Task List email notification in SharePoint 2010

Question: I have a task list with email notification set up. I am getting the email notification once I add a new item to the list. Is there a way that I get the email without title column in the form. I tried making the title hidden in list settings content type but it does not work. Can any one suggest on how to get this. I am currently using SharePoint 2010. Please find the image I have uploaded for better clarity
Answer: I don't think it is possible OOTB, so I would suggest create a custom notification workflow in SPD 2010 and customize it with the columns you want to show.
Another work around (just came now while I am typing - not tested):
Option 1:

Create a custom content type inherting from Task and remove the title and see if this works

Option 2:

Rename the title field to something else that you can use for something else (like comment or notes) and with the order option put it at the bottom of the list
Comment: Hi Ahmed, Option 1 when I am trying to create a new content type inheriting from task I don't find an option to delete title. How would I delete the title column for the new content type
Comment: HI Ahmed even if i renamed the title to something it is showing as Title in the email which I receive.
Comment: the only thing left to try is my first suggestion, just create a simple workflow and customize its body the way you like!
Comment: Ahmed I know workflow will work but my client is having a template which is used to create sites..there are 5 of these lists with different names in the template .. so If I create a workflow on each list then I should create 5 workflows on each site we create using this template.We have already 75 sites created based on this template and there are many more to come in future. So this is not a viable solution for the client ..rather I would need to explain them this and ask them to use the default title instead.Thanks for your suggestions.


Exclude posts without category from loop

Question: I'm trying to exclude all the posts that doesn't have a category assigned to from the main loop, i searched everywhere and i found a billion ways to exclude some categories or filter from specific category but not what i need to do, is it possibile?
Answer: Hi @Raffaele:
The function wp_get_object_terms(...) can provide you with the information you need. I've written a has_category($post_id) function that can be used in the loop like this:
<?php while ( have_posts() ) : the_post(); ?>
   <?php if (has_category($post->ID)): ?>

<?php the_title(); ?>

   <?php endif; ?>
<?php endwhile; ?>

And here is the has_category() function:
<?php
function has_category($post_id) {
  $has_category = false;
  $terms = wp_get_object_terms($post_id,'category');
  if (is_array($terms)) {
    foreach($terms as $index => $term)
      if ($term->slug=='uncategorized')
        unset($terms[$index]);
    $has_category = (count($terms)>0);
  }
  return $has_category;
}

Note that my has_category() function treats posts with the 'uncategorized' category as having no category. There are probably more performant ways to accomplish this but what you see above should work.
-Mike
Comment: The downside to this method is that you don't always have the same number of posts per page. When you ignore a post you don't add an extra one at the end of the page.
Comment: What about `query_posts` with `category__in`?
Comment: @t31os - Probably. There are many roads that lead to Rome, this was just the one I chose to write about. :)
Comment: @Jan Fabry - True.


Problems adding ESP8266 wifi board

Question: I just received an ESP8266 wifi module and I am trying to add the board. However I am having an issue. All websites/tutorials say to use http://arduino.esp8266.com/stable/package_esp8266com_index.json, however nothing is there. Can it be found somewhere else?
Comment: Can you please add more information to your question.
Comment: I am mirroring (eventually when the uploads finish) most of the files here: http://majenko.co.uk/esp8266
Answer: It looks like the server is down.  Isitdownrightnow reports that it's been down for almost 4 days: http://www.isitdownrightnow.com/arduino.esp8266.com.html
There is a discussion about it over on the ESP8266 forums: http://www.esp8266.com/viewtopic.php?f=26&t=3134&start=8
Let's hope it will be back again soon.

Problems adding ESP8266 wifi board


If my printer can print at 1200 x 4800 dpi, what resolution do I save my tiff at for max printed resolution?

