A word for a man of few, but well thought-out, words

Question: I recently lost a friend and I'm looking for the words to describe him. He was a man of few words but his words were deliberate, they weren't spur of the moment thoughts. He meant the things he said and they carefully and accurately described his true thoughts. Is there a word for this?
Thank you, everyone! I have enjoyed reading your replies as I reflect on my friend. As some have mentioned, I think I may have already found the words and summarising it in one isn't necessary.
Comment: Quite frankly, I think you might already have found them: your point will be largely lost if it sounds as though you had to consult a thesaurus to make it.
Comment: He sounds *thoughtful and succinct*.
Comment: A _"man of few words"_ is (1) one who is thoughtful and disciplined in speech (2) A man who expresses himself without talking very much (3) A man of few words will rarely be thoughtless in his speech - he will measure every word.
Comment: This is an interesting question in a way.  The right word is not easy to find, in seeking to described a valued friend or relative.  It is not always a single word that that is wanted.  What you have yourself written sounds as if it says exactly what you wanted to express.  You could shorten it a bit.  If you deleted from "his words were" and continue "... a careful and honest expression of his true thoughts."
Comment: I regret to say, in more than 60 years of listening, I've never met any word anything like that.
Comment: I think you realized this already, but the phrase "a man of few, but well thought-out, words" is hard to beat.
Answer:
"I like men who have a future, and women who have a past."
With his razor-sharp tongue and pithy, piercing insights, Oscar
Wilde was considered to be "the foremost wit of his age."
Philosophical Library; The Wisdom of Oscar Wilde (1967)

pithy (adj.)

Having substance and point : tersely cogent
Unlike a great many other science books, the pithy, lyrical text never bogs down in a mudflat of facts.
— Leonard S. Marcus, Parenting, December/January 1996
M-W

Precisely meaningful; forceful and brief:
A pithy comment.
AHD

(Of speech or writing) expressing an idea cleverly in a few words:
A pithy remark
Cambridge

Of language or style: full of concentrated meaning; conveying meaning
forcibly through brevity of expression; concise, succinct; condensed
in style; pointed, terse, aphoristic.
1753 Finding something to say to each, in his pithy, agreeable manner.
S. Richardson, History of Sir Charles Grandison vol. VI. liii. 339
Of a person: that speaks or writes pithily; terse, succinct,
aphoristic.
1922 He was pithy; he was prudent; he never said a word too much.
E. von Arnim, Enchanted April (1989) 5
[OED online]
Comment: Your first definition of "pithy" might even be better: _tersely cogent_. But then again, it would be very strange to see any of these words appear in such a setting.
Comment: How is that a word for a man of few words, however well thought out?
Comment: @RobbieGoodwin At you talking about *pithy* or something else?
Answer: Laconic

using or involving the use of a minimum of words

This has in fact almost idiomatic character, as short sentences with highly condensed meaning are known as laconisms.
Comment: That's the word that occurred to me, too.  However, the Wikipedia page you link adds "…especially a blunt and elliptical rejoinder."  I'm not sure whether the word often carries that nuance — it isn't mentioned in any of the dictionaries I checked — but if so, maybe it wouldn't be such a good match for OP's situation?
Comment: This doesn't convey the accuracy of the words, though.
Comment: Laconic does mean using few words, but connotes being abrupt or even rude, rather than thoughtful, so it might not be the best option for memorializing someone.
Comment: How is that a word for one whose words are well thought out, however few?
Comment: "Laconic" derives from Lakon, an old name for Sparta. The Spartans were (supposedly) famous for the devastating one-liner comeback. The whole point of the term laconic is that you don't say much, but when you speak, it's carefully considered and right to the core of the matter.
Answer: Succinct

marked by compact precise expression without wasted words
Comment: A phrase or sentence can be succinct, but I don't think it can be applied to a person.
Comment: I have heard people described as "succinct" but it is a word better used for the expression not the expressor.
Answer: Considered
Note that "considered" implies "thought given to" whereas considerate implies "kind to others".
Aside, I applaud your taking the time to think of the words, to describe a person who took time to think of their words. It is likely a thing they would appreciate.
In this case you are being both considered, and considerate.
Comment: This is probably the best match here for the question as asked.
Answer: Another possible word choice would be measured.

You use measured to describe something that is careful and deliberate.

