philips.com/Asse...12_10-2017.pdf
Of course, if you can provide references that contradict the Philips
engineers ...

John Howells

"GTAUK" <nospamgtauk@bigfoot.com> wrote

For confirmation see
http://www.research.philips.com/Info...cleDetail.asp?
lArticleId=2848
and
http://www.research.philips.com/Asse...12_10-2017.pdf
I assume that, unlike some in this forum, the Philips engineers do know what
they are talking about. I just wish I could find the interesting photograph
they once had that showed the effect of a slight flaw in a disk that was
spun faster than 10,800 rpm.

John Howells

"Odie" <odie_ferrous@athotmaildot.com> wrote in message
news:406ECA30.FE72593C@athotmaildot.com...
Er, WTF are you talking about if you want to compare a cd drive to a car
then you can if you want buy the skoda of a cd drive that goes say at 24x
max, then you can move up to ya luxury ford that goes at 48x or as you
eliquently put it a performance car, or a 52x drive, just cos the
technology exists doesnt mean its always used, or needs to be used.

Well that is technically very true, however we are far from the limits a
disk can spin at, new technology to actually hold the disk in the drive can
be designed (which is pretty easy....tougher spring....larger hole in the
centre of the disk....thus more surface hole area for the drive to hold the
disk, different grabing mech for the drive.. etc) and numerous other cheap
and simple methods, but getting the laser to read it acurately is still the
most difficult scientific thing to do.

"Dave" <Fake@NGGGGGGG.com> wrote

Perhaps you should tell Philips how wrong they are:
http://www.research.philips.com/Asse...12_10-2017.pdf

John Howells

"John Howells" <john@howells-99.freeserve.co.uk> wrote in message
news:c4mjt5$h5i$1@titan.btinternet.com...
?
Er from the second link i gave i dont really have to (sorry the first didnt
work, try tinyurl next time), i quote from that PDF file.............
'TODAY, A CD-ROM CAN BE READ 48 TIMES FASTER
('48X')'
Er........me contradict philips!!! er i would but i dont have to bother if
the information is old and out dated already.
ignorant nonsense, from me!!!!! perhaps you should take a long look in the
mirror and wake up to 52x read technology thats been with us a
while...........
PLONK

"John Howells" <john@howells-99.freeserve.co.uk>
snip.........
?
Quote Mr Howells...........
'the Philips engineers do know what they are talking about'
oh yes of course they did in the past when cds could only read at 48x (see
his second link for that gaff) 52x read is possible now mr Howells, i
suggest before you insult others you insult your old outdated info. and you
gullabilty in the belief you have for it.

"John Howells" <john@howells-99.freeserve.co.uk> wrote in message
news:c4n12n$g3g$1@hercules.btinternet.com...
Oh another useless outdated link
wake up things can go faster then that, theres a possiblity of 16x writable
dvdr by the end of the year, not how do you think that compares to
there.......world record 48x cd *sniggers*

"Dave" <Fake@NGGGGGGG.com> wrote in message
news:c4n101$tri$1@news6.svr.pol.co.uk...
To quote from the Philips article you did not bother to read from the other
note:

limited by the highest safe rotational velocity of the polycarbonate discs.
Similar to the CD-R system that reached its maximum speed of 52x
corresponding to 180 Hz at a disc radius of 55 mm, the DVD speed-race will
end at about 16x DVD speed. The increase in recording speed is achieved by
improvements of the recording media, the recording system and the write
strategy. This article shows the feasibility of dye-based recording at
speeds of up to 16x.
<<

But, of course you would know better than the experts in Philips! I only
quoted the second, slightly older, article reference above because it went
into a little more detail about why the limit existed, and so you could carp
about the small difference between 48x and 52x. I note you quote no
reference to refute their claims to a 16x upper limit for a DVD.