Question: I have a color laser printer with max resolution specified to be 1200 x 4800 dpi, which is vertical by horizontal resolution based on this answer. I want to print an image at the highest possible resolution, so first I create a tiff file of the image using Matlab, which allows me to specify a single dpi value when I save the file. Do I specify 4800 dpi? Would the printer then print my image at 4800 dpi in the horizontal and 1200 dpi in the vertical? (The use case: I am seeking to print out a small color image containing tiny squares which need to be distinct when seen under a magnifying glass.)
Comment: To future readers : Be cautious, this post and some of the answers are not very clear on the differences between DPI, resolution, pixels and dots.
Comment: What kind of printer is it? Laser? Inkjet? something else? Also: is it colour or B&W? And what about your images? Are they colour? greyscale? or bitmaps? all this will affect the answer (as I've tried to explain)
Answer: The answers here already explain what DPI is, but your question isn't really what DPI is, but what the highest DPI setting is that you should use for your image.
Just a recap so others don't have to read the comments I posted on the other answers:
DPI is a conversion from pixels to physical size, such as cm, inch, etc. When a program or printer uses the DPI setting, it will basically calculate how small or big on the paper the image should be without changing the actual image itself. So a 1024x768 image with a low DPI setting can fill an entire A4 paper, but will look very pixellated when printed, as where the same image printed with a very high DPI setting will appear very small on paper.
Now, what happens if you print on a higher DPI setting than the printer supports, the same basically as when you use your photo editor and resize the photo to a smaller image. You lose details.
This makes the question really hard to answer. If you specify a DPI that is too low, the image gets bigger on paper. If you specify a DPI that is too high, you lose details in the image which can result in text not being readable anymore, or lines vanishing, depending on how much fine detail the image has.
Although I cannot answer the question for sure, because I don't know how well the printer copes with a DPI that is too high, I suspect that if you go higher than the 1200DPI setting on the vertical axis, you will lose details. So even though 4800 DPI is on the wide axis, I suspect that 1200DPI should be the maximum DPI setting you should use in order to ensure that you won't actually lose any information.
You could test this by creating an interlaced pattern based image with one pixel black, then one pixel white, then one pixel red then one pixel white, then one pixel green and one last pixel white and repeat that vertically (so you get a long vertical line (you can make these pixels wider though, so the line is easier to spot), then print it out on 1200DPI and on 4800DPI and see if you are keeping the information, or that some colors vanish.
Even better would it be if Matlab can somehow specify different DPI settings for the entire image. It is also possible that the printer calculates the dimensions based on a formula and thus the max DPI setting you could use is 3/4th of 4800DPI, namely 3600DPI (because 1200DPI is 1/4th of 4800DPI, so you reduce that from 4800DPI to compensate for going over.
So my answer is going to be: experiment a little to make sure. The information in this answer should help you understand how and why it works like this.
Comment: Thanks to all for the light bulb that the file DPI and the printer resolution are unrelated. Once I understood this, I stopped making a tiff file. Instead I printed directly from the Matlab figure window and experimented as suggested.  In Printer Properties, I choose '4800 x 1200 dpi equivalent' since that was the maximum DPI I could select, and in the printout I was able to see all the needed detail with a magnifying glass. My education here was a group effort and I am sorry I can only select one answer, since all were helpful.
Comment: You're welcome. :) Glad you sorted it out, and that I could assist in some way. I'm sure others will also learn from this group effort. :)
Answer: There are already a lot of good answers, but one piece of the explanation seems to be missing, so I'll focus on that; the relationship between pixels and printer dots.  The 1200x4800 printer resolution doesn't refer to image pixels, but the mechanics of how the printer can reproduce those pixels.
You have a specific, and somewhat unique, use case, but this general question can apply to a lot use cases.  I'll cover the situation in general, which may be of use to other readers, and then apply that to your requirement.
Background
A pixel is the smallest meaningful element of an image.  It contains information about the image, itself (as opposed to detail about how to recreate it on a specific device).  If it is a grayscale image, the pixel tells you how dark that spot is.  If it is a color image, the colors will be defined by a color space.  For monitors, it's typically primary colors of red/green/blue.  For a printer, it's typically primary colors of cyan/magenta/yellow (black is often added because it's difficult to create pure black by mixing colors; photo inkjet printers sometimes add additional colors that are hard to reproduce by combining other colors).  The pixel color is defined by the intensity of each component primary color.
To reproduce the pixel color on a monitor, the monitor has a subpixel for each primary color and can vary the brightness of each subpixel.  A printer can't do that; it can only print or not print a dot of a primary color (and put multiple primary colors in the same area).  Some inkjet photo printers can actually vary the size of the dot a little, but otherwise work the same way.  Printers recreate the pixel color by printing a pattern of tiny dots.  For each primary color, it varies the intensity of the color by how many dots it puts in the pixel's area.
Printer resolution
Printers are designed to reproduce a document or image that looks good when viewed at a normal distance.  They use some tricks to accomplish it that are invisible at normal viewing distance but visible under magnification.  As I'll explain, what you want to do is to work at a level that the printer isn't really designed to support.
The printer resolution refers to how tightly it can put down dots to create shades of each color.  I'm going to oversimplify a little because the resolution, say 4800 dpi, refers to how close together the dots are, not the diameter of the dot.  If the dot diameter is no more than 1/4800th inch, there will be paper showing through gaps between the dots, so it will not be able to achieve 100% color intensity.  If the dots are larger in diameter than 1/4800th inch, they will overlap and you will lose some increments of shading.  But for this explanation, lets assume perfect dots.
If it can print a grid of 16x16 dots within the area of a pixel, it has 256 dots to work with.  It can use anywhere between none and all to reproduce 256 shades of the color (excluding white for none), which is typically the color depth of an image.
At 4800 dpi, printing a pixel resolution of 300 ppi gives you 16 dots in that direction to recreate the color intensity.  In the other direction, 1200 dpi for the same 300 ppi gives you only 4 dots for recreating the color intensity.
In this case, 4x16 gives you get a grid of 64 potential dots, which provides a color depth of 64 shades.  So at 300 ppi, it can't accurately reproduce the original color precision of 256 shades per primary color, it can reproduce only every fourth increment of shading.  But 1/300 of an inch is pretty small; you can only see that detail with magnification.  So the printer employs an optical illusion.  By making surrounding pixels more or less intense to compensate, from a normal viewing distance, the errors blend and cancel out.
The higher the printed pixel resolution, the fewer potential dots per pixel in the grid.  The printer can reproduce fewer shades of the color, so color accuracy degrades.
There is also an issue of detail size at normal viewing distance.  For something like a line to be visible as a line, it needs to be wide enough to be perceived by your eye as a feature.  In the image, a line must be at lease one pixel wide to exist.  If you print that pixel too small (too high a pixel print resolution), it becomes essentially invisible as a line.  It becomes more like shading; color on the page that makes the paper off-white, but not really visible as a feature.  That is similar to how printers produce color shading -- dots or lines too small to be seen as a feature that add some percentage of color to the paper.
Image resolution
If you think about a fax, that is typically 200 dpi black and white. Normal-sized text tends to look a bit blocky and jagged.  Black and white laser printers produce smooth text outlines at 400-600 dpi, which is fine enough resolution to require magnification to see the detail (the text characters are typically represented as vectors, which don't have a ppi measurement).
If it was a grayscale image, 200 ppi would look much better, and 24 bit color (8 bits per color) at 200 ppi looks pretty good at normal viewing distances.  At normal document or picture viewing distances, 24 bit color at 300 ppi gives you pretty much all of the detail your eye is capable of distinguishing.  At higher pixel resolutions, you would lose the ability to differentiate some of the smallest image details.
Printers rely on that fact to fake it.  Your software application defines the pixel resolution, which determines the size of the image and the size and density of the image detail.  The printer driver figures out how to best reproduce that given the constraints it has to work with.  It can only lay down dots of primary color at intervals limited by the printer's resolution to simulate the color depth of the image pixels.
But your eyes can't see detail at that level.  It you printed an image at 4800 ppi, every pixel, regardless of its color shade, would be reduced to the presence or absence of a single dot (color depth of 1 shade) of each of its component primary colors.  So the printer would need to pick from a pallet of 8 possible colors to reproduce any of the 16.8 million colors a pixel could be.  You also wouldn't be able to distinguish any of the detail; it would look like a muddy blob.
Determining what resolution to save the image for typical use
For typical use, basically ignore the printer resolution, that will just affect how accurately it can reproduce the image.  Determine the image resolution based on how the result will be viewed.  In a typical document or photo print, 300 ppi is a good target.  If you may need to enlarge the image, or part of it, a higher resolution will preserve smaller detail for that purpose (base the ppi on how much you might need to enlarge).  If the image will be viewed from a distance, like a poster, 150 ppi or even less might be adequate.
If you use a ppi spec greater than what you really need, you will be storing and working with a much larger file.  Resolution is in two directions, so doubling the resolution quadruples the image pixels and the file size.  This can slow processing time to work with it.  It will also limit the printer's ability to use its tricks, which could result in a poorer print reproduction.
Special "microfiche" use case
You have a special use case where you want to print small and then magnify.  You will bump against two kinds of problems that are limitations of the printer technology.  One is the color accuracy that was previously discussed.  The other is the precision at which the dots are placed.
When you are viewing content printed at say 300 ppi, the pixels are already small enough to require magnification to see them.  The dots used to create the pixels need to be at a certain density, but the placement doesn't need to be all that precise.  From dot to dot, or line to line, if a dot is off position by 50%, you're talking about roughly 1/10,000th of an inch at 4800 dpi.
The printer also uses what is essentially "randomization" of some dot placement to avoid accidentally creating groups of coloration dots that happen to form a pattern that is perceivable as an artifact or feature.  It also manipulates dot location to create the color error offsets in adjacent pixels.
The high dot resolution isn't intended for you to use to print detail, it's the secret sauce the printer uses to synthesize the detail visible at normal viewing distances.  So what would happen if you tried to print at a pixel resolution approaching the printer's dpi?
If it was just text, you could theoretically print at 1200 ppi (this will be limited by the direction with the lowest resolution).  This would sort of mimic how simple text characters are displayed on a monitor.  In practice, though, this would be very crude, perhaps to the point of being barely usable.  The printer isn't designed to place the individual dots with the precision that would produce nice smooth lines.
If you are talking about color images, it would be even worse.  there would be too few dots to reproduce a broad range of colors, and the dot placement would be too random to reproduce accurate detail.  If you weren't at all worried about color accuracy you might get something usable at up to about 400-600 ppi (only guessing, you would need to test it).  But the appearance under magnification would likely be a bit "faxish".  It would also be horribly "grainy" because you would be looking at the component dots.  It definitely wouldn't pass for something "photographic".
In the days of dot matrix printers, people with a lot of time on their hands "digitized" photos into ASCII art.  By that, I mean converted pixels to alphabetic characters of similar darkness density to create a "document".  Printing the document would produce something that was recognizable as a picture from across the room, but at normal viewing distance, you could see all the characters.  Your magnified image would be similar.
Simple colored squares wouldn't be quite as bad as long as color accuracy and clean outlines aren't important.  If they are actually next to each other, you would get irregular outlines and color bleeding between them due to imprecise and randomized dot placement.
The bottom line is that the printer resolution isn't designed for printing detail or accurate color at that resolution.  It's just a resource the printer uses to simulate decent-looking output at normal viewing distances.  The dots don't change, they're the basic component used to create output.  At different pixel resolutions, more or less of them are used to create each pixel.  Regardless of the printed pixel resolution, under magnification, you'll be viewing the contents of the secret sauce.
Comment: This is a great reply, think you for taking the time to walk through each component and relationship. The internet is full of DPI != PPI articles (which is obvious) but few have spent enough time on explaining details like how each technology compensates for it's characteristics.
Answer: Printer DPI (dots per inch) and image resolutions, measured in PPI (pixels per inch) -- confusingly enough too many sources use DPI for this also, even though they shouldn't -- are not the same, nor are they equivalent.
With one exception (see below), when printing greyscale or colour images, you do not need one pixel for every dot a printer can print in order  to have ooptimum quality. As harrymc pointed out, in the case of colour or grayscale images, 300 PPI is usually enough. The increase in printer resolution merely means you have access to more shades of gray as pointed out by the formula in the first answer in the link (<code>(Output Resolution / Screen Frequency)^2 + 1 = Gray Levels</code>) provided in the question.
The exception is line art which you want to save as a bitmap (not the file format, the bit depth), where every pixel is either black or white and cannot be any other colour. In the case of line art, you ideally want to match the printer's resolution. That said a line 1/1200th of an inch wide is thin indeed and finer detail is probably wasted on anyone looking at the image at a normal viewing distance (40-60 cm) since it roughly matches the human eye's acuity (see this answer). So 1200 PPI is usually enough for line art.
Comment: The reason why one would want the highest DPI is to be able to scale the image down on paper without changing the resolution, so one could then place many of these images next to eachother on paper. This is often done to archive lots of information to a small physical size, where one uses a magnifying glass to aquire the data. I believe this is the quiestion OP wants answered. That said, no where in the answer do I read what DPI setting he needs to use to get the max out of his printer.
Comment: @LPChip: You are lucky that it was I that received the downvote for suggesting that DPI cannot help for enlarging an image with a magnifying glass (or printing a small image). There is a confusion of terms here, but I'm unable to make it clear to the poster that there is no magic possible. Maybe you can do better.
Comment: @LPChip - Your use case is correct: I am seeking to print out something tiny which I will read with a magnifying glass. I will edit the question.
Comment: @harrymc I would've posted an answer if I was able to properly formulate it and have the answer to the question he has. I know exacly how DPI works from a photo editor perspective as I had to deal with it when I created my Album art for the shop that printed my album, but as to know how to deal with different height and width settings of a printer, not sure. In theory, exporting the image with DPI of 4800 would not change the amount of pixels, but tell the printer how small to make it. But he may lose details on the vertical axis. So 1200dpi might be the max. I'm just not sure.
Comment: @harrymc but I'll give it a shot, anyway.
Answer: Dots per inch (DPI) is :

Dots per inch (DPI, or dpi) is a measure of spatial printing or video or image scanner dot density, in particular the number of individual dots that can be placed in a line within the span of 1 inch (2.54 cm).

