Linux Archive

Linux Archive (http://www.linux-archive.org/)
-   Fedora User (http://www.linux-archive.org/fedora-user/)
-   -   Listings Question About Ping (http://www.linux-archive.org/fedora-user/614076-listings-question-about-ping.html)

Paul Allen Newell 12-24-2011 07:57 AM

Listings Question About Ping
 
To all:

I was able to fire up one of my backup machine (32 bit F14) and, via a
ssh from cygwin, could see that a directory I had created under cygwin
had protections of "drwxrwxrwx". It displayed as "black" on a mid-level
green (aka totally unreadable). I ran "chmod go-w <theDir>" and then did
another listing ... it was back to blue over black (and I gotta admit,
the blue is too deep to really stand out). But blue is what I expect for
a 'ls' (now that I know /etc/bashrc is redefining 'ls').


I am thinking that most of my issues are from cygwin files/dirs that
don't have protections in the Microsoft world being mis-read under F14
and that the solution is a script to properly set protections when
bringing a file/dir over from cygwin (?).


Can't wait to see how I got RGB red on black as that is the one I want
to do the "silver bullet" on.


This has very little to do with alot of the conversation on this except
to show that F14/bash/whatever is trying to display based on what it can
find out about a file and if such is not set right, the visuals will suffer.


Paul
--
users mailing list
users@lists.fedoraproject.org
To unsubscribe or change subscription options:
https://admin.fedoraproject.org/mailman/listinfo/users
Guidelines: http://fedoraproject.org/wiki/Mailing_list_guidelines
Have a question? Ask away: http://ask.fedoraproject.org

Marko Vojinovic 12-25-2011 04:12 PM

Listings Question About Ping
 
Wow, look, another OT thread to contribute to! :-D

On Sunday 25 December 2011 23:35:15 Tim wrote:
> Tim:
> >> We're mostly sensitive to green, then red, then blue.
>
> Joe Zeff:
> > Not quite, AIUI. The wavelength the human eye is most sensitive to is
> > in the "greenish yellow" range, much more yellow than green.
>
> Well, as far as coloured sight goes, the primary colours are red, green,
> and blue. That is, the sensors in our eyes are attuned to those
> colours, with a small spread either side of them.

[me loading extension_Biochemistry... done]

Um, no, the "red" receptors in the eye are actually peaked at green-yellow,
not red. Let me quote a piece from

http://en.wikipedia.org/wiki/Color_vision#Physiology_of_color_perception

<quote>
For example, while the L cones have been referred to simply as red receptors,
microspectrophotometry has shown that their peak sensitivity is in the
greenish-yellow region of the spectrum. Similarly, the S- and M-cones do not
directly correspond to blue and green, although they are often depicted as
such. It is important to note that the RGB color model is merely a convenient
means for representing color, and is not directly based on the types of cones
in the human eye.
</quote>

You can find more details on http://en.wikipedia.org/wiki/Photopsin , and the
picture at

http://en.wikipedia.org/wiki/File:Cone-fundamentals-with-srgb-spectrum.svg

shows clearly which part of the spectrum is covered by S, M and L
photoreceptors, and how well it is covered.

At least as far as humans are concerned. ;-)

> From the point of the receptors, it is green
> that we see the most. If one were to draw a rainbow across a page as a
> graph of the sensitivity of our eyesight, there's a peak around the
> green, that slopes off either way, with the blue side sloping off faster
> than the red side.

That would be http://en.wikipedia.org/wiki/File:Eyesensitivity.png .

> > Considering that the Sun is a yellow dwarf, it's much more likely for us
> > to find the wavelengths near and/or at its peak output to be easiest to
> > see rather than something off to one side.
>
> It's not actually yellow.

[me loading extension_Astrophysics... done]

True, it's white, not yellow. The sunlight only appears to be yellow on Earth
because of the atmospheric refraction.

Otherwise, the Sun emits pretty much the same amount of (visible part of)
light of each color, summing up to white. The peak frequency is mostly
somewhere near blue, actually.

The picture

http://en.wikipedia.org/wiki/File:Solar_Spectrum.png

can give you a good idea of EM emmision spectrum of the Sun that reaches Earth
(the upper atmosphere and the ground surface). The vast majority is actually
in infrared, but the most intensive part is the visible light.

