Ubuntu 10.04: Useless Mount Woes

I was using Ubuntu 10.04.  I had begun using Ubuntu in the belief that I would have a more logical computing experience than I had had in Windows, and in many ways that had been true.  But the whole realm of file permissions just baffled me, and once again it was causing me hassles and lost time.

This time, the problem had to do with what I might call "ghost mountpoints."  I had previously had my external USB drive (named DAILY) listed in fstab, for some purpose or other, but then it seemed that that had been causing a problem, so I removed it.  So now I had a new problem.  Apparently Ubuntu would just take it upon itself to create a nonexistent "mount point" in the /media folder, bearing the same name (i.e., DAILY); and if you unplugged and replugged the drive, it would not adopt the old one, but would instead create a new one, with an underscore appended to it.  So now I had /media/DAILY and /media/DAILY_ and /media/DAILY__ mountpoints, and when I tried to use scripts and such that would refer to plain old DAILY, they would not find it.

The problem, as it had now developed, was that I could not delete those old mountpoints.  They were all empty, but when I went to them in Nautilus -- to, say, /media/DAILY -- and right-clicked on it, the "Move to Trash" option was greyed out; and if I chose Unmount, it said this:

Unable to unmount DAILY
umount: /media/DAILY mount disagrees with the fstab

It said that because I had just now typed "sudo gedit /etc/fstab" and had revived the line that I had previously commented out, the one that provided for recognition of DAILY; and then I had typed "sudo mount -a" to mount the damned thing.  On the other hand, if I went to its sister, DAILY_, and tried the same steps, I got this:

Unable to unmount DAILY
umount: /media/DAILY_ is not in the fstab (and you are not root)

both of which were true.  But then if I typed "sudo nautilus" and went at it through the administrator's (root's) Nautilus, the Unmount option would do nothing, and the Move to Trash option would leave me with this:

Cannot move file to trash, do you want to delete immediately?
The file "DAILY_" cannot be moved to the trash.
Unable to trash file: Device or resource busy

But the Delete option would then give me this:

Error while deleting.
There was an error deleting DAILY_.
Error removing file: Device or resource busy

But what was it busy with?  There was nothing in it!  I did a search for that last error message and, sure enough, found a total of nine hits from the entire Google version of the Internet.  One source gave me the idea of trying "sudo umount -d /media/DAILY."  But I forgot the -d and that command just hung.  I killed that Terminal session and tried again, but it still hung.  I left that hang and tried the same thing with DAILY_.  That hung too.  Back at the drawing board, I tried the same thing but with -f instead of -d.  (This was what I had meant to do in the first place, but the smell of dinner had distracted me.)  Those hung too.

I found a tutorial on solving the problem on a jump drive, where you could just copy your files over to another drive and then delete directories etc.  I didn't want to have to do that with a 500GB external drive.  I tried rebooting the system without the external USB drive connected.  A disk check ran during reboot.  I also got a notice, during reboot, that DAILY was not connected; it noticed, now that I had it included in fstab.  When the system came back up, those DAILY, DAILY_, and DAILY__ entries were gone.  I wished there were a better way of getting rid of them -- it remained to be seen whether that problem would recur, now that DAILY was listed in fstab -- but at least a reboot and/or disk check had done it this time.

Sound Device Problem in VMware Workstation 7

I was running Windows XP as a guest in a virtual machine (VM) in VMware Workstation 7 on an Ubuntu 9.10 (Karmic Koala) host.  When I used Workstation's VM > Removable Devices > Sound Card > Connect option, I got this error message:

Failed to open sound device /dev/audio:  Device or resource busy
Failed to connect virtual device sound.

I had also gotten this message:

Failed to open sound device /dev/dsp: Device or resource busy
Sound will not be available

I had been having this problem ever since I started using VMware.  I had previously changed the sound device (using VM > Settings > Hardware tab > Sound Card > Use physical sound card) from /dev/dsp to /dev/audio, and had also changed the sound card so that it would not connect at power on.  These and other efforts (e.g., rebooting) had fixed things temporarily, but then stopped working.