DPI is a measure of how many dots in an inch, or in other words the quality of the
image. A higher DPI helps when you are printing the image on a larger surface,
such as a high-quality printer, to avoid pixels being "smeared".
The DPI has effect when the image is created, usually by a scanner,
or in your case Matlab. Changing it afterward makes no sense.
The DPI is a property of the entire image and has no horizontal or vertical components.
You may specify any DPI that works with your printer.
The default is usually 300, but for a high-quality printer 600 or 1200 is enough.
You may have meant resolution rather than DPI, and in this case the best
one is the one that matches the printer,
The print quality also depends on the program you are using for the print,
as well as on the printer being set to high quality print.
Comment: I was not the one who downvoted you, but it seems that a printer can actually have different DPIs in the horizontal and vertical directions based on [link](https://superuser.com/questions/160219/what-advantage-does-a-2400x600-dpi-printer-have-over-a-1200x1200-dpi-printer). But I don't know how this works with software that assumes one DPI value for the whole image, like Matlab does.
Comment: I was also not the one who downvoted it, but it doesn't actually seem to answer the question, rather only explain what DPI is. If I were the OP, this answer would not help me. For example, would OP need to do 4800x1200=... DPI? or is 4800DPI for a square inch? Or is 4800DPI already higher than the max, and is the max 3/4th of 4800DPI?
Comment: @KAE: There might be some confusion here between DPI and resolution.
Comment: @KAE: Yes, very different. The resolution determines the number of pixels/dots in the image, which is what the printer prints. DPI is just a property of the image relating more to the setting of the scanner that created it. Image resolution smaller than the printer page means that the printer must create pixels by approximation.
Comment: @LPChip: The image is filled with pixels. The DPI is only meaningful during the creation of the image, since it indicates (normally to the scanner) how many pixels to generate per inch. In the poster's case, he can set Matlab to a given resolution, and the DPI is then really just a comment and has no effect when displaying the pixels.
Comment: Why the immediate downvote?
Comment: @LPChip: The explanation was because of the confusion between DPI and resolution. DPI in my experience has little effect on print quality - resolution is the important parameter. The DPI I advocated is quite enough for high-quality print.
Comment: @harrymc: I am likely confusing DPI and resolution. The printer [specification](https://www.ricoh-usa.com/en/products/pd/equipment/printers-and-copiers/multifunction-printers-copiers/mp-c6502-color-laser-multifunction-printer/_/R-416623) says it is capable of "printing at up to 1200 x 4800 dpi". Meanwhile [Matlab](https://www.mathworks.com/help/matlab/ref/print.html#bukyb6e-1-resolution) says the user can save the tiff file "indicating the resolution in dots per inch". Are these different? If so what resolution do I choose in Matlab to print the image at the highest resolution on the printer?
Comment: @harrymc: I am printing something tiny which must be legible when looked at under a magnifying glass. That is why I need the highest possible resolution that the printer can produce. I control the DPI value when I create the file, so what should I choose given the printer's specifications?
Comment: You cannot create pixels from nothing. Only in films is it possible to infinitely enlarge images, in real life the pixels are smeared. A large image can be displayed as smaller and still be legible, but no way that a small image can be enlarged without losing quality, unless it is in vector format such as PDF which can always adapt.
Comment: A strong enough magnifying glass will be able to see the individual pixels, not the image. What you need to do is have several versions of the image in various resolutions, and switch to larger-resolution when magnification is required. Or make the image the best quality that is practical (resolution) and hope that the magnifying glass is not too strong. Displaying it larger will help.
Comment: DPI is a conversion between pixels and physical size. A photo in photoshop can have a resolution of 1024x768 with a low DPI and print to an A4 paper almost full screen. But if you make the DPI high and not change the resolution, then it prints out tiny. So if you change the DPI of an image without changing the resolution, it will be bigger or smaller printed, so getting the max DPI setting is definitely something you want to look for to get the best result on an as small possible space, so you can fill the paper with more image.
Comment: @LPChip: Correction : The DPI can be used by the printing program to scale the image when printing, in the sense that so-many-pixels-per-inch. But that can be overridden to accord with the pixels.
Answer: I know I'm way late to this party and you've all likely figured it out but I'm gonna bump this necro thread for the sake of anyone else looking for information.
The source of confusion here is that everyone seems to be using the term DPI to describe both the amount of dots of ink a printer can produce on physical paper, and the pixel density of the digital image they are trying to print.
This is wrong, and why people are confused and asking was 4800 x 1200 DPI equals to in terms of their software (which is a single number).
DPI is for printers ONLY. It is how many tiny dots make up each "pixel" when printed to paper. PPI refers to pixels per inch and is how much individual pixel data is recorded / used in the digital image. People are saying DPI when they mean PPI when they talk about their digital image resolution. These 2 are not interchangeable nor related although many software engineers have misused the terms in their UI design leading to this misrepresentation.
if your picture is 10 inches wide at 100 PPI and you change the PPI to 300 then likely you will see your image resize to 1/3 the size on your screen down to 3.33 inches. If your image only has 1000 pixels across then at 100 / inch it would need to be 10"  wide, but if you are now going to use 300/inch  (which does not change the resolution as you still have 1000 pixel) then this can be achieved in 1/3 the space since you've essentially just pushed everything closer together. This can actually cause a LOSS of clarity when it comes time to print depending what dimensions the printed product is created with.
Basically the PPI setting in your software is meaningless and you can only determine optimal PPI if you know the size of the image to be printed - also it will not change the resolution of the displayed image. An image that is 72ppi vs 300ppi digitally are exactly the same, although some people seem to think that one is "hi res" and the other is "low res".
Here's a link I found that explains things fairly well if you need more information on the subject: http://www.rideau-info.com/photos/faq.html
Comment: You wrote a long explanation on what DPI is and what it isn't, but forgot to answer the question: "what resolution do I save my tiff at for max printed resolution?"


AWS CloudFront Root Object Update Latency

Question: I deploy a single-page application website by pushing assets to AWS S3 and serving the files through CloudFront. As per this answer, it isn't possible for me to serve files directly from S3 using SSL under my own domain, so I don't have a choice about using CloudFront if I want to serve files in this way.
When I redeploy, I generate a new timestamped, root HTML file (which itself links to the updated JS and CSS bundles), push it to S3 along with everything else, and then make that new file the new Default Root Object for the CloudFront distribution via the AWS. This prevents CloudFront from caching everything and hiding the updates.
The problem is that, occasionally, CloudFront takes a long time to update the root object. As I write this, I'm tabbing over hitting refresh every 60 seconds waiting for an important change to hit production. CloudFront shows the correct (newest) root object via the web console but it also shows "Status: In Progress."
At times, this delay is barely noticeable, and other times it's quite long. Today it is approaching an hour delay.
How can I avoid this? I'm open to both changes to this deployment method using S3 and CloudFront OR switching to an alternative platform that is known to handle this use case better.
Comment: Do a cache invalidation on `/` after changing the root object.  Changing the root object doesn't remove old responses to requests for `/` from the cache.
Comment: Interesting Michael, I'll try that out. Thank you!
Answer: This is how I solved it.
Enable caching values to 0 seconds in cloud front.
I have also noticed browser caches document served.
I had to add http headers to S3 bucket to serve every object not to cache,
<code>Cache-Control: no-cache, no-store, must-revalidate
Pragma: no-cache
Expires: 0
</code>
Documentation on Object Expiration:
http://docs.aws.amazon.com/AmazonCloudFront/latest/DeveloperGuide/Expiration.html
If you set your cache to a long time and like to remove the cache from CloudFront, you can do the invalidation on the root object.
Hope it helps.


How to program DSP inside ADAU1772 codec?

Question: I have read ADAU1772 audio codec datasheet but there is no information about internal DSP's instruction set and how to program it. There is a guide for evaluation board with ADAU1772 but I do not have that board. What is more pins of my ADAU1772 are permanently connected to FPGA so I have to program it using FPGA. I just need information which registers inside audio codec I should write and what are possible instructions. Unfortunately I can not find any information on Analog Devices website.
Comment: Look up sigmadsp software
Comment: I have read about SigmaStudio but I am not able to program ADAU1772 directly using it because the only way to communicate with codec is via FPGA. What is more SigmaStudio does not support Linux and I found no tutorial how to make it run on Ubuntu. I wish I found some instruction how to program DSP in low level way.
Answer: The instruction set of the Sigma DSP family is not available.
The only way to create a program is to use the Sigma DSP software.
When you want to load this program into the chip, you can do this in several ways:

using the Sigma DSP software
using a microcontroller connected through i2c: but read the docs, it is not that easy!
by telling the adau to autoload its program from an i2c eeprom


What method is used in multcomp::glht to adjust the confidence intervals?

Question: I know I can specify the adjustment for p-values (Bonferroni, Holm, etc). But I can set nothing for confidence intervals. How is that handled? I would like to set the Dunnett method for the confidence intervals, but it sets only the contrast. Neither in the documentation I cannot read about except that it is "multivariate" confidence intervals. How are the confidence intervals adjusted for multiplicity?
Answer: Let the ANOVA statistical model
$$
y_{ij} = \gamma + \mu_i + \sigma\epsilon_{ij}, \quad
i = 0, 1, \ldots, m, \quad j = 1, \ldots, n_i
$$
where $\epsilon_{ij} \sim_{\textrm{iid}} \mathcal{N}(0,1)$.
Introduce the statistics
$$
t_i = \frac{\bar{y_i} - \bar{y_0}}{\hat\sigma\sqrt{\frac{1}{n_i} + \frac{1}{n_0}}}
$$
where
$$
\hat\sigma^2 = \frac{\sum_{i=0}^m\sum_{j=1}^{n_i}{(y_{ij}-\bar{y}_i)^2}}{\nu}
$$
with $\nu = \sum_{i=0}^m n_i - (m+1)$.
Then, under the null hypothesis $H_0\colon \{\mu_0=\mu_1=\cdots = \mu_m\}$,
the random vector $\mathbf{t}=(t_1, \ldots, t_m)$ follows a multivariate Student distribution with $\nu$ degrees of freedom and scale matrix $\Sigma$ given by
$$
\Sigma_{ij} = \begin{cases}
1 & \text{if } i = j \\
\sqrt{\frac{n_i}{n_i+n_0}}\sqrt{\frac{n_j}{n_j+n_0}} & \text{if } i \neq j
\end{cases}.
$$
Under $H_0$, let $q_p$ be the equicoordinate $p$-quantile of $\mathbf{t}$:
$$
\Pr(t_1 \leq q_p, \ldots, t_m \leq q_p) = p.
$$
Then the two-sided adjusted $100p\%$-confidence interval of $\mu_i - \mu_0$ is given by
$$
(\bar{y_i} - \bar{y_0}) \pm
q_{1-\frac{1-p}{2}}\times\frac{\hat\sigma}{\sqrt{\frac{1}{n_i}+\frac{1}{n_0}}}.
$$
A bit more details on my blog.
Comment: This is excellent answer. Thank you. This should be really part of the documentation, like in SAS pages. Just one more question. So here I can see this gives me simultaneous confidence intervals. The same method seems to be used for Dunnett and Tukey. Am I right, that only the contrast is different (pairwise vs all-to-control), and the method of adjustment is the same? Is this comparable to Bonferroni? I am asking as my reviewer asked me to adjust p-values for each comparison using Bonferroni and Holm. He also asked me to adjust the CIs. I assume I could do that by correcting the alpha
Comment: and display just the univariate Cis, calculated using the corrected alpha, according to the method I want, yes?


RDP violation without credentials

Question: On a Windows Server 2003 machine seems like someone has logged in through RDP without using credentials: there is a logged access, but there are nor userid nor password.
I am wondering how is this possible, and I can't figure out a valid scenario, so I'm asking here.
This has been made by an attacker who then created an administrator account and re-logged in through his brand-new own-created account.

EDIT: ok, I now got the logs: in the Windows Event Logs there are some actions performed by a user that use a SID instead of a username. Those actions leads to a successfull login as sadmin, the renamed Administrator account, and that is the violation.
So he doesn't created a new account but he exploited the administrator one.
Comment: This is impossible to explain without logs. Logs are your data; any explanation is based on what's logged. "There is a logged access"---what is in this log entry, and what other events happened shortly before/after. Without that information, no one can provide meaningful help.
Comment: You mention this was made by an attacker - was this a pen test?
Comment: No, this was not a pen test
Comment: @Flash - if you have the event logs at hand, this would help an answer. There could very well be an exploit in use here, especially considering this is on a Windows 2003 server.
How do you know there were no credentials used? Was this observed by eye, through a SIEM tool event or a raw log?
Comment: After some struggle, I now have the logs. I'm trying to update the answer to ask your questions.
Answer: As Chris already mentioned, an exploit could be run against the RDP server, or another gained access via another service (Telnet, SSH, Apache Server, etc...). Whether this was via a zero-day exploit or a brute force attack, is another matter.
Two exploits come to mind though, CVE-2008-4250 and CVE-2012-0002. However, without logs, I cannot know for certain. Furthermore, my answer is restricted to remote access attack vectors. Physical attack vectors have not been considered.
Comment: The CVE-2012-0002 seems to be the most probable scenario, but I can't be sure.
Answer: Highest chances are they either found a valid exploit on the RDP version on this system and they gained access without credentials, or they found an exploit at another exposed service running in the same machine, got administrative access through it and launched an RDP connection to their new user. Scenario no.2 (gaining access from another service) could happen in other ways as well. That could include physical access (badusb, infected files through USB, quick access to keyboard when no one was looking etc), payload drop through malicious emails or fake web pages and way more, sometimes beyond imagination. So, there are lots of possible and VALID scenarios, since everything running in this server (including the server itself) sounds outdated.