> If you were going to argue the line of us
> being sensitive to the colour of the sun, actually it's far more logical
> that we're least sensitive to the strongest colours about.

[me loading extension_Darwinian_Evolution... done]

Why would that be? As per the spectrum picture above, the most intensive
radiation from the Sun is in the part of the spectrum that is visible to us.
I'd say that this is just good adaptation of humans to the environment --- the
most efficient way to collect information about our surroundings comes by
observing the most intensive radiation available --- which turns out to be the
"visible" part of the Sun's spectrum.

And then there is the biochemistry part --- in order to actually observe some
part of the Sun's spectrum, biological organisms need biomolecules which are
chemically sensitive to those wavelengths only. The number and types of such
biomolecules may be quite constrained by laws of chemistry and biology (IIRC
there are at most 12 of them to be found in a single animal), having nothing
in particular to do with available sunlight itself. That's why most animal
species can detect the visible light, some can see ultraviolet, but very few
(if any) can see infrared. This is a consequence of the fact that there are
basically no molecules which are specifically sensitive to infrared spectrum,
despite the abundant amount of it provided by the Sun. For more info, see:

http://en.wikipedia.org/wiki/Color_vision#In_animals
http://en.wikipedia.org/wiki/Evolution_of_color_vision

> And for our next off-topic, do we have someone who'd like to discuss the
> theory of relativity for us? ;-) Makes a change from discussing why
> Gnome and Windows suck.

[me loading extension_Relativity... skipping: already hard-coded]

In any discussion related to theory of relativity it always helps to have an
expert around --- so you can consider yourself lucky. ;-) Since this part of
the thread is already completely OT, feel free to ask whatever you like about
relativity, I'll try to respond as long as I don't become too busy with real
life stuff... :-)

HTH, :-)
Marko


--
users mailing list
users@lists.fedoraproject.org
To unsubscribe or change subscription options:
https://admin.fedoraproject.org/mailman/listinfo/users
Guidelines: http://fedoraproject.org/wiki/Mailing_list_guidelines
Have a question? Ask away: http://ask.fedoraproject.org