The men spoke in soft, measured tones.
Her more measured response will appeal to voters.
[Collins]
Answer: Concise
adjective
marked by brevity of expression or statement : free from all elaboration and superfluous detail
Answer: Apologies for the John Wick reference, but searching for one word in this case would lose on impact and meaning. I assume both are important to you.
You could say: "He was a man of deep silences but when he did express himself he did so with well deliberated thought rooted in deep purpose"
Answer: taciturn

tending not to speak much

I feel that laconic, which is listed as a synonym and suggested in other answers, would tend to describe utterances that were oblique or even sarcastic; but that taciturn does not have those overtones; it simply means 'doesn't say much'.
Comment: Neither connote careful use of words.
Comment: How is that a word for one whose words are well thought out, however few?
Comment: Taciturn is more likely to imply shyness, reluctance to speak, or unfriendliness than wisdom and thoughtfulness.
Answer: Articulate
adjective
able to express thoughts and feelings easily and clearly
Comment: This doesn't convey "of few words", though.
Comment: How is that a word for a man of few words, however well thought out?


Lastpass VS Sxipper. which one is better at their thing?

Question: Well, i've been using sxipper for some time now, but recently came across lastpass. I can't tell which one is more secure or has a better functionality, sxipper however seems easier to use.
Comment: Which browser, what OS?
Comment: sxipper is a firefox only plugin so, it would seem, he would be using firefox.
Answer: My vote would go to lastpass for being cross platform and supporting multiple browsers and being able to keep the database accessibly to all of them.
The security of lastpass has been debated
You can also see other password options here
Comment: I don't now about sxipper, but lastpass can also use two factor yubikeys which helps. They recently had a tiny amount of unexpected traffic on their network and took pretty conclusive counter measures to protect the end users, which is encouraging. It goes without saying dont use either of these systems to store any sensitive passwords, but rather the many, many low-security passwords you need everyday to live online (and even then you can bump them up a bit now you dont need to remember them).
Answer: Lastpass is ubiquitous and cross-platform.
I believe the lastpass to be much more secure though.
Answer: I don't know how LastPass dose it, but Sxipper never stored any password off site, that means that all your passwords are stored on your computer.  Only form completion schemes where stored on Sxippers server. Now I don't know what do you consider secure, but in my opinion, the most secure option is when only you and your computer know your passwords(Sxipper), not a third party server(LastPass).


What is the best practice for using AngularJS filters in a controller/service?

Question: I've seen both of the following methods to use a filter in a controller/service:

$filter('myFilter')('myStuffToFilter', myFilterArgument)
myFilterFilter('myStuffToFilter', myFilterArgument)

They work equally well. Which method constitutes best practice?
Answer: While this is not a ground-breaking issue, I believe there is a difference and it's worth sharing (as did pkozlowski.opensource in his answer to a related question). Option 2 is better for the following reasons:

Cleaner syntax: It's a little cleaner, more straight forward and avoids the sequential parentheses syntax which is less common.
Provided solution: The myFilterFilter object is not available for code injection by accident. The AngularJS creates these <filtername>Filter objects for all filters (pre-defined and custom) and makes them available to the injector.
Documented solution: The AngularJS documentation recommends this solution in their documentation here.


How to ask a question across multiple Stack Exchange sites?

Question: How do you ask a question on Ask Ubuntu, Server Fault, the Unix and Linux SE, and Super User all at once?  My particular question is about Ubuntu so I put it there, but it could easily fit at any of the others.
Comment: You don't. Ask your question on the most appropriate site.
Comment: You should either ask how to do something, or ask for a feature request to be able to do something that you currently can't.  Based on your tags, you know that this can't be done.  The text of your question should be in line with that.
Comment: @Bart I did add the feature-request tag...I would like such functionality.
Comment: Fair enough, but I fear the answer will be "not gonna happen". Cross-posting is a bad bad thing and should not be done. You're better off taking the advice you've been given in the answers.
Answer: The simple answer: Don't.
The more detailed answer:   Each SE has a specific set of FAQ and guidelines that specify what kind of questions may be appropriate there, and yes, there's a lot of overlap between the different SE sites.  Your example is likely a usage issue of Apache on Ubuntu, so my gut feeling tells me that asking the question on Ask Ubuntu would be better than spreading it out everywhere.
This also encourages you to have a narrow scope with your question.  This improves the quality and usefulness of the question, and has an effect on the answers, too.
Comment: You should be specific with the scope of your question.  Do you want an answer that pertains to Ubuntu, Apache, or a use of Apache with Ubuntu?  From here you select which SE you want to ask your question on.
Comment: why can't you  check a box for "also, put this on unix and linux"?
Answer: You should choose the Stack Exchange site where you think your question has more chance to get an answer between those sites where the question is on-topic.
If the question is about different aspects, for which a different Stack Exchange is appropriate, then you should split the question in different questions you ask in different Stack Exchange sites. You should not ask the same exact question on different sites, but rather tailor the question for the site where you are asking it.


