Steven S. Holland

So I have been using the Ubuntu linux distribution on my work desktop for a few weeks now, and have acclimated pretty well. There are still some things that I need from Windows here and there, and I was looking for ways to run a virtual version of windows inside my Ubuntu OS. After asking around to a few people who are way more knowledgable in Linux (Aaron, and Justin, mainly) I was looking into VMware. VMware costs money, though, and so I decided I would give VirtualBox a shot, since it is free (it’s also open source), and from what I have read online it’s a good alternative to VMware. Instead of potentially killing my Ubuntu installation at work (which has required an awful lot of tweaking and extra libraries for the code I am running), I gave it a test run on my laptop, starting with the inverse problem of running a virtual machine of Ubuntu OS inside WinXP.

I must say that it was extremely easy, and fast to install the virtual box. I ran into a few issues with the screen resolution inside the virtual box, but that was fixed by installing some extra files that virtualbox default loads onto the desktop of the ubuntu installation. So far I have not noticed a lag in opperation (I alloted 256MB of memory to the virtual machine, and gave the system an 8GB partition of the hard drive), and it solved one of my huge complaints about Ubuntu a year ago, last spring, when I had installed it and played with it — the network settings for the wireless card are by default accesible to the Ubuntu virtual machine, so I should be able to connect readily to different wireless networks without so much hassle with the wireless networking settings (which, unless I missed something, only allowed one network setting to be stored at a time). So far I am liking it a lot. Now the real test will be on Monday when I attempt to install WinXP on top of Ubuntu…

There is a reason devices have a third prong: Dell’s new laptops don’t have a third prong (an earth ground). As the article mentions, users are reporting feeling slight shocks when touching the brushed aluminum casing…which is possible due to the absence of the third prong, which normally grounds the outer casing appliances (those with metal cases) or exposed metal pieces on an appliance. Without the earth ground, the AC power is converted to DC just fine, but the DC voltage is “floating” with respect to earth ground. For example, the AC mains could be converting to, say, 20Vdc, but this is simply 20Vdc between the plus and minus output of the power supply, and the minus side of the supply can be any voltage and is not necessarily the same as the earth ground potential. Normally one of two things happens: 1.) the minus side of the DC supply is connected to earth ground, or 2.) if no electrical connections are made to the outer casing, the outer case is connected to earth ground. This is done to ensure that anything the user touches will be at the same potential as the user, and no shock would result. If the case was not brushed aluminum, and instead plastic, the user would notice no difference, except when plugging in peripherals.

What I wonder is what the grounding of the case looks like. If the case has no electrical connections at all, and the case is developing a static charge that is discharging (which can develop thousands of volts - dragging your feet on the carpet and touching a door handle can easily build up tends of thousands of volts), there is no danger from these shocks, other than an annoyance. If, instead, the case is actually used as the ground reference for the computer, then this can potentially cause harmful shocks since power can be drawn out of the computer supply when the potential difference between the case and the earth ground is shunted through a user.