Date: Fri, 15 Mar 2002 19:02:26 -0700 From: Scott Long <scott_long@btc.adaptec.com> To: Chris Dillon <cdillon@wolves.k12.mo.us> Cc: freebsd-scsi@freebsd.org, freebsd-fs@freebsd.org Subject: Re: CD-MRW a.k.a Mt. Rainier support Message-ID: <20020316020226.GA12097@bunsenhoneydew.btc.adaptec.com> In-Reply-To: <Pine.BSF.4.32.0203131116220.31162-100000@mail.wolves.k12.mo.us> References: <Pine.BSF.4.32.0203131116220.31162-100000@mail.wolves.k12.mo.us>
next in thread | previous in thread | raw e-mail | index | archive | help
On Wed, Mar 13, 2002 at 11:59:06AM -0600, Chris Dillon wrote: > > CC'd to freebsd-fs since this is somewhat fs-related... > > Is anyone working on implementing support for CD-MRW (apparently > included in MMC-3) into either the SCSI cd driver or the ATAPI cd > driver? Where/how would be the best place to implement this so that > it will work with either ATAPI or SCSI drives? Would implementing it > in the SCSI cd driver be best, since we now have the option of using > ATAPI drives with CAM? > > In case anyone is wondering what CD-MRW (Mt. Rainier Re-Writable) is, > it is a new standard (currently only available in the Yamaha CRW3200 > series, that I know of), that allows on-the-fly transparent > formatting, hardware defect management, and 2K-block logical > addressing of CD-RW discs and specifies a specialized UDF filesystem > to be used along with these hardware abilities. This will make drives > supporting this standard act like a more traditional magnetic-media > removable drive, thus greatly simplifying reading/writing to CD-RW > discs. Since MRW uses a new format it is not backwards compatible > with any existing CD-RW formats, though it is possible to _read_ a MRW > formatted disc in a regular drive with the proper software support. > MRW uses UDF as its standard filesystem, which we do not yet support, > though I envision using the hardware MRW support of the drive to put > just about anything you want onto it, including FAT or UFS, to use it > as a "regular" drive. > > I'd love to take a shot at implementing this if someone isn't already, > though I'll need to find the specs for the hardware side of Mt. > Rainier. Apprently it is implemented in the new MMC-3 command set. > Anyone have any pointers? This drive sounds very interesting. Unfortunaley, until the standard becomes ubiquitous, any UDF implementation will still need to understand read-modify-write and sparing tables. UDF is the natural format for it since with removable media you want inter-changability with other systems, but there should be nothing stopping you from putting UFS on it too. I've already started a UDF implementation for FreeBSD. Patches for 5.0-CURRENT can be found at http://people.freebsd.org/~scottl, along with a link for slightly older -STABLE patches. The current status is that CD-RWs and DVD-ROMs can be read (though Sparing Tables are still missing for CD-RW), and once I've cleaned up and filled in the code some more, I intend for it to go into 5.0-RELEASE. I'd welcome any help on the project, escpecially if someone wants to tackle the writing support. Scott To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-scsi" in the body of the message
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?20020316020226.GA12097>