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Progress w/ UDF Filesystem Support in 2.4.0?

Posted by Cliff on from the how-far-have-we-come-and-how-far-do-we-need-to-go dept.

LionMage asks: "I know Slashdot covered this a long time ago, but we have a new kernel now, and other things have changed as well. I followed the evolution of the experimental UDF drivers back in the 2.2.x series of Linux kernels, and Ben Fennema seemed to have both read and write support working. He claimed to be able to write to a CD-RW in UDF format, and I tried his drivers with my DVD-RAM drive with some measure of success. Recently, I installed SuSE Linux 7.1 on my machine, and discovered that the DVD-RAM drive was detected as two different devices, a CD-ROM drive and a "CD writer." OK, well, we'll forgive that little transgression. What's interesting is that inserting a DVD-RAM cartridge with data on it will in fact yield positive results when mounted. So clearly, the 2.4.0 kernel has some UDF support in it. (Unless this is a case where SuSE threw in support on a whim.) But I can only mount UDF volumes read-only. What's the point of a DVD-RAM drive under Linux if you can't write to it? A visit to Ben's page showed that little progress has been made recently, and there are no patches for the 2.4 series kernels. Can anyone comment on UDF support in the current Linux kernel, and how it's progressing? Alternately, are there perhaps some other drivers I'm unaware of which allow write support?"

2 of 8 comments (clear)

  1. Packet writing by TheMutantPenguin · · Score: 3
    UDF write support is available as an option in the kernel (EXPERIMENTAL and DANGEROUS) if you had noticed that you can compile kernels yourself also.

    What's really needed for UDF CD-RW and DVD-RAM write support is packet writing. That allows you to write data to the disk in little packets instead of a big stream, so you can write files at a time. Problem is, it's not in the kernel yet; Jens Axboe has a relatively old patch for a 2.4.0-test kernel that I gave up trying to apply to even 2.4.0. When fully implemented, packet writing will allow you to mount -w /dev/cdroms/cdrom0 (or the equivalent packet device if it is implemented using a separate device) /cdrom and then work with files on the CD-RW just like normal files -- with reading and writing. Fun? Go yell at people and it'll get implemented.

  2. Why you got a CDROM and CDR for the same device by Nailer · · Score: 2

    You have an ATAPI IDE CDROM writer. ATAPI uses a SCSI like command set over an IDE bus.

    The `CD ROM' is /dev/hdx, the IDE device for your CD writer

    The `CD writer' is /dev/scdx, the SCSI device for your writer.

    UDF and DVD ioctl support is is Linux 2.2.16 or 2.40 or newer. There's some serious bugs in 2.4.1 which mean you`ll want to avoid that particular version.

    Since iso9660 bears a similarity to UDF, you can actually mount many DVDs using this driver, but they'll fail when ISO9660 does - after 2 gig.