Origin of "rolled up the sidewalks"

Question: Locally (western United States), a town where the businesses have closed for the evening, particularly if they closed unusually early, is described as having "rolled up the sidewalks".  What is the source of this phrase -- actual removable sidewalks, or merely figurative ones?
Comment: It's figurative (or a witticism). Evocative hyperbolic imagery.
Comment: In the John Denver song, it is rendered as "roll back the sidewalks" - http://www.metrolyrics.com/saturday-night-in-toledo-ohio-lyrics-john-denver.html . I suspect they were temporary wooden roll-ups placed on stringers at the doorway in muddy weather. And you wouldn't want to leave them out at night for the hobos to use as firewood. Plus they would need cleaning. Compare to puncheon floor and corduroy road.
Comment: Unquestionably fictitious. But first usage will definitely be interesting.
Comment: It's an old expression -- I recall hearing it said about a small Kentucky town during the summer of 1966.  I seriously doubt that you can identify an "origin", as it's a sort of obvious metaphor.
Comment: Google books finds uses back to 1938.
Comment: Sidewalks of some sort are one of the signs that a town has come into being as such. (Imaginary) sidewalks that are temporarily laid down in the day and rolled up at night would be an indication of a town being not quite there yet - still pretty undeveloped. Only daytime use of sidewalks would indicate that nothing is happening there at night. Incipient urban life, but so far just a hick town.
Comment: Never heard this expression before, but it immediately makes me think of rolling up the marquees that jut out over the sidewalks. It would have to be a bit of a mangled phrase originally for that to fit, of course; like "the proof is in the pudding" from "the proof of the pudding is in the eating/tasting".
Comment: Perhaps it links to rolling up the shutters on the front of a shop? That is certainly relevant to a street of closed shops.
Answer: How did the expression 'roll up the sidewalks' arise?
I think that the expression is simply a form of humorous exaggeration, indicating that the people doing the "rolling up" have ceased to welcome foot traffic to their door (or through the town) until the next day. I don't think that sidewalk rolling up was ever a phenomenon in the United States.
Traditionally, many small shops in towns in the United States have had canvas awnings over their front doors and/or windows. The shopkeepers would unroll the awnings with a handcrank every morning before they opened for business and then roll up again when they close for the night. During the day these awnings added a decorative touch to the storefront, as well as providing shade from the sun and shelter from the rain or snow, and thus giving passers-by a practical reason to linger at the store's windows.
Awnings have been subject to municipal ordinances in various U.S. towns and cities for more than a century. From Annual Reports of the Various Departments of the City of Columbus, Ohio (1910) [combined snippets]:

To prohibit the erection of awnings, signs and sign posts, boards, poles or other devices, structures or things in the streets and alleys of Columbus except under certain conditions. Be it ordained by the Council of the City of Columbus, State of Ohio:
That no owner or occupant of any house, store or other building, shall erect or construct, or cause or permit to be erected or constructed any awning, sign, signpost, board, pole, or other device, structure or thing, in front of such house, store or other building, on any street in this city, that shall project over the sidewalk of such street more than eight feet from the wall of such house, store or other building; nor that shall be less than eight feet above the pavement of the sidewalk in front of such house, store or other building; ...
Provided, That no wooden awning or other roof shall be constructed over any sidewalk in the city, but all awnings shall be made of canvas or other like material, and so constructed as to be rolled up to the wall when not in use; and, provided further, that this section shall not be construed or understood as applying to railings or other protection around entrances to vaults, basements or cellars.

Although the most common technical name for the design these awnings is "retractable," they are also sometimes called "rollup awnings"—as, for example, by this company. The rolling down and rolling up of shop awnings is familiar to anyone who has spent time in towns and small cities. It's a representative early-morning activity in Joni Mitchell's 1970 song "Morning Morgantown," set in the West Virginia city of Morgantown:

When morning comes to Morgantown/ The merchants roll their awnings down./ The milk trucks make their morning rounds/ In morning Morgantown.

Because not much else is going on in a town or small city at 7:00 a.m.—no hordes of office workers crowd the sidewalks as they head to work—the rolling of the awnings becomes conspicuous activity—and the rolling up of the awnings signals the end of the town's commercial life for the day.
Suggesting that at a certain time of the evening or night the town rolls up not merely the awnings on its storefronts, but even the sidewalks is a humorous way of saying that there is no commercial nightlife at all after a certain time. It's similar to the old Texas joke, "Nightlife in Waco [Texas] ends when the Dairy Queen shuts down at 6:00."
Another possible influence on "roll up the sidewalks" is the expression "roll out the red carpet," meaning to great someone important with appropriate fanfare and respect. What's rolled out may presumably be rolled up afterward, and that notion might be extended humorously from a carpet to a sidewalk. However, "roll up the red carpet" isn't an especially common expression: a Google Books search turns up only 21 unique matches for the phrase.

How old is the expression?
With regard to how old the expression is, the discussion of "roll up the sidewalks at night" at Barry Popik's The Big Apple suggests that the expression goes back to the very early 1900s at least:

I don't know if there is a "correct" version, but I'm pretty certain that "roll up the sidewalks" is the older one. It used to be a staple in the comedian's or writer's repertory for referring to quiet towns. Small, "sleepy" towns have been characterized probably for a century or more as places where they roll up the sidewalks at night. It has become a very common cliché.

And Jonathon Green, Chambers Slang Dictionary (2008) pushes the probable origin date back to the middle 1800s, in its brief coverage of the expression under a longer entry for sidewalk:

roll up the sidewalk v. {mid-19C} (US) of shops and entertainments in towns or cities, to close down at nightfall.

But actual instances in print from the 1800s seem hard to come by. Popik's discussion of the phrase lists instances from 1922 (in an [Portland] Oregonian newspaper article), 1924 (in an item in The Journal of Electrical Workers and Operators), and 1926 (in a Charlie Chan novel by Earl Biggers, serialized in the New York Post in 1925). A directed Google Books search for these instances finds matches only for the Biggers novel (in reprint form). Green doesn't cite any examples. The earliest Google Books match I could find is from Kenneth Collings, Just for the Hell of It (1938):

After depositing our combined mountain of luggage in the Hotel des Arcades, two newspaper correspondents decided to hire a car and go out to look at the night life.
There is none," I assured them.
"How do you know? Ever been here before?"
"No, but there is no night life. I can guarantee that they roll up the sidewalks at nine every night."

And the earliest match in an Elephind search is from "Collegian Curiosities," in the [Urbana, Illinois] Daily Illini (23 December 23, 1933):

Dartmouth college, one of the granddaddies of American scholastics, prides itself on its magnificent isolation on the banks of the Connecticut. . . . Hanover [New Hampshire] is a sleepy little burg where they roll up the sidewalks at 9 o'clock. . . . And on moonlight nights the village fathers don't turn on the street lights. . . .

An interesting variant pops up in Spencer Bayne, Agent Extraordinary (1942):

The tiled lobby of the modernistic hotel was sparsely populated. Damascus pulls in its sidewalks by eleven o'clock.

Here the rolled-up awning image yields to a withdrawn welcome mat or portable cart image. The same wording appears in Loften Mitchell, "'Home' Makes It to Jackson," in The Crisis (March 1972):

Waites and I said goodbye to Margaret and her family and went to visit Dr. James Anderson. He and his wife, Selena, had a barbecue going on next to his backyard swimming pool. I have never seen so many barbecued ribs in one place in my life. And the lies were so long that I nearly forgot the Jackson State dormitory pulls in its sidewalks.

And Catalog of Copyright Entries: Third Series, Volume 17, Part 5, Number 1, Music, January–June 1963 (1964) lists a 1963 song performed by Al Hoffman titled "Ev'ry Night at Nine O'Clock (They Pull in the Sidewalks)."

A very different theory
John Hart & Susy Ziegler, Landscapes of Minnesota: A Geography (2008) offers a completely different explanation of the phrase:

At the end of a hard day or week working in the snow, most lumberjacks were much too tired to walk into town, even if one was near, during the working season. Most jacks went to work in the sawmills, or back to their farms, when they were paid off at season's end, but some earned a reputation for carousing in bars and brothels.  Small towns were said to roll up their sidewalks when the lumberjacks were coming. Many sidewalks were made of boards held together with wire, and the jacks' cleated boots would have chewed them to splinters. (In 1887 alone the city of Minneapolis laid no fewer than sixty-seven miles of board sidewalks.)

Tearing up boardwalks with their hobnailed boots would certainly ensure endless work for lumberjacks. But this vignette doesn't exactly claim that towns actually removed their boardwalks (by rolling them up or otherwise) when the threat of visits from lumberjacks became acute—it asserts only that they "were said to."

Conclusion
As I said at the outset of this answer, I think that the likeliest source of the expression is as a humorous exaggeration of the idea that at a certain time of night, visitors and (especially) potential customers are no longer welcome in a town, neighborhood, or business district. The image of rolling up a sidewalk also indirectly implies that the town is very small, since any large-size municipality is likely to have a lot of sidewalks laid.
The idea of rolling up sidewalks may be rooted in the practice of rolling up awnings in front of businesses at the end of the business day, and may also be influenced by the idea of rolling up a red carpet after using it to welcome visiting dignitaries. Removable boardwalks are a phenomenon in some beach towns and may have been known in the nineteenth century, but whether anyone would have characterized them as "sidewalks" is unclear to me. Still, they may contribute yet another influence to an imaginary phenomenon invoked for startling effect. I find the hobnail-booted lumberjack explanation that Hart & Ziegler put forward highly implausible.
Like JEL, I can't find any nineteenth-century instances of the expression "roll up the sidewalks." But I couldn't find any as early as the 1917 example that JEL cites either. In fact, the best I could do was to confirm a 1925 instance from a Charlie Chan mystery novel. On the evidence turned up so far, I think early twentieth century is a more likely origin period than middle nineteenth century.
Finally, the existence of the variant "pull in the sidewalks" from no later than 1942 suggests that the usage in either case is metaphorical, not descriptive of actual practice anywhere.
Comment: Tldr, you didn't have to write an essay. Just saying, this answer would probably be infinitely better if it could be condensed into a few paragraphs.
Answer: I have not been able to find an original source and the phrase doesn't seem to be more than a century old (and not even that). The OED gives a definition, but no origin.
A comment I read somewhere, however, seemed to make a bit of sense. Rolling up the sidewalks are a simile of sorts; just like you'd roll up the carpet when it's no longer needed, the sidewalks are no longer needed when there's nothing going on, so they metaphorically roll them up.
Answer: Other than the unattested assertion in a reputable source — Cassell's Dictionary of Slang, 2005 — that the phrase 'to roll up the sidewalks' dates from the middle of the 1800s, I can find no evidence of figurative or comedic use of "roll up the sidewalks" (et al. variants) than 1905, in A Bundle of Burnt Cork Comedy, by Harry Lee Newton:

We had to take the girls home early, because they roll up the sidewalks there at nine o'clock.