Can I change my air ticket and hotel booking after getting a Singapore tourist visa?

Question: I'm a Chinese citizen holding US green card, and just submitted my Singapore tourist visa application with air ticket and hotel booking at Singapore consulate in the US. I wonder if I ever make changes to these reservations when I see a lower price available, will such change affect my visa review/approval process, or will it cancel a granted visa?
Answer: Singapore asks visa applicants applying in the US for

A copy of air ticket and hotel reservations. Detailed proposed itineraries (flight and hotel) will also be accepted.

If you submitted a proposed itinerary with your application, which is still under review, go ahead and and book. If you provided confirmation for your tickets and hotels, it may be wiser to wait until your visa is issued. After visa issuance, changes which do not significantly alter your itinerary are acceptable.
The Immigration & Checkpoints Authority notes that

A Singapore visa is not an immigration pass.  It is a pre-entry permission for the holder of a valid Singapore visa to travel to, and seek entry, into Singapore.  The grant of an immigration pass will be determined by the Immigration & Checkpoints Authority (ICA) officers at the point of entry. Possession of a valid visa alone does not guarantee entry into Singapore.

Should you need to, you can reach Singapore's Ministry of Foreign Affairs at email@example.com or at +65 6379 8000.


Stock sorting options?

Question: Is there a way to view the stocks screen that's not just a list of what you have?  Maybe be able to search my stocks for specific items?
Comment: I think the game leaves out a lot of stuff you have no access to just because there is so many junk. (Sperm whale creates on butcher the following parts: teeth, tripe, hearts, meat, bones, sinew, organs, skin, hopes, dreams, soul, etc). You really don't want that clogging up your stocks screen.
Comment: If you use the Masterwork mod, it adds in search options in quite a few useful locations.
Answer: DFHack can add search option to Stocks screen, see dfhack#search.

The search plugin adds search to the Stocks, Animals, Trading,
  Stockpile, Noble (assignment candidates), Military (position
  candidates), Burrows (unit list), Rooms, Announcements, Job List and
  Unit List screens.
Answer: You can use my Improved Stocks Screen plugin for DFHack r3: http://www.bay12forums.com/smf/index.php?topic=125164.0 that makes it easier to find what you're looking for.
Answer: In the stocks screen, use the right arrow key to move to the list of stocks, then tab to explode the current group from by-count to by individual item.
At that point you can also zoom to any such item or designate them for dumping, melting or reclaiming.
NOTE: You can only do this if your stockpile records are up to date and the item count is lower than the maximum accurate count of your current precision level.

Stock sorting options?


json contract erc20 is safe?

Question: I created my first contract erc20, implement a mint function, the case is, if I copy the code json, I paste it in another wallet I can use the interface of the contract equally, although this is not the address that created the contract. So my question, if we could get the json of any token could we have access to its interface? Is it safe that nobody can access the json except the address that created the contract?
Answer: I think you're referring to the Json ABI, the Application Binary Interface.
It's not a security risk. It merely enumerates the functions and arguments coded in the contract. This informs software clients about the structure of the function interfaces. While it is not impossible to interact with a smart contract without the ABI, all courteous developers publish it. Knowledge of the source code is sufficient to derive the ABI. It's a compiler output along with the bytecode.
Knowledge of the contract interface helps generic user interfaces such as wallets present human-readable forms. This is how etherscan.io constucts their read contract and write to contract tabs (if the source, and therefore ABI is verified.).
Knowledge of the ABI doesn't elevate user privileges in any way. They still have to sign with their own accounts.
Hope it helps.
Comment: Thanks for your answer, I understand that it is safe since to configure Json interface it is necessary to obtain it from the source code and that only the creator obtains the contract. No one else would have access to the json interface.
Comment: It just doesn't matter if it falls into the public domain, and it probably should, just the contract source code. If possession of those things bestows inappropriate power then there is surely a bigger security problem and a determined attacker will need neither of those artifacts to exploit it. I tried to summarize what the ABI actually is. Perhaps research. My guess is it's not what you think.
Comment: "just like the contract source code." - they should both be on public display.

json contract erc20 is safe?


Executing PE files in ASP.Net on Linux without using Mono

Question: Can anyone tell me is it possible to executing '.exe' or '.dll' file(s) to run Asp.net on Linux server?
I know its possible with the use of Mono project.
But is it possible with the use of Mono Project?
Thanks in advance.
Answer: Mhh... NOT(really)
You can't execute natively exes on Linux only with Wine. I don't know if is gonna work running an asp.net server (IIS) on Linux with Wine.
Maybe you should get a try.
BTW: why not use Mono? Is it very good now. It has evolved much


How much faster can i go after moving from 2x10 to a 3x10 gear setup?