RDP violation without credentials


10 Trading.com - Fake or not?

Question: I invested small amount of money 5 years ago and then panicked and withdrew it all, 10Trading was the company and I believe they were closed down, however periodically I receive emails suggesting I still have an investment of bitcoin that needs refunding to me as 10Trading is shut, Is this just a very elaborate scam? or could I be owed money.. I don't understand bitcoin but the emails ask for various details and suggest it can be put into a Blockchain wallet or Kraken, which I have had help to set up but still suspicious of the emails should I block all contact?
Comment: It is a scam. If you withdrew your money five years ago, AND the company was closed down, then you don't have any money or cryptocurrency on deposit there. They are asking you for "various details" which means they are trying to phish information from you. Block all contact.
Comment: If it's real, they will just give you the money and maybe ask for ID (be cautious about giving them ID). If they demand money before they give you the money, then it's a scam. If they ask for your Blockchain Wallet password or Kraken password, it's a scam. If it's real, they only need your bitcoin address and they don't need to know anything else about your wallet.
Comment: @user253751 While we could construct contrived scenarios where it could happen, in actual practice I feel extremely confident in saying that if someone reaches out to you and claims to be in possession of bitcoin to which you have a claim, it is a scam 100% of the time.  You don't need to check anything.  it's *always* a scam.
Comment: @GrandOpener ... unless it was a trading platform where you bought some bitcoin and then the platform shut down
Answer: There is a long history of somebody purchasing a dead trademark and url to make people believe that an old favorite is back.
This goes beyond that.
They have some information that tells them that you used to have an account. Their plan for you is to convince you to provide them with more information about you. This they can then use to get money from you directly, or they want to use the security and ID information you provide them to see if they can use that information in other places.
If you closed your account, and they went out of business, there is no reason to provide them with any more information. Ignore them. Block them.
Comment: Also if after reading this you're thinking "That all makes sense....but...what if I **do** have millions in bitcoin?"? This is what they're counting on.

10 Trading.com - Fake or not?


ExtJs infinite-scroll grid with ajax proxy

Question: I try to solve some problem but I stuck. So I want to make something like this using not jsonp proxy type but ajax proxy type. I have some site with API I can not access source PHP code. When I set
verticalScrollerType: 'paginggridscroller',
invalidateScrollerOnRefresh: false,

for my gridpanel and
pageSize: 200,
buffered: true,
proxy: {
    type: 'ajax',
    startParam: 'offset',
    limitParam: 'count',
    url : 'https://api.vkontakte.ru/method/audio.get',
    extraParams: {
        total: 50000
    },
    reader: {
        type: 'json',
        root: 'response'
    }
}

for my store the grid is filled with my data but scroll do nothing (when I drag it, contents of grid did not scroll down). When I try to change proxy type with jsonp my data is not loading at all.
What is the correct way to make grid infinite-scroll and is it possible to make store's proxy of ajax type? And how to make it works with my custom startParam and limitParam?
Answer: Try to use guaranteeRange(0, your_page_size-1) instead of very first load()


Remove pin lock from an old forgotten phone

Question: I broke my current phone so I thought that I would use my old Samsung j1(2016) but it seems that I forgot the 10 digit pin code (10 because the code used all digits including 0). I searched the net but the phone doesn't have developer option activated, custom rom/recovery and wifi/3g deactivated.
Please help me I don't want to delete all my data.
Answer: You can Unlock your device using Odin to flash firmware but it can't stop get formatted during flash process.
When flashing a firmware it clear the internal storage.


How does Package Disabler app work?

Question: There are two apps that can disable system apps (bloatware) from Samsung and LG devices. Those do not need root or any special permission. Can anyone explain how this works?
Answer: There is a difference between disabling and removing bloatwares. Disabling can be done without root, but removing them can be done with root only.
The app for LG that you mentioned changes device ownership permissions. It asks you to make itself the device owner. Quoting this site,

A Device Owner is an application that runs as a device administrator on your Android 5.0+ device. The Device Owner app can use the programming methods in the DevicePolicyManager class to take control of the configuration, security and other applications on the device. A device can have only one Device Owner. No other applications can utilize the methods in that class to control the device.

As a device owner, the app can modify the partitions that cannot be otherwise accessed without root. Basically you can consider this a restricted root access (restricted because root permissions have many more privileges compared to device ownership).
Remember that making any app a device owner is kind of playing with your phone's security, so don't do that unless you trust the app fully. In root, you have an option to deny root access. Here, you won't even know what the app is doing under cover, and it might be late before you actually remove it.
Comment: Do you know how the samsung app works? It seems to not require the device owner permission (but device admin).

How does Package Disabler app work?


If I shoot a hockey puck on ice, is the force of me shooting it applied throughout its travel, or is it a one time force?

Question: For example, if I take a slap shot on a hockey puck, from what I understand, the forces acting on the puck are friction, the normal force, and the puck's weight. And, since I'm not constantly either pushing the puck, or pulling the puck there are no other forces acting on the puck, because me shooting the puck was just a one time force. Am I thinking about this correctly?
Comment: Depends on the time frame you look at. You could consider your driving force to be a one time event or you could model it as a time interval of acceleration (which is of course short, compared to the time, the puck travels on ice without this force).
Answer: Yes, you are thinking about it correctly. No force is required to keep the puck in motion. This is an important idea in physics. It is actually a common misconception among physics students that a force is required to keep an object in motion, so it is good you do not have this misconception.
Comment: "Physics students" here includes Aristotle, for instance
Comment: Or Zeno who did not believe in motion at all.


Reuse of USB after ubuntu installation

Question: This might seem like a stupid question but...

After using a USB to install Ubuntu, is it possible to use it as a regular USB again or is it like a CD install and the USB is now only good for installing Ubuntu?
Thanks.
Answer: Yes you can.
Infact you can keep the Ubuntu setup as it is and use the remaining free space to store other things, just incase you need Ubuntu installation in future.
Answer: You can use it normally, just be sure you have cleaned up the MBR for the case you leave the device plugged in at restart (when USB boot is still enabled).
Easiest is to format the whole partition (or use a partition manager to clean up the whole device). GParted should be able to do this for you.
Some (sketchy!) technical background:
The USB device is a flash device, where bits are stored non-volatile, but eraseable and changeable. Bits at a normal CD-ROM will really be "burned" in as the reflection capacity will be permanently changed when creating a CD. When booting up your computer, there is small memory ROM that contains a bootloader, that is looking up for devices containing a MBR at the first 512 bytes, that will be executed and load the OS (or in your case the first steps of the Ubuntu installation process).
So if you want to use the USB device as normal data storage again, you should also clear up these first 512 Bytes, as the bootloader from the USB could be loaded otherwise when leaving the device plugged in at reboot. Then the bootloader could throw an exception, as it would normally expect the Ubuntu installation files to be present onto this device.

Reuse of USB after ubuntu installation


Android Studio Google map api and API key for release

Question: For android studio google map api, when you generate a signed APK in android studio does the API key get updated in the   android code for release?
Answer:
when you generate a signed APK in android studio does the API key get updated in the android code for release?

Android Studio does not issue API Keys for Google Maps API. You change your API Keys in the Google APIs Console. So, you will be using the same API Key.
Now, there are a few things you need to take into consideration. If you add package restrictions to your API key, you normally have to provide a SHA-1 signature which is unique to your app. This signature does change between Build Variants (debug, release, etc.). So, when you generate signed APK for the Release Build Variant, the app's SHA-1 signature will be different. And you will need to reflect that on the API Key settings (if you have restrictions configured) by:
1- Adding the new SHA-1 signature and package name in the list of restrictions. See image below

2- Or, by creating a new API Key dedicated to the release variant only and adding the necessary package restrictions there.
Retrieving the SHA-1 signature
There are plenty of information out there about how you can find the SHA-1 signature of your package(s). Mostly using the keytool utility which is provided by the JDK (I think).
Yet, the easiest way to retrieve the SHA-1 fingerprint of your application package is by running the signing report gradle task in Android Studio. To do that:
1- Expand the "Gradle" tool window
2- And navigate to your app module's signing report task

3- Double-click the signingReport to run it
4- It will produce the MD5, SHA-1 and a SHA-256 fingerprint in the "Run" window
Comment: So will the API key be different in final release version upon generating APK release in Android Studio?
Comment: No, never. Unless you're using different API Keys for different build variants or product flavours
Comment: well then I don't understand my google map shows in emulator but not live downloaded and installed on a actually device??
Comment: I checked my release XML. seems at the point of APK generated the map api key is not populated in the release XML for me
Comment: I now have a SHA1 for debug variant and another SHA1 for release variant. And I have the API key in the XML. Still does not work in release version. Any idea?


need help to install rvm on ubuntu 10.04

Question: I followed the instruction on this tutorial.
http://coding.smashingmagazine.com/2011/06/21/set-up-an-ubuntu-local-development-machine-for-ruby-on-rails/
I got stuck on installing RVM.
<code>$ bash < <(curl -s https://rvm.beginrescueend.com/install/rvm)
$ cd
$ nano .bashrc
$ [[ -s "$HOME/.rvm/scripts/rvm" ]] && . "$HOME/.rvm/scripts/rvm"
$ source .bashrc
$ type rvm | head -1
</code>
error message: bash: type: rvm: not found
i went back check line by line, found out that .rvm folder never get created.  I use the same tutorial on another ubuntu box, have no problem at all. coudlnt figure out what I did wrong this time.
Answer: You could try
<code>curl -L https://get.rvm.io | bash -s stable
</code>
as per the rvm documentation. Good luck


How can I set up MongoDB on a Node.js server using node-mongodb-native in an EC2 environment?

