Virutalbox: Resizing a static disk

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Yesterday I launched one of my virtual machines to find out that I am low on space. I wanted to expand the static (fixed size) disk but apparently this couldn’t be done on a static disk. Some posts indicated that one could clone the disk as a dynamic one and then resize that.

I wanted to resizing the vdi disk from 7GB to 12GB. To do this I

  1. converted the static disk into a dynamic disk using
    vboxmanage clonehd disk-name.vdi new-disk-name.vdi
  2. resized the disk using
    VBoxManage modifyhd new-disk-name.vdi --resize 12000  #12000 is 12000MB
  3. replaced the disks in the settings of the machine (ie; removed the old disk and added the new disk)

But this did not solve the problem. Albeit the disk is now dynamic and 12GB in size, still the additional space was detected as unallocated space in the virtual Ubuntu 12.04. Given that the unallocated space was added to the end of the partition table, there was no way of resizing the root partition. Continue reading

Image from history: Programma 101

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Image from history: Programma 101

Programma 101, the first commercial personal computer.
It was invented by the Italian Giorgio Perotto and had a memory of 240 bytes.

Image from history: IBM PC 5150

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Personal computer of the 80's

This image shows the IBM’s personal computer of the early 1980’s, the 5150 characterized with its 16-256 KB memory. I’ve always preferred my terminal to be green on black 🙂

“Smartness” and “Intelligence”

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Many people assume that superior intelligence or ability is a key to success. But more than three decades of research shows that an overemphasis on intellect or talent—and the implication that such traits are innate and fixed—leaves people vulnerable to failure, fearful of challenges and unmotivated to learn.
Teaching people to have a “growth mind-set,” which encourages a focus on effort rather than on intelligence or talent, produces high achievers in school and in life.
Parents and teachers can engender a growth mind-set in children by praising them for their effort or persistence (rather than for their intelligence), by telling success stories that emphasize hard work and love of learning, and by teaching them about the brain as a learning machine.

source: http://www.scientificamerican.com/article.cfm?id=the-secret-to-raising-smart-kids 

Mettalicity of stars

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As any student who studied a bit of chemistry knows that metals in the periodic table are various, after all the periodic table is usually taught to students as including group 1 and group 2 corresponding to alkali metals and alkaline earth metals, respectively.

Since the universe is mostly made up of hydrogen (74%) and helium (24%) [1], astronomers often refer to all the other elements we know of as “metals”. What we know about the “metallicity” is that it is tightly related to the age of the star. In other words, astronomers categorize stars into populations (I, II, III) based on their metallicities. Initially a star is born with mainly hydrogen and some helium (i.e; low metallicity). As the star burns the hydrogen, the helium gets more abundant and as the helium and hydrogen are consumed new elements (metals) are formed. So logically, young stars have low metallicities (these belong to population II) and old stars have high metallicities (population I)! Population III stars are those that have no metallicities and are yet to be discovered.

The metallicity is denoted by the letter Z as well as [Fe/He], the latter of which is read “the ratio of iron to helium” (i.e; abundance of Fe / abundance of He). For example, one of the brightest stars in our sky is Sirius, a main sequence star. It has a [Fe/He] = 0.5 [2]. It should be noted here that Z and [Fe/He] are calculated differently so they have different but correlated values, where [Fe/He] is logarithmic in that [Fe/He] = log(abundance of Fe / abundance of He)!

Below is an example of a plot of the logarithmic (base 10) abundance versus the atomic number, Z, of the elements, the latter not to be confused with metallicity, in the solar system!

Abundance of elements in the Solar system

Footnotes

[1] of all baryonic matter!
[2] The Abundance Patterns of Sirius and Vega [H. M. Qiu et al. 2001] doi:10.1086/319000