60× CD-R(OM) / Multibeam disc drive?


#1

There are some 24× DVD burners such as the iHAS324.
The rotation speed is slightly above 72× of a CD.

A DVD of course is constructed more robust. However, many CD drives are limited on CDs to 48×.
Some burn 56× but read 40×. The SH-S182 burns single layer WORM DVD’s (+R -R) at up to 18×, but reads only 16×.

Additionally, what happened to the multibeam drives from the early previous decade? A good multibeam BD drive could nearly reach SSD speeds.

Some disc drives reached 56× of reading speeds, others reached 52×. But today, everything is 48×/16× and 40× CD-RW, 40× CDDA DAE.


#2

Sony offers multi head/beam drives for it’s blu-ray ODA cartridge system but it costs a fortune. Cost per gigabyte for the cartridge is more or less reasonable when you take in consideration that you use the highest grade blu-ray media available - but the drive cost more than $7500.

https://pro.sony.com/bbsc/ssr/cat-datastorage/cat-opticaldiscarchive/product-ODSD77U/


#3

Kenwood’s 72x TrueX multi-beam CD-ROM was very fast. Its speed was particularly impressive when reading the early part of a disc when the rotational speed was low. But it had its limitations and only worked properly on certain types of CD. [IIRC there was a very good review on CDSpeed2000.com - which should be available on Archive.org.]

Factory-pressed CD-ROMs and some types of phthalocyanine CD-R were fine. But it handled audio CDs very badly and struggled to read most CD-R (especially cyanine & AZO, but also lesser quality phthalocyanine). Often it was unable read all the way to the end of the disc. 80 minute discs were a particular problem and it seemed unable to read CD-RW at all.

With this in mind, it seems likely that adapting the technology to the smaller track pitch & pit size of DVD (never mind BD) would have been an enormous (perhaps insurmountable) problem and required a large investment. But even back in 2000/1 it was obvious that optical drives were rapidly becoming commodity items with prices plummeting to the point where there was minimal profit. And with the price of writers falling rapidly, the future of read-only drives would have looked especially bleak. As far as I can see, incorporating the multi-beam read technology in a write-capable drive would have required a second OPU with conventional optics.

As far as I am aware, the Sony Blu-ray cartridge drives nixa_mk mentioned use multiple single-beam OPUs to read/write multiple platters as once (as HDDs do). Whereas the TrueX multi-beam technology Kenwood used split a single laser beam into 7 beams directed at different points the same disc (positions fixed relative to the OPU), with a multi-beam optical receiver & associated controller somehow managing to make sense of 7 simultaneous (non-sequential & overlapping) data streams.

[OT]
What I would have loved to see was an optical disc writer with a second independently positionable OPU positioned opposite the main one (~180°). In principle a disc could be verified (read back) during the writing process, thus saving a lot of time (& lost data among the ignorant masses). The writing side of the drive would act as the master and control the rotational speed. The secondary read-only slave side would just need a reasonably-sized buffer to hold the written data until it has been verified and a controller able to adapt to any changes in the rotational speed dictated by the master. This should have been possible using the technology readily available 15 years ago.


#4

Actually the Sony works with a second independently positionable OPU positioned opposite the main one. Check the video presentation after the 8:15: https://youtu.be/afTnetraM3Y?t=496

It reads single platter at the time - that’s why all the marketing hype for the read/write speeds is based around file sizes that can be stored on single blu-ray disc.

I’ve seen once one of those units in person but I never had opportunity to use it or take it apart.


#5

Very interesting. Thank you.

Do you know if the second OPU is used for simultaneous verification while writing? (Maybe they’ve copied my idea? :givewink: :bigsmile:)


#6

From what I can find on the Sony web site brochures it is specified that is capable of verification on the fly but write speeds are halved.

Their new generation of ODA drive is equipped with 8 OPUs so it can read/write both sides of double sided discs simultaneously + it offers land and groove recording.

Definitely there is still optical storage development but I doubt it will ever end up in the consumer market.

p.s. Sony ODC1500R cartridge, when disassembled, is source for quad-layer blu-ray recordable media (if you own BDXL drive that has actual firmware support to write on QL media).


#7

Thank you for the information.

Hmm. Could mean they are normally writing to a single side with two OPUs simultaneously. But I wouldn’t have thought that was technically possible, unless each OPU writes to a separate layer. Or it could just be that they are doing the verification in the same way that DVD-RAM does, by alternately writing and reading, and not using a separate OPU for verification.

It is most annoying when these companies give so little information about what their products are actually doing. You would expect the business/enterprise market to buy such expensive equipment based of a careful reading of specifications, datasheets and independent test reports. But instead corporate management seem to be even easier to seduce with glossy animations and meaningless pseudo-science marketing speak than your average consumer who worships at The Temple of Shiney. :rolleyes:


#8

Unfortunately corporate management is interested in buying whole system/workflow, usually based around marketing hype and better price offering. Datasheet reading is for us, the people who need to figure out how to integrate what management just bought :slight_smile:

In the pro audio/video market it always been like this - only few review here and there, usually done by smaller production companies who actually own the equipment. Good source of additional information is visiting expos where sometimes you can talk to someone who was somehow involved in the product development or testing. I had few awkward situation when engineering discovers that marketing got carried away with their story telling.


