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[Discuss] Fedora 28 Doesn't See External DVD Drive on USB Port
- Subject: [Discuss] Fedora 28 Doesn't See External DVD Drive on USB Port
- From: cra at wpi.edu (Anderson, Charles R)
- Date: Sun, 30 Dec 2018 04:58:35 +0000
- In-reply-to: <7c902faf-5ea7-a1d3-430c-c53dfbd272a3@thekramers.net>
- References: <CAPnB49Enbzd6hQHonQRNEOpFjjOP_BdBuDkzBzMC=AWC7C5d8Q@mail.gmail.com> <20181230001241.paq2dcc6ye7ymdfd@randomstring.org> <CAPnB49EJxGxR4HpTXWAO6srrFiDe5EThcP+c2hknBofKS7bqdg@mail.gmail.com> <7c902faf-5ea7-a1d3-430c-c53dfbd272a3@thekramers.net>
I'll also point out that CD/DVD devices are usually named /dev/sr0 /dev/sr1 etc. where the "sr" stands for "SCSI ROM" and the numbers 0, 1, etc. are not partitions, but actual different physical drives. Older systems may use /dev/scd0, /dev/scd1, etc. So in my request for output, you should also post this: dmesg | grep 'sr[0-9]' On Sat, Dec 29, 2018 at 11:51:24PM -0500, David Kramer wrote: > I doubt the solution to that other person's problem is the same one you > are having, but it's possible.? Let me explain it in more detail, > because it actually has nothing to do with external DVD drives > specifically, which is muddying the waters. > > These days, most storage devices emulate the old SCSI (Small Computer > System Interface) standard at the API level. That is, the hardware is > different, but the commands that an OS or BIOS would send to an old SCSI > drive.? That's why the devices are named /dev/sda, dev/sdb, etc.? The > devices are named in order as they are discovered, so the main drive is > /dev/sda, and if you have a second disk it would be /dev/sdb. > > Partitions are named by appending the partition number to the device > they are on.? The first partition on the first device is /dev/sda1, and > the second partition would be /dev/sda2. > > Let's say you plug in a thumb drive after that.? That would be the third > disk, so it would be /dev/sdc.?? If you then plugged in your external > DVD drive, it would probably be /dev/sdd.? That all works pretty well. > > Here's the problem: Let's say you have some configuration file, whatever > it is, that refers to a disk, because you have a second hard drive in > your computer.? let's call it /dev/sdb.? Now let's say you plug in your > external DVD player and it comes up as /dev/sdc, and all is right with > the world. > > BUT: If you remove that second drive from your computer and there is no > longer a /dev/sdb, and you do not update that configuration file, then > when you add your external DVD player, it will come up as /dev/sdb > instead.? That configuration file is telling your computer that /dev/sdb > is something else.? And there we have the problem. > > Now this file in particular, /etc/fstab (and you need to use sudo to > edit it) tells the computer what each drive is for and how to mount it > and to where.? It is a BAD file to have incorrect information in for > that reason, and that is the problem described in your mail.? I doubt > that's your problem, but if you send us the contents of that file, we > may be able to confirm. > > Some good news: There IS a better way. Partitions can also be identified > by user-specified labels, and that eliminates the whole > who-got-connected-first problem. It also lets you set up rules, like > automatically mounting THIS particular external USB device, but not this > other one. > > Hope that helps. > > > On 12/29/18 10:12 PM, Nancy Allison wrote: > > Thank you, Dan. > > > > You've provided some details that I can follow, but I am not well enough > > grounded to know how I would use them. (For example, I have no idea where > > fstab lives or how I get to it.) If I can find someone to help me out > > painstakingly, with a generous donation of their time and effort, I (they, > > really) can undoubtedly fix the problem. I may wait until the next > > InstallFest for help. > > > > But this leaves me wondering, can it really be that everyone using Fedora > > 28 struggles along with this same problem that obviously affects plenty of > > people? CDs and DVDs are not used as much as they once were, but they are > > still in use. If you google "fedora 28 doesn't recognize external dvd > > drive" you get people struggling with this back in 2010 and 2011. Is this > > what Fedora is like -- everyone struggles with problems individually? And > > you really have to have a lot of technical knowledge to deal with these > > problems as they come up. Maybe Fedora is just too tecchie for me, but it > > seems as if Ubuntu was, too, when I used it before Fedora. Maybe Red Hat is > > easier for a non-technical person to handle? > > > > Just thinking out loud. Thanks for the additional info. > > > > On Sat, Dec 29, 2018 at 7:12 PM Dan Ritter <dsr at randomstring.org> wrote: > > > >> Nancy Allison wrote: > >>> Hi, all. > >>> > >>> When I plug in my external disk drive into my Fedora 28 machine, it does > >>> not show up in Nautilus. > >>> > >>> I go looking online, and, sure enough, this problem has occurred for > >> plenty > >>> of people for 5+ years over many releases of Fedora. > >>> > >>> I find a discussion in which someone evidently solved the problem. Here > >> is > >>> what the person reported: > >>> > >>> "NVM - found the cause. Old entry in fstab for a second swap not present > >> on > >>> sdb1 and first USB disks being assigned sdb. Cleaned that up and now all > >>> drives plugging correctly. > >>> Willtech ( Sep 23 '18 )" > >>> > >>> How do I apply this information? Where is fstab? When does a first swap > >>> occur? When does a second swap occur? What does it mean to be assigned > >> sdb? > >> > >> /etc/fstab consolidates mounting information. > >> > >> Each active line defines: > >> > >> <file system> <mount point> <type> <options> <dump> <pass> > >> > >> For example: > >> > >> /dev/scd0 /media/cdrom0 ISO9660 ro 1 1 > >> > >> device/partition name, then where you want it mounted, then the > >> type of filesystem. > >> > >> If you have a single disk called /dev/sda, for instance, you > >> might see your external CD show up as /dev/sdb. If there's > >> already a /dev/sdb listed in the file, that will conflict. > >> > >> Hope that helps. > >> > >> -dsr-
- References:
- [Discuss] Fedora 28 Doesn't See External DVD Drive on USB Port
- From: nancythewriter7 at gmail.com (Nancy Allison)
- [Discuss] Fedora 28 Doesn't See External DVD Drive on USB Port
- From: dsr at randomstring.org (Dan Ritter)
- [Discuss] Fedora 28 Doesn't See External DVD Drive on USB Port
- From: nancythewriter7 at gmail.com (Nancy Allison)
- [Discuss] Fedora 28 Doesn't See External DVD Drive on USB Port
- From: david at thekramers.net (David Kramer)
- [Discuss] Fedora 28 Doesn't See External DVD Drive on USB Port
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