Some time back, I had found that I got this problem when Second Life was running in Ubuntu (that is, not in the WinXP guest).  More recently, I had had the same problem when Firefox was running in Ubuntu.  What I worked out that time was as follows:

For the time being, the solution seems to be either (a) to watch videos and other webpages that use Flash, do it in a browser session that is running inside your VM, not in a browser running in Ubuntu, or (b) after watching a video or otherwise using Flash in Ubuntu, kill the program that used it (e.g., Firefox) and manually reconnect with your sound card inside the VM.

So now I powered down my VM (i.e., not just suspended) and went into Workstation's VM > Settings > Sound Card option.  There, I put my settings at "Connect at power on" and Use physical sound card:  Auto detect.  I saved that and killed all browsers in Ubuntu, including Firefox and also Google Chrome.  I then powered on the VM.  WinXP had a hard time booting itself -- it always seemed to reboot a couple of times before it finally got itself together -- so while I was waiting, I started another session of Workstation and, in that one, I set the sound card to "Use physical sound card:  ALSA: Default sound card," and powered up that VM as well.  That one booted.  The one set to Auto Detect seemed frozen, so I changed it to "Use physical sound card:  OSS:  /dev/dsp" and tried again.  It gave me a notice that VMware Tools was not installed (it had been installed previously), but it booted, and Tools did appear to be running OK.

At this point, sound was working OK in the one that used ALSA, but not in the one using OSS.  That is, when I tried the virtual machine that was using VM > Removable Devices > Sound Card > Connect in the OSS, I got an error message.  I changed it to ALSA, like the other one, and then the sound worked in both.  The solution reached previously, of killing competing programs in Ubuntu, seemed to be the answer again.

Later, though -- after rebooting, I think, and anyway after running Firefox in Ubuntu again -- I found the audio was stuttering.  It stuttered at different speeds if I used ALSA or OSS, but either way it stuttered.

I played a sound file in the VM, and while it was stuttering along, I went to Ubuntu's System > Preferences > Sound > Applications tab.  There, I saw "ALSA plug-in [vmware-vmx]" listed, and underneath it I saw "No application is currently playing or recording audio."  That message was flickering on and off with each stutter in the sound.  A search along these lines led to a thread in which someone suggested reinstalling the ALSA packages.  In System > Administration > Synaptic Package Manager I did a quick search for ALSA.  I saw that I had a number of ALSA-related programs installed.  I started to mark one of them, alsa-base, for removal, but when I did so, Synaptic indicated that it would also need to remove a package called ubuntu-desktop.  That sounded pretty major, so I bailed out of the reinstall-ALSA approach.

I did a different search and came up with a thread in which someone said that VMware Workstation 7 supports ALSA perfectly, and if you are getting stuttering it may be because of a setting in the WinXP guest, not in Ubuntu or Workstation.  Following the advice there, I went into XP's Control Panel > Sounds and Audio Devices > Volume tab > Speaker settings > Advanced > Performance tab.  There, as advised, I set both the Hardware Acceleration and the Sample Rate Conversion Quality sliders to the lowest possible settings.  I clicked Apply and OK and then rebooted the XP guest.  With ALSA as the chosen sound card setting, and with the sound card connected in VM > Removable Devices > Sound Card, I found on reboot that I had no sound at all.  I tried changing from ALSA to OSS and auto detect and back to ALSA.  Now I could connect the sound card, and now I had sound.  But I still had stuttering.  I tried typing “/dev/audio” into the box in place of ALSA, and (after reconnecting the sound card) that sped up the stuttering but did not eliminate it.

I wondered if the stuttering was due to a larger problem with the VM.  I wondered this because its performance was generally slow at this point, and had been slow before I started this latest round of tinkering.  (In other words, I hadn’t caused that slowness just by playing with the sound problem.)  I suspended the VM and shut down the system.  Next day, I started the machine and tried again.  There was still a bit of stuttering, but the situation was much better.  (See also this other writeup on audio problems in Ubuntu and VMware.)