#9

You know a lot.
I can imagine, that a good multibeam BluRay reader/writer at 10000 rpm could reach speeds close to SSD.


#10

Here is one accurate documentation from a SE-218: http://www.farnell.com/datasheets/1634413.pdf


#11

Unfortunately, Sony’s ArchiveDisc is a seperate and proprietary system, as far as I know.
I hope, that the HVD will be good.

Possible features: Redunadnt information on seperate positions on the disc, and user-specifyable redundancy per sector and physical sector length as well as RAM and forensic capabilities could make a giant breakthrough.


#12

I thought so too.
Could also be useful for portable/car CD players, but especially for high speed reading and multi-pass/accuracy burning.

For DVD+RW/-RAM, due to accurate DPM (data position measurement), enabled by high wobble frequency, a laptop drive can burn the same circle of data with two passes (rotate twice) for more quality.

Actually, if I operate the SH-S182 (internal disc drive) externally (external adapter), I see two red laser beams on the ceiling of the disc drive, around 3mm away from each other.

MultiPass burning can also be used on DVD+R for more accuracy or to fix little gaps caused by a dirty surface that can be cleaned.


#13

I expect your SH-S182 is the Lightscribe version. All Lightscribe have a second red LED, to read the code printed around the hub on Lightscribe discs. On most drives it is on all the time and can be seen when the tray is open. (I know of only one drive which doesn’t leave the LED on all the time.)

I have never heard of an optical drive burning the same area of a disc twice. I wouldn’t have thought it was possible to achieve the necessary precision of timing & position to match the ‘pits & lands’ of the first write. And I can’t see anything to be gained by doing so. In the case of dye-based discs, any healthy writer should have more than enough laser power for a single pass to cause the dye to decompose and allow light to reach the reflective layer (thus replicating the lands of a factory-pressed CD). As far as I can see a second pass would only make matters worse and there is nothing to be gained. And in the case of phase change discs it seems possible that might begin to erase the data written in the first pass.

A two-pass process is normally used when packet-writing discs. This is the default write method used writing to DVD-RAM (formatted to UDF or FAT32) as though it was an ordinary removable disc. But the method used is write & verify not write & overwrite - the second pass only reads the disc to verify the packet of data which has just been written to disc. Any data packets which don’t verify successfully are re-written, is necessary to another sector on the disc, and the file system adjusted accordingly. (With the correct software, the same method can be used with CD/DVD±RW and even CD/DVD±R.)


#14

Which one, if you don’t mind me asking?

Very interesting, thank you.[quote=“Ibex, post:13, topic:399507”]
A two-pass process is normally used when packet-writing discs. This is the default write method used writing to DVD-RAM (formatted to UDF or FAT32) as though it was an ordinary removable disc. But the method used is write & verify not write & overwrite - the second pass only reads the disc to verify the packet of data which has just been written to disc. Any data packets which don’t verify successfully are re-written, is necessary to another sector on the disc, and the file system adjusted accordingly. (With the correct software, the same method can be used with CD/DVD±RW and even CD/DVD±R.)
[/quote]

You know a lot. I assume, that MyCE is really a place for optical disc passion.


#15

CDFreaks/MyCE was without doubt the world’s premier optical disc site. There were a few pretenders to its crown, but they never came close to the quantity (& quality) of active members we used to have. Back in the old days we had some real experts in their field as regular members. There are still a few long-term members around - some are regular inhabitants, others visit only sporadically. Alas most seem to have lost interest in optical discs and moved on to other things. But there has always been much more to the CDFreaks/MyCE forum than optical disc discussion - fun, games, news, jokes… The rules of the house are very liberal.
Some regular members never went near the technical forums and only joined for the social side of things.

I still consider myself to be a CD Freak and regularly optical discs as my medium & long-term storage medium. But I haven’t been around much this year due to declining health (and difficulties using the new forum software).

The Cdrinfo.pl forum seems to be an active optical disc forum these days - and a little bit of it is even in English! A few active CDFreaks/MyCE members use that forum as well.

Not at all, no problem with asking. :givewink:

I can’t remember for certain which drive it was. I think it was the last but one lightscribe drive I bought, so probably an LG GH22LP20. But that drive is packed away in storage (along with ~60 others), so I can’t easily check.


#16

The new forum software is actually very modern (especially UI and autosave), despite I rather despise AJAX (especially for YouTube comment extraloading.
This is the legacy forum: http://web.archive.org/web/20140701175913/https://club.myce.com/
Classic forums work much better on older devices/browsers and also rely less on AJAX (+more lightweight). Quora has a modern page, but does not allow anything before finishing to load, which is horrible when data plan throttled after running out of high speed data bandtwhith.[quote=“Ibex, post:15, topic:399507”]
GH22LP20
[/quote]


Wow, even ×16 speed on DVD-R DL (not only +R DL like WriteMasters).

Optical discs are NOT obsolete:

Really a CD freak.
However, I have collected some disc drives in 2014 and 2016 from school computers that were not needed anymore.
The new computers use slim laptop drives, even the desktop PCs. Some of them have two laptop drives (1cm thickness) instead of one desktop drives.