les 12-26-2011 05:31 PM

Listings Question About Ping
 
On Sun, 2011-12-25 at 17:12 +0000, Marko Vojinovic wrote:
> Wow, look, another OT thread to contribute to! :-D
>
> On Sunday 25 December 2011 23:35:15 Tim wrote:
> > Tim:
> > >> We're mostly sensitive to green, then red, then blue.
> >
> > Joe Zeff:
> > > Not quite, AIUI. The wavelength the human eye is most sensitive to is
> > > in the "greenish yellow" range, much more yellow than green.
> >
> > Well, as far as coloured sight goes, the primary colours are red, green,
> > and blue. That is, the sensors in our eyes are attuned to those
> > colours, with a small spread either side of them.
>
> [me loading extension_Biochemistry... done]
>
> Um, no, the "red" receptors in the eye are actually peaked at green-yellow,
> not red. Let me quote a piece from
>
> http://en.wikipedia.org/wiki/Color_vision#Physiology_of_color_perception
>
> <quote>
> For example, while the L cones have been referred to simply as red receptors,
> microspectrophotometry has shown that their peak sensitivity is in the
> greenish-yellow region of the spectrum. Similarly, the S- and M-cones do not
> directly correspond to blue and green, although they are often depicted as
> such. It is important to note that the RGB color model is merely a convenient
> means for representing color, and is not directly based on the types of cones
> in the human eye.
> </quote>
>
> You can find more details on http://en.wikipedia.org/wiki/Photopsin , and the
> picture at
>
> http://en.wikipedia.org/wiki/File:Cone-fundamentals-with-srgb-spectrum.svg
>
> shows clearly which part of the spectrum is covered by S, M and L
> photoreceptors, and how well it is covered.
>
> At least as far as humans are concerned. ;-)
>
> > From the point of the receptors, it is green
> > that we see the most. If one were to draw a rainbow across a page as a
> > graph of the sensitivity of our eyesight, there's a peak around the
> > green, that slopes off either way, with the blue side sloping off faster
> > than the red side.
>
> That would be http://en.wikipedia.org/wiki/File:Eyesensitivity.png .
>
> > > Considering that the Sun is a yellow dwarf, it's much more likely for us
> > > to find the wavelengths near and/or at its peak output to be easiest to
> > > see rather than something off to one side.
> >
> > It's not actually yellow.
>
> [me loading extension_Astrophysics... done]
>
> True, it's white, not yellow. The sunlight only appears to be yellow on Earth
> because of the atmospheric refraction.
>
> Otherwise, the Sun emits pretty much the same amount of (visible part of)
> light of each color, summing up to white. The peak frequency is mostly
> somewhere near blue, actually.
>
> The picture
>
> http://en.wikipedia.org/wiki/File:Solar_Spectrum.png
>
> can give you a good idea of EM emmision spectrum of the Sun that reaches Earth
> (the upper atmosphere and the ground surface). The vast majority is actually
> in infrared, but the most intensive part is the visible light.
>
> > If you were going to argue the line of us
> > being sensitive to the colour of the sun, actually it's far more logical
> > that we're least sensitive to the strongest colours about.
>
> [me loading extension_Darwinian_Evolution... done]
>
> Why would that be? As per the spectrum picture above, the most intensive
> radiation from the Sun is in the part of the spectrum that is visible to us.
> I'd say that this is just good adaptation of humans to the environment --- the
> most efficient way to collect information about our surroundings comes by
> observing the most intensive radiation available --- which turns out to be the
> "visible" part of the Sun's spectrum.
>
> And then there is the biochemistry part --- in order to actually observe some
> part of the Sun's spectrum, biological organisms need biomolecules which are
> chemically sensitive to those wavelengths only. The number and types of such
> biomolecules may be quite constrained by laws of chemistry and biology (IIRC
> there are at most 12 of them to be found in a single animal), having nothing
> in particular to do with available sunlight itself. That's why most animal
> species can detect the visible light, some can see ultraviolet, but very few
> (if any) can see infrared. This is a consequence of the fact that there are
> basically no molecules which are specifically sensitive to infrared spectrum,
> despite the abundant amount of it provided by the Sun. For more info, see:
>
> http://en.wikipedia.org/wiki/Color_vision#In_animals
> http://en.wikipedia.org/wiki/Evolution_of_color_vision
>
> > And for our next off-topic, do we have someone who'd like to discuss the
> > theory of relativity for us? ;-) Makes a change from discussing why
> > Gnome and Windows suck.
>
> [me loading extension_Relativity... skipping: already hard-coded]
>
> In any discussion related to theory of relativity it always helps to have an
> expert around --- so you can consider yourself lucky. ;-) Since this part of
> the thread is already completely OT, feel free to ask whatever you like about
> relativity, I'll try to respond as long as I don't become too busy with real
> life stuff... :-)
>
> HTH, :-)
> Marko
>
>
Hi, Marko,
This is a great offer. I have a smattering of knowledge about some
things, and complete blanks about most in physics.

One of the recent things I became aware of is something called
ballistic transport of electrons in carbon nano-tubes. I read somewhere
(and don't remember where) that electrons in carbon nano-tubes appear to
exceed the speed of light. I have made really precise measurement of
various electrical things, such as 500femto farad capacitors, and
currents into hundreds of picoamps, along with time measurements
resolved into the attosecond range, so I realize that there is a lot of
capability out there, but how is it that the speed of an electron
through a carbon nanotube can be measured repeatedly at speeds greater
than light speed? I have a few ideas, but I haven't read any articles
on how the actual physical measurement was made.

