Talk:ATAPI
Shouldn't most of the second half be in an SCSI page ?
I am the developer of libburn, which operates CD, DVD, and BD drives via SCSI commands (SPC, SBC, MMC).
I wonder why no http://wiki.osdev.org/SCSI or ./MMC exists. It could consolidate the info about the commands to be used on optical drives attached via "real SCSI", PATA, SATA, USB, ...
OS developers who want to enable porting of CD/DVD/BD burn programs need to offer an SCSI passthrough interface. This interface has to transmit SCSI command descriptor blocks and payload data to the drive. Then it has to return payload data and/or indicate that there emerged sense data (usually error conditions). An example is Linux ioctl SG_IO.
The SCSI gestures of writing to optical media are described in http://www.libburnia-project.org/browser/libburn/trunk/doc/cookbook.txt Interesting for those OS developers who want to integrate optical burning into the OS itself.
BTW: The last four of the external links should rather go to http://wiki.osdev.org/ISO_9660
Scdbackup 15:12, 15 October 2013 (CDT)
- I have created a new article Optical Drive which gives an MMC
- oriented overview of handling such drives.
- There would still be missing an article between ATAPI and Optical Drive
- which takes most of the SCSI related stuff from ATAPI, and from Optical Drive
- the sections before Optical_Drive#Readable_Disc_Content.
- But i myself have only experience with optical drives. The SCSI article
- would also have to refer to tapes and hard disks.
- Scdbackup 07:35, 19 October 2013 (CDT)
The page says:
An AudioCD (CD-DA) stores data in a Joliet filesystem.
This is plain wrong. The only filesystem-like structure on CD-DA is the two-level hierarchy of sessions and tracks. CD-DA blocks cannot be read by the usual SCSI command READ, but rather by SCSI command READ CD. They bear 2352 bytes of audio data each.
Joliet is a Microsoft extension to ISO 9660 filesystems. (One may of course store audio files in a filesystem. But that is not CD Digital Audio.)
Messed up too:
A data CDROM stores data in an ISO 9660 filesystem. A DVD may store data in a UDF or RockRidge filesystem.
Rock Ridge is the POSIX-enabling extension of ISO 9660 filesystems. Data CD, DVD, and BD (Blu-ray) can store any kind of data in blocks of 2048 bytes each. ISO 9660 is widely readable. Joliet and Rock Ridge enhance it for MS-Windows and Unix.
UDF (based on ECMA-167) is intended as successor of ISO 9660 (ECMA-119). But except by the specs for video entertainment on DVD and Blu-ray, there is not much sincere use of it.
Scdbackup 15:31, 15 October 2013 (CDT)
- The problematic statements are now replaced by a short overview of
- the session-track structure and a link to Optical Drive
- Scdbackup 07:37, 19 October 2013 (CDT)