Date: Tue, 9 Jan 1996 08:16:07 +0100 (MET) From: J Wunsch <j@uriah.heep.sax.de> To: freebsd-scsi@FreeBSD.org Subject: Re: Good News :) Message-ID: <199601090716.IAA09073@uriah.heep.sax.de> In-Reply-To: <199601090144.UAA24177@hda.com> from "Peter Dufault" at Jan 8, 96 08:44:14 pm
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As Peter Dufault wrote: > > > I've burnt my first CD today! > > > > Well, i sorta mis-burnt two of them, but the first step has been done. > > Details on the tools you used, please. And did you do it single > user or multi user? This was just the proof-of-concept stage. The tools were scsi(8) (actually, a bunch of them -- thanks, Peter!) and team(1), wrapped together by a Perl script. Using dd(1), the burner starved immediately. With team(1), it looks better. You can run enough processes pre-reading data from the disk, thus caching it in memory. This was running in ``slight multi- user'' mode, i.e. multi-user stage with just a single user logged in, no X11, no heavy background tasks. I forgot to raise the process into rtprio, however. While the first attempt went through but rendered me with an unusable disk since i've totally misunderstood team's man page, the second one starved after burning about 50 MB. The CD is mountable, the directory structure is intact, but it experiences lotta errors when reading most of the files. Anyway, the ~ 50 MB are way more than the machine has RAM, so it's still proving that it can be made work. Burner and source disk are on different SCSI busses, but i'm not sure if this is really necessary. It's just the configuration of that machine (one bus for the dis[s], another one for the slow peripheral devices). The bad news is, manufacturers of CD burners disagree about the command set. My experiment ran with a ``Plasmon Data RF4100'', and with some minor hassles (downloading from an US BBS via transatlantic phone lines, ick) i could get their SCSI manual. Judging from Linux' cdwrite, most burners seem to be only slightly different in the command handling, with the major exception of Yamaha. They do just everything different. So when stuffing all the invocations of scsi(8) back into the kernel, i'm thinking of an lkm-based interface, where the actual CD-R handler must be plugged in as a loadable module. Who is interested in dicussing further issues of the concept (once i've got further)? Should i do this in this list? -- cheers, J"org joerg_wunsch@uriah.heep.sax.de -- http://www.sax.de/~joerg/ -- NIC: JW11-RIPE Never trust an operating system you don't have sources for. ;-)
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