Regards,
Les H


--
users mailing list
users@lists.fedoraproject.org
To unsubscribe or change subscription options:
https://admin.fedoraproject.org/mailman/listinfo/users
Guidelines: http://fedoraproject.org/wiki/Mailing_list_guidelines
Have a question? Ask away: http://ask.fedoraproject.org

Marko Vojinovic 12-27-2011 12:07 AM

Listings Question About Ping
 
On Monday 26 December 2011 10:31:02 les wrote:
> On Sun, 2011-12-25 at 17:12 +0000, Marko Vojinovic wrote:
> > Wow, look, another OT thread to contribute to! :-D
[snip]
> > [me loading extension_Relativity... skipping: already hard-coded]
> >
> > In any discussion related to theory of relativity it always helps to
> > have an expert around --- so you can consider yourself lucky. ;-) Since
> > this part of the thread is already completely OT, feel free to ask
> > whatever you like about relativity, I'll try to respond as long as I
> > don't become too busy with real life stuff... :-)
>
> Hi, Marko,
> This is a great offer. I have a smattering of knowledge about some
> things, and complete blanks about most in physics.

Glad to help out! :-) If you have many questions, maybe it would be a good
idea to take it off-list, since otherwise we might get bashed for contaminating
the Fedora archives etc... ;-)

> One of the recent things I became aware of is something called
> ballistic transport of electrons in carbon nano-tubes. I read somewhere
> (and don't remember where) that electrons in carbon nano-tubes appear to
> exceed the speed of light. I have made really precise measurement of
> various electrical things, such as 500femto farad capacitors, and
> currents into hundreds of picoamps, along with time measurements
> resolved into the attosecond range, so I realize that there is a lot of
> capability out there, but how is it that the speed of an electron
> through a carbon nanotube can be measured repeatedly at speeds greater
> than light speed? I have a few ideas, but I haven't read any articles
> on how the actual physical measurement was made.

I am not familiar with the details of the measurment process those folks use,
but in general --- I would do "something" (like bombing the nanotube with an
electron gun) to accelerate the free electrons past the speed of light in the
nanotube, and then try to capture the Cherenkov radiation it emits. You can
read more about the latter on

http://en.wikipedia.org/wiki/Cherenkov_radiation

Measuring the Cherenkov radiation should be fairly simple in principle (it's
just detecting light coming out of the nanotube --- using for example
photomultiplier detectors, or whatever else is suitable), though the actual
frequency of that light may vary according to how fast I can make the
electrons travel through the nanotube. If they move fast enough, the nanotube
should just "glow", similar to the "blue glow" of a nuclear reactor core.

However, being a "theoretical" physicist, I cannot say whether the above
"thought experiment" construction would be feasible. Maybe those folks are
doing it differently (also more efficiently and more precisely, I guess). There
is usually more than one method to measure any physical quantity, so...
Hence, since I am not familiar where did you read about that result, I cannot
comment on any actual experiment (and I am not an expert in carbon nanotubes
either :-) ). But the description above should give you a general idea how
these things could be measured in principle. :-)

All that said, I should just make a small-and-obvious remark that none of the
above contradicts theory of relativity in any way. Relativity deals with the
speed of light in *vacuum*, whereas the speed of light in various materials
(including nanotubes) can be significantly smaller, and various particles (such
as electrons) can easily be pushed to outrun it. But both speeds are still
smaller than the speed of light in the vacuum, in accord with special
relativity. Just a comment to avoid any possibility of confusion in that
regard. :-)

Best, :-)
Marko


--
users mailing list
users@lists.fedoraproject.org
To unsubscribe or change subscription options:
https://admin.fedoraproject.org/mailman/listinfo/users
Guidelines: http://fedoraproject.org/wiki/Mailing_list_guidelines
Have a question? Ask away: http://ask.fedoraproject.org

Paul Allen Newell 12-31-2011 05:47 AM

Listings Question About Ping
 
On 12/23/2011 6:56 AM, Aaron Konstam wrote:


It is not the blinking that bothers me. Its the impossibility of reading
the file names in some colors. Black letters on a red background is a
good example.


Someone asked me to post if I found anything interesting on this thread.
I already posted that potentially my problem with "colored ls's" exists
because of protection issues when moving a cygwin file to a fedora box.


Well, I am still waiting for Best Buy to return my primary Linux box
(online they claim its been fixed and is heading back to the store which
supports my theory that it is a hardware, and potentially HP, whatever-up).


But I did notice tonight when trying to move a cygwin directory to a
backup F14 box that 1) I am definitely seeing representational issue
with how cygwin gets permissions and 2) a broken link on a Fedora box
show up as red on black .. no blinking (I am tempted to caps that bit).


