TOPIC: USB
Carrying out a hard reset of a home KVM switch
20th March 2017During a recent upgrade from Linux Mint 18 to Linux Mint 18.1 on a secondary machine, I ran into bother with my Startech KVM (keyboard, video, mouse and audio sharing) switch. The PC failed to recognise the attachment of my keyboard and mouse, so an internet search began.
Nothing promising came from it apart from resetting the KVM switch. In other words, the solution was to turn it off and back on again. That was something that I did try unsuccessfully. What I had overlooked was that there were USB connections to PC's that fed the device with a certain amount of power which was enough to keep it on.
Unplugging those USB cables as well as the power cable was needed to completely switch off the device. That provided the reset that I needed, and all was well again. Otherwise, I would have been baffled enough to resort to buying a replacement KVM switch, so the extra information avoided a purchase that could have cost in the region of £100. In other words, a little research had saved me money.
A very silly mishap
15th April 2009Last night, something idiotic happened to me: I tripped up in my main PC's cables and brought the behemoth crashing about the place. There was some resulting damage, with the keyboard PS/2 socket being put out of action and a busted USB port and mouse. When this happens, thoughts take on the form of a runaway train and the prospect of acquiring a new motherboard and assorted expensive paraphernalia trot into your mind; there are other things that more need my cash. Of course, the last time to be making such big decisions on computer components is when a mental maelstrom has descended upon you.
Eventually, I got myself away from the brink and lateral thinking began to take over. What helped was that most of the system is unaffected, enabling me to write this post with it. While a spare will work for now, a new ergonomic mouse is on order, cheaper alternatives to the keyboard conundrum have come into play. If PS/2 wasn't an option, then USB remains one, and that was the line of attack that was taken.
It involved a visit to the nearest branch of PC World after work, from where I came away with a new USB hub and a USB-compatible keyboard for less than the price of a new AM2+ Gigabyte motherboard that would have served my needs. Though an otherwise functional Trust keyboard may have been retired, that was a less expensive option than a full PC rebuild, which I may still need to do, albeit with far less immediacy than what flashed before my eyes within the last 24 hours. In fact, acquiring some cable ties should be higher on the acquisition wish list to avoid cable-induced tumbles in the future. It really does pay to be able to step back and see things from a wider perspective.
Getting VirtualBox 2.02 working on Ubuntu 8.04
10th October 2008
Having run VirtualBox OSE (1.5.6) for a while now, I succumbed to the idea of grabbing the latest version from the VirtualBox website and putting it on my main Linux box. The idea of having 64-bit support proved irresistible, and I did get OpenSolaris to start, even if its installation on a VMware VM meant that it stalled along the way.
To accomplish this, I needed to rid my system of all traces of the old version before 2.02 would install, with a system reboot being needed before the process of installation fully completed. Then, I fired up a Windows XP virtual machine, only for it to completely freeze. The hint as to the cause came when I opened up the VM's settings for the following message to greet me:
Could not load the Host USB Proxy Service (VERR_FILE_NOT_FOUND). The service might be not installed on the host computer.
While it didn't stop things in their tracks when it came to accessing and changing those settings, it was a vital hint for working out what was happening. It now seems that a problem with USB port support was the cause. The fact that issuing the following command got things going for me appeared to confirm the prognosis.
sudo mount -t usbfs /sys/bus/usb /proc/bus/usb/
Of course, not wanting to have to issue the same command over and over again, I was after a more permanent solution. That involved adding the following lines to /etc/fstab:
#usbfs
none /proc/bus/usb usbfs devgid=46,devmode=664 0 0
A reboot later, that change apparently was enough to settle the matter, and I am now able to run VM's as before. Seamless application mode is going well (the host key - right Ctrl by default - + L key combination is sufficient to toggle the setting on and off), even if it has a few quirks. Two that I have spotted include the usual Ubuntu screen furniture disappearing when maximised windows are displayed, and the Windows taskbar appearing when two or more applications are running. That last one may be just as well because individual applications don't get an Ubuntu taskbar icon each, which is perhaps an idea for a future enhancement. Updating Guest Additions in a VM's doesn't seem to change the behaviour, but any imperfections are curiosities rather than complaints given how well things run anyway, unless you decide to confound matters by closing and minimising windows, but resolving that is just a toggle away. It's all looking good so far...
iPod, identified
9th December 2007Plug in an iPod to a PC running Ubuntu, and it will recognise what it has got. That act mounts the player as a hard drive and fires up the Rhythmbox Music Player. The usual file transfer capabilities are available, and it does something that was thwarted partially by iTunes when I last tried it: transferring files from your iPod to your PC. Only music bought from the iTunes store can be copied from the player back to the PC. Unsurprisingly, you cannot update the iPod's firmware or anything like that. To do such things, you need the iTunes player and that means having either Windows or OS X. While I do wonder if it can't be that difficult to port the OS X version to Linux since they both share UNIX roots, it's over to the Windows VM for me on this one for now.
However, while VMware on Windows will happily pick up USB devices as they are connected so long as the VM is in focus, the behaviour on Linux seems to be different. As shown above, you have to go to the VM menu and potter down the chain (Removable Devices > USB Devices) to make the device of interest accessible. Dialogue boxes asking you if you wish to disconnect the device from the host operating system will appear, and the process may be unsubtle as you progress with it. In fact, Ubuntu was delivering warning messages about how its iPod connection got lost; it would have been wise to unmount the thing in the first place. Accessing USB devices like this opens up other possibilities: using Windows for scanning and for printing digital images.
Returning to the iPod story, Windows will see it once it has been made available and iTunes can access it accordingly. Then, you are free to update the gadget's firmware or manage the music stored on it if you prefer.