I was looking at DVD-RAM properties in ImgBurn (Windows),
and noticed there is ~120MB reserved space, which are spares.
SCSI MMC-2 shows a spare area in each of 24 zones.
SCSI MMC-4 has information in section 6.27.2.11 on primary and supplementary spares.
BACKGROUND INFO: DVD-RAM has spare areas used for defect management. This is done by the drive
itself, so there's no way around it. As far as the OS is concerned, a DVD-RAM is exactly like a
hard drive. Any bad sectors are remapped automatically and the OS never knows about them. The
Primary Spare Area (PSA) is always 26 MB and is at the beginning of the media. The Secondary Spare
Area (SSA) is variable-size and is at the end of the media. By default, it's about 100 MB. But the
cool part is, if you think the PSA is enough, you can reformat a DVD-RAM to eliminate the secondary
spare area. To do this:
3. Once you have the media, you want to do a low-level format. To do this, run ImgBurn, and open up
Tools > Settings > Write. Check the box next to "Prefer Format Without Spare Areas." This sets
ImgBurn to format without a SSA if possible. Then do a full erase. (It calls it a full erase, but
it's actually sending the FORMAT UNIT command to the drive.) After you do this, eject and re-insert
the disc so that Vista recognizes the extra space.
Eric Gisin wrote:
>
> I was looking at DVD-RAM properties in ImgBurn (Windows),
> and noticed there is ~120MB reserved space, which are spares.
> SCSI MMC-2 shows a spare area in each of 24 zones.
> SCSI MMC-4 has information in section 6.27.2.11 on primary and supplementary spares.
>
> I found more useful info here: http://www.sharkyforums.com/showthread.php?t=308269
Hello, Eric:
That's a pretty old article, dating to February of 2001; personally, I didn't
buy my first DVD burner (Panasonic SW-9571, an OEM model with DVD-RAM support),
until June, 2003.
> BACKGROUND INFO: DVD-RAM has spare areas used for defect management. This is done by the drive
> itself, so there's no way around it. As far as the OS is concerned, a DVD-RAM is exactly like a
> hard drive. Any bad sectors are remapped automatically and the OS never knows about them. The
> Primary Spare Area (PSA) is always 26 MB and is at the beginning of the media. The Secondary Spare
> Area (SSA) is variable-size and is at the end of the media. By default, it's about 100 MB. But the
> cool part is, if you think the PSA is enough, you can reformat a DVD-RAM to eliminate the secondary
> spare area. To do this:
>
> 3. Once you have the media, you want to do a low-level format. To do this, run ImgBurn, and open up
> Tools > Settings > Write. Check the box next to "Prefer Format Without Spare Areas." This sets
> ImgBurn to format without a SSA if possible. Then do a full erase. (It calls it a full erase, but
> it's actually sending the FORMAT UNIT command to the drive.) After you do this, eject and re-insert
> the disc so that Vista recognizes the extra space.
>
> = ImgBurn Disc Info (factory formatted) =
>
> Preferred Format Capacity:
> Sectors: 2,236,704
> Size: 4,580,769,792 bytes
> Time: 497:04:54 (MM:SS:FF)
>
> Maximum Format Capacity:
> Sectors: 2,295,072
> Size: 4,700,307,456 bytes
> Time: 510:02:72 (MM:SS:FF)
It just doesn't seem worth the risk, merely to gain an extra 100MB of disc
capacity!
Previously John Turco <jtur@concentric.net> wrote:
> Eric Gisin wrote:
>>
>> I was looking at DVD-RAM properties in ImgBurn (Windows),
>> and noticed there is ~120MB reserved space, which are spares.
>> SCSI MMC-2 shows a spare area in each of 24 zones.
>> SCSI MMC-4 has information in section 6.27.2.11 on primary and supplementary spares.
>>
>> I found more useful info here: http://www.sharkyforums.com/showthread.php?t=308269
> Hello, Eric:
> That's a pretty old article, dating to February of 2001; personally, I didn't
> buy my first DVD burner (Panasonic SW-9571, an OEM model with DVD-RAM support),
> until June, 2003.
>
>> BACKGROUND INFO: DVD-RAM has spare areas used for defect management. This is done by the drive
>> itself, so there's no way around it. As far as the OS is concerned, a DVD-RAM is exactly like a
>> hard drive. Any bad sectors are remapped automatically and the OS never knows about them. The
>> Primary Spare Area (PSA) is always 26 MB and is at the beginning of the media. The Secondary Spare
>> Area (SSA) is variable-size and is at the end of the media. By default, it's about 100 MB. But the
>> cool part is, if you think the PSA is enough, you can reformat a DVD-RAM to eliminate the secondary
>> spare area. To do this:
>>
>> 3. Once you have the media, you want to do a low-level format. To do this, run ImgBurn, and open up
>> Tools > Settings > Write. Check the box next to "Prefer Format Without Spare Areas." This sets
>> ImgBurn to format without a SSA if possible. Then do a full erase. (It calls it a full erase, but
>> it's actually sending the FORMAT UNIT command to the drive.) After you do this, eject and re-insert
>> the disc so that Vista recognizes the extra space.
>>
>> = ImgBurn Disc Info (factory formatted) =
>>
>> Preferred Format Capacity:
>> Sectors: 2,236,704
>> Size: 4,580,769,792 bytes
>> Time: 497:04:54 (MM:SS:FF)
>>
>> Maximum Format Capacity:
>> Sectors: 2,295,072
>> Size: 4,700,307,456 bytes
>> Time: 510:02:72 (MM:SS:FF)
> It just doesn't seem worth the risk, merely to gain an extra 100MB of disc
> capacity!
It is not really a risk, as you will get a write error, when it
runs out of spares (I think I have already seen that on some very
bad Verbatim disks with a not to good either Lite On writer).
reserved spares on DVD-RAM 
Linear Mode
