Re: [PATCH] growisofs error and dvd+rw-format manual page

["Thomas Schmitt" <scdbackup@gmx.net>]

Hi,

not being in charge for dvd+rw-tools i am curious enough to read
and comment on the proposed man page.

Honza Horak wrote:
> If  a  DVD-RW medium is in the later one,

Shouldn't that be "latter" rather than "later" here ?


> a non-virgin DVD-RW in Sequential Recording
> mode needs to be blanked before writing a new initial session

One should stress that only -blank=full makes a used sequential DVD-RW
capable of performing multi-session. Fast blanked DVD-RW can only do
Disk-At-Once. (Some drives confess the inability, some do not. None can.)

Full blanking lasts as long as full writing.
So formatting DVD-RW is very desirable for multi-session use cases.


> Virgin BD and DVD+RW media  need  to  be  initally  formatted  prior
> usage.

"initially" rather than "initally".

One should replace "need" by something like "may".

DVD+RW get formatted by growisofs as needed when a burn run is desired.
(I once tested that when i had no own stake in operating optical drives.)

BD-R media may get formatted when they are still empty.
I understand growisofs 7.1 does this automatically and unconditionally
when a burn run is desired. (This is not always a good idea, though.)
growisofs_mmc.cpp:
        case 0x41:      // BD-R SRM
            if ((disc_info[2]&3) == 0)  // blank
                bd_r_format (cmd);

I also understand that BD-RE get formatted automatically:
        case 0x43:      // BR-RE 
            if ((disc_info[2]&3) == 0)  // blank
                bd_re_format (cmd);

I think the main use cases for dvd+rw-format are:
- Formatting DVD-RW to make them overwritable
- Blanking used DVD-RW to make them sequentially writable from scratch
- Formatting BD-R, BD-RE, and DVD-RAM with custom spare area sizes
- Re-Formatting BD-RE and DVD-RAM to change their spare size


> Use -blank=full to change

This sentence looks incomplete.


> Under Linux it will most likely be an ide-scsi device  such as "/dev/scd0."

Cough. ide-scsi is dead since kernel 2.6 came out.
Further it seems that "sr0" has finally won the battle against "scd0".

Maybe one should mention /dev/hda for older Linux 2.6 with IDE/ATAPI
and /dev/sr0 for newer Linux or SATA or USB. (Have there ever been
DVD drives with SCSI bus interface ?)

Overview of drives with suffienct access permissions:
  xorriso -devices
or
  cdrskin --devices


>        To blank a CD-RW, you have to use another utility, e.g. wodim:
> wodim blank=all -immed dev=/dev/cdrom

Blanking CD-RW in "all" mode lasts long and is not necessary for the
purpose of re-usability. It might serve privacy and it might revive
media which were spoiled by a bad drive.
Normally one uses "fast".

I could offer
  xorriso -outdev /dev/cdrom -blank all|fast|as_needed
or
  cdrskin blank=all|fast|as_needed -immed dev=/dev/cdrom

"as_needed" is a wizzard-ish mode which decides by itself what must
be done to get a medium which can be written from scratch.


>        To blank a BD or DVD+RW, run:

One should mention that this is not blanking but simply overwriting
old data to make them (nearly) unreadable.

(The command also applies to formatted DVD-RW and to DVD-RAM.)


Now i am curious whether Andy Polyakov is still around.


Have a nice day :)

Thomas