detail information

The NEC ND-7551A 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:

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 - ................

0030 - 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 - ................

0040 - 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 - ................

0050 - 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 - ................

0060 - 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 - ................

0070 - 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 - ................

0080 - 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 - ................

0090 - 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 - ................

00A0 - 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 - ................

00B0 - 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 - ................

00C0 - 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 - ................

00D0 - 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 - ................

00E0 - 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 - ................

00F0 - 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 - ................

0100 - 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 - ................

0110 - 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 - ................

0120 - 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 - ................

0130 - 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 - ................

0140 - 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 - ................

0150 - 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 - ................

0160 - 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 - ................

0170 - 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 - ................

0180 - 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 - ................

0190 - 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 - ................

01A0 - 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 - ................

01B0 - 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 - ................

01C0 - 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 - ................

01D0 - 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 - ................

01E0 - 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 - ................

01F0 - 00 00 00 00 52 0A 00 71 2C 2C 2C 6E 2A 2A 2A 1A - ....R..q,,,n***.

0200 - 1A 00 00 11 22 05 02 81 81 05 02 81 81 06 03 00 - ...."...........

0210 - 81 06 03 00 00 0A 0B 0C 0C 0A 0B 0C 0C 09 0A 0B - ................

0220 - 0B 09 0A 0B 0B 4D 61 74 73 75 73 68 69 74 61 20 - .....Matsushita.

0230 - 45 6C 65 63 74 72 69 63 20 49 6E 64 75 73 74 72 - Electric.Industr

0240 - 69 61 6C 20 43 4F 2E 2C 4C 54 44 2E 0D 20 20 20 - ial.CO.,LTD.....

0250 - 20 20 20 20 20 4D 30 31 4A 33 30 30 32 0D 20 20 - .....M01J3002...

0260 - 20 20 20 20 20 01 01 82 00 6A 2C 2C 2C 82 94 96 - .........j,,,...

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

Verbatim DVD-RAM 3x without verification

Let’s try to read back the discs that we wrote:

Verbatim DVD-RAM 3x

As we can see from the picture above, the media was read back at 5x using the Z-CLV technique.

Since we have no equipment to perform any quality measuring tests with the DVD-RAM format it will be skipped, but on the other side it should not be necessary since any DVD-RAM writer shall verify the written data by default itself.

On the next page we will take a look at the test drive’s Labelflash performance.

DVD+R DL/-R DL Writing performance

Labelflash