Question: I got help from many people here, and now I want to contribute back. For those who are having trouble making a Node.js server work with MongoDB, here is what I've done.
Comment: Please put this in the form of a question, then move the answer part down to an answer.  I appreciate what you're trying to do, but please keep it in the form of Q&A.  Thanks.
Comment: By the way, it is just the tip of the iceberg.  I still have to explore 1) how to make replicate mongoDB, 2) how to make replicate mongoDB locally, 3) how to do sharding, 4) multiple instance and load balancing, 5) how to manage multiple instances with nodejs server, 6) how to manage local data in each instance.    There are lots of things I have to look up. :)  If you have any reference, please let me know.
Comment: for load balancing use HAProxy: http://stackoverflow.com/questions/4360221/haproxy-websocket-disconnection/4737648#4737648
Comment: mongodb needs to run on its own instance if you planning to load balance your node app using HAProxy. It makes it easy to shard your db.
Comment: ok. I will take a look.  Do you know if I use AWS load balancing service, will it work?  also, I still don't understand one thing.  If each instance save data locally, then that's mean if I have 10 instances, then it will save in 10 places?  and each instance may have different data?
Answer: This was originally posted by the question asker. A mod asked him in the comments to post it as an answer, but got no response. So, I cleaned it up and am posting it myself.
When you look at the code, you will notice that the createServer code is inside db.open. It won't work if you reverse it. Also, do not close the db connection. Otherwise, after the first time, the db connection will not be opened again. (Of course, db.open is declared outside of createServer.) I have no clue why createServer is inside db.open. I guess it may have to do with not opening too many db connections?
Also, one problem I face is that when I run it via SSH, even if I run the server in the background (e.g. $ node server.js &), after 2.5 hours, the server dies (not the instance though). I am not sure if it is because of terminal connection or what.
Here is the procedure & code
Environment: EC2, AMS-Linux-AMI
Purpose: Take an HTTP request and log the query, IP and timestamp into MongoDB.
Steps
1) After creating the instance (server), install gcc.
$ yum install gcc-c++

2) Download Node.js files and unzip them. (I used version 2.6.)
$ curl -O http://nodejs.org/dist/node-v0.2.6.tar.gz
$ tar -xzf node-v0.2.6.tar.gz

I renamed the unzipped folder to just "nodejs"
$ cd nodejs
$ sudo ./configure --without-ssl
$ sudo make
$ sudo make install

make takes a long while.... After that you can try running the sample in nodejs.org
3) Install MongoDB. I installed version 1.6.5, not 1.7.
$ curl -O http://fastdl.mongodb.org/linux/mongodb-linux-x86_64-1.6.5.tgz
$ tar -xzf mongodb-linux-x86_64-1.6.5.tgz
$ sudo mkdir /data/db/r01/

I renamed the folder to "mongodb"
Run the db process:
$ ./mongodb/bin/mongod --dbpath /data/db/r01/

Then if you like, you can run and try out the command line. Refer to MongoDB's website.
4) I recommend that you create your own AIM based on your instance. It will take 20 minutes. Then, recreate the install and run MongoDB again.
5) Install node-mongodb-native
$ curl -O https://download.github.com/christkv-node-mongodb-native-V0.8.1-91-g54525d8.tar.gz
$ tar -xzf christkv-node-mongodb-native-V0.8.1-91-g54525d8.tar.gz

I renamed the folder to node-mongodb-native
$ cd node-mongodb-native
$ make

6) Here is the code for the server:
GLOBAL.DEBUG = true;
global.inData = '';
var http = require('http');
sys = require("sys");

/* set up DB */

var Db = require('./node-mongodb-native/lib/mongodb').Db,
  Connection = require('./node-mongodb-native/lib/mongodb').Connection,
  Server = require('./node-mongodb-native/lib/mongodb').Server,
  BSON = require('./node-mongodb-native/lib/mongodb').BSONNative;

var host = process.env['MONGO_NODE_DRIVER_HOST'] != null ? process.env['MONGO_NODE_DRIVER_HOST'] : 'localhost';
var port = process.env['MONGO_NODE_DRIVER_PORT'] != null ? process.env['MONGO_NODE_DRIVER_PORT'] : Connection.DEFAULT_PORT;
var db = new Db('test01', new Server(host, port, {}), {native_parser:true});

db.open(function(err, db) {
    http.createServer(function (req, res) {
        res.writeHead(200, {'Content-Type': 'text/plain'});

        global.inData = {'p':'', 'url':''};

        // get IP address
        var ipAddress = req.connection.remoteAddress;
        global.inData.ip = ipAddress;

        // date time
        var d = new Date();
        var ts = d.valueOf();
        global.inData.ts = ts;

        // get the http query
        var qs = {};
        qs = require('url').parse(req.url, true);
        if (qs.query !== null) {
            for (var key in qs.query) {
                if (key == 'p') {
                    global.inData.p = qs.query[key];
                }
                if (key == 'url') {
                    global.inData.url = qs.query[key];
                }
            }
        }

        if (global.inData.p == '' && global.inData.url == '') {
            res.end("");
        } else {
            db.collection('clickCount', function(err, collection) {
                if (err) {
                    console.log('is error \n' + err);
                }

                collection.insert({'p':global.inData.p,
                  'url':global.inData.url,
                  'ip':global.inData.ip,
                  'ts':global.inData.ts});
                res.end("");
                //db.close();  // DO NOT CLOSE THE CONNECTION
            });
        }
    }).listen(8080);
});

console.log('Server running at whatever host :8080');

This may not be perfect code, but it runs. I'm still not used to the "nested" or LISP kind of coding style. That's why I cheated and used global.inData to pass data along. :)
Don't forget to put res.end("") in the appropriate location (where you think the HTTP request call should be ended).
Comment: thanks.. I wasn't no response though but just misunderstand what the mod wants me to do. :)  anyway, thanks for your help.
Answer: By the way, the answer I posted above works for CentOS and Fedora.
For people who have Ubuntu, here it is:
# for Gcc
$ sudo apt-get install build-essential

# for SSL
$ sudo apt-get install libssl-dev

Then just install node.js and mongodb as described above.

Also, after few months of development, I find out using "npm", "express" and "mongoose" can bring my life much easier.  Also, I have installed other tools, like debugger.
# Install Node Package Manager
$ sudo curl http://npmjs.org/install.sh | sh

# for debugging
$ sudo npm install node-inspector

# for Profiling
$ sudo npm install profile

# Install Express, the Node.js framework
$ sudo npm install express

# Install Template Engines (Now, let's install Jade, jQuery Templates and EJS. You can pick the one you want)
$ sudo npm install jade jqtpl ejs

# XML related, install node-expat and then node-xml2js-expat
$ sudo apt-get install -y libexpat1-dev
$ sudo npm install node-xml2js
$ sudo npm install xml2js-expat

# Install Mongoose, (Mongo Driver)
$ sudo npm install mongoose

Reference:
http://npmjs.org
http://expressjs.com
http://mongoosejs.com
Answer: It looks like there might be a bug. It won't allow me to use a var for the first argument in a:b inside collection.insert({
It is treating first agument as 'a' or a, hard coded, either way.
I will look into this and post a fix on github
Comment: I posted it a long while ago.  Now I'm using Expressjs and Mongoose (and Mongolian).  I suggest you to use the same thing and make your life easier. :D


Plaintext DNS traffic in a WPA2 session?

Question: The question I have is, in WPA2 session between the AP and client are DNS requests sent plain text?
Trying to wrap my head around the latest glibc exploit.
Thank you
Ted
Comment: Plaintext at the application layer, yes, but ultimately encrypted at the physical layer.
Answer: No, DNS requests are not sent in plaintext over the air between the access point and client device.  All traffic between the two is encrypted according to the WPA2 spec using the supplied key, including DNS requests.
Once the encrypted traffic containing the DNS request is received by the AP, it is decrypted and can be examined, and it is at that point that the DNS request exists in plaintext again.  It will then presumably be forwarded on to its destination via a wired connection, but not necessarily.
As far as how this relates to the recent glibc vulnerability, only a device that is connected to the network can possibly intercept or read DNS requests.  A device must either be connected via a wired connection, or it must be able to authenticate with a wireless AP.  WPA2, while not as easy to crack as WEP, is still crackable if the malicious device is listening when a valid handshake occurs.  A handshake can be forced by sending out what's known as a "deauth frame".  This forces devices in range to re-authenticate with the AP, which allows the attacker to capture the handshake.  Once captured, the attacker can use this data from the handshake to crack the password.  Depending on how much processing power they have and how secure your password is, this could take anywhere from a few minutes to a whole week.  A week is a lot of time and energy to invest in cracking some random person's wifi (an attacker will likely move on to the person who has "pony123" as their password), so you can inoculate yourself against this kind of attack by choosing a secure wifi password (avoid dictionary words, use upper- and lowercase letters, use numbers, and maximize the length).
Once a malicious device has access to your network, it can potentially interfere with DNS requests and exploit the vulnerability in the glibc library.
What can you do about this?  First, make sure all of your affected operating system instances are patched.  Then make sure you aren't using any apps that are also affected.  Any application that is statically linked to glibc will also need to be updated with the patched version.  Dynamically-linked applications will be effectively "patched" when the OS is patched.  You can also set your DNS server IP addresses manually (for example, use Google's 188.8.131.52 or Level3's 4.2.2.X range) which will cause your device to ignore DNS responses from spoofers (assuming they aren't also IP spoofing).  And, obviously, choose a secure wifi password.
Comment: Thank you. Just trying to understand how an attacker would exploit the glibc bug.
Comment: Edited with more context concerning the glibc exploit.


I have Blockchain.info wallet which i can't find

Question: I opened up an account with a site called Blockchain.info got a username and password, got a Bitcoin wallet address. I then bought some bitcoins sent them to that address, the bitcoins left but now i cannot access any blockchain.info site that gives me access to my account. Does anyone know what is going on with Blockchain.info?
Comment: "now i cannot access any block chain site that gives me access to my account": This is extremely vague.  What exactly did you do, and what happened?
Answer: 1) Blockchain.info was down for a few moments in recent days - please re-check it's availability.
2) Blockchain.info sends an email confirmation with your wallet's "Identifier". This is your login/username. Try searching your email for "blockchain" and see if you have that email.
Subject: Welcome To My Wallet
Body:

This email contains important information about your new bitcoin
  wallet. Be sure to keep this safe and stored separately from your
  password.
Login Link:
  https://blockchain.info/wallet/9c......
Notifications: Notifications Are Disabled Confirmation Code: D9028
Verification Link:
  https://blockchain.info/wallet/verify-email?data=xxxxxxxxxx

Clicking the first link to your wallet will pre-fill your identifier (login), and just need the password you set when you started. That will get you into your account.


