Messages in this thread | | | Date | Wed, 8 Mar 2006 14:52:07 +0100 (MET) | From | Jan Engelhardt <> | Subject | Re: [slightly OT] dvdrecord 0.3.1 -- and yes, dev=/dev/cdrom works ;) |
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>>>> Yes. A 650 MB *CD*-RW (DVD-RW too?) formatted in packet mode only has like >>>> 500-something megabytes to allow for the sort of seeks required. On >>>> DVD+RW, you get the full 4.3 GB (4.7 gB) AFAICS. >>>> >>> DVD-RAM physically is formatted like a hard disk. It is broken up into >>> zones that hold different numbers of sectors which are individually and >>> randomly read/writable. CD/DVD+-RW media is organized as a single long >>> groove that consists of an unbroken series of large blocks composed of >>> small blocks with user and control data interleaved and error corrected. >>> It is for this reason that historically it could only be recorded from >>> start to finish in one pass. >>> >>> There are two modern techniques to allow pseudo random write access for all >>> forms of CD/DVD +/- RW media. These are packet mode, and mount rainier >>> mode. MRW mode formats the disk into 32 KB blocks made up of 2048 byte >>> sectors which are individually writable as far as the OS knows, because an >>> MRW compliant drive is required to internally handle any required >>> read/modify/write cycles to update the 32 KB blocks. MRW mode also >>> reserves some of the disk for sector sparing which the drive firmware also >>> handles. MRW mode is typically used on dvd+rw media. IIRC, this format >>> typically "wastes" about 10% of the capacity of the medium. >>> >> I doubt that. 10% of a 4.3 GB disk are, well, roughly 430 MB, which would >> make df show 3.9 GB as mountpoint size, not 4.3 GB. [MB and GB are powers of >> 1024 here.] >> > Was that DVD recorded MtR or packet? > Hm. I'd say `cdrecord ... -format` (whatever that does), if required. Otherwise just write to it (mkfs/etc.).
Jan Engelhardt -- - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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