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[Libcdio-devel] Re: Submission of new mmc function for libcdio

From: Thomas Schmitt
Subject: [Libcdio-devel] Re: Submission of new mmc function for libcdio
Date: Sun, 31 Jan 2010 19:39:08 +0100


> Are the states:
>    1. writing from scratch (blank)
>    2. overwritable (but not necessarily blank)
>    3. erased (and now blank) but not known new media
> distinguishable using MMC

I don't know about a method to distinguish 1
and 3.
Number 2 is distinguishable by profile number
and probably by Disc Status of READ DISC
INFORMATION as proposed by Frank.

The decision to declare them blank is due to
libburn traditions with CD. I would advise to
distinguish them from really blank media in

Especially because these media can be used on
Linux and FreeBSD without any special burn
program. Just open device file, use lseek,
read and write as normal.

> Also, although I can see why libburn may find it useful to combine drive and
> media status here, I'm not sure it would be advisable from the standpoint of
> a developing general library.

A strict distinction between drive and media
might be not really comprehensive.
The state BURN_DISC_EMPTY (= no media loaded) is
quite a hybrid of drive and media property.
Nevertheless i would include it in a list of
media states.
BURN_DISC_UNSUITABLE can happen e.g. if you put
a blank CD-R into a DVD-ROM drive. The drive
might tell you profile 0x0000 and not more.
The media is not to blame. But not usable either.

Most of MMC exposes the drive as a thing that
has current features and a current profile.
One has to dig quite deep to get to real media
info like the DVD Book type or the Blu-ray
Disk Type Identifier.
(READ DISC STRUCTURE Format Code 0 delivers
different formats for DVD and BD.
MMC-5, for DVD, for BD)

Have a nice day :)


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