John Howells

"John Howells" <john@howells-99.freeserve.co.uk> wrote in message
news:c4n20b$i1c$1@hercules.btinternet.com...
It wasnt a case of not bothering to read the first link, it was more a case
of not bothering even trying to click on it as the link was too long,
(which you should have noticed when you read back *hint:the link wont go to
the article, only the informationcenter homepage*, *hint: not all the link
is highlighted in blue* *hint:use tiny url for link posting* *hint:get a
life* etc but being the all high and mighty, butt licker of phillips (who
BTW IMO cant make a decent dvd writer to save their lifes) you should have
known that..... then again a persons that believes their outdated '48x
world record' claim and who uses outdated software to post to Newsgroups
wouldnt know anything.
*snipped the cut&pasted crap from an article nobody could read unless they
could really be bothered to p*ss about cuting and pasting it into their
browsing software*

"Dave" <Fake@NGGGGGGG.com> wrote

So I have to choose whether to believe a report from Philips that you are
afraid to quote, or the unsubstantiated ramblings from someone who believes
that the specific posting software used somehow affects the truth of the
message. Tough choice!

Bye - PLONK

John Howells

"John Howells" <john@howells-99.freeserve.co.uk> wrote in message
news:c4n53k$q6e$1@titan.btinternet.com...
No you don't have a choice, you don't have the thought process to actually
have the ability to choose, let alone accuse me of rambling when you
yourself cut and pasted a whole load of crap from a out dated article.

Also if ya gonna repeatedly post the same bloody link several times in the
same F**king thread and even worse cross post it to several F**KING groups,
learn how to post it properly, you wasted your time and others, with ya
repeated cut and pasted link dribble, due to the fact that you have an
inability to actually understand that typing a link longer then a specific
amount of characters, effectively renders it useless,
..........hmmm........'useless', now there is a very fitting word for you.

Secondly learn to know the difference between an article/document that's up
to date and a article/document not up to date, you my friend are a dumb
half-witted, 'repeatedly post the same non-functioning link', baboon of the
highest order.
You wouldn't know the difference between advances in technology and a MS
update.

"Dave" <Fake@NGGGGGGG.com> wrote in message
news:c4n09l$8bh$1@newsg3.svr.pol.co.uk
Now your just being stupid.
If you start changing the shape of the disk then it is no longer a
standard CD or DVD.
Obvoiusly if you re-design the media you can make it go faster.

Have you never heard of CDs with a slight physical flaws literally
exploding inside 52x CD drives?

Yes getting the laser to read it is difficult but there's no point in
going further if CDs are going to start disintegrating.

--

Brian Gregory (In the UK).
ng@bgdsv.co.uk
To email me remove the letter vee.

"Brian Gregory [UK]" <ng@bgdsv.co.uk> wrote in message
news:406f3be4$0$3306$cc9e4d1f@news-text.dial.pipex.com...
So whats a standard cd..........is it 8cm or 12cm in diameter, i know of
both sizes, both are called cds

It can go faster right now if the companys really wanted, the only reason
it doesnt is limits with regards to other technology and reliability

Yes but normally that happens when you can physically see a flaw to the
disk....if ya stupid enough to put say a fractured (or flawed in any way)
cd into a drive which spins at high RPM, what do you think will happen.

Well thats true, but a cd could go faster if they wanted to right now
(apart from the reading of the disk there is no problem), there is a point
when it becomes totally unreliable (maybe dangerous), but above 52x isnt
it, id be willing to bet we have a dvd format (either current or future)
that will spin at higher RPM speeds then a cd does at 52x.

Dave wrote:

In terms of RPM and structural loads it's pretty much the same. 1x DVD
turns at about 3 times the rotational velocity of 1x CD, so 16x DVD turns
about the same speed as 48x CD.

You don't seem to understand the problem. Polycarbonate plastic has a
certain tensile strength and certain density. When spun at a given RPM
there will be a tensile stress induced in the disk. Increase the RPM and
the stress increases as the square of the rotational velocity. At some
point the stress exceeds the tensile strength of polycarbonate and the disk
comes apart.

Now, it's concievable that a stronger plastic could be used, but
polycarbonate is pretty much the strongest thermplastic around--anything
stronger would be a thermoset that would require a new type of pressing
machine, which the recording industry is not going to accept without a
fight.

There isn't any way to design around this and still have disk that has a
hope in Hell of being played in existing DVD players.

--
--John
Reply to jclarke at ae tee tee global dot net
(was jclarke at eye bee em dot net)