The next appearance was in 1917:

From The Kane Republican, Kane, Pennsylvania, 13 Dec 1917.

Cassell's gives a very specific definition of the figurative sense:

of shops and entertainment in towns or cities, to close down at nightfall.

Cassell's definition differs from the more general sense given in OED Online:

to cause all entertainment or leisure pursuits to cease (in a location).

While Cassell's places the origin of the expression in the US, OED Online places it more broadly, in North America (that is, including Canada). Yet the earliest (1925) and later attestations provided by OED Online are from US publications.
The broader sense observed by the OED lexicographers, along with the assertion in Cassell's that the phrase originated in the mid-1800s, suggests that a conceptual origin may be found in the confluence of two events in the later 1800s. One of these events was the building of the "original boardwalk" in Atlantic City, New Jersey, which opened to the public in 1870:

The original boardwalk was actually a temporary structure, which was pulled up and stored during the offseason.
From Boardwalk Stories, "A History of the Boardwalk".

The Atlantic City boardwalk is, however, the "original boardwalk" only when  'boardwalk' is used in a narrow specialized sense, that is, when the term designates one among a set of notable promenades, "especially of planks, along a beach or waterfront" (American Heritage® Dictionary of the English Language, Fifth Edition) usually associated with a well-known city business or entertainment district. The more general sense of 'a wooden path', arose much earlier, as is evidenced by this clip from The Pittsburgh Gazette, 29 Jan 1845:

Another possible concrete (that is, not figurative) origin of the phrase was the patenting of the "movable sidewalk" in 1871:

In 1871 inventor Alfred Speer patented a system of moving sidewalks that he thought would revolutionize pedestrian travel in New York City.
From Smithsonian.com, "Moving Sidewalks Before The Jetsons".

Both of these 19th century events received attention in the popular press, and they may have given rise, perhaps by a slow-burgeoning conflation in the popular imagination, to figurative uses of the phrase in the early 1900s.
I have, however, found no textual evidence linking the notions of moving sidewalks and temporary boardwalks in the late 1800s with the early 1900s figurative mentions of the rolling up of sidewalks after the usual hours, or season, of business.
Comment: @JOSH, my *speculation* is that one possible origin of the later figurative phrase *may be* in the earlier actuality of moving sidewalks and temporary boardwalks. I have no evidence other than the consonance of the three ideas, especially with regard to the reference to business/entertainment districts of towns, and the historical sequence of the currency of the three ideas'.
Comment: So your assumption is that the idiomatic expression originated from those removable side/broadwalks and that it is not just an hyperbole. Am I correct?
Answer: A possible meaning and origin might be to remove the display stands from the sidewalks which were common in Europe and it was done in the past in the USA too. Now it is not commonly done in the USA anymore.
An example would be at a farmers market when the market is done the farmers remove or roll up their display stands.
Another is that they used to use temporary boardwalks that can be rolled up. See:
http://mitchellismoving.blogspot.com/2013/12/fuengirola-rolls-up-sidewalks.html
In the past, it was done when the streets were not paved and muddy so people would place these temporary sidewalks.
Comment: "Now it is not done in the USA anymore." It is in my town - It's still very common to see extensive sidewalk displays. http://downtownhendersonville.org/wp-content/uploads/2014/09/DSC0294.jpg
Comment: The phrase also exists and is still commonly used in Germany.
Comment: @Michael how is it being used in Germany? Does it mean to remove the display stands?
Comment: No, it means that the town/area is somewhat old-fashioned or boring, no possibilities to have fun in the evenings. Not sure about the root either
Answer: I wonder if it's German in origin. They have an expression to describe a town where nothing happens - in the evening, 'da werden die Bürgersteige (or Gehsteige) hochgeklappt'.
Comment: Can you translate the German for us?
Comment: Also some context—how old is the phrase? The earliest example of the English phrase I've seen is the attestation in the OED, from 1925 (there is also a 1927 book in Google Books with the phrase), so if the German phrase goes back further that would be a bit of evidence in favor of the theory.
Comment: This could be a good answer, but it needs a bit more.
Comment: Google translate says it means "because the sidewalks are folded".
Comment: @Doug GT is half right: it means "then the sidewalks/pavements are folded up".

Origin of "rolled up the sidewalks"


Search box text colour

Question: Just noticed that the colour of the text displayed on the search results page does not show the search query very clearly until the search box is re-selected.
Blank search box waiting for a query:

Non-selected search box on results page:

Selected search box on results page

Perhaps the 2nd image (non-selected search box on results page) could at least be made to look like the placeholder text in the 1st image (blank search box), as it is often useful to view and edit a search query to improve results. If users are to be discouraged from editing a query using the top-right search box (and instead it is intended that they modify their query in the search box in the centre of the page above the results) perhaps the top-right search box should revert to just having place-holder text ready to accept a new query.
(Using Safari 5.1.1 on OS-X 10.7.2)
Comment: Is the new color scheme temporary or an indefinite change to the site? It's cool, but less usable.
Answer: The fix will be in the next production build.
Comment: Awesome! Thanks, Jin! :)

Search box text colour


God doesn't give with both hands

Question: Does "God doesn't give with both hands" mean that one can't have everything in life?
Answer: It's a variant on the established idiom give with one hand and take away with the other, an idiom which according to Collins Dictionaries means "to help someone in one way, but also do something which has the opposite effect, for example harming them or preventing them from achieving what they want". In other words, to both help and harm.
Hence your example means God does both good things and bad things, rather than always helping.
Comment: Do you have any citation that it's a simple variant?
Comment: There's also the biblical passage from Job, "God giveth and God taketh away" which probably adds to the ecosystem of idioms
Comment: When God isn't busy using his hands for giving and taking away, he uses them to open and close doors.
Answer: Children are naturally "gimme gimme", and bad parents go along with it, giving whatever is asked for, even if it figuratively takes two hands to do it.
That paragraph continues: "You're young, beautiful, brilliant. There has to be something you can't have.".
Children need limits, not only because limits are good for them, but because they actually feel more secure and loved when limits are imposed.
As they get older, they need to break limits in order to feel and express their maturity and independence.
Lenient parenting means that this natural rebellion will take a much more extreme form.
If told not to get a tattoo before 18, many teens will, just to prove that they can.
Had they instead been told to wear decent clothes and not to let their hair get so long, they'd have grown slightly long hair, worn torn baggy jeans, and not even considered doing something as silly as getting a tattoo simply in order to rebel.
In this case, the person is "young, beautiful, and brilliant", a combination that means that everything is available to them with a wonderful future that requires no effort.
But if they are also alcoholic, they will be forced to work hard to achieve that future, and will be forced to develop strong character, which (from a religious point of view) is what life is all about.
Answer: It kinda means you can't have it all in life. Take for instance in the bible, the case of Jacob and his wives Rachel and Leah, Rachel had the beauty and was well favored but she was barren, while Leah whom was despised, God blessed her with children. You see, there has to be a balance, so God would still remain a just God by the end of the day. His ways are just perfect.
Comment: Thank you all for your detailed explanations!
Answer: 'God doesn't give you with both hands' implies you can't easily and quickly get what you want.

God doesn't give with both hands


Is there a tool to map ecryptfs plaintext and encrypted filenames?

Question: Ecryptfs encrypts filenames and sometimes I need to find particular file, so I would like a tool to map the encrypted filenames back to their plaintext file name.
Answer: As of ecryptfs-utils version 96, ecryptfs-find is the best way to go from an encrypted path to a non-encrypted path. It meets the needs of most users that need to map between filenames, but there are some things to note about the tool:

It doesn't decrypt filenames. It maps the filenames based on the inode number corresponding to a file.
You must have a live eCryptfs mount. "Offline" mapping of filenames is not possible with ecryptfs-find.
ecryptfs-find may return multiple results and only one of them will be the actual decrypted version of the path you're looking for. If an inode has multiple hard links, paths to each hard link will be printed.
Comment: regarding #2, then what's the point?  If there is already a live mount,why not just run regular 'find' on that?
Answer: You would want to use the utility ecryptfs-find
Answer: ecryptfs-map does this: https://gist.github.com/monperrus/7a114ccc1c2fd20dcc5e852cdf813c5d
it is much faster than ecryptfs-find because it does not iterate over the whole filesystem tree with find.


When earth is filled to the brim with plant-life, can it cause a hyperoxic environment?

Question: Say humans found a way to exponentially increase the capability of plants to grow. Is it possible for it to cause an environment that can cause oxygen toxicity in humans?
Comment: This is a good question an amenable to hard science.  What is max O2 produced in a greenhouse?  My cursory search did not turn up answer but it is knowable.
Answer: No, there is not enough CO2 that can be converted by plants.
Current CO2 is roughly 400 parts per million, Oxygen is roughly 21% of the atmosphere 210,000 parts per million.
Changing all CO2 to oxygen would result in a negligible difference in the atmospheric oxygen.
Comment: @Willk The question specifies earth.
Comment: Right you are.  Woops.
Answer: Studies show that 0.5 bar of oxygen can be tolerated indefinitely.

