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Linux Software

What's the Best Way to Build a Linux CD-Rom JukeBox 15

An Anonymous Coward asks: "Picture this: a mega SCSI based server box with a bunch of cd-rom drives. What's the best way to build this beast so that it can serve iso-9660 and hfs CDs to smb/cifs, nfs and appletalk clients? Is there any particular way to deal with SCSI IDs and LUNs? Is there an easy way to improve request performance by caching on disk or RAM?" Hey...sounds like an interesting topic!
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What's the Best Way to Build a Linux CD-Rom JukeBox

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  • HD space is really cheap now in comparison. Just copy the CD to the HD and serve it up from there. I guess this only doesn't apply when you're changing CD's all the time, but if you're talking about an office jukebox type system then I'd just do away with the CD's altogether.
    --
  • There used to be a neat cd-rom server package called 'cdfile' available from http://www.psocd.com (or www.pso.fr) which would cache files etc so that you could use the cheap cd changers (I have a Nakamichi 7 disc) unfortunately it was priced at like $50/disc so it was out of my price range for personal use, and the domain doesn't seem to exist any more.

    If you want lots and lots of cds you might need to use devfs if you run out of devices. Hardware to look at if you're rolling your own would be the Mylex BT-930 which is a cheap dual channel ultra narrow controller, or maybe the Diamond Dual Fireport 40 if you can find them. You can also find preassembled cd towers which translate the scsi ids to LUNs so you get more mileage out of your scsi cards. www.corpsys.com usually sells this sort of stuff, although you pay for it.
  • I'm trying to do something along these lines with
    3 or 4 double-speed panasonic cd drives that i've managed to get. i was thinking of using mars_nwe to enable the CDs to be mounted from my win98 clients. Any other ideas?
  • Well, because my current Win98 system is broken for the MS Networking client :)

    Also we have NetWare servers where I work, and actually getting to set up the server and clients myself should give me some good insight.

  • How do Macs deal with having the information copied to a hard drive? Esp. an HFS cd to a linux ext2 partition, then being shared via netatalk?
  • I've got a demo unit sitting on top of my machine right now. It's tiny, has a built in hard drive, and is actually a tiny linux/samba machine!

    It's a tiny computer with a scsi interface that will run cds, dvds, cdr, and scsi hard drives. It'll cache images of cds or dvds to disc and serve them up with samba (or novell, or mac, or whatever). It's administered through a web interface, and is a pretty slick little number. Looks cool, too.

    One version is an external unit with a built in hard drive, and external scsi connector. Another is a smaller external device with no hard drive and just the scsi. Yet another is an internal unit (to put into a drive tower) with both the scsi and 2 ide channels. So, you could build a 7 bay cd tower with it. But instead of 7 cdrom drives, put the Zerver in the top slot, then a cdrom, then a cdr drive, then a dvd drive. Then polish it off with 3 nice, fat scsi drives. (figure about 4GB for 7 cds or so, to be safe.)

    Nifty little thing. The ones without hard drives cost about $750-800. After trying it out, we're going to get two of them. (We already have the cd towers, so it's the best thing for us, anyway.)

    Or build your own linux box and do the same thing with it. Cache images of cds to disk and serve them up with samba. I kinda like this cute blue box that does exactly that out of the box by itself. (And is smaller than my phone!)

    Found it at http://www.microtest.com

    No, I don't work for them or anything. It looked like a good idea, and they had a 30 day free trial. So I tried it out, and it works great. (Sending it back is REALLY going to suck.)
  • We are running a 56 CD Tower from Meridian [meridian-data.com], and a smaller 14 drive one from them.
    They came with some crappy Novell emulation type software, we finally got annoyed enough and went Linux.. The hardware is kind of expensive, but rock solid and cool looking on the server racks :> Lots of blinky lights when the drives are being accessed. We have had the smaller tower since end of 94(was not running Linux till last year) and it have not had any hardware failures..(KNOCK ON WOOD!!)
    The bigger tower has a pentium 166, 64 meg of ram and a 1.6 gig HD, the other has a 486sx25, but I was having a problem with IDE controllers on the 486 so I had to bastardize an old P100 with 16 meg of ram and use that for a controller for the CD drives.
    The 166 runs great off of its internal mboard. The smaller tower has 2 Adaptec 1542 scsi cards, the big one has 2 Adaptec 7870's.. the LUNS were all handled by the OS w/o any hitches at all.. If I remember correctly I did have to manually create the /dev devices for some of the higher # drives using mknod.
    Anyways all the CD's are mounted, then exported via Samba(would be just as easy with Appletalk and/or NFS) and users are authenticated via our NT Domain.. we went from 2 to 3 CD lockups a day that had to be manually reset to zero downtime other than to swap CD's when new ones arrived...... CD's in the tower are only quad speeds, but performs great from the far side of our network.. seems like it is your local CD drive... no problems running AVI's and stuff across a couple of 10 meg routers.
    One note on performance... 16 meg does not seem to be a problem on the smaller tower. It dips into its 20 meg swap file occasionally, but I have not noticed any performance problems..maybe someday I should slap some more memory in it if I think of it. There are a couple of caching options you can set to really improve Samba performance on Static file systems.. one is setting get wide cache, and there is another one I can't think of right now but can look up if you are interested... they do seem to make quite a diff. on previously accessed CD's.
    Anyways upshot of all this typing is that they really rock under Linux... saved us a bundle over trying to buy the companies "new improved" NT or Novell based access solutions...
  • There was a writeup in the Linux Gazette on this a few months ago; you can find it at http://www.linuxgazette.com/issue34/jachim.html [linuxgazette.com]. They basically added a secondary IDE controller to a normal Linux PC, for a total of 4 ide channels, and filled all the spare IDE units with CDRom drives for a total of 7 cdroms and whatever fit on the boot drive served. The biggest trick was probably finding a large enough case, but we're all getting good at that by now, right? By combining this approach with the first one suggested (copying CD contents to a big honkin IDE hard drive) you could get an extremely large amount of storage on line for very little money. And yes, Virginia, performance under heavy load would suck, and no you would not want to do something silly like this with your main mail, home directory, or SQL server; with a reasonable amount of traffic the machine's usefulness for other tasks would become extremely limited due to the amount of interrupt activity generated by those 4 IDE channels. However, it would be one very cost effective way to get a large amount of data dependably available and on-line.

    $.02
  • You would be suprised by how much you could fit on a +9Gig harddrive.. I have a server that serves several CD's worth of information just off one 9 gig ide drive.
    if you have the money for it SCSI drives would give you better performance.
    Using a disk you don't have to wait for the cdrom's to spin up when you request information, because it's already 'cached' on the disks.
    anyway, that's my $0.02
  • Recently I visited a "Computer Wrecker" who had a lovely "toy" a 250 disc SCSI CD stacker... now that would make a nice jukebox hey?... they retail for A$20,000 but i'm sure i'll be lucky enough to pick it up for a few hundred... I just have to find somewhere to put it...
    Thats my 5cents worth

"When the going gets tough, the tough get empirical." -- Jon Carroll

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