Question: My 26" mountain bike currently has a 2x10 gear setup with SRAM components: a SRAM S-1250 crank with 38/24 chainrings, and a SRAM PG-1030, 10-speed, 11-36t cassette. I feel that when riding on non-technical dirt trails I am maxing out my drive-train, meaning that I am not able to accelerate beyond a certain speed when riding the 'hardest' gear.
I have been reading about the Shimano 3x10 system which may allow me to reach higher speeds, due to higher possible transfer ratios. So, how much faster can I with a 3x10 setup? please elaborate on the math in your answer...
Comment: There are several gear inch calculators online, such as [this one](http://sheldonbrown.com/gears/) on Sheldon's web site.
Comment: You could just get a not-so-compact, double-chainring crankset, with a 44 bigger chainring, and a suitable-sized smaller chainring. Personally, I always felt that mountainbikes deserve triple chainring, and would happily use a 46-36-26 oldschool crankset with a cassette like yours IF it accepted these extra-narrow current chains...
Answer: Well, if you switch to 3 in front, and then make it a 52/38/24 set (equal steps) then your theoretical new maximum speed would be:
[new max]=52/38*[Your current max]

Currently at your top speed one revolution of your crank leads to 38/11th of a revolution of your rear wheel. This will become 52/11th or about 1.37 times as much.
This is not the whole story however. You probably know that wind resistant is much more of an issue at higher speeds than rolling resistance. So (unless you are really strong) your actual maximum will be quite a bit lower than the theoretical maximum calculated above. This tool allows you to set your speed or power output and calculate the other. If I assume your current max as 30kph, your bike weight at 9kg, your weight at 70kg (don't be offended, I'm just guessing), and you are on MTB tires and in the "hoods" position (whatever that is) then your power output at that speed would be about 220 Watt. With the extra chainring in front your theoretical maximum speed would be 41.1kph (all other variables being equal) but to attain it you would need to about 470 Watt! More than twice as much!
Obviously in your current situation you are not pedaling efficiently at your maximum speed because you are spinning your legs like crazy, but a 1.4 times speed gain is probably too much to hope for. As a test to see where you can get you could ask your friendly LBS owner if he'll lend you a bigger front chainring for a test ride and see if you can find out from that at what point you max out.
Comment: Note that derailer capacity is primarily expressed in "teeth" -- the difference between largest and smallest rear cog plus largest and smallest front cog.  You can exceed this capacity if you shift carefully and avoid "illogical" cog combos, but it's a bother.
Comment: If you want to keep a low lowest gear, you will have a hard time finding derailleurs capable of shifting a 52-38-24 with a reasonably wide-spread cassette. Drive train capacity (the added difference between largest and smallest chainring/cog) correlates closely with the ratio between highest and lowest gear. You cannot spread out your gears without at some point getting problems with derailleur capacity.
Comment: Going up to 52 is insane - typical mountain bike 3's are 44, 48/11 is road bike compact. There would be few people in the world could push 52/11, let along do it efficiently. The only people to benefit from this configuration would be his orthopedic surgeon and the manufacturers of replacement knees.
Answer: Assume your wheels have a circumference of l = 2 m. With a 38x11 gear you will cover
d = 38 / 11 * l
  = 6.91 m

per crank revolution. Assume that you can pedal at a cadence of 90 rpm, that will give you a speed of
v = d * 90 rpm * 60 min
  = 37.3 km/h

On a road which allows for such speed you should be able to pedal at a higher cadence if you have good riding technique, i.e. achieve even higher speeds.
The maths don't care about brand names, but take a Shimano XT triple with 42-32-24 teeth instead:
d = 42 / 11 * l
  = 7.64 m

This results in
v = 41.2 km/h

at 90 rpm, which is
(41.2 * 100 / 37.3) - 100 = 10.6%

faster. Actually, the ratio of the two different big rings will give you the same (42 * 100 / 38) - 100 = 10.6% as well.
If you keep your 11-36 cassette, the drive train will have a total capacity of (36 - 11) + (42 - 24) = 43 teeth, which may be more than what your rear derailleur can take care of.
Apart from that it is often easier to maximize downhill speed by optimizing aerodynamics instead of pedaling.
Answer: I am going to skip the gear ratio discussion because others have covered it, and it really isn't the most important consideration.
If you're spinning out frequently, you'll want a higher top gear, but you can only go so high with those cranks-- probably 42, max, on the big chainring. That might be enough to keep your from spinning out while still retaining the capabilities of the bike.
If you decide to swap out the cranks/chainrings and get something more like a road-bike or cross bike, you will mess with the intended design of the "mountain" bike. There is nothing wrong with doing that but the gears are low on a mountain bike for very good reasons like negotiating stumps, ruts, rocks, mud/gravel and even very short 100% grades.