The current partial pressure of oxygen in the atmosphere is 0.2 bar, so to go beyond that threshold the oxygen level should rise of more than 250%.
Apart from the lack of that much oxygen in the atmosphere, consider also that more oxygen in the atmosphere and a lot of vegetation means higher chances of fires and more sustained fires.
Fires of course would produce CO2 and consume O2, shifting back the equilibrium.
The reality is that, due to the high reactivity of oxygen, it's really difficult to have it unbound in large amounts.
Comment: The interesting question is where it would all get bound up. Could have some really interesting impacts on animal life.
Answer: The scenario you're describing has occurred in the past, at least in the sense that O2 levels have been much higher than they are now. They were at their highest levels during the Carboniferous period about 300 million years ago, at 35% compared to 20% today.
This isn't high enough to be toxic to humans, and in fact the result was that all forms of life were able to grow much, much larger. Insects in particular were colossal compared to today, and it was the O2 levels that permitted that.


Why did The Doctor need a device to erase Clara's memory?

Question: The 10th Doctor was able to erase Donna's memory of him just by touching her head. Why did he need a device to do exactly the same thing to Clara?
Answer: Using the device makes the process painless
In his conversation with Ashildr, the Doctor makes clear that he could wipe Clara's memory telepathically, but suggests that using the device will make the process painless.

DOCTOR: I'm taking her back to Earth. Somewhere safe, somewhere out of the way. I'm going to wipe her memory of every last detail of me.
DOCTOR [OC]: It'll be like our friendship never happened.
ASHILDR [OC]: That may not be what she wants.
DOCTOR [OC]: 'I've done it before. Usually, I do it telepathically, but this time, I've got something better.
DOCTOR: It's quite painless.
Season 9, Episode 12: Hell Bent. Transcript from Chakoteya.net

That suggests that wiping Donna's memory was painful. The scene in Journey's End where the Doctor wipes Donna's memory certainly shows that she was in distress. It was hard to tell just from that episode if that was due in part to pain or due only to that fact that she didn't want to change back to her old self. The conversation with Ashildr suggests that there was pain.
Comment: Maybe, it was The Doctor who experienced the pain.
Comment: @w3d "Usually I do it telepathically, but this time, I've got something better". "It's quite painless". He says it's better, and the only thing he says that could be a reason is "It's quite painless". Not proof, but I think it's at least a suggestion.
Comment: "That suggests that wiping Donna's memory was painful." - it does?!
Comment: True. That's why I avoided saying who experienced the pain.
Answer: I suspect the real answer is just "because there's no other way for the scripwriter to make it so the Doctor's memories get wiped instead." The device is merely a Macguffin to set that up.
If you want an in-universe explanation, maybe because this Doctor likes to improve upon things, e.g. sunglasses instead of screwdriver?
Answer: Remember that Donna isn't just getting a memory wipe, she needs the memories suppressed to survive

The Doctor explains that the human brain cannot take in the Time Lord mentality: if she continues in her current state, she will die as her mind will burn up. In tears, Donna protests that she wanted to continue her adventures with the Doctor as "DoctorDonna" and was willing to spend the rest of her life with him. Saddened, the Doctor says that he is so sorry; Donna then realises what he is about to do and begs him not to send her back. The Doctor then tells her that they had the best of times. Ignoring her pleas, the Doctor presses his fingers on Donna's head, wiping her mind of all her encounters with the Doctor, rendering her unconscious as a result.

By contrast, The Doctor is trying to hide Clara from her fate

DOCTOR: There was only one way to keep Clara safe. I had to wipe some of her memory.

There's also the fact that sometimes The Doctor does things that seem unintentional when that was his plan all along. I wouldn't put it past him that he let Clara wipe his memories by using the device instead of telepathy.
Answer: He didn't delete Donna's memories
Donna didn't just have memories of her time with the Doctor, her mind was infused with Time Lord knowledge.  The Doctor took the knowledge and the memories, and enclosed them within her mind, cutting them off.
There was a chance that Donna could regain her memory; which she does when the Master returns.  When that happens, the Doctors defence mechanism activates.
With Clara, he wants to completely erase the memories.  But, its not her memories he erases - it's his.  The whole conversation about erasing Clara's memories is a red herring.  All along the Doctor planned to erase his memory of her, to protect her and save her life.  For that, he needed the device.
Comment: Do you have any evidence to suggest that the Doctor always _intended_ to erase his own memories instead? None of the narrative supports your claim.
Comment: An interesting theory.  Didn't the Doctor leave her alone with said device for a time?  If your planning on using a device to wipe ones mind it's probably not a good idea to leave it alone with the one your going to wipe. Lends a bit of credence to the theory anyway. It would be so like the Doctor to do something like this. :)


How to unlock without a disc or password

Question: My friend bought an old iMac at a garage sale. It's locked, no start up discs. The people he bought it from have moved already. We don't know where.
How can we get into the computer without the usernames and passwords?
Comment: Define: `locked`.
Comment: Also, what version of OS X is on it?
Comment: Great, sell your computer and leave user accounts and possibly personal data on it. Startup discs can be found using bittorrent or a mac geek friend will have them.
Answer: If you're running OS 9, you may need another mac (though i suspect a PC with firewire and a HFS driver would do) and a firewire cable. You will need to delete preferences pertaining to keychain access and any keychains in the preferences folder in the system holder (source). The first imacs ran this so its plausible
If you're running OS X on the imac
Single user mode would do the trick unless there's open firmware password protection in place
To go into single user mode

Press the power button to start the computer.
Immediately press and hold the Command (Apple) key and one of the following:
    the "s" key for single-user mode.  (Command-S)
This should boot into a white screen, and iirc throw you into a command prompt

These instructions should work for older versions such as 10.4. Khafshoh S' version works for newer systems 10.5 and better - 10.7  also has yet another option for resetting the password  involving the 'resetpassword' command in lion recovery.
Instructions for changing the password are based off here
You would then mount the file system as writable with
mount -uw /
then find out what the accounts on the system are with
ls /Users/
then change their passwords with
passwd username
reboot and get back into graphical mode with
reboot
Then check the accounts to work out which one is the admin account.
Comment: You guys are awesome. I was doing pretty well following your instructions but got hung up on root # and while playing around with that came upon master password hint: Mrs. Homer. Doh! Typed in Marge, and I'm in.
Comment: Oh, you could/should probably post that as an answer and select that then. Otherwise, the question will get bumped up every so often as unanswered.
Answer: You should choose one of these options mentioned here:
How to Hack the User Password in Mac OS X Without an OS X CD. | OSX

Boot into single user mode (press Command-S at power on)
Type fsck -fy
Type mount -uw /
Type launchctl load /System/Library/LaunchDaemons/com.apple.DirectoryServices.plist
Type dscl . -passwd /Users/username password,  replace "username" with the targeted user and - "password" with the password you wants.
Reboot

or

Reboot
Hold apple + s down after you hear the chime.
When you get text prompt enter in these terminal commands to create a brand new admin account (hitting return after each line):
mount -uw /
rm /var/db/.AppleSetupDone
shutdown -h now
After rebooting you should have a brand new admin account. When you login as the new admin you can simply delete the old one and you're
  good to go again!
Comment: Don't run around begging for votes. If that's really the only reason you're here, you're in the wrong place. I would start by not copy and pasting your answers from other sites, because this is plagiarism and not encouraged.
Comment: Interesting that there's two methods to do this. The one i've suggested is similar to the standard unix way of doing things. I'm curious to what dscl is, since its not something i've come across so far. Any ideas?


iPhone playing songs NOT on any of my playlists

Question: I have deleted some songs my roomie used to listen to but they keep playing when I activate music play on iOS 7. I can't figure out how that would happen. A song will come on. I will go to my only playlist. It won't be there but it's still playing. Next week same thing. Makes  no sense. Help I hate his music!
Answer: Playlists are just organized subsets of your music library, so you might not have the song on the playlist, but still have it in the collection.  Even if you just have a single playlist, that doesn't mean that every song on your phone is in it. iTunes will default to the first song alphabetically if you tell it to "Play" when it doesn't have a playlist loaded (i.e. the first time after turning on the phone).
At least under iOS 6 (I haven't upgraded yet), you can see all songs by tapping the "Songs" tab at the bottom of the Music app.  If his music is there, you can delete it from there.  If it isn't, then there's something else going on.


Chroot vs Docker

Question: I'm trying to learn the basics about containers (Docker in this case). As far as I learn from the Docker doc and several readings, Docker basically provides isolation by running the container using runc (previously using LXC). Either ways it uses the same kernel as the host machine. Thus, the container image needs to be compatible with the host kernel. I find this very similar to what a chroot does. Could somebody explain to me any differences and/or advantages on using Docker rather than chroot? (besides the extras provided by Docker as packaging, docker-hub, and all the nice features provided by Docker)
Comment: I think having this specific question is good because chroot was the "first" isolation solution in Linux AFAIK. And it's the first question that comes in mind because chroot shares the host kernel also.
Comment: Stack Overflow is a site for programming and development questions. This question appears to be off-topic because it is not about programming or development. See [What topics can I ask about here](http://stackoverflow.com/help/on-topic) in the Help Center. Perhaps [Super User](http://superuser.com/) or [Unix & Linux Stack Exchange](http://unix.stackexchange.com/) would be a better place to ask.
Comment: I actually found this question when considering how paths and packaging were different- as well as the implications on security- in respect to "Chroot vs. Docker".  These are absolutely fundamental questions. So it seems a fair question that a developer might pose to themselves before requesting their infrastructure colleagues to provision hosts for them. Indeed, I felt the question was well written and worthy of an upvote.
Comment: The salient points (re: kernel namespace isolation) are already answered in no end of "how does Docker differ from X?" questions, even if we don't already have one for chroot specifically.
Answer: Docker allows to isolate a process at multiple levels through namespaces:

mnt namespace provides a root filesystem (this one can be compared to chroot I guess)
pid namespace so the process only sees itself and its children
network namespace which allows the container to have its dedicated network stack
user namespace (quite new) which allows a non root user on a host to be mapped with the root user within the container
uts provides dedicated hostname
ipc provides dedicated shared memory

All of this adds more isolation than chroot provides
Comment: There are also cgroups (for cpu and memory limits), reduced capabilities, seccomp, selinux/apparmor, and ulimits. The filesystem is also layered, potentially read only, and allowed to be overlaid with volume mounts.
Comment: Great answer Luc, but could be improved incorporating @BMitch 's feedback into the answer itself where it won't be potentially missed.

