What does “root” means?

In computer terms, with root we can mean:

  • Root as user
  • Root as in file path

If we mean root as an user, we mean the main user, the one with the “master” control of the machine. For example, if you have root on Android, it means you can do whatever you want it it.

If you mean root as a file path, it’s the base, just place the file outside any folder. If you’re using the D: drive, by saying “place the file in root”, it means just place it on D:

How to convert a VM from VirtualBox to KVM

Converting the virtual machine images is very easy, but many guides suggest you to convert¬† from VDI to RAW and then from RAW to QCOW2. It doesn’t really make sense, you’ll waste double the time, and it’s gonna be hours if the drive is big.

To convert from VDI to QCOW2 just use qemu-img:

qemu-img convert -f vdi -O qcow2 [VBOX-IMAGE.vdi] [KVM-IMAGE.qcow2]

If the virtual machine was Windows-based, probably will crash at first boot, because of the virtual hardware changes, and because there are no virtio drivers installed (unless you make a VM with IDE emulation)

For fix the BSOD at boot you can do onf of this:

Personally I chose the first option, but then I had to install again hundreds and hundreds of security updates, it would have been better if I installed the patch before migrating.

Update: I noticed that the converted Windows XP VM uses the cpu at 100% even when idle. This is a nasty bug that would take ages to fix. I tried to force enabling ACPI, but all I can get is a BSOD on boot. I’ll just scratch the VM and rebuild it…

How to do a quick CPU benchmark on Linux

With Enki (a Brain Training app for coders – if you want to try iy, and you need an invite, you can my code: MAGNE985) I found a quick benchmark to for Linux, to see the speed of a CPU core.
dd if=/dev/zero bs=1M count=1024 | md5sum
This line tells the CPU to calculate an md5 hash for an 1gb of “zeroes” and measure how long it takes. For example, on the Pentium G3420 that I have in my office I get this:
dd if=/dev/zero bs=1M count=1024 | md5sum
1073741824 byte (1,1 GB) copiati, 2,10036 s, 511 MB/s dd if=/dev/zero bs=10M count=2048 | md5sum
21474836480 byte (21 GB) copiati, 49,0278 s, 438 MB/s
while on an Intel Xeon W3520 (my web server) I get this:
dd if=/dev/zero bs=1M count=1024 | md5sum
1073741824 bytes (1.1 GB) copied, 2.79137 s, 385 MB/s

dd if=/dev/zero bs=10M count=2048 | md5sum
21474836480 bytes (21 GB) copied, 56.9042 s, 377 MB/s
Hey! It takes 10 seconds more! What? An expensive Xeon is slower than a cheaper Pentium????
Yes, the server is outdated, but I did not expect to have such a difference! It is time to change my web server!
confronto-xeon

How to solve the Adobe Shared Technologies failed install problem

I wanted to try the Photoshop Elements demo (it’s on sale for cyber monday for just $40!), but it wasn’t working.

Searching on the Internet, it looks like it’s a common problem to have an error like those:

¬†“The wizard was interrupted before Adobe Photoshop Elements could be installed. Below mentioned application has failed to install: Shared Technologies.”

“The Adobe Premiere Elements installation wizard was interrupted while installing Shared Technologies.”

“The installation process has encountered an error while installing Shared Technologies.”

Why? The reason is simple, but it’s not explained by the error message.

The installer does not run correctly if it has more than 255 characters in the file path.

This is because, usually, the setup is run from d:\setup.exe , and a few people gets the error.

Instead, when you download a demo from the Internet, you can run it from a long path, as this:

c:\users\myusername\download\programms\demo\image-editing\photoshop\setup\unzipped\setup\setup.exe

The file path it’s too long, and it doesn’t work.

So, if you get this error while installing Adobe Shared Technologies, move the setup in another folder, for example c:\temp

The best video converter EVER!

SUPER is an awesome video converter. It can convert any kind of video without problems. Even rare containers like *.NSV, *.STR, *.VIV!

It can produce any video format:

super1

Once chosen the video container format, we choose the video codec, the audio codec, the video resolution, the framerate, the bitrate, and presto! In just a few minutes, it converts ANYTHING!

super2

SUPER (acronym of “Simplified Universal Player Encoder & Renderer”), can be downloaded from the official Website, but, that Website is a kind of a mess, so you can download it from here (version updated to April 2009).

Update 18th august 2016: their latest installer contains adware. Be careful and read carefully what are you agreeing to, don’t install toolbars and other useless and deceiving adware.