ASP .Net MVC - Images not being shown in published build

Question: I am developing an ASP .Net MVC application and on my dev machine, the application runs as expected and, more importantly, the images mentioned in the CSS file are displaying correctly too.
However, when I publish this application to a testing server, the web app runs fine, but the images are not shown.
If I modify the URL in IE when testing the output from the test server, the image is returned, meaning that the file is there but it just won't appear within the view page when using the site normally.
I have tried alternative servers too, but the result is the same.
To confirm, here's a line from the CSS page referencing the image...
background-image: url('/Content/Images/Logo/myLogo.jpg');

Any suggestions?
Cheers
Brett
Answer: The URLs are not correct, likely due to the fact that you are publishing in a subfolder and so they are no longer at the root of the server.  I usually use Url.Content( "~/Content/Images/..." ) to build the url instead of hard-coding it.  That way it will take into account the routes when building the path.
Example:
 <img src='<%= Url.Content( "~/Content/Images/banner.jpg" ) %>' alt="Banner" />

Answer: I had the same issue, but I found the reason why it was forcing authentication on the Contents folder.
When a user is not logged in yet, they are classified as Anonymous Authentication. In IIS7 (which is what I am using, guessing it is the same in IIS6) you need to open the authentication window in features view. Then edit the Anonymous Authentication, to use your application pool identity, or the default one, just make sure that user has permissions to read in that folder.
That fixed it for me, hope it works for you.
Answer: Possible relative paths are wrong...Possible that they are wrong for CSS file itself. You can use FireBug to see if CSS loaded correctly, then you can examine image request, often in such situations you will see red(error) items. This could help to localize problem.
Comment: Good plan - I'll download FireFox and FireBug and will see if that helps.