Chroot vs Docker


Metrology: How are the most accurate measurements made?

Question: How is a most accurate measurement made when there is no other equipment to verify it? Consider you base your apparatus on a set of theory and assumptions, and the result does not match prediction. How can it be determined if the theoretical basis is incorrect of if the fault lies with the measurement equipment?
Comment: Its not clear which field you are referring to. But some excellent related discuss can be found here https://physics.stackexchange.com/questions/615177/how-do-you-make-more-precise-instruments-while-only-using-less-precise-instrumen
Comment: Funny story, I read this as "Meteorology," and it took me quite awhile to realize it was not digging into why weather predictions are notoriously inaccurate compared to other sciences...
Comment: This is a great question. I think that what actually happens is people work hard to overcome the "...when there is no other equipment to verify it" situation. If the result is seen to be important and the question remains for a period of time, some group writes a proposal to create "other equipment" specifically to address the issue. Search "positron peaks GSI" or refer to "[The one that got away](http://teacher.pas.rochester.edu/Phy237/DownLoadDocuments/TheOneThatGotAway.pdf)"
Comment: and [Search for Narrow Sum-Energy Lines in Electron-Positron Pair Emission from Heavy-Ion Collisions near the Coulomb Barrier](https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.75.2658) Experimental results that could only come from one place simply did not agree with accepted theory, so a proposal for new equipment was written, new results were obtained, and the matter was resolved.
Comment: For time, you own multiple atomic clocks and take averages.
Comment: Lol, that happens.
Answer: Say there is a physical parameter $x$. We can measure it with many (ideally different) experiments to get a best estimate of $x$ with uncertainty which I'll denote by $\hat{x}_e \pm \delta x_e$. Likewise, we may have a theory which predicts the value $x$ from other physics parameters $\{y_1, \ldots, y_n\}$ each of which may be defined or measured with some uncertainty. This produces a theoretical estimate of $x$ which I denote by $\hat{x}_t \pm \delta x_t$.
If the $n$-sigma (choose your favorite value for $n$, maybe 1, 2, 3, or 5) error bars for $\hat{x}_e$ and $\hat{x}_t$ are non-overlapping then we say the two estimates are not consistent. Note that the definition could work for multiple experiments or multiple theoretical calculations which may be inconsistent.
If two estimates of $x$ are inconsistent then there are a few possibilities. The most likely possibility (especially if $n$ is large) is that one of the estimates is incorrect. Either the experiment isn't measuring what it think it's measuring or the theory is missing some other unknown effects. There is another possibility which is that the experiments were just extremely unlucky. If an experiment is performed and the result is plotted with a 5-sigma error bar there is still a tiny chance that the "true" value is not covered by that error bar.
In any case, when such inconsistencies are found in science it is typically an opportunity for more work on both the theoretical and experimental side to improve things or find the source of the discrepancy. A real world example of this is the proton radius puzzle. There I believe at least two experiments are inconsistent, and I'm not sure the state of the theory. I haven't read up on this in a while.
edit: To answer your question directly: Other than double checking work, we can't know if the problem is with the experiment or the theory. We can double check the work done on each end. We can perform new experiments or do different theory calculations to get at the same result. Otherwise we have to just improve both experiment and theory until the discrepancy is resolved, possibly discovering new science along the way.
Comment: Thank you, I feel this clarifies previous discussions very well and backs up the idea that the scientific method works by improving the certainty of the existence of a certain  physical theory, off of which we base of the measurement equipment which we are discussion. Answer Accepted.
Answer: You are going to need to narrow down the exact type of measurement made.
As far as I know, gauge blocks are ultimately measured by interferometers and flat surfaces ultimately measured using optical flats.
How the light sources used are calibrated for wavelength and temperature? I don't know. I suspect there is an atomic clock hidden in there somewhere. That simply might be based on the physics of the light sources used (i.e. spectral lines of the gas used).
And temperature measurements are specified by definitions of the phase change temperature of different materials under specific conditions so you don't really need a "master" measurement. That's the reason we are trying to base all units of measurement on the universal constants rather than a physical master like the kilogram platinum-iridium block that used to be used.
And when measuring millionths of an inch, things like the temperature, airflow, lights, and body heat need to be controlled and math done to compensate for the material deformation. As far as I know all mechanical measurements are based on symmetries because you can check symmetries but once you get to this high a level it gets more difficult to spot just how they do it. I always thought it plausible that it's all a self-consistency thing: a big loop of dependencies.

"How can it be determined if the theoretical basis is incorrect of if fault lies with the measurement equipment?

Statistical voodoo may be involved at the highest levels. Terms like "five sigma" certainly seem to come up often when physicists talk about measurements on the bleeding edge. And since it's based on pure math, it is assured to work so long as the proofs supporting it are correct.
Comment: Also check out this video: https://www.youtube.com/watch?v=T-xMCFOwllE
Comment: You might try asking the Fermilab youtube channel. They might just reply to you. After all, they are measuring things only they can measure using machines only they have so they need to know how to check everything.
Comment: When I initially thought of this question I was pondering voltmeters and how more accurate ones were produced when there was no others to verify the results. Of course nowadays calibration (for high end machines) is done with millions of Josephson junctions which give a known voltage...

How would we know the voltage produced:
Quantum effects, which boil down to QFT:
QFT is a theoretical model verified by a plethora of of means ....
in the end it all boils down to the assumption of constant physical constants i.e. speed of light, time etc and how these are measured.
Comment: I think that all one can do is make the assumption that a theory is verifiable if  several pieces of equipment which all preferably function through different principles all back up the same physical theory with their results. I'm still thinking about this so please contribute further if u wish. (thank you very much for your answer nevertheless)
Comment: @SirStrategic That's my thought too and what I meant when I said "loop of dependencies". You can troubleshoot two things at once after all, it's just really, really not ideal and you shouldn't if you don't have to. On my end, I did wonder how they calibrated photodetectors and light sources.


Are there a finite number of ideas?

Question: I never want to run out of new ideas to contemplate. Some people say that technological progress will eventually reach a natural stopping point but my logic is that new inventions will always exist because as long as there are human minds in the universe, we will always wonder about what is next. Is my logic correct or does it have inherent flaws?
Comment: But Futurism was an early 20th century movement. https://en.wikipedia.org/wiki/Futurism What do you mean by Futurism?
Comment: That's assuming civilization never regresses, which has happened before and could still be the case. When fossil fuels will be depleted and hydrogen or batteries will have failed to replace it, temperatures will be up a few degrees dramatically changing our supply chains for food production, people will still wonder "what is next?", but it will be about food and shelter.
Comment: I would say Godel's Incompleteness shows the set of true things is not recursively enumerable, so can always be added to - like number lines iteration is possible infinitely
Comment: I think that your question is somewhat vague. What exactly do you mean with "idea"? Does something only become an idea once a person thinks of it or is it one before that?
Answer: It depends on what you mean by "idea". It sounds like by "idea" you mean something similar to what contemporary philosophers mean by "proposition" (something that has a truth value and can be the object of belief).
It's very widely accepted that there are infinitely many propositions. For example, for all natural numbers n, one can contemplate the proposition that there are n dogs.
Whether a human being can contemplate an infinite number of propositions at the same time is an empirical (not philosophical) question, which will depend on what one means by "contemplate".
Answer: Futurism is normally linked to the movement in art that originated in Italy, early in the former century:
https://en.m.wikipedia.org/wiki/Futurism
See also:
https://futurism.com/
It accentuated newly invented technologies like cars, planes, the radio, rockets, new materials, household and garden equipment, electricity, etc. It put an emphasis on the new, the dynamics of invention, and the dynamics of youth and discovey. Perfectly fit for the newly developing fascist ideas whirling around in the Italy of the new leader Mussolini (former anarchist and socialist!). "Avanti!" (forwards!) was heard out of many mouths and meant to hurry and install a new order in which technique played a huge role. The "autostrada" were realized (serving as an example for the "Autobahn" in Nazi  Germany.
This is not to say that the artists embraced fascism. The were just fond of technological inventions and progress (like you).
What about the eternity claim? In principle, there is no boundary to technological ingenuity of people. New ideas will always develop. There is no funamental upperbound and if there is one it will never be reached in practice.If the situation is right or just for the sake of or to make money with. In the thoughest circumstances people always find a way to survive, be it by technique or other means.
Of course there is a practical limit on how much things you can actually construct. But the old can always be rcycled into the new.
Of course one has to take into consideration that relentless engineering has consequences in Nature. The more technique is realized, the less Nature remains and biodiversity will dimish as can sadly already be seen around us in a changing climate. Another political climate is needed badly if mankind wants to survive and make it it into the future! But if we put our shoulders beneath it the production of energy and its transportation can be made neutral. Natural resources like the sun and carriers like hydrogen can be realized. Up till then I take my bike and hire a car if needed (to race the road... Avanti!). And let's hope that the world will not be thrown back to the stone age after nucleair conflict escalated to global proportions. The threat is still there and people in the stone age (whereto Einstein refers  when talking about an eventual fourth worldwar) at least couldn't have fear for global annihilation. Technique is not the one and only way.
Comment: Probably the OP was thinking of futurology or [future studies](https://en.wikipedia.org/wiki/Futures_studies) rather than anything linked to the art movement--"futurism" is sometimes used to mean the same thing, for example if you go to amazon's "look inside the book" feature of [The Oxford Handbook of Science Fiction](https://www.amazon.com/Oxford-Handbook-Science-Fiction-Handbooks-ebook/dp/B00NHWZ6F2/?asin=0199838844&revisionId=&format=4&depth=2) and search for the keyword "futurism", p. 15 does use it as a synonym for futurology.
Comment: @hypnosifl I think this is relevant too; https://futurism.com/ I think futurology is trying to predict the futurr. This *can* be what he means but I dont think so. He is interested in prrsent day tech. Not that of the future (well he might be actually, I dont know, but I dont think he wants to predict. Only if men will always find new tech things.
Answer: There might be or not be infinite ideas floating around. There is no other means for investigate and count them than by looking at the ideas themselves. Looking at an abstract idea of ideas will not do.
The number of experienced ideas is finite untill now. One may speculate about other universes (parallel or previous) and try to figure out if for infinitely many worlds there is at least one idea different from others is available.
Suppose there were infinitely many big bangs before our own. Each one resulting in a universe comparable to ours. Will there be ideas floating around in the latest universe that weren't floating around previously? I am inclined to say yes. Human ingenuity knows no limits (as a figure of speech).  But i have no formal proof as I don't think that ideas can be formulized. Well, it is possible, but when doing this you create a new idea about ideas and I don't think that's a good idea. Especially because infinitely ideas simply cannot be experienced by one person or whole humanity all together. You can split every idea up in sub-ideas or calculate the maximum number by looking at all possible configurations of particles in phasespace but in doing that, again you replace the ideas by an abstract idea of them. The contemplation of an infinite ideas is beyond anyone's reach.
If you could already now contemplate such an idea then future people would have nothing to come up with anymore. They would just have to take a look in the great book of ideas.
Maybe the world of ideas, as contemplated by Plato, contains infinite ideas to be drawn from (in the shadow cave you can even have indirect acces). But, again again, it is the contemplation of the ideas themselves that counts. Assigning infinity or a huge figure to the number of them doesn't make the ideas more or less valuable.