Skew and Kurtosis are so similar?

Question: I've been taking the histogram of the optical flow in videos and plotting the kurtosis and skewness of each frame. At the end of the video, I noticed that the skewness and kurtosis follow each other - ie, when the skewness goes up so does the kurtosis and same when it goes down. In fact, the kurtosis almost looks just like a scaled version of the skewness.
I know skewness and kurtosis are supposed to be different concepts entirely, since they are different moments (the graphs of x^3 and x^4 do not look similar at all ) but it just makes me wonder why take both when they both seem to be similar? How are they useful separately? Also would it be due to my distributions? For what distributions would this kind of behaviour occur?
For reference the functions I am using are scipy.stats.skew and scipy.stats.kurtosis so I'm assuming that they are using sample skew and kurtosis
Answer: A simple and direct answer is that skewness and kurtosis are both defined in terms of the $Z-$values, $Z = (X-\mu)/\sigma$ : Skewness = $E(Z^3)$ and Kurtosis = $E(Z^4)$. When talking about a data set, you can just replace the expectation operator "$E$" with the ordinary average.
Since raising a number to either the third or fourth power amplifies values that are greater than 1 (in absolute value) and diminishes values that are less than 1 (in absolute value), both skewness and kurtosis are primarily measures of the heaviness of the tails of the distribution of $X$.
Note that the $Z$-values than are less than one in absolute value correspond to $X$-values that are less than one standard deviation from the mean; greater than one correspond to values that are more than one standard deviation from the mean. Hence, the averages of the $Z^3$ and $Z^4$ values are highly influenced by the $X$-values that are many standard deviations from the mean; i.e., by the tails or outliers.
Consider skewness first.  By definition of skewness, and by definition of center of gravity, the graph of the probability distribution of $Z^3$ balances (i.e., has a center of gravity) at the skewness of $X$. Hence, if the tails are heavier on the left side of the distribution than on the right, then skewness is negative. Conversely,  if the tails are heavier on the right side of the distribution than on the left, then skewness is positive.
Now consider kurtosis. The graph of the probability distribution of $Z^4$ balances (i.e., has a center of gravity) at the kurtosis of $X$. Note that the kurtosis of the normal distribution is exactly 3.0. Hence, if the tails are heavier on either or both sides of the distribution than the tails of the normal distribution, then the kurtosis is greater than 3.0, and the probability distribution of $Z^4$ falls to the right when a fulcrum is placed at 3.0. Conversely, if the tails are lighter on either or both sides of the distribution than the tails of the normal distribution, then the kurtosis is less than 3.0, and the probability distribution of $Z^4$ falls to the left when a fulcrum is placed at 3.0
Hence, skewness and kurtosis really do not measure things that differently - they are both measures of tail heaviness. The biggest difference is that skewness considers relative heaviness in one tail versus the other. The Wikipedia entry on kurtosis displays both lower and upper bounds for kurtosis in terms of skewness.
There is a mistaken but remarkably persistent meme out there that kurtosis measures "peakedness or flatness" that might be a source of confusion.  Your work shows (yet again) that this characterization is false. See  here for a clear explanation of why the "peakedness/flatness" characterization is wrong.
Answer: Skewness and Kurtosis are similar, but different.
Skewness is the degree of distortion from the symmetrical bell curve or the normal distribution. It measures the lack of symmetry in data distribution. It differentiates extreme values in one versus the other tail. A symmetrical distribution will have a skewness of 0.

Kurtosis is all about the tails of the distribution — not the peakedness or flatness. It is used to describe the extreme values in one versus the other tail. It is actually the measure of outliers present in the distribution.
High kurtosis in a data set is an indicator that data has heavy tails or outliers. If there is a high kurtosis, then, we need to investigate why do we have so many outliers. It indicates a lot of things, maybe wrong data entry or other things. Investigate! Low kurtosis in a data set is an indicator that data has light tails or lack of outliers. If we get low kurtosis(too good to be true), then also we need to investigate and trim the dataset of unwanted results.

Mesokurtic: This distribution has kurtosis statistic similar to that of the normal distribution.
Leptokurtic (Kurtosis > 3): Distribution is longer, tails are fatter. Peak is higher and sharper than Mesokurtic, which means that data are heavy-tailed or profusion of outliers.
Platykurtic: (Kurtosis < 3): Distribution is shorter, tails are thinner than the normal distribution. The peak is lower and broader than Mesokurtic, which means that data are light-tailed or lack of outliers.
Hope that helps.

Skew and Kurtosis are so similar?


How can I determine the cause of CF card corruption?

Question: I installed qnx in my CF card and made it bootable and it was working well.  However, yesterday it stopped working while my system was running.  Checking the filesystem revealed that it was corrupted.  I tried to view the log files but they are corrupted and inaccessible.  How can I find out how it became corrupted and which files are corrupted with bit by bit.  How  can I view the hex file of cf card data.  The card is using an ect2 filesystem.
Comment: Are you sure it isn't just that the CF card is broken? One died on me recently in a similar way...
Comment: Presumably "ect2 filesystem" is "ext2 filesystem". How long has this device been running. Is there anything in the system configuration to mitigate CF cell burnout due to excessive writes to particular sectors? Wear-leveling can be important if nothing is done to mitigate repetitive writes to the same area of a file system.
Answer: dd_rescue may be used to obtain a raw dump of a failed device in a way that avoids read aborts due to failed sectors.  This will not necessarily tell you why it failed, but, monitoring if failed sectors occur, and potentially where they are in the file system could help you gather information pertinent to finding a probable cause.
If the operating system image is not configured in a way that limits repetitive writes to particular sectors of a compact flash device, an OS that chatters a lot (logging, etc) can easily access the meta data area of a file system so many times that the FLASH sectors where they are stored reach their maximum write count long before the rest of the media fails.  It can be critical to use a CF device that employs wear levelling algorithms if the OS image is not crafted to avoid high volume of writes to certain areas of the media.
dd_rescue would give you a raw dump of the file system.  If that's what you mean by "the hex file of cf card", then I heartily recommend it.  I have used it to recover data from hard drives that have sustained hardware failures.
If you want to try to recover the log files, PhotoRec does wonders, but for a large partition, it is time consuming and a monumental task to pick through the output of the tool.  PhotoRec can get some file extensions (pictures, mp3's, and so on) correct, but the file names are completely lost.  It does well at recovering text files.  If the CF card failed in the meta data only, this utility would let you recover the content of the log files.
These utilities are on the SysRescueCD.
Hopefully you have not written to the CF card since it failed.  Never write to a failed device if you want to recover it later.  Always mount the media read only.


Can't connect to sql server 2008 named instance

Question: I have sql server 2005 and 2008 running on a server on my local (and very straightforward) network.  Using sql management studio 2008 and visual studio 2008, I can connect over the network to the 2005 instance which is the default instance.  I can't connect to the 08 instance (named MC08).  I can connect to both when logged in to the server.  Remote connections have been enabled for MC08 and dynamic ports is turned off (assigned to port 1045).  The sql browser service is running as well.  This used to work so I'm not sure what has changed.  I can't connect using the IP address either. Nothing unusual in the event log either.  Any ideas?
Comment: Connect with what?  If you are using a non-standard port, you may have to specify that within your connection.
Comment: connect with sql server management studio.  Should I turn dynamic ports back on?  I thought the sql browser service would handle the static port.
Comment: Firewall blocking 1045 perhaps?
Comment: Checked the firewall and its not the problem.
Answer: Have you tried your.sql.server.fqdn\MC08.
The port specification in SSMS is totally braindead though.  For whatever reason they decided to use comma(,) as host and port delimeter instead of colon(:).  So if you want to use a port number use this connection string: your.sql.server.fqdn,1045.
Comment: My server is not using/connected to a domain. I tried adding the ",1045" and that didn't either.
Answer: For completeness I will also point out if you have multiple NICs on the server this can happen because of the client firewall: the SQL Browser response will not necessarily come back from the same IP that the client sent it to (because it uses multicast), and thus that response will be dropped by the firewall.  That was fun to troubleshoot..
Answer: Apparently this whole issue is stemming from a change in internet service providers from this past summer.  Everything worked when I was on comcast.  I switched to charter when I moved this summer and did not have any reason to debug/modify my applications that used sql 2008 databases until this past week.  To resolve the issue, I put an entry in the hosts file on my client pc for the sql server box.  That does not explain why I could connect to the default instance on that box and not the named instance, but either way the problem appears to be solved.  Comcast just let you hook up the modem and then the router.  Charter won't work with a router unless you use mac address cloning and clone the mac address of the pc used in the initial install.  That's the only thing I can see that's different.
Answer: Verify that the TCP/IP interface for the IP you want is enabled.
Additionally, try testing with ODBC DSNs and test with TCP/IP and Pipes.
Or use

telnet your.sql.server.fqdn 1045

And see if you get a blinking cursor, which confirms there's no firewall problems.
Answer: If you have UAC turned on, you may need to start management studio as administrator to connect to the 2008 SQL instance.
Right click -> run as Administrator
Answer: As you can connect to the default instance we will assume that your network and DNS (or some other form of name resolution is working).
Although you have made the 2008 named instance use a static port, the SQL Browser service will still be used to establish the port from the name you supply.
If no response is recieved from the browser service then the SQL client will try port 1433.  I'm assuming that becuase you can connect to the default instance but not the named instance that the problem is probably with this step.
You've aready said the browser service is running so that leaves.
1) Check that UDP post 1434 (or the sql browser service) is allowed through the server firewall.
2) Check that UPD port 1434 is allowed through the firewall of your PC.  (I never found this as an issue from XP but have found it an issue on Windows 7 Pro)
I'd suggest the first step would be to turn off the firewall of the PC you are connecting from.


