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Posted by Bill Vermillion on 01/29/07 18:35
In article <r4lbr2l8kbm03c452fom9qiosgrf4q9pbg@4ax.com>,
MassiveProng <MasiveProng@yourhiney.org> wrote:
>On Mon, 22 Jan 2007 17:25:06 GMT, bv@wjv.com (Bill Vermillion) Gave
>us:
>
>>In article <ii8rp29a07pigd5m63s6vl6tp7d34f82hn@4ax.com>,
>>JoeBloe <joebloe@nosuchplace.org> wrote:
>>>On Thu, 4 Jan 2007 13:14:17 -0000, "M.I.5?"
>>><no.one@no.where.NO_SPAM.co.uk> Gave us:
>>
>>>>But that would have been an entirely new format. Same size disk maybe, but
>>>>a new format all the same.
>>
>>>
>>> You don't get it. All optical disc technologies evolve.
>>
>>> DVDs right now have different res previews and extras than the film
>>>segment, and it peels off the disc at a different bit rate.
>>
>>> What I mentioned would be no harder than that, and using CLV, very
>>>little would need to be changed. DVDs are read at varying RPM rates
>>>as the disc progresses. An LD could be read the same way, providing
>>>the varying rate and best use of the optical data area real estate.
>>
>>For the widest majority of LD's produced they were read the same
>>way. CLV - Constant Linear Velocity - means the disk speed varies
>>according to the place on the disk. CAV - constant angular
>>velocity - is the one that rotates at the same speed throughout.
>
> I don't need a primer on the methodologies used in Laser Disc
>manufacture.
>>
>>Technically after the first few CLV disks were released, they found
>>that there was a herringbone problem, so while they were still
>>called CLV, there were CAA - Constant Angular Velocity.
>
> Absolutely incorrect! CLV and CAV were BOTH available from the
>beginning and are BOTH DISTINCTLY different from each other.
They were NOT both available from the beginning. And the first
player was the Magnavox and the only disks available were
CAV. I remember seeing the first Magnavox display locally -
Orlando. Which was several months after the first LD players went
on sale in Atlanta - the only place they were available.
I saw the first Pioneers when I was on vacation and it was probably
in Billings Montana - as Pioneer debuted in several cities and then
spread nationwide.
> The Laser Discs used by the video game industry REQUIRED CAV to get
>addressed frame access! "Dragon's Lair" and "M.A.C.H. 3" were
>perfect examples of the first.
Yup. And I have one of the players that were used in the games,
and I have Dragon's Lair and Space Ace in the original distribution
format - the disks that had an aluminum back side not plastic.
> CAV discs were exactly 54,000 frame, one half hour per side discs.
> NASA released their discs this way and I have a "google earth" type
>disc from over a decade before you guys could do such a thing online,
>though without map overlays or coordinate references.
I have one of the early disks with tones of still frames on
aircraft. I never did find a copy of ???? [the Colorado city] that
you were able to navigate through the city and then choose which
street to move down at each intersection.
>CLV discs were 1 hour per side, and despite the fact that they changed
>the manner they generated the WORM, the disc was STILL CLV from center
>to edge, and a laser was STILL unable to pause and read a single frame
>over and over again, and the players REQUIRED field frame memory to
>accomplish a paused frame.
The best references for most video are the old posting of Bob
Niland, but a google search will turn this up on Wikipedia [ which
is not know for it's accuracy].
---------
Constant Angular Acceleration
Constant Angular Acceleration (CAA) is a variant of CLV that was used
on the Laserdisc format. The initial specification of CLV (as it
applied the laserdisc) resulted in several playback artifacts to be
present in the audio/video portion as well as compatibility problems
with laserdisc players as produced by different manufacturers.
In the mid 1980's, Pioneer electronics, introduced the CAA scheme
where the speed in rotation of the laserdisc was lowered in steps and
eliminated most playback artifacts and compatibility issues. Since its
introduction, most manufacturers of laserdisc discs adopted the CAA
format but still referred to their CAA-encoded product as CLV.
-----------------------
>> That meant
>>that there were bands of CAV - that changed rotational speed every
>>little bit - so that adjacent frames did not interfere with each
>>other as they did in pure CLV format.
> Nope. The disc did slowly change speed, but ALL CLV discs did so
>from the beginning. What part of CONSTANT and LINEAR do you not
>understand? Fats rotational speed at hub and slower speed at edge
>were ALWAYS part of the normal operation of a CLV disc. The
>improvements you mentioned were NOT a transformation to CAV EVER!
