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Newbie question re: DVD-ROM error measurement - 4/1/2005 1:09:25 PM   
wth727

 

Posts: 2
Joined: 4/1/2005
Status: offline
I make DVD-R DVD-ROMS which are tested and then commercially glass
mastered for distribution.

I have questions about DVD-R DVD-ROM and measuring error rates.

DVDiNFO Pro does not report any CRC errors, and the PIE/PIF/Jitter test
does not work on either a SONY DRU-510A or a NEC ND 3520A -
they just sit there at 0%, without errors (I see there many be a needed
NEC firmware update for V3.53).

*ANY suggestions about where to look for more info or other help
will be most welcome!

Background:

I do something quite unusual - I create a multiplatform Java executable
(with different platform's JREs) which executes FROM DVD-ROM,
to reads 2+ GB of compressed data in many parallel streams
to subset and write out 25 GB of data. (This 'zero footprint' approach
saves users about 3 GB of disk space).

This means that the DVD-ROM is being used as a random access drive,
unlike the more linear reads for video or file copies. The DVD-ROM read
errors are ONLY a problem when the random accesses are used
(no problems with simple file copies).

I get differing DVD-R results on different platforms, and it seems clear that
some drives/machines have no reported errors and retries, while others
have them and they may be fatal; Sun DVD-ROM drives
and some older Dell DVD-ROM drives seem to be worst.

The execution time can be twice as long from a DVD-R as from a glass mastered
disc with the same contetnts, so I assume it is slowed by unreported errors.

BUT - The glass mastered DVD-ROMs are always fine, as are most DVD-R DVD-ROM
runs.

Ideas? Comments?

Thanks, Bill
Post #: 1
RE: Newbie question re: DVD-ROM error measurement - 4/1/2005 2:08:37 PM   
Iggy


Posts: 3381
Joined: 7/22/2004
From: Jupiter
Status: offline
How about getting a Plextor drive? This way you can use plextools.

(in reply to wth727)
Post #: 2
RE: Newbie question re: DVD-ROM error measurement - 4/1/2005 5:25:12 PM   
zebra


Posts: 225
Joined: 6/20/2004
From: .:Australia:.
Status: offline
quote:

ORIGINAL: wth727

The execution time can be twice as long from a DVD-R as from a glass mastered
disc with the same contetnts, so I assume it is slowed by unreported errors.

BUT - The glass mastered DVD-ROMs are always fine, as are most DVD-R DVD-ROM
runs.

Ideas? Comments?

Thanks, Bill


Thats a really cool post there Bill.

i. The reason DVDInfoPro will not report parity errors on either the Sony or the NEC, is because NEITHER drive currently supports this capability in firmware. The NEC will be supporting it soon. As soon as you have the (non-publically available currently) firmware, DVDInfoPro will let you report parity errors using this hardware! Cool huh? As for the Sony...veeeery old hardware. We are working on getting this enabled, for other users as well! :-D

ii. As for the CRC errors, it really should run these tests. Something seems a little odd there! The CIRC error scanner should just work. What version of InfoPro are you running and how is the optical hardware connected to your system?

iii. The glass platter/dvd-r issue is an interesting one that does not really surprise me. Your work, I find, very interesting.

I will wager that the ability of a reading mechanism (PUH/OPU block) to read media is highly dependent upon the reflectivity and refraction coefficients of the material it is made of. Logically, a PUH/OPU cannot be optimally calibrated to read ALL kinds of reflectivity indexes perfectly. As a result, at an educated guess, this is why we sometimes see such a difference in readback performance!

Makes sense?


_____________________________

Glory may be fleeting, but obscurity is forever

My home - Speedlabs.org

The Zebra BLOG!

(in reply to wth727)
Post #: 3
RE: Newbie question re: DVD-ROM error measurement - 4/5/2005 1:46:24 PM   
wth727

 

Posts: 2
Joined: 4/1/2005
Status: offline
Thanks very much for the replies!

I have ordered a Plextor drive and have Plextools, so
I and look forward to the added info. I will be especially
interested in comparing the error rates on the DVD-R DVD-ROM
masters with the commercial glass-mastered released DVD-ROMs.

I do hope for any other insights re: linear reads vs.
many-threaded random reads from DVD-ROMs!

cheers, Bill

(in reply to zebra)
Post #: 4
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