How to make an executable file appear in search

Question: I've downloaded a program and in order to run it I open terminal, cd into the directory it's stored in and run it by typing ./<program>. This is a bit of a hassle as I use this program on a daily basis. How do I set it so that I can find the program by typing the name of the program (TeamSpeak) into search when I press the super key?
Answer: To have your program show up in the Unity Dash (pressing the Super key), it needs a launcher (.desktop) file in the proper place.
So create a file named TeamSpeak.desktop in the directory ~/.local/share/applications containing the following:

[Desktop Entry]
  Name=TeamSpeak
  Comment=Voice communications system for games
  Exec=/full/path/to/program
  Terminal=false
  Type=Application

After you do that, it should show up in the Dash.
Answer: You need to add the program to the PATH. Go to your home directory. Press Ctrl+H, you can now see hidden files. Open .bashrc in your favourite text editor and add this to the end of the file (changing the directory to the correct one):
export PATH="$PATH:/directory/of/program"

Save and exit.
Open the terminal and run:
source .bashrc

Now try running your program.
Comment: Shouldn't that be export PATH?
Comment: Good catch! Updated. Just seen that you wanted to launch from pressing super! So I was a little irrelevant anyway. Sorry, perhaps would be good to have that at the start of the question?


How to use full screen in RDP

Question: I'm connecting a desktop to a laptop which has a 3000*2000 resolution, if I keep this resolution, the reaction of the desktop would be a bit slow, But when I change it to 1920*1080, RDP became a float window(Some shortcut also don't work if I do so). So I want to know if there's a way to decrease the display resolution of RDP connection without shrinking the window.
Answer: At least, with the Windows official client you cannot do this. If you select full screen, they use the actual screen resolution.
I only think maybe can work if you change screen resolution on Windows before connecting. Another option, find a non-official RDP client.
Answer: As far as I remember, you can modify the .rdp file and set the desktop height and width. Here's the link to .rdp options: https://technet.microsoft.com/en-us/library/ff393699(WS.10).aspx
Also try using another RDP, this for example: https://www.donkz.nl

How to use full screen in RDP


How to include diagrams in posts on stack exchange

Question: Where is this documented? I have been including FENs which have mostly turned into diagrams, but I suspect someone may be helping.
Comment: See balpha's answer to [this earlier meta post](http://meta.chess.stackexchange.com/q/3/167).
Comment: The link in @ETD's comment above doesn't work for me (I get an SSL version mismatch error using latest supported version of Chrome on Windows 8.1 -- I know, I should upgrade, but this is an old laptop...), but rearranging the parts of the domain name to [this](https://chess.meta.stackexchange.com/questions/3/can-we-implement-a-replayer-for-chess-analysis-on-the-site) does work.
Answer: If I give an example of how to do it then you will just see the diagram!
The best way is for you to edit a post which has such a diagram so that you can see exactly how it is done. Copy the part that is displaying the diagram, paste it into your text editor, change it with the data for your game and then try posting it. Of course you should just cancel out of the edit of the original post.
That's how I did it the first time and even now if I want to include a diagram I edit one of my old posts to copy and paste a working example.
Comment: You could have included it here so people don't have to search through all the questions to find one holding diagram - it would be possible then to open edit here and see how it looks - in this format answer is not useful


In S01E01, what was Robert Ford (Hopkins) doing in the storage area with the old cowboy host?

Question: In Westworld S01E01, Was he there just messing around being sentimental?
Had the host 'woken up' and he had gone to investigate like the response team?
Answer: The way I remember it was the response team have detected some unauthorized activity and go to investigate. I think Ford was the "unauthorized activity". I just assumed he was down there tinkering and getting ready for his big narrative.
Answer: This is speculative, but Ford likes to go down and have a (mostly) one-sided conversation with the old cowboy host (Michael Wincott, right?). Probably as a way to remind himself of what the hosts once were, crude, almost Disney level animatronic dolls.
He has several encounters with it over the season, plus he has a basic piano playing host in his office. So he seems to like to surround himself with past achievements and reminders of what the park used to be.
Given the outcome in the season 1 finale

 he also wants (so he says) to set the hosts free and advance their sentience, so these old hosts may serve to drive him on. They may also be the only things he was capable of without Arnolds help, they are his personal "best" so to speak


Using the same ESP8266's GPIO for 3.3v and 5v

Question: I am designing a pcb which should receive various types of sensors. The microcontroller is an ESP32 and the external input are RJ11 linked to I2C GPIOs of the uC. I have already planned a LevelShifter (considering that the voltage of ESP32's GPIOs are limited to around 3.3v) so that the ESP32 can receive sensors with 5v outputs.
The problem is that I want to use the same GPIOS connected to the output of the LevelShifter to take into account 3.3v sensors that could be could be connected to the RJ11 port. For this I thought of using jumpers to either connect the output of the RJ11 port (sensor) directly to the I2C GPIOs of the ESP32 if the sensor is a 3.3v type. On the other side the jumpers are to be placed so that the I2C GPIOs of the ESP32 are connected to the output of the Level Shifter.
Here is what I tried below.
I suppose if the sensor is 3.3v type I cannot connect it to the LevelShifter.
Is this right ? Is there any risk that the floating pins will disturb the communication between uC and sensor through the chosen "way"?
Do you have better solution to suggest me for this case?
Sorry for my English.
Comment: ESP uses 3.3V doesn't it ? So use 3.3 everywhere https://www.ti.com/interface/i2c/general-purpose-ios-gpios/products.html#p0min=1.62;2.3&p0max=1.98;3.6  Scale sensors with R's
Comment: connect both power supply voltages to the connector ... place the level shifter at any sensor that requires it ... no jumpers required
Answer: So you want to connect either 3.3V sensors OR 5V sensors to the (one) RJ11 connector? In that case, for 3.3V sensor, I suppose you also want to provide 3.3V power instead of 5V power?
My solution would be to leave the level shifter in place, and (only) jumper the power at the RJ11 side between 3.3V and 5V.
Comment: The problem is that the output voltage could also be different (not only the supply voltage is attended to be different).
Comment: In that case switch the supply voltage and the secondary I2C voltage independently.


Why don't browsers restrict cookies per-tab to combat CSRF attacks?

Question: Why are the cookies shared between browser tabs? does avoiding this prevent CSRF on cookie based authentication web sites? Is sharing the cookie between tabs favored for easily accessing the website from multiple tabs without authentication?
Answer: Yeah, the cookie is a "browser thing"... not a "tab thing". Is to favor multiple login on the same site on different tabs what in the most of the cases is an advantage.
Yeah, you are right, in the hypothetical case of to have "tab cookies" the CSRF attacks make no sense because as I guess you know very well, the Cross Site Request Forgery attacks are based on:

A user have an already existing session on website A.
Then, clicking on an evil link maybe on website B or in an email or however, another request is done (this is usually done in other tab) launching a forged request trying to do something on website A "abusing" of the already set existing session or cookie on the victim's browser to perform any "evil action".

If you want a separate session on a browser there are ways to achieve that like using private browsing. That separates the session/cookies from the other sessions. That's because is like "other instance of browser", but between tabs of private browsing you'll share session/cookies in the same way.
Hope it helps.
Answer:
Why are the cookies shared between browser tabs?

Because it would break the entire purpose of cookies.
A cookie has three components:

A domain
Some data
An expiration

Every time your browser makes an http request, it checks the (local) cookie database for any cookies that have a domain matching that of the request; if it finds any, it sends them along to the server.
This mechanism was built to provide persistence for the otherwise stateless http. Without cookies, we would need to provide our username and password on every single request to an authenticated site.
If cookies were universally changed to be per-window, a great many things would quickly get annoying. Not only would you need to log in to Amazon again every time you opened your browser, but you'd need to log in every time you opened it in a new tab - whether that's because you closed the previous one when you were done shopping, or because you're opening results in tabs to compare them.

does avoiding this prevent CSRF on cookie based authentication web sites?

It would combat CSRF, yes. It would not be foolproof, since you would still retain cookies from other sites in that tab.
If you ever attempted to apply this policy to a user, they would immediately find some sort of workaround, and probably end up with a less secure system as a result.
If you want to write a browser plugin to do this for yourself... go ahead, but I suspect you'll find the user experience hit too much very quickly.


Can I register in Google cloud and Amazon cloud without credit card for free trial?

Question: I want to register on the site for free trial, but as I have seen, they want from me a credit card, unfortunately I do not have a credit card (because the conditions of my country to obtain it are impossible), is there another way to register without credit card ?
Answer:
So far as I know You can get a prepaid virtual credit card and register for AWS cloud
But for the Google cloud you will need a original credit card. These prepaid credit cards wont work
Answer: Just in case: if you are affiliated with a public research institute, you can indeed register without a credit card. See section 2.4 in of the AWS Research Cloud Program handbook version 1.2.
Answer: Unfortunately there is no way to sign up without a credit card. One possibility would be to find an American or citizen of the UK willing to open the account on your behalf with their own card, maybe pay them with bitcoin or another digital currency.
Comment: Thats not something you want people to do..


Is the expression 学识渊博 usually used in a pejorative sense?

Question: For example, as a sarcastic remark in the sense of "pedantic" or "know-it-all"?
Comment: "Knowledgeable" comes to mind.
Comment: What makes you think so?
Comment: This is usually a positive word.
Answer: No. It's usually used as a commendatory term. But it can be also used in a pejorative sense (the rule is called 褒義貶用).
PS: This is not used in a conversation, or it's an irony.
Comment: So 褒义贬用 means "a sarcastic compliment" or "to make a sarcastic compliment"? I might add that to CC-CEDICT.
Comment: @trideceth12 To use a commendatory term as a derogatory term. (um, sorry for my poor English)
Comment: @trideceth12 Yeah. That's right. But it's a grammatical concept, not a word.


How fast until you feel wind in space?

