DVD RAM and CDR\RW tests
WHAT IS DVD-RAM?
DVD-RAM (DVD–Random Access Memory) is a disc specification used in computers as well as camcorders and personal video recorders. The term DVD-RAM is a misnomer as the technology is not based on computer memory chips and DVD's can inherently not use the random access method.
Compared with other writeable DVDs, DVD-RAM is more closely related to hard disk technology, as it has concentric tracks instead of one long spiral track. Unlike DVD+R, DVD-R, DVD+RW and DVD-RW, you do not need special DVD burning software to write or read DVD-RAMs on a computer. DVD-RAMs can be accessed like a usual floppy disk or hard drive. DVD-RAM is more suited to data backups and use in camcorders than DVD±RW.
Advantages of DVD-RAM:
Long durability of minimum 30 years.
Can be rewritten > 100,000 times (DVD±RW ca. 1,000 times).
No DVD burning software required in computers – discs can be used and accessed like a removable hard disk; MS Windows requires a special DVDRAM driver or InCD program, although Windows XP can write to FAT32 formatted discs directly.
Very fast access of smaller files on the disc.
Automatic hardware verification of written data, no need to run a software
verification after the burning finished
The cartridges make it very handy (where applicable).
In video recorders, DVD-RAM can be written to and watched (even separate programs) at the same time (known as time-slip or time-shift).
Disadvantages of DVD-RAM:
Many DVD recorders do not support DVD-RAM.
The medium is more expensive than DVD±RW.
DVD+RW can be written faster than DVD-RAM when writing large amounts of data.
We didnt many types of DVD RAM here in the review basement at the time of writing this review but the brands we tested all recorded at their maximum rated speeds. They also transferred at maximum speed with no slowdowns noted and the scandisc tests showed no errors. More testing is needed but the early signs look good.
We can not measure DVD RAM the way we normally measure DVD+/-RW or DVD+/-R D/L media and so these tests will be a little less indepth. DVD RAM has built in error correction on the disc. As long as you store the media well it should stay very readable for many many rewrites. So you will not see any K-Probe or PxScan test results for this media type. In its place comes a CD Speed file and disc surface scan test to check for any uncorrectable sectors on the recorded DVD RAM media.
CDR and CDRW tests
During these test we will measure the quality of the written media by counting the number of C1 and C2 errors. Again just like with our PIE/PIF tests on DVD+/-R media we are using a Liteon device in conjunction with K-Probe to measure these potential errors. This device is the Liteon 5239V CD Writer with firmware 2$04 and tests will be carried at a read speed of 40x. A brief explanation of what each test measures is listed below:
C1: indicates BLER, which is the number of E11+E21+E31.
C2: indicates the number of E22.
The existence of C1 and C2 errors on a CD is perfectly normal, since they can be corrected by most drives CIRC logic. However, these numbers should not be too high since they can create uncorrectable errors when the disc\'s playability decreases (for instance, by means of dust, fingerprints, scratches, etc.).
As a guideline a good disc in our opinion will display low C1 errors averaging no more than 10 and no C2 will be present. On Audio CDs and VCDs reported C2 errors can cause skipping and pixelation. In our private tests reported CU levels almost certaintly will cause issues and mean a back up of the discs contents will be needed very soon.
The NEC ND-4550 offered very good support for many types of tested CDR Media. It maximum speed of 48x for most media is about as fast as you would want to record CDR on a DVD writer. Not every media was supported at its maximum rated speed but the results are very acceptable with almost every CDR tested recording with no C2 errors. We found the odd C2 error on the CDRW media but that is not ususal, especially on high speed CDRW media. As it is meant for short term backup these C2 errors should not be an issue in our opinion.
It supports upto 90 minute CDR but does not have support for 99+ minute media. Again supporting upto 90 CDR minute media is good enough support wise for a DVD Writer although squeezing those extra mbs onto a CDR would be of course, always welcomed. The most we managed to overburn to our Infiniti branded 99 minute media using the Nero CD Speed Overburn test was 92:48:38. This is consistent with older NEC DVD writers such as the 3520 we have tested.
Please note that as the main objective of this review is to measure how well the NEC ND-4550 records DVD Media we have not tested as many pieces of CDR\RW media for each test to gain an avergae. We have simply recorded two discs of each media branding to give the writer at least one disc to learn if required and shown the second discs results. Although DVD Writers should offer good support for CDR\RW media we cannot expect them to deliver the same sort of support as a CD writer. If you want the best support for CDR\RW media we recommend buying a dedicated CD writer such as our Liteon 5239V or a Plextor CD Writers.
|