Are there a finite number of ideas?


I am a graphic artist, am I allowed to create logos or products for Christians?

Question: If, for example, I am asked to make a logo that says "Love Jesus": I am a Muslim and I love Jesus son of Mary, and so do they, but they do so in a manner that is not acceptable in Islam. Is it acceptable to create this logo?
Comment: Nous sommes un site anglophone; j'essaierai de traduire cette question pour vous, mais les reponses seront en anglais.
Answer: Bismillah Hir Rahmaan Nir Raheem
As Salaamu 3laykum,
I hope you and your family are doing well. If it was a I love Jesus shirt and it was for Muslim buyers only then it would be permissible. If you are selling it to Christians then we know their view Jesus (Peace and Blessings Be Upon Him) is wrong. So knowing that then you would part of their shirk. As Muslims we are commanded to stay away from even resembling non-Muslims in their beliefs and supporting them in their beliefs.
However, again if this is only for Muslims then there is nothing wrong with the shirt. If you change your niyyah and make this logo to help spread the deen of Islam by telling Christians through the shirt that we respect and love Prophet Jesus (Peace and Blessings Be Upon Him) that would be a great thing to do.

Have a Nice Day!

Note #1: If you downvote my answer, please be courteous and say why you downvoted in a comment below.
Note #2: This is my own personal answer that I have derived from what I have researched.


Correlation between two time-series of unequal size

Question: How can I estimate some measure of correlation between two time-series of unequal size? Is it a good approach to interpolate to the same size? I just want to check for a trend in the values of a variable over time but my experiments had slightly different durations.
Comment: Can you be a bit more specific as to what you mean by "unequal size"? Are the series measured on different frequencies but over the same total period, or on the same frequency but different periods, or does one series have "holes" in it?
Comment: I would advise to decimate the bigger one instead. Interpolation introduces artefacts. All the best
Comment: Are you interested in contemporraneous correlation, or cross-period correlation?
Answer: The answer to such questions depends on understanding the properties you require of a similarity/correlation measure pertaining to your use case.  If you describe your use case, we might be able to help you better.
If time series are of different lengths, you could do one of the following:

Rescale the longer series to a smaller length using averaging and then apply correlation.
Use Dynamic Time Warping https://en.wikipedia.org/wiki/Dynamic_time_warping, which uses an edit-distance like approach to computing similarity between two sequences of differing lengths.
Embed the two time series into a smaller, fixed-length "feature space" and then do similarity in the embedded space.  The embedding could pick features of the time series that you are most interested in (e.g., number of peaks, auto-correlation at various lags, etc.)


What is this large plant that came up when I turned my soil?

Question: I turned my soil recently and this huge plant started to grow. I have put my hand there to show the size. It does not seem to be a weed so I would really want to know if this is some kind of vegetable or fruit plant. Can someone help me identify? Thanks.
Comment: If you rub a leaf and smell it, you should be able to tell if it's a squash (at least, if you know what squash smell like). I don't think it's a hollyhock, but I've seen another plant (I think a flower) that looks a lot like a squash. How big were the seed leaves? Do you see a seed shell anywhere?
Answer: That looks like a squash of some kind. It will probably send out runners and spread quite a bit. The fruit should be edible, but I can't really tell what it will look like. It may be more like a pumpkin (it resembles Cucurbita maxima).
Comment: Squash, pumpkin or even a cucumber. Something from that family at least.
Answer: It looks like Hollyhock. The stems will grow tall with beautiful flowers
Comment: I thought about hollyhock too.
Comment: Leaves seem a little smooth for that: https://www.google.com/search?q=hollyhock&biw=971&bih=526&source=lnms&tbm=isch&sa=X&ved=0ahUKEwiE6e611bbMAhUBMz4KHVeSCdgQ_AUIBigB#tbm=isch&q=hollyhock+sprout
Comment: Well it could be a pumpkin or hollyhock. If it is the former it will spread on the ground or climb up a wall and in the case of the latter it will just grow tall.
Answer: Do you eat cantaloupe or muskmelon at your house?

A few years ago I used some compost in my flower garden and surprise! I had a plant similar to yours growing amongst my marigolds. I let it keep growing, very sure it wasn't a weed. Like others have mentioned I thought it was a squash or cucumbers.  It ended up being a muskmelon. We eat it for breakfast a lot and so some seeds had ended up in the compost, then my garden.
Unfortunately they require quite a long time to grow (80-90 days above 70 degrees F or something like that) so I never got to eat one of them. (I live in New England, so I would have had to start them much sooner and kept them warm)
Let it grow and see what you've got. If it is a muskmelon, and you're in a more friendly zone for melons than I, pinch off all but one or two fruits so they are nice and sweet, and keep them on pea gravel or elevate them off the ground some other way so they don't rot on the soil. Once they start to ripen (you will see the flesh beneath the web-like texture start to turn orange) only water enough to prevent wilting, to further increase the  sweetness.
Answer: It could be a pumpkin plant or some kind of squash, but to me it looks a lot like a pumpkin plant that sprouted a little while back.
Answer: Called velvetleaf in the west, but in the midwest, we call it a butterprint plant. Typical farming weed. Will eventually get yellow flowers under the leaves that will turn into quarter sized seed cups with a spoked type flat top.
Comment: Hi, I think you may be right. Others seems to think otherwise  do you have any photo for comparison.
Answer: It's a pumpkin plant I have the exact same thing growing but I planted the seeds
Answer:
I have one like this in my front garden that popped up. I looked it up on the Plantnet app and it came up with Velvetleaf - a wildflower that will have yellow/orange flowers.
Answer: I think its a squash.  Flowers are yellow sort of trumpet style. I think velvet leaf starts getting tall and rangy and doesn't have trumpet like flowers.
Comment: Hi Shona, it looks like you have two accounts. Please use the one with your name.


How do I connect this display to an Arduino Uno

Question: I am completely new to this, and a novice when it comes to electronics but I want to learn.
Can someone pls tell me how I would connect the display in the photo here with an Arduino Uno (which I have ordered).  The plan is to interface my car with this transparent display to produce a form of HUD.
I have done some searching but to no avail so far, would appreciate being pointed in the right direction.
many thanks
Comment: What do you know about this display? Do you have a datasheet, a make/model, any information to go on? We really can't tell you much from a picture.
Comment: Thank you. Not yet but I will try to find out.  This was the only transparent display that I could find available for purchase.
Comment: Can can always scrap the electronics and [drive the LCD yourself](http://awawa.hariko.com/avr_lcd_drive_en.html). But you need quite a few IO pins, looking at that ribbon cable. Also it's not really a beginners project.
Comment: You don't need a transparent display. You can project a bright LED up to the windshield and it will be reflected in your line of sight, you will have to deal with projecting a flipped image so it appears correct to the observer.
Answer: You're in for a lot of work. Everything on the PCB is useless to you, so you'd have to interface the raw panel to the Arduino.
The first matter is to remove the panel from the board. You will need to desolder all of the connections, and then solder either some sort of rigid connector or individual wires to the large ribbon connector. The only advice I can give you is "be prepared to fail".
Once you've done that, you will need to read AVR340 in order to learn how to drive the panel. Note that the Uno itself does not have enough pins to drive the panel directly, so you will need to get an I/O expander or two for this.
Did I mention that you're in for a lot of work? Well, I'm mentioning it again. Good luck though.
Comment: Thank you. I suspected it wouldn't be straightforward. This is the info I was looking for - somewhere to start.
Comment: @DrT Do you have an update on how the project went. I'm interested in whatever, even if it failed, as I learn a lot from HOW / WHY things fail.


php pecl install mac os x 10.6

Question: Does anyone know how to install pecl for mac os x 10.6. I have tried googling with no luck.
Comment: this possibly should be a superuser question, what pecl plugin you trying to install because it may be available via macports?
Comment: Good question. Trying to figure it out myself.
Answer: PECL should ship with PHP on OSX 10.6. If not, it may be a part if the development libraries packaged with OSX's install disc. You can identify if it's installed by typing the following in your Terminal.app (should return a path).
which pecl

If your unable to find PECL
Sometimes it's easier to re-install PHP. Look into macports, or homebrew. Both package managers ship the latest PHP5 (including PECL).
Verify PECL is working
Updated your local database with the latest packages, and install a simple package (like bbcode.)
sudo pecl channel-update pecl.php.net
sudo pecl install bbcode

Install a PECL package without PECL
This is hit-n-miss depending on the package. To install a PECL package manully, you would follow the traditional ./configure, make, and make install process.
# Download the package
curl -O http://pecl.php.net/get/bbcode-1.0.3b1.tgz
# Extract archive
tar zvxf bbcode-1.0.3b1.tgz
# Change directory
cd bbcode-1.0.3b1
# Apply local php settings
phpize
# Run configuration script
./configure
# Compile
make
# Verify build
make test
# Install on system
sudo make install

Answer: The most straight forward method if you don't want to go through brew is install directly from the pear website.
$ curl -O https://pear.php.net/go-pear.phar
$ php -d detect_unicode=0 go-pear.phar

for more configurations see the pear website

php pecl install mac os x 10.6


How can I prevent TeamCity from creating artifacts for pre-tested commits?