Undergraduate Topology

Question: I am developing an introductory topology course for undergraduates, and I am wondering what topics to cover.  At my institution, real analysis is not a prerequisite for the course, so it is more than likely that the intended audience has not been exposed to this material.  Does anyone have any suggestions?
Comment: Welcome to MO! Since this question does not have one right answer, but rather asks for a list of suggestion or varying opinions it should be ask in Community Wiki mode. To achieve this, please 'edit' the question (button below the text of the question) and tick the appropriate box and save this edit. (I also flagged for moderators to do this in case you do not see the request in time, this has implications for all answers, or should have difficulty doing this.)
Comment: This might have been a nice question for the new Mathematics Educators Stackexchange site.
Comment: @JW: I second you, this question is interesting but really belong to Math Educators SE. Is it possible to migrate it? I don't see the option anymore.
Answer: In the 1970s I developed an undergraduate course on knots, (source book was by Crowell and Fox) to replace general topology and homology, as it was very easy for students to understand the point of the course, there were interesting relations with group theory, and lots of specific calculations and other things to do. The course was eventually taken over by others, and resulted in a book,
Knots and Surfaces, by N.D. Gilbert and T. Porter
which had good reviews.
For me, it led to giving popular talks on "How mathematics gets into Knots", and eventually to the exhibition you can see on the web site for the Centre for the Popularisation of Mathematics. In these talks I could also talk about mathematics, including, for example, the importance of analogy in mathematics. This led to one boy at a talk for children, some aged 12, asking: "Are there infinitely many prime knots? " Wow! So giving this undergraduate course has led to all sorts of fun and rewarding things! My copper pentoil knot used with string to demonstrate the ideas of the fundamental group has also travelled to many countries, see for example the pdf of a  William J. Spencer Lecture   in Kansas, April, 2012.
Comment: Ronald,you don't get enough credit for your very inventive and original attempts to reform a basic course in topology. You should get more.
Comment: @The Mathemagician   Many thanks for the comment! One person has called my exposition "idiosyncratic". I suppose that means I never assume an account of topology, or mathematics, is a kind of sacred text - "paths" have to be of length 1, "topologies" are defined in terms of open sets, "groups" are the fundamental idea, ...An exegesis shows one has to consider how the ideas arose. see http://pages.bangor.ac.uk/~mas010/einst.html,  and also try to make the abstract ideas "concrete". See also my Galway exposition on my preprint page, for "anomalies in algebraic topology". I keep trying!
Answer: I've found that doing low-dimensional manifold topology is very appealing to undergraduates. I used the "Topology Now!" text by Messer and Straffin and, while the text isn't perfect, the approach was wonderfully successful.
Comment: I second the suggestion to focus on low-dimensional topology. Some particularly fun parts of low-dimensional topology for a first course are: classification of surfaces (including Part 1 of Conway et al "Symmetry of Things"); some baby knot theory (Reidemeister moves, quandle invariants like the number of three-colorings of the knot diagram, and also some invariants that are not diagram-based). It is also worth telling the students without proof that intuition from low dimensions often fails as you move higher up. Exotic smooth structures and non-smoothable manifolds come to mind.
Answer: I second Aeryk's suggestion to focus on low-dimensional topology.  More generally, I think that algebraic topology can be more exciting than point-set topology.
That said, when I was an undergraduate, I do remember being quite excited about the Bourbaki program and point-set definitions and so on.  I remember one "first course in topology" that alternated days: low-dimensional topology on even days and point-set on odd.  Except the point-set portion began with set theory, cardinal and ordinal numbers, and the axiom of choice; then moved on to metric spaces; and only then introduced point-set topology. I basically think that to motivate the point-set definitions, you had better start with metric spaces.
If on the other hand you focus more on broadly-defined algebraic topology, then in addition to the low-dimensional topology of manifolds (surfaces, knots, etc.), another good topic is Brower fixed-point theorem as an application of fundamental group functor on pointed spaces.  Perhaps, if you are very ambitious, you can prove that 2dTQFT = commmutative Frobenius algebra, and talk more generally about cobordism equivalence.  Oh, and especially given the recent sad news, be sure to include a little Morse theory and Outside In.
Comment: +1 for "to motivate the point-set definitions, you had better start with metric spaces.  (I'm not saying you should do point-set topology, but that if you do it, metric spaces should come first.)
Answer: If the intent is to provide breadth, then many of the suggestions others have made are quite appealing, especially if it is made clear what branches of topology are being introduced and what a student should do outside of class to develop depth in any or all of the branches.
If the intent is to provide depth, there are likely several texts out there, one for each branch, with suggestions.  I remember covering Munkres first course in Topology starting with chapter 2; even though we skipped over the set theory and foundations, I was intrigued enough by them to study set theory and foundations while in graduate school.  Although the class did not go all the way through the book that first semester, we got exposed to quite a bit, and I developed more of a taste for formalism from that class more than from any other that I took as an undergraduate.
If the intent is to provide both depth and breadth, I suggest part of it be run as a student seminar.  A later topology course I took had me present Sard's theorem; if nothing else came from that course I at least know how to prepare to explain Sard's theorem for my next opportunity.
Gerhard "And This Was Decades Ago" Paseman, 2012.08.22
Answer: I think you could do a lot worse than to focus on modern applications by using the texts of Edelsbrunner and Harer and/or Zomorodian on computational topology as touchstones and an avenue towards current work in topological data analysis. These books are self-contained treatments that focus on Morse theory and homology over $\mathbb{Z}/2\mathbb{Z}$, and there are a lot of materials and software available for a course to be built from.
Answer: As a resource for low-dimensional topology, I would suggest The shape of space by Jeffrey Weeks. It covers how to build compact two-manifolds and some three manifolds. Exercises include playing tic-tac-toe on surfaces and forming sums of surfaces. It then moves on to some three dimensional topology with a heavy focus on attempting to visualize the spaces.
Answer: We give a Geometry and Topology course at Macquarie for students with no real analysis, using notes written by a colleague. Here is the homepage for the course, so you can get an idea of what we do.
EDIT: The homepage link doesn't work any more. The closest thing to it that we make publically available seems to be this (which may only last for the current year).
More edit: Here's the week-by-week lecture schedule (2 hours of lectures a week):
Topological spaces
Surfaces
Surfaces and Surgery
Characterising Surfaces
Graphs on Surfaces
Graphs and Map Colouring
Graphs and Map Colouring
Knots and Links
The Alexander Number of a Knot
The Alexander Group of a Knot
The Alexander Module
The Alexander Polynomial
Comment: @Sebastian, done.
Answer: I would start with degree of maps and show applications to other fields, such as proving that $\mathbb C$ is algebraically closed via polynomial mapping of circles of increasing radii, contracting them onto the unit circle, and computing the degree of the composition map.
Then discuss homotopy and prove hairy sphere theorem. Then classification of 2-surfaces and Euler characteristics. Perhaps rudimentary Morse theory, starting with classification of surfaces and explaining why $e(S^n)$ depends on parity of $n$.
Discussing fundamental groups would be a good idea if and only if the audience have learnt group theory before; otherwise you'd risk to go astray from visual into algebra. Keeping things visual helps; I wouldn't go into knot theory though.
Comment: @JW: I like knot theory, even worked on it as an undergrad. However, knot theory has a few problems that make it unsuitable for the first course in topology for people with limited math background. First, application to other branches require too much depth into the subject; not presenting applications would make knot theory look artificial (compare with immediate apps of degree of maps or winding numbers.) Second, meaningful exposure would require lengthy side tours, such as explaining what groups are. Third, not easy to generalize into higher dimensions, even from $S^1$ to $S^2$ embeddings.
Comment: Any particular reason for not going into knot theory?
Answer: I think it depends on your students' backgrounds and goals. You mention that real analysis is not a prerequisite for the course, but what are the prerequisites? Can you assume any or all of linear algebra, multivariable calculus, discrete mathematics, a transition to proofs course and abstract algebra? Are your students interested in applications of topology outside of mathematics or within mathematics, or would they prefer to learn the subject for its own sake (or all three)?
For instance, you can give the course an analysis flavor by focusing on metric spaces and general topology. On the other hand, you could go straight to homology (see Peter Giblin's Graphs, Surfaces and Homology) if your students have taken / are concurrently taking a course in group theory, or you are prepared to teach the requisite group theory during the course itself.
If you'd like to focus on general topology with applications outside of mathematics, Introduction to Topology: Pure and Applied is a nice option.
Computational topology, as mentioned in another answer, could be an option for students with strong applied interests. Robert Ghrist has an intriguing draft text on applied algebraic topology available at his website, which could be a source of inspiration. There's also a question on teaching undergraduates computational topology at the Mathematics Educators Stack Exchange, although it's aimed at engineering students rather than mathematics majors.
Answer: Since Real Analysis is not a prerequisite for Topology in your institution, I suggest  including a chapter on
"Metric Spaces" in the course. Then moving on to a chapter on
"Topological spaces",
"Product Topology",
"Compactness",
"Countability and
"Separation Axioms (with Urysohn's Lemma)" and
"Connectedness".
Advanced topics like The Stone-Čech Compactification, Urysohn's theorem, Ascoli's theorem, etc can be omitted.
This should be enough for one semester, which will give students a fair idea of General Topology.
Interested students can learn advanced topics like manifolds, algebraic topology, homotopy etc.