Question: I couldn't find this question asked anywhere else, so I thought I would ask it here: does anyone know how fast you would have to be traveling in space to feel 'wind' from the particles in front of you? Say a piece of thin, 0.05 N piece of paper traveling in perpendicular to it's width and length. How fast would it need to travel before it would experience, say, 1 N of force?
Comment: What part of space? The particle content of intragalactic space is wildly different depending where in the galaxy you are, and intergalactic space is again a very different environment.
Comment: possible duplicate of [Would a fast inter-stellar spaceship benefit from an aerodynamic shape?](http://physics.stackexchange.com/q/29955/)
Comment: When you say space, I presume you actually mean, say, the Earth's air at sea-level, rather than vacuum?
Comment: You can calculate the force by dimensional analysis, $F = const\times\rho v^2 A$ IIRC. But calculating the dimensionless constant probably requires an experiment...?
Comment: Related: http://physics.stackexchange.com/q/25378/2451
Comment: You will probably feel photon winds (from photons hitting you) which will move you a lot in respect to time.
Answer: That's rather an unusual question though interesting, but it amuses me to make an even more unusual answer.
Disclaimer: this is in no way a rigorous answer, as many assumptions, simplifications have been made (even entire phenomenons such as gravity attraction if the velocity is not perpendicular, solar pressure from photons...) - only a reflection on drag alone. But I think you figured it out since it's Superman we are talking about here.
If you were actually flying like Superman, how strongly would you be affected by drag?

We'll see not only

how fast you need to go to get 1N of force from the drag, but also
what your top speed would be assuming we know how strong Superman's thrust is.

Drag equation
As innisfree said in the comments, the usual formula to quickly get estimates is the drag equation:
$$F_D=0.5 \rho v^2C_DA$$
Let's fill in the gaps, what do we have, what do we want?
Cross section
Loading the above picture in an image editor, Superman's head diameter is ~200px; a lasso select yields a cross sectional area perpendicular to the velocity of ~124900px². Assuming Superman has a head 1.5 times bigger than the average male (just because), this is 725px/m, which means the area is really 0.238m².
Coefficient of drag
This is an experimental parameter linked to the airflow around the geometry, but we'll take it as 0.82 for that of the side of a cylinder.
Drag force / Thrust force equilibrium
When calculating Superman's top speed, we'll assume he can develop the equivalent of the thrust of a medium airplane such as the Airbus A321, or 114kN (after all, he's been seen struggling to stop a plane). No comments on how he's supposed to achieve thrust. Top speed will be reached when drag and thrust oppose eachother.
Fluid density
As said in other comments, the density of the fluid surrounding you is not the same everywhere. In average though in the universe, it is between 0.1 and 1 $atom/cm^3$, or very roughly $1.67*10^{-24}kg/m^3$ seeing it's mostly hydrogen... For comparison, this is $10^{17}$ times less than at 100km of altitude (or the conventional "end" of our atmosphere), according to the simplified model (a more accurate model is available here) in SI units:
$$\rho \approx 1.21e^{-x/8000}$$
Calculations - 1N of force
First, let's answer your question. Rearranging the formula to find the speed at which 1N of drag is developed:
$$v=\sqrt{\frac{2F_D}{\rho C_DA}}$$
We find that you need to fly at:

10km/h at sea level (sanity check)
19km/h at 10km (planes altitude)
68km/h at 30km (stratospheric balloons)
5427km/h at 100km ("end" of atmosphere)
Impossible in outer space ($10^{12}$km/h or much more than the speed of light)

Calculations - top speed of Superman
Still considering the maximum thrust of 114kN, the same equation tells us that Superman can go as fast as:

3537km/h at sea level (or 2.9 times the speed of sound - machs)
6608km/h at 10km of altitude (or 5.4 machs)
23066km/h at 30km of altitude (or the orbital speed at 4000km of altitude)
1.8 million km/h at 100km of altitude (maybe that's why he does not age that much - starting from here numbers become irrelevant as Newtonian mechanics is no longer valid as we get closer to the speed of light)
Just under the speed of light in outer space (would have been above)
Comment: You'd have to stop using that Newtonian pressure formula once you started approaching the speed of light -- the momentum transfer with the ISM particles would start becoming relativistic, so you'd have to calculate the 3-force.
Comment: Wow, I never expected such a comprehensive response! :) really entertaining answer.
Comment: Yes, I very briefly mentioned relativistic effects on the top speed at 100km of altitude, but I'll make that clearer.

How fast until you feel wind in space?


Content > Design >Config shows no records on fresh 2.1.3 install

Question: Fresh install of Magento 2.1.3 with Lumo sample data has no records to edit in Content > Design > Configuration.
How can I fix this?
Answer: A better way to fix this is to run the reindexer command:
bin/magento indexer:reindex design_config_grid

This will update the design_config_grid_flat with the correct values for your site. If you get a message that the index is locked you may need to reset it with:
bin/magento indexer:reset design_config_grid

Answer: May be , your magento instance does not installed properly that why it is created issue.
IN magento 2.1.3 ,Content > Design >Config section does not exit.
You can see at ,Content>Configuration>Design Configuration
You can see theme assignment at Content > Theme >Config
Please check design_config_grid_flat table data.
If does have then run this query
INSERT INTO `design_config_grid_flat` VALUES ('0',NULL,NULL,NULL,''),('1','1',NULL,NULL,''),('2','1','1','1','');

Comment: Thank you I inserted the line you quoted as the table had no rows in it...this then gave me the option to change the header information etc...but upon viewing the store none of the new information is visible..Im adding a second pic so you can see the result of the insert...I have the Luma sample data installed so was expecting to see that change


.htaccess redirect conflict wordpress /wp-admin

Question: I will try to be the most specific as I can when I request help in solving this problem, though I don't have much knowledge about the configuration files used by Wordpress here!
The main folder in the website have this code in .htaccess as my objective was to remove .html from pages
RewriteOptions inherit
Options +FollowSymLinks
RewriteEngine On
RewriteCond %{THE_REQUEST} \/index.html\ HTTP [NC]
RewriteRule (.*)index.html$ /$1 [R=301,L]
RewriteCond %{REQUEST_FILENAME} !-f
RewriteRule ^([^\.]+)$ $1.html [NC,L]

I've also installed wordpress to a /blog folder only inside the main folder. Now I can't access /wp-admin/ (*/blog/wp-admin/), and am receiving an ERR_TOO_MANY_REDIRECTS
How might I correct this?
Comment: Default wordpress .htaccess code are you removed
Answer: Replace your .htaccess content with this:
RewriteOptions inherit
Options +FollowSymLinks
RewriteEngine On
RewriteCond %{REQUEST_FILENAME}.html -f
RewriteRule !.*\.html$ %{REQUEST_FILENAME}.html [QSA,L]


About the hypotheses for a ring to contain a maximal ideal

Question: Most proofs I see that every ring has a maximal ideal (with Zorn's lemma) assume that the ring is commutative and has unit. However, while working out my own proof - assuming that ideals for non commutative rings are bilateral - I did not use the commutativity hypothesis. Either my proof is wrong or the commutativity hypothesis is superfluous. I was wondering which of this conditions, between commutativity and having unit, is necessary for the theorem to hold.
Answer: Having a unit is definitely necessary. Consider the ring $\mathbb{Q}$ where addition is normal addition but multiplication is given by $x\cdot y =0$ for all $x,y \in \mathbb{Q}$. Then ideals are simply additive subgroups of $\mathbb{Q}$ of which there are no maximal elements. This post talks about some more interesting examples A (non-artificial) example of a ring without maximal ideals
The condition that $R$ be commutative is not necessary. It sounds like your proof would be correct. The same outline of a proof is given here.
Comment: I would say that having a unit is "sufficient," as finite rings without unity do have maximal ideals.  Anyway, I don't know whether there is a necessary and sufficient condition for a ring to have a maximal ideal.
Comment: @Zvi Yes perhaps my use of ''necessary'' is a bit misleading but I think it is how the OP intended the word to be used. As in if the condition that $R$ has a unit is dropped, then the theorem is no longer true. The first question I linked to has some discussion on necessary and sufficient conditions.


Is there a snip tool (Windows) equivalent for ubuntu?

Question: Is there a snipping tool similar to the one in Windows which lets you view it even though you haven't saved anything?
Answer: ksnip
ksnip is pretty much exactly like the Windows snipping tool. The UI looks very alike and you would use it in the same way.
You can install via snap with:
sudo snap install ksnip

The source code and other installation options can be found on their GitHub page.
Here are some screenshots of ksnip:

To get more answers you might also want to try the SE site Software Reccomendations.
Comment: @user1141101 You are very welcome!
Comment: very good but I preferred install it from .deb file fo avoid snaps that I've disinstalled from my system. Downloaded .deb file from here : https://github.com/ksnip/ksnip/releases
Comment: @pat Thank you for the comment, I have added the GitHub page to my answer.
Answer: Don't know exactly what you mean, because I don't use any windows snipping tool.
I use "Screenshot 3.36.0" (install package gnome-screenshot). Which I have bound to the "print-screen"-button.
Which this you can copy the screen (or window) to the clipboard or save to file.


When i marinate pork with spices and vinegar , can i also add the sauted onion paste overnight with it?

Question: When making pork vindaloo the recipe says to marinate the pork OVERNIGHT with a mix of spices ( fried and made into a paste with a tablespoon Vinegar ) , the second part is to saute onions till they are golden brown and the add the pork. My doubt is , can i saute the onions and make it into a paste and add it with the overnight marination , will it spoil the taste or will it better it ? Thank you ! You guys are awesome !
Comment: It will essentially be a different dish. Whether it will be better or not is a matter of opinion.
Answer: The separation of the processes is about the chemical reaction between the spices and the pork first. The onions add a different set of chemicals and oils that are unwanted during the marination process. So, no, the taste will probably be different as the onions will change texture overnight, and the addition of the chemicals and flavors from the onions will change the flavors that are absorbed into the meat.
Comment: Just cast my mind back to a previous experience making Chicken Dopiaza... If left too long to marinate, the onion mixture will make the chicken less palatable.


How does a bluetooth earphone receive and play a song at the same time? Multi threading?

Question: I'm guessing the bluetooth earphone has a buffer to hold bytes from the song. This means that it will receive and play the song at the same time. How is this done? Something as small as a bluetooth earphone can't have multi threading can it?
Answer: Typical bluetooth earphones have processors that are as powerful as the ones that powered cellphones just a few years ago. Samsung's newest bluetooth headphones use a 32-bit Arm Cortex M3 CPU, similar to the processors used in smartphones just a few years ago.
Comment: Which headphones are you referring to? Is this also true for truly wireless earphones like the apple airpods?
Comment: Many current models including Samsung's. Apple's Airpods have an even more sophisticated processor designed specifically by Apple. Even the H1 processor could recognize "Hey, Siri!" right on the 'pods.