Question: Right now, TeamCity is creating 2 sets of artifacts each time I do a successful pre-tested commit, one when it builds the solution with my local changes against which to run the tests, and a second time when it gets triggered by the VCS repository change.
How can I prevent it from creating artifacts for its build-to-test before commit?
Answer: Check build.is.personal system property or BUILD_IS_PERSONAL environment variable to be defined.
Answer: Use a different build configuration for the VCS triggered build, one that doesn't have any paths configured for saving Artifacts.

Go to the Administration page and copy the existing build configuration.
Under "Build Triggering" on the original configuration, disable "Enable Triggering when files are checked into VCS"
Under "General Settings" on the copy remove everything from Artifact Paths


Google Chrome isn't properly working

Question: Since I did some updates from Software Updater, Chrome isn't working. I can open it but all the web pages that I go in to, doesn't load completely, though the little black wheel is not indicating that is still working. I've already tried to update Chrome, reinstall, delete and install it again but is still the same.
Thanks in advance for your help. There's an image of Youtube's main page and that's how Chrome is showing the web pages.
Comment: I have the same problem, I have recently updated my PC with Xubuntu and Chrome, Opera and Brave don't load pages properly: not all the images are loaded, there is some "styles" missing, etc.
It is curious that Chromium works correctly and also Firefox
Answer: This seems like a configuration version mismatch issue ... Although newer versions should deal properly with old configuration files, but sometimes things that are not expected happen e.g. corruption, invalid lock/status files, user installed extensions, outdated/invalid website specific caches/settings ... etc.
At this point and before proceeding, in Google Chrome, you might want to login to your Google account, "turn on sync" and wait until all your personal settings get saved in your google account … This will make it easier to restore them after your browser is fixed.
To see if this is the case, close Google Chrome first ... Then backup its configuration directory(should be ~/.config/google-chrome) by renaming it like so:
mv ~/.config/google-chrome ~/.config/old-google-chrome

Now, open Google Chrome and visit a website to see if it works normally and if that is the case, then you know what the culprit is.
Now, your Google Chrome is almost like a clean install ... To restore your previous settings, history, bookmarks ... etc.:

The preferred way is to login to your Google account and "turn on sync" if you have that enabled previously previously and that should restore all your saved settings ... Please see the comment by @xtrchessreal(Thank you @xtrchessreal for confirming that)

Or, alternatively, you can close Google Chrome again and copy the old configuration directory's contents over to the new configuration directory with cp's option -n, --no-clobber(do not overwrite an existing file) like so:
cp -nr ~/.config/old-google-chrome/* ~/.config/google-chrome/

Oftentimes, this will keep the newly created version specific configuration files made correctly when you last launched Google Chrome and restore your old configuration.
In rare times, you might need to selectively copy over the contents of the old configuration directory until you isolate the cause.
Comment: @xtrchessreal If you just follow the first step to rename the configuration directory and **do not** copy back any of the old configuration files in the second step, then you will notice that you are not logged-in to your google account anymore which means it is almost like a new installation ... So, logging-in should synchronize like a new Google Chrome install does ... I haven't tried it myself though so I can't confirm it, but it should.
Comment: @Raffa Yes I was not logged, which I then did but the sync function is something you must do additionally.  Click on your profile top right it asks to "turn on sync?" you click "Yes I'm in" then you must enter your passphrase.  This should then load everything as before.  I still had to go to history and "restore all tabs" to get back completely.  These websites then need to be logged in again, if you have Saved Passwords its just a matter of clicking what is stored in Saved Passwords memory.  I'm all good now, thank you for the extra help.
Comment: Thank you! It worked! Although, when I tried to restore previous settings, etc, it went back as it was before, like the web page flashing and not loading correctly so I had to go back to the first step you've described and left it like that. Thanks Raffa!
Comment: I followed your answer, the websites work properly but I've had to set my bookmarks to view them again where before they where always showing.  The tiny icons are not present inside the bookmarks and subfolders.  Now I am worried that my sync may be wiped out if I turn it on again. It used to be on normally as a standard.  If you know please help and complete the answer to show the next steps - thank you.  If its just that Chrome believes this is a new computer then I should be able to turn on sync and everything will come back - right?  Waiting for confirmation before taking further steps.
Comment: @xtrchessreal Many thanks for confirming that ... I added it to the answer.
Answer: For me seemed the issue is to do with Hardware acceleration (Ubuntu 22.04, Version 114.0.5735.198 (Official Build) (64-bit))
chrome://settings/system uncheck Hardware Acceleration and relaunch.
Comment: this one worked for me
Comment: Worked for me too. Navigation is slow but at least pages does not look destroyed anymore.
Comment: Hardware Acceleration seems to be partially fixed in Chrome Version 115.0.5790.98 (Official Build) (64-bit) and can be reenabled.

Google Chrome isn't properly working


2mm clearance between the chainstay and the rear tire

Question: I use a pair of club roost cross terra (27 1 3/8) on a vintage raleigh bike (maybe it's raleigh record). Originally the bike had 27 1 1/4 tires.
If I'm correct, 1 1/4 is 32mm wide and 1 3/8 is 35 mm wide.
The clearance between the chainstays and the rear tire is 2mm on both sides. Is this acceptable?
The brakes are just fine and I only use the bike for daily commuting.
Comment: So long as the tire doesn't rub it's fine.
Comment: Technically, you can go until the tire doesn't rub. However, practically, most people want a few more mm clearance (this is up to your own comfort level), especially due to frame flex and other factors which can use up the tolerance. FWIW, I'd want more than 2 mm clearance, personally, even on my commuter.
Answer: Clearance is clearance.  It will work fine until your wheel goes out of true, or you ride in conditions that produce 2mm of extra width on your tire (mud, snow, etc).  Or alternately some combination of the two.  Depending on your frame material (I am too lazy to look yours up, but I'll assume steel) it will probably rub on almost every ride at some point when you flex the frame enough for it to touch.
Comment: Agreed. If the tire rubs when you stand up to pedal, then there's probably not enough clearance.


Why does a rocket spin during launching

Question: Why does a rocket spin during launching?
https://www.youtube.com/watch?v=BuPY5l45UC8
Answer: The thrust from the rocket is not quite "straight down", but at an angle - and slightly offset from the center. If the (solid) fuel burns ever-so-slighly unevenly, the surface that the burnt fuel pushes against will be at a slight angle; and since the rocket has relatively small angular momentum about the long axis, it will readily spin.
Note - once the fuel is almost spent, the rotation stops (aided by the fins which try to keep the rocket straight).
If you are trying to aim a rocket, imparting a bit of rotation might be a good idea. Just as the rifling of a gun barrel cause the bullet to spin about its axis, this has two effects: first, if the shape of the rocket/bullet is slightly asymmetrical, the rotation will cause a "self-correction" of the deviation this incurs. You will go up-right-down-left and end up pointing in (roughly) the right direction. Second, the rotation will stabilize the bullet against the torque caused by the drag when the bullet is not pointing straight in the direction of travel. Instead of "tipping on its side" (think about how a playing card falls when you drop it "straight"), the rotation will keep the bullet pointing in the direction of travel.
In summary - it's accidental in this case; but when it is done deliberately, it's a good thing.
Comment: Doesn't the jet engine inside liquid fuel rockets provide some of the angular momentum?  I am not sure if it reaches max rpm prior to liftoff but if it did not, it could cause the rocket body to turn in response to the torque created by the accelerating engine shaft.
Comment: @honeste_vivere - did you watch the video. This is a solid fuel model rocket we're talking about.
Comment: Ah, no I did not glance at it.  So there is no liquid fuel parts?  Okay, then my comment is clearly moot.  Thanks...
Comment: Plus, there are no "jet engines" in liquid fuel rockets, either. A pair of turbopumps per nozzle, yes, but that's a different story altogether.
Answer: In a nutshell, the rotation slows the rocket's reaction to disturbances which might throw it off course.
This is similar to how a spinning gyroscope can remain upright and seems to resist forces which would seem to topple it.
Comment: Did you watch the video before writing this?
Comment: Any rocket will rotate about its CG, which due to axisymmetric rocket design is along the roll axis. If a slight perturbation starts the rocket spinning, it will tent to continue to do so due to this design. If the rocket is intentionally sent spinning, it gains the benefit I mentioned. I couldn't get the video to load, so I went with a general answer. If you look at the question, it isn't specific to the linked video.

Why does a rocket spin during launching


In a private FB group, a girl said all moms in Area were racist. She contacted my employer. Can I be fired?

Question: Conversation continued with me asking on what grounds she had for such allegations, she would just continue to name call. She contacted my company and said she demanded I be fired. I took screenshots of the portions of the convo that I could get to. I blocked her. Removed my employer from my profile and contacted my boss and HR. Can I really be fired on baseless accusations?
Comment: What country/state are you in, what is your employment type?
Comment: I even have the group admins post saying that I hadn't said anything racist and that she was instigating
Comment: Usually if a young mother starts ranting at you you discount it as  stress. Soon enough they get distracted and either look after their kid or rant at someone else.
Comment: United States, employer based in Ohio, I work remote in KS. I am Project Manager and work with individuals from all over the world, of all ethnicities/races
Comment: So you are a full time salaried employee?
Comment: Yes, I am full time salaried
Comment: No, not at all. I just asked her questions on how she could make such a generalization. I only said she was being immature and judgemental.
Comment: Keep us updated please. I'd eventually like to know your employer's answer to this question.
Answer: When you say "a girl said all moms were racist", I imagine a fourteen year old. And if "all moms are racist" nobody can take that as serious evidence that you are racist. If you don't get complaints from co-workers, or from customers, with actual examples of racist behaviour, and if you don't behave in an unacceptable racist way in public, you'll be fine.
In this particular case, a random person demanding that you get fired will have very little effect. If you have screen shots where she claims that "all moms are racist", nobody can take her serious.
Comment: It's not likely that a single prison will be able to get them fired. However if the complainer gets some momentum via social media, the company is likely to drop them like a hot potato. That's just the way it works thesedays.
Comment: She is a mom in a bi-racial relationship (she disclosed, I did not know), this is a private "Mom" group. She, and the conversation, were deleted.
Comment: Momentum alone doesn't do anything. If there is a video of a badly out of context joke, or Twitter post, or whatever, sure. If it is just pure rage and demand, and there is no substance, then no. It really depends on what caused it.
Comment: @Nelson I would think it depends on the employer's determination of how much of a liability the employee is to the company achieving their business goals (or maintaining PR image) which we can't know. One company could react very differently than another.
Answer:
Can I really be fired on baseless accusations?