Undergraduate Topology


Remove default field theming in a module

Question: I was just wondering how to remove the default theming divs of a field in Drupal 7, from within a module (so not with a theme function!!).
In my case: I implemented my own field in a module, now I'm using hook_field_formatter_view to display it. I read here that you can implement your own MYMODULE_theme() function in your module to declare a new field formatter.. but some default divs are still there:

   <-- this one

   <-- and also this one

Is there a way to hide/edit them? I know of the template functions but its better to have the code inside the module..
Answer: I think you should try Fences.


Podcast Software for Mobile

Question: Im looking for program that works on my windows mobile that i can listen to pod casts with im looking for the following.

Ability to download pod casts from
RSS feeds
Ability
( You would think this is a not
something i would have to ask for,
but the pod cast players i found did
not support pasting in the url to the
rss feed)
Bonus: Ability to share the
podcast list with my windows computer

Limits
Cannot be itunes.
Answer: Check out Pocket Podcasts.
Answer: I use Juice for my windows machine, which doesn't specifically say it can be used for windows mobile, but since it's open source, perhaps you can get it to work.  Their web page also has links to several related sites, of which, podnova, might fit your needs.  They specifically say:

Tired of synching your podcasts
  through iTunes?
Let us stream all your favorite
  content right into your pocket.
PodNova Mobile m.podnova.com
Answer: BeyondPodcast
Watch the demo, it is awesome.
Answer: BeyondPod is awesome. Manage it all from your phone.

Podcast Software for Mobile


How To make LXTerminal of lubuntu 16.04 transparent?

Question: I want to know How To make LXTerminal of lubuntu 16.04 transparent ?
Answer: Open the LXTerminal and select Edit from the top menu and then Profile Preferences->Colors.  From that screen you can change your terminal to transparent, partially transparent, the colors, etc.
Comment: can you please post the screenshots  because I dont have this `Profile Preferences->Colors`
Comment: I think that the settings of lxterminal only provide "fake" transparency. In other words, you'll see the root window and not necessarily the window immediately below the lxterminal window. It's possible that using something like compton maybe needed for true transparency.
Comment: @DKBose i've installed compton but issue still persists.
Comment: @YaShChaudhary for me it was "rightklick" on the terminal window > then click "preferences" > then click on "background" > there you can set the "Opacity"
but for me (using i3 window manager) that was no solution, because of mentiones "fake transparency"
Answer: First install "compton"
apt-get install compton

