detail information

DVD-RAM:

The NEC ND-4551A is a so-called Multi recorder, meaning is also supports the DVD-RAM format.

This drive is one of few drives that also support the DVD-RAM format, lets us look at the recording side of the disc, and as you can see it got differences from the other DVD+R/RW/R DL and DVD-R/RW/R DL discs.

You could see a very fascinating pattern of darker spots, supposedly these spots are used for calibration while writing and reading.

A DVD-RAM's disc can be formatted in the following formats:

• FAT32
• UDF 1.02
• UDF 1.50
• UDF 2.00
• UDF 2.01
• UDF 2.50

By formatting a DVD-RAM disc with FAT32 it will act like a removable hard drive and all writing will be done in the 'background processes". Meaning you do not have to wait for it to finish - you can start or work with other applications while the DVD-RAM is working without noticing any 'hangs" or CPU slowdowns.

Lets us take a look at the media we are going to use in these tests:

Panasonic branded DVD-RAM media certified at 2-5x:

0000 - 16 0F 04 42 00 03 10 00 00 26 5F 5F 00 00 00 00 - ...B.....&__....
0010 - 80 20 00 10 00 00 00 00 00 00 00 22 00 00 00 00 - ..........."....
0020 - 10 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 - ................
01F0 - 00 00 00 00 52 0A 00 79 36 36 36 73 34 34 34 1A - ....R..y666s444.
0200 - 1A 00 00 11 22 81 85 88 88 00 85 88 88 01 84 87 - ...."...........
0210 - 87 01 84 87 87 0A 0C 0E 0E 0A 0C 0E 0E 09 0B 0D - ................
0220 - 0D 08 0B 0D 0D 4D 58 4C 31 36 0D 20 20 20 20 20 - .....MXL16......
0230 - 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 - ................
0240 - 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 - ................
0250 - 20 20 20 20 20 00 00 00 00 00 00 00 00 00 00 00 - ................
0260 - 00 00 00 00 00 01 01 79 04 70 36 36 36 79 80 80 - .......y.p666y..

0000 - 16 0F 04 42 00 03 10 00 00 26 5F 5F 00 00 00 00 - ...B.....&__....
0010 - 80 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 - ................
0020 - 10 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 - ................
01F0 - 00 00 00 00 52 0A 00 7B 34 34 34 77 2F 2F 2F 1A - ....R..{444w///.
0200 - 1A 00 00 11 22 05 02 00 00 05 02 00 00 06 03 01 - ...."...........
0210 - 00 06 04 02 01 0A 0B 0B 0C 0A 0B 0B 0C 09 0A 0B - ................
0220 - 0B 09 0A 0B 0B 52 49 54 45 4B 20 4D 30 32 00 00 - .....RITEK.M02..
0230 - 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 - ................
0240 - 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 - ................
0250 - 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 - ................
0260 - 00 00 00 00 00 01 01 82 00 74 33 33 82 7E 7F 00 - .........t33.~..

But now the interesting part - writing and reading DVD-RAM media.

Panasonic DVD-RAM 5x without verification

Panasonic DVD-RAM 5x with verification

Traxdata DVD-RAM 3x without verification

Traxdata DVD-RAM 3x with verification

For those not familiar with DVD-RAM, you might think that something went wrong during the write process, when the verification option is turned on - since the 5x media was written at approximately 2.04x and the 3x media written at approximately 1.28x. But do not worry - that is pretty normal for DVD-RAM discs, the reason for the 'low" speed is - the drive constantly reads back the data after writing it to verify that it's written correctly. We can also call it a 'bullet proof" writing/verify technique - with no data loss/errors.

Another advantage with DVD-RAM is that the discs can be formatted/erased/written at over 100.000 times before it will/can cause/report any errors. Let's try to read back the discs that we wrote:

Panasonic DVD-RAM 5x

Traxdata DVD-RAM 3x 

As we can see from the pictures above, all media was read back at 5x using the CLV technique.

To round off this section we have included two quality scans:

Verbatim DVD-RAM 5x

Traxdata DVD-RAM 3x