Yes, unless you have a contract with your employer that protects you from being fired: "The Ohio Supreme Court has held... that the right of an employer to terminate an employee's employment for any cause at any time is absolute, and cannot be limited by principles that protect persons from gross or reckless disregard of their rights, or from willful, wanton, or malicious actions or acts done intentionally, with insult, or in bad faith..." Employment-At-Will and Wrongful Discharge
in Ohio
Most likely your employer won't fire you since there is no evidence but there doesn't have to be evidence. In most parts of the Internet it's a really good idea not to identify your employer or even use your full name.
Answer: Don't worry. If your company fires you based on somebody making a generalized claim, then talk to you lawyer to get a settlement fee, anyway that company is not  work to continue working for.
In the majority of the case:

The person in question actually did not contact your employer just wants to threaten you

In the majority of the remaining cases and in a professional company:

HR receives email from somebody ranting about one of your employees on facebook.
HR briefly discusses with legal if the allegations are targeted against the company and not person (e.g. if the poor person wrote something: your hiring policies favor racists or "you dont care about racism")
if yes, they may thing about a cease&desist regarding libel
if no and they are in good mood, they may ask back if the person sending the email was experiencing this while you were on the job
if no, they will inform the persons that they addressed this at the wrong place and that no further emails in this regard are desired
If yes, they may ask for proof.
If there is no proof or the proof is weak and unsubstential, they again may ask the person, potentially with a cease&desist to be careful what she says publically.
Comment: "Dear Ms. X: Be advised that someone is signing your name to stupid letters."


How do you organize C# code in to files?

Question: In C#, the questions of what types to create, what members they should have, and what namespaces should hold them, are questions of OO design.  They are not the questions I'm interested in here.
Instead, I want to ask how you store these in disk artifacts.  Here are some example rules:

Put all of an assembly's types in a single source file.  One friend who did this said "files are an archiac code organization tool; today I use classview and Collapse to Definitions to browse my code".
Put all your code in one assembly.  Makes deployment & versioning simpler.
Directory structure reflects namespace structure.
Each namespace gets its own assembly.
Each type goes in its own assembly.  (Listed as an extreme example.)
Each type gets its own source file.
Each member gets its own file; each type gets its own directory.  (Listed as an extreme example.)
Answer: Whatever you do, just PLEASE do it consistently.  I don't believe there is any one single answer (though there are a few wrong ones).  But just make sure you stay true to your form as this will be the key for your successor(s) to find things easily.
Answer: Currently I do:

One assembly for production code + unit tests
directory structure mimics namespaces
one type per file
nested types get their own file, using partial types.  That is:

// ------ C.cs

public partial class C : IFoo
{
    // ...
}

// ------ C.Nested.cs
partial class C
{
    public class Nested
    {
        // ...
    }
}

Answer: I do it quite similarly. One point where I differ:

one type per file

I declare delegate types where I need them, i.e. not in their own file but rather in the class that uses them.
Answer: I create one assembly per architectural layer. (WinUI.exe, BusinessWorkflow.dll, BusinessComponent.dll etc.
Then, one physical file per class.
So that's "vertical".
Namespaces, conceptually, go horizontally, grouping domain level functionality together. All the customer stuff goes in a "Customer" namespace, say, Orders go in "Accounting.AccountsPayable" for example.
As each assembly only reference the one beneath it in - architecturally, your intellisense is constrained nicely by relevant references within your domain model.
(Have to agree with above though - consistency is vital.
Answer: For tiny projects with less than a dozen classes, just one class per file.
For enterprise projects, I have multiple projects in a solution.  They are grouped by purpose  (business classes, interfaces, UI).  Each class has its own file.
Answer: No matter how small a type is, put each type into a separate file - Exception: nested classes and delegates
By the way, using a partial class to separate for the sole purpose of placing a nested type in its own file seems like an overkill.
Partial classes should be used judiciously and typically to be used for file generation tools - You have to consider how to "name" your partial classes for nested classes.  Coming up with an intuitive name for physical nested file can be tidious and it is definately not a simple task.
For projects, name your projects to reflect namespaces - Exception: When a nested namespace gets big, I would migrate a nested folder into another project.
Answer: I prefer the conventional one-file-per-public-class, with folders inside the project (which map to sub-directories) used to group conceptually related classes as needed to keep the Solution Explorer view manageable. If your class names are well chosen the folders shouldn't be strictly necessary, but they are helpful if the project has a lot of classes.
Using separate files for nested types seems like overkill, at least if the nested classes are relatively simple 'helper' classes, and particularly so if they are private.
The main practical objection to your friend's "everything in one huge file" scheme is that Visual Studio tends to get very, very slow when it tries to deal with very long code files.
Answer: I prefer this kind of organization in whatever language.
Related small classes in their own file(s).
Big classes in their own file.
Directories for separate subprojects.


native XML Database: eXist or Sedna?

Question: I'm trying to decide on which native XML database to choose: eXist or Sedna (both are open source)
I'm using cakePHP, Ajax and WAMP for my website.
I will be using the XML database only for reporting purpose coz' i'm having some semi structured data which cannot be stored in MYSQL.
Which one is well documented?
Which one is easier to learn?
which one has better community support such as forums, etc..?
What are the advantages and disadvantages of both of them?
thank you.
Answer: Also try BaseX, offering a very helpful mailing list and wiki documentation.

native XML Database: eXist or Sedna?


Annoying adverts showing on top of other apps

Question: On my sister's Huawei 360 adverts appear on top of other applications whenever wifi or mobile data connectivity is on. These adverts are so annoying since the sometimes freeze the phone covering the whole screen with a small x on the right hand side corner. They also consume a lot of data. They can show even on whatsapp.
I have checked if there are any launchers but only the default one appers, Also I dont any funny apps in data usage under apps that use background data. Could these apps be the one installed via USSD code or phone serial number?
Comment: It's quite difficult to answer, without having knowledge of your installed apps.
Answer:
The first reason for these annoying ads might be because of your browser when you have accidentally clicked on any of adds shown.Those malicious adds may install some apps in your ROM(internal memory) which may not be uninstalled so easily or will re-appear every time you connect to internet.
So, you could take backup and restore the phone to factory settings.
I did the same way when i was attacked by these malicious apps.
PS: these type of apps may import your photographs and other data. Please be cautious and do factory setting ASAP.
Comment: @user145490 There are three ways around privileged ads. The first involves rooting the phone, manually identifying the offending apps, searching for their packages inside **/system/app** or **/system/priv-app** and delete them (tedious, but less aggressive). The second is to try finding your device's stock ROM, and flash it. The third is similar to the second, but is about flashing a custom ROM, yes.
Comment: Notice that **ROM** is another way to call the **firmware**, or **operating system**. If those advertising applications pushed themselves to the **/system** partition of a device, then a mere factory reset won't help.
Comment: @DeathMaskSalesman How would one go around that then? Would it involve installing a custom rom?
Comment: @DeathMaskSalesman I would not recommend the first one, as you can really screw up your OS (and maybe notice that too late) when deleting the wrong files with root
Comment: @Namnodorel And that sums up pretty well why root tends to be disabled by default, doesn't it? One should _always_ make backups before toying, and _always_ inform themselves before deleting or messing with something unknown. Root is powerful, but that power is not without risk.


If Lucifer was top perfect creature, how could he fall? [Catholicism]

Question: Since God's creation is good/perfect, how could a creature as good/perfect as a top angel actually fall, according to Catholicism? What is the mechanism of corruption that can corrupt a perfect being? Since God is incorruptible, He is then still the absolute perfect, while any other creature with free will cannot be absolutely perfect. But then, what is the guarantee that humans or saint angels will not fall again, being already in heaven?
Comment: It is the beatific vision that guarantees our will fixed in God's will. It seems the angels didn't have it prior to their fall and their will was not fixed in God's. Something like you wouldn't trade a sin for a penny if you just won a lottery with mega-millions.
Comment: Being a top angel might actually make it easier to sin by thinking "I'm practically as great as God."
Comment: @AndreasBlass But he knew he wasn't as great as God, as no one can ever be.
Comment: Yes, he's smart enough to know that. But one who knows he's not as great as God yet still thinks he's anywhere near comparable to God still sins by pride.
Comment: It appears as though angels cannot create, while God can.
Answer: Angels, incorporeal intellectual beings, cannot become less perfectly angelic (unlike humans, who can become more or less human); also, every angel is its own species. However, there can still be "evil of fault" (malum culpæ) in angels, not in their intellects but in their wills. Angels have freewill.
Comment: Do you mean that angels can either be completely good or completely evil, and nothing in-between?
Comment: @sequence All angels are naturally good; even [demons (fallen angels) are not naturally evil](https://isidore.co/aquinas/summa/FP/FP063.html#FPQ63A4THEP1).
Comment: Yes but if I understood your answer post correctly, humans can be less human, but angels cannot be less angelic. Does this mean that fallen angels are necessarily absolutely evil?
Comment: @sequence Angels cannot become less angelic. By nature, all angels (even fallen angels) are good. Fallen angels' wills make them do evil.
Comment: Isn't it true that people also apply their own will in order to do evil? @Geremia
Comment: @sequence Yes. And when humans do evil they become less human.


hg command for git bundle

Question: In git, there is a command 'git bundle' which bundles a git repository into 1 big file.
Is there the equivalent command for 'hg'?
Comment: What research did you do before you asked this question? I'm asking this since I'm confused about why you didn't find the command in Mercurial when it is named the same? It would be helpful to us if you could write email@example.com and point out where we need to improve the documentation. Thank you.
Answer: Hg supports the same command.  Here's the help for it:

U:\>hg help bundle
hg bundle [-f] [-t TYPE] [-a] [-r REV]... [--base REV]... FILE [DEST]

create a changegroup file

    Generate a compressed changegroup file collecting changesets not known to
    be in another repository.