I might be dealing with a cygwin ssh view of a fedora box (you might
gather that I don't have visual access to the fedora box ... lean times
require lean setups which I do hope to change by begiining of the new year).


But, I need an example from the community of a "ls" showing a blinking
item to understand why it might make sense.


Best,
Paul

--
users mailing list
users@lists.fedoraproject.org
To unsubscribe or change subscription options:
https://admin.fedoraproject.org/mailman/listinfo/users
Guidelines: http://fedoraproject.org/wiki/Mailing_list_guidelines
Have a question? Ask away: http://ask.fedoraproject.org

Reindl Harald 12-31-2011 10:01 AM

Listings Question About Ping
 
Am 31.12.2011 07:47, schrieb Paul Allen Newell:
> But, I need an example from the community of a "ls" showing a blinking item to
> understand why it might make sense.

ln -s /dfdfdfdf ./hmpf
ls -l -h --color=tty -X --group-directories-first --time-style=long-iso

--
users mailing list
users@lists.fedoraproject.org
To unsubscribe or change subscription options:
https://admin.fedoraproject.org/mailman/listinfo/users
Guidelines: http://fedoraproject.org/wiki/Mailing_list_guidelines
Have a question? Ask away: http://ask.fedoraproject.org

Paul Allen Newell 12-31-2011 05:27 PM

Listings Question About Ping
 
On 12/31/2011 3:01 AM, Reindl Harald wrote:


ln -s /dfdfdfdf ./hmpf
ls -l -h --color=tty -X --group-directories-first --time-style=long-iso


Reindl:

Thanks. It didn't show up at first and suspected that it might be the
cygwin terminal. So, I ran startxwin to get an xwin and then I can see
it when I ssh to the backup F14 box. Once that solved, I see that, using
whatever Fedora aliases 'ls' to, that a 'ls -Fl' shows it. Sorry for not
trying that first, but I needed a "this will do it" example to make me
suspect my end.


Appears that hmpf is red on black and /dfdfdfdf is blinking white on red
(x shell is default black type on white background). Since this isn't a
Cygwin list, I won't bother with any more on that, but at least I have a
confirm that I probably will see it when I get my primary fedora box back.


And I might add, it does blink and it is ugly. The question is whether
it is uglier than the missing file (smile). I am even more inclined to
agree with Craig that it is effective at getting me to want to fix the
underlying problem so the blinking stops.


Paul



--
users mailing list
users@lists.fedoraproject.org
To unsubscribe or change subscription options:
https://admin.fedoraproject.org/mailman/listinfo/users
Guidelines: http://fedoraproject.org/wiki/Mailing_list_guidelines
Have a question? Ask away: http://ask.fedoraproject.org

Reindl Harald 12-31-2011 05:58 PM

Listings Question About Ping
 
Am 31.12.2011 19:27, schrieb Paul Allen Newell:
> The question is whether it is uglier than the missing file (smile).
> I am even more inclined to agree with Craig that it is effective at
> getting me to want to fix the underlying problem so the blinking stops.

well, that is exactly what it is meant for :-)

--
users mailing list
users@lists.fedoraproject.org
To unsubscribe or change subscription options:
https://admin.fedoraproject.org/mailman/listinfo/users
Guidelines: http://fedoraproject.org/wiki/Mailing_list_guidelines
Have a question? Ask away: http://ask.fedoraproject.org

Paul Allen Newell 12-31-2011 06:03 PM

Listings Question About Ping
 
On 12/31/2011 10:58 AM, Reindl Harald wrote:


well, that is exactly what it is meant for :-)



Some things have to be seen to be believed ...


--
users mailing list
users@lists.fedoraproject.org
To unsubscribe or change subscription options:
https://admin.fedoraproject.org/mailman/listinfo/users
Guidelines: http://fedoraproject.org/wiki/Mailing_list_guidelines
Have a question? Ask away: http://ask.fedoraproject.org


All times are GMT. The time now is 04:16 PM.

VBulletin, Copyright ©2000 - 2014, Jelsoft Enterprises Ltd.
Content Relevant URLs by vBSEO ©2007, Crawlability, Inc.