And what part of Constant Angular Accelleration do you have
problems with. And I remember when my good friend got Blazing
Saddles in one of the first CLV formats and you could see the
patterns.
>>>The physics are such that the data rate for the outer portion
>>>of the disc is capable of a higher data rate than the hub
>>>portion, for any given RPM.
> NOT AT ALL!
Sure it is. That's the method behind the ZBR in HD technology.
If you rotate at a constant rate the bits/pits/whatever are going
to be spread further apart, so if you increase the data stream
you can put more data on the disk. That's what they did
with CLV. Slowing the disk works in LD. Changing the read/write
rate in HDs is the same principle. You optimize the space where
you store the data - and you can change the data rate or you can
change the rortation rate.
> CLV discs SLOWED toward the outer edge. SAME data rate and pit pith
>ALL THE WAY THROUGH.
As above - because they changed the disk speed. But as I said is
'capable' of a higher data rate. Many thought that CAV disks
looked better on the outer bands but I never noticed the
difference.
> The industry as a whole knew where they were going.
>CDs came out YEARS before LDs did, dumbass.
I KNOW that. I saw the first CDs demoed at the AES in NYC.
They had a total of 50 titles in print and they were hoping the CD
would take off before R-DAT was successful.
> Try again, Billy. You read your wikiTard page too fast, and it
>likely contains errors from what you wrote here.
Sorry - I dont' go to Wiki. I don't trust it - even though I did
include the bit on CAA above.
....
>>The largest problem from my POV was NOT the size but the
>>manufacturing process where the sides were plated and then glued
>>together.
>
Correct and the small thin music LDs - 8" format - didn't have that
problem. The looked like a giant CD with the printed disk.
....
> LaserDiscs had adhesive seepage problems, but that was not what led
>to their demise.
The seepage - at least the gooey edges - seemed to be restricted
to the 3M made disks where they used sheets of glue-material
instead of a liguid glue.
>> I have 3 or 4 eight-inch LDs - that required a spacer to
>>play them on a standard player as they were only one side.
> You have a retarded player. ALL of my LD players would play ALL 4
>form factors available at the time, with NO adaptation(s) required.
When the thin disks came out there were a lot of adapters sold
so people did not have to go out an buy a new player.
>>These were free demos that you could get from Warner Bros.
> Whoopie doo. They were likely illegally released discs that were
>technically a NON-conformant form factor that was meant for studio
>only use initially.
No - and I just ran across an invoice. I mis-remembered. They
were $8.95 and had selections from the music LDs. These were being
sold so people might by the full LD of the artist.
>>> Maybe we should go back to piano roll methods. That's what a
>>>holocube is essentially.
>>Ah - multi-layer piano rolls. Interesting concept! Manufacturing
>>might be a pain though :-)
And how would your read the holes that were covered by the others.
I'd guess you'd have to have transparent rolls that were laminated
and then refocus to get the right layers.
> They wrote ten GB to a roll of shipping tape in Germany over five
>years ago.
It's been at least 10 years since one company was producing a large
capacity 'tape' for backups. They could access at high speed
anywhere in the tape under 2 mintues. I don't recall the name of
the company but they were Canadian. All I can think of is Rosetta,
but that was the company that was writing data to small disks
which could go from plastic to stainless steel [for long term
storage].
It was basically storing optical images so in the worst case
you could use a high powered microscope to see what was on the
disk. It was said to be able to withstand an office fire
with the only problem being the stainless steel turning a bit brown
- but the data was still readable. But storing images is not
what I'd call an efficient method of storage..
Ahh - a quick search on Google revealed the the optical tape
company was Creo. And I now recall that one of it's uses
was to be storing data from the ships who were out using
seismic sounding to hunt for oil deposits. What fit on one CREO
tape replaced thousand of data tapes.
And now with data tapes at 500GB to 1TB per cartridge, the
$100,000+ for the CREO looks pretty bizarre. But then again
$300 for 16K of memory about 30 years ago looks bizarre too.
There were so many interesting technology approaches that were
tried and 1)never made it to market or 2) made it but failed.
> Holo-cubes may be in your future.
Holo [or hollow] desribes my brain when I mistype the acronym
in my original post. I think my brain was on vacation.
Even spel-chekurs don't fix that.
Bill
--
Bill Vermillion - bv @ wjv . com
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