    If you omit the destination repository, then hg assumes the destination
    will have all the nodes you specify with --base parameters. To create a
    bundle containing all changesets, use -a/--all (or --base null).

    You can change compression method with the -t/--type option. The available
    compression methods are: none, bzip2, and gzip (by default, bundles are
    compressed using bzip2).

    The bundle file can then be transferred using conventional means and
    applied to another repository with the unbundle or pull command. This is
    useful when direct push and pull are not available or when exporting an
    entire repository is undesirable.

    Applying bundles preserves all changeset contents including permissions,
    copy/rename information, and revision history.

options:

 -f --force      run even when the destination is unrelated
 -r --rev        a changeset intended to be added to the destination
 -b --branch     a specific branch you would like to bundle
    --base       a base changeset assumed to be available at the destination
 -a --all        bundle all changesets in the repository
 -t --type       bundle compression type to use (default: bzip2)
 -e --ssh        specify ssh command to use
    --remotecmd  specify hg command to run on the remote side

The command for the reverse operation is hg unbundle.
Comment: Here is a link to it in the full documentation. http://www.selenic.com/mercurial/hg.1.html#bundle
Comment: Yeah, it has the same name in Mercurial... that's not coincidence because Git got its bundle command from Mercurial :-)

hg command for git bundle


Non-catalysed exhaust gas

Question: I'm writing up an academic paper (medical) on in-car exhaust levels and their effect on health. So as to ensure detection of leak-points that are located further along than the catalytic converter, in the discussion I would like to recommend the testing of an exhaust gas that is not affected by passing through the catalytic converter. Would I be correct in thinking that toluene is one such gas, and if so, would it be a good marker gas to use? Many thanks!
Comment: If you are measuring the actual outputs from a real engine, then carbon monoxide would be a good candidate as it is a key target for catalytic converters and is easy to measure. Toluene would not be as the amount will vary hugely by fuel composition and is probably not a major feature in exhausts from modern engines anyway.
Comment: Hi matt_black, many thanks for your comment. As it happens the study measured precisely that - I put CO dataloggers in in a bunch of cars driven by laypeople - and the results were pretty worrying! Some of the highest readings, interestingly, fell very quickly as the engines warmed up. This made me think that the CO may have originated from leaks distal to the catalytic converter - which is why a dual test, of CO and also of a non-catalysed gas, would be necessary to detect all in-cabin leaks. You can read about the project here - https://www.airsafe.london.
Comment: While the possibility of leaks from the exhaust is worth exploring, it would not be my first or most likely hypothesis explaining the presence of CO inside the car. Just normal atmospheric circulation will lead to that. And while cold engines might produce more CO, cold catalytic converters *certainly* do so the profile of the gas over time inside the care doesn't need leaks to explain the pattern observed.
Comment: If you're interested in learning more about the many factors that influence in-cabin CO, Kaur, Niewenhausen et al 2009 is a good place to start - from there, read Alameddine et al 2016, Hachem et al 2021 and Lim J 2019. Then look at the field studies - Moreno T et al 2019, Hachem M et al 2021, and round off with the Lancet meta-analysis (Cepeda et al 2016). And then once my paper is out, you could even read that too. TLDR, cars do often leak.
Comment: (and much thanks for the practice in thesis defence - always helpful! have a good one)
Comment: (oops sorry - Harik G et al 2017 is the second field study, not Hachem)
Answer: A much better tracer for leaks than toluene would be helium.
Compared to toluene, helium is a noble gas and hence unlikely to react at the temperatures and presence of the catalysts in a converter.  (Different to toluene, it plausibly would pass unchanged the combustion process of an Otto, or Diesel engine, too.)  It is inflammable and non-toxic. Its monoatomic molecules are considerably smaller in size, than a toluene molecule and hence can pass smaller cracks and openings.  At ambient conditions, helium already is a gas .
Helium sniffing already is a technique introduced in the industry to check e.g. joined gas pipes and vacuum installation for leaks: an external probe aspires air for instance next to a fitting, while the tubing is flushed internally with some of helium.  The air aspired outside is submitted to a small mass spectrometer attuned to the very signal of helium and of high (often adjustable) sensitivity.  The technique equally benefits from the the low terrestrial concentration of helium (except a few known natural sources and artificial processes) and hence low background.

(image credit to TQC Automation & Test Solutions)
A little cart can house both the gas cylinder with the tracer gas and the necessary equipment:

(image credit to Leybold, which provides some additional information here)
Comment: Hi there Buttonwood, this is really helpful: very much appreciated.

Non-catalysed exhaust gas


Bad Quality whilst exporting an animation

Question: I am dealing with a problem when exporting the animation I've tried to create on my own. I don't think I messed up something during the animation process, so it has to be something with the output settings. Just like with the donut tutorial (which I exported with the same settings and without any quality loss), I rendered all frames into a separate folder. Only then put them into Video Editing as "Image/Sequencer", chose all output settings, and clicked "Render Animation", as I should. In the Render environment, I see it played in high-quality, just as it should. But then, when I open the video in Windows Player, it seems like it stretches the video to default 1920x1080, whilst it's set to 500 x 500 in the output settings (same whilst animating). I checked all the output settings, but haven't found an issue regardless. I have attached some screenshots to give a clearer view of what I am talking about.
Comment: The object in the image doesn't look very stretched to me... is it really stretched to 16:9 ratio or is the player just showing the open spaces left and right in black which makes the black background of the video look like it's stretched out to the sides?
Comment: Yes. In file settings, it shows it is 500x500, as on the output. But yes, It looks like it stretches the resolution of a screen. I do not know what is the reason exactly. Maybe you did not spot it, but there is also a significant quality drop. So I can see pixels and noise whilst opening the animation in Windows Player (and other players as well), compared to Blender. In Blender, it looks just fine.
Answer: I also sometimes have videos smaller than full HD and when I open them in the player, the video player maximizes its window and makes the video display larger.
However, this is not a problem with Blender, but with the video player. Or maybe with the video format you choose. But if the file says it's 500 x 500 then it is all fine with the file. Maybe there is a setting in the player to play the video in original size.
What I meant by "it is not stretched to 1920 x 1080" is that the aspect ratio didn't change. It might be scaled to fit the height of 1080 and of course this might result in worse quality because not all software scales bitmap perfectly. But again: this is not a Blender problem. By the way, this is how it would look stretched to 1920 x 1080 and your object definitely isn't stretched like that:
Comment: I've just tried to rerender my animation, but at 1000 x 1000 Resolution. I exported without any loss. So there might be a problem with players themselves, as they are unable to play 500 x 500 correctly. Have tried to storm through the settings, did not find anything to tweak. I just found that 1000 x 1000 also looks good, which is why I am happy to stick around it in case I am unable to fix the issue.
Comment: Although it's still not a Blender problem, here's one solution anyway: if you're using VLC player for example, in the menu bar there is _Video_ > _Always Fit Window_. If you uncheck this, a 500 x 500 video will play in 500 x 500. You can also right-click on the video and choose from the context menu. Something similar is in good old Windows Media Player. I'm sorry I don't know all software video players, might be that yours doesn't have such setting since there was nothing to find...
Comment: I have downloaded VLC Player and made the adjustments you listed. It actually worked and started showing the animation as 500 x 500. But here is a question. If I upload this video to the web, it will still be stretched and quality-low. It looks like 500 x 500 is just not an ideal format that fits worldwide. Anyway, thank you for your help. Now I am a bit more aware of what was the problem :)
Comment: You're welcome but as I said, that's not a Blender problem and maybe you should try to find a solution in a different forum.


gcloud compute images import SLES 15 SP2 BYOL

Question: Currently trying to do a gcloud image import in order to bring our own license for SLES 15 SP2 gives:
<code>[import-image]: 2020-07-30T23:00:04Z Error running workflow: step "wait-for-translator" run error: WaitForInstancesSignal FailureMatch found for "inst-translator-import-image-54bdm": "TranslateFailed: error: Import of sles-15.2 is not supported. The following versions are supported: [opensuse-15.1, sles-15.1, sles-12.4|5]"
</code>
I haven't been able to locate any info on when this would be supported. Any pointers or info on that would be appreciated.
Answer: At this time, import is not supported for SLES 15 SP2.
Please see Compute Engine > Doc > Feature support by operating system


is RSA private key less than public?

Question: when i generate RSA key pairs by OpenSSL, it seems like private key (private exponent) is always less than public key (modulus). Is it by RSA design?
Comment: This question appears to be off-topic because it is about RSA keys and doesn't contain a programming question.
Answer: It's not a requirement, but there is no reason for it to be larger than the modulus:
The private exponent d is calculated from the public exponent e and modulus n to satisfy:
ed ≡ 1 mod φ(n)

Now, if we assume that d > φ(n), then we can define d' = d mod φ(n), and not only is d' < φ(n), but the above relation still holds, i.e.:
ed' ≡ 1 mod φ(n)

Thus d' is also a valid private exponent, and since φ(n) < n, d' must also be less than n.
Since a larger private exponent requires more storage, and (at least in the naïve implementation) makes decryption slower, the smallest possible private exponent is the most suitable.
Answer: No it is not important to the cryption itself. (Check wikipedia how rsa works). Maybe its implemented this way but its no must for the algo
Comment: wiki says that private exponent d "is the multiplicative inverse of e (modulo φ(n))". Does it say anything to non-math-professor? - No. Can you prove mathematically that formula d⋅e ≡ 1 (mod φ(n)) does not mean what i asked about?
Comment: It should mean something, we did it in 10th class :o i dont understand your actual problem

is RSA private key less than public?