Then run the following command for testing:
compton --opacity-rule 45:'class_g *= "X-terminal-emulator"'

It's an opacity of 45%, change it to what you like.
Above I typed "X-terminal-emulator", but to get the string you have to type, do the following:
1.) type xprop enter
2.) now there should be a crosshair -> klick on your terminal
3.) search for "WM_CLASS(STRING)"
4.) use this in 'class_g *= '...'
You can copy a basic configuration from /usr/share/doc/compton/compton.sample.conf or here http://duncanlock.net/blog/2013/06/07/how-to-switch-to-compton-for-beautiful-tear-free-compositing-in-xfce/ into the file ~/.config/compton.conf (you must create this if not present)
To make this permanent you can put this command into your profile settings.
Answer: After installing compton (see eli's answer)
Edit your ~/.config/compton.conf file to include the following line:
opacity-rule = ["90:class_g *= 'X-terminal-emulator'"]

This will make your terminal's opacity 90%.
Also add compton to your autostart for lubuntu in ~/.config/lxsession/Lubuntu/autostart


Magento 2.3: Backorder is not working. how its work?

Question: Backorder is not working on Magento 2.3. How it works?
Comment: I have enabled these two options but its not working
Comment: Have you checked https://docs.magento.com/m2/ce/user_guide/catalog/inventory-backorders.html official guide?
Comment: yes but it not show add to cart button
Answer: My team ran into this issue on a Magento v2.3.1 build and had to enable MSI to get things working. Once you've done this, make sure that you are able to set a negative Out-of-stock Threshold.
Though it isn't explicit in Magento's Documentation, and might actually be a current bug, if you're on v2.3.x of Magento, you'll need to enable MSI for Backorders to function properly. You can read read more about MSI and how to enable it here
UPDATE: it is a bug
The fix for the bug is in this commit here, and will likely be merged into the next version of 2.3. If you're on Commerce or Commerce Cloud, you should be able to reach out to support for a patch. With this fix, you will not need to enable MSI.
Answer: Please check after Clear cache and Reindex
if still not working then
Can You please check Back-order Settings on individual product Edit tag on admin
Click on 'Advanced Inventory' Below Quantity field.


Gated contact form

Question: I want to create a user form that will be filled by an enduser. I'd like to store the forms data in the database.
Answer: If you just want to add a simple contact then look at Contact Form by Pixel & Tonic.
For anything more complex then I'd suggest looking at the Guest Entries plugin also made by Pixel & Tonic. This enables you to use front-end forms to post to the database.
You may also want to look at the docs for creating User registration forms on the front-end.
Answer: There's no shortage of form builder plugins.
I've used FormBuilder and  Formerly on client sites.
Sprout from Barrel Strength is a good pick as well if you want a paid product with commercial support.

Gated contact form


Error creating dbschema file with VSDBCMD.exe

Question: I have a VS 2010 database project that needs a database reference to a Dynamics CRM database. I have remote access to the 32-bit Windows 2003 R2 SP2 server. My strategy is to create a .dbschema file and use it as the reference.
The two best resources I have found for creating the .dbschema file are from stackoverflow and MSDN.
The error I received is:

The database schema provider could not be determined from the supplied connection string.  Check if the connection string is valid for the ADO.NET provider used for your database provider and that you have the privileges necessary to connect to the server.

The steps I have done are:

Create a temporary folder C:\temp
Copy contents of folder C:\Program Files (x86)\Microsoft Visual Studio 10.0\VSTSDB\Deploy to C:\temp
Copy some DLLS from the list below of the folder C:\Program Files (x86)\Microsoft SQL Server Compact Edition\v3.5 to C:\temp

At this point the MSDN instructions say that I should have the files

DatabaseSchemaProviders.Extensions.xml
Microsoft.Data.Schema.dll
Microsoft.Data.Schema.ScriptDom.dll
Microsoft.Data.Schema.ScriptDom.Sql.dll
Microsoft.Data.Schema.Sql.dll
Microsoft.SqlServer.BatchParser.dll
Sqlceer35en.dll
Sqlceme35.dll
Sqlceqp35.dll
Sqlcese35.dll
System.Data.SqlServerCe.dll
VSDBCMD.EXE

This is almost true.

DatabaseSchemaProviders.Extensions.xml is actually located in C:\temp\Extensions\SqlServer\ so I also copied it to C:\temp in case it needs to be at the same directory level
Microsoft.SqlServer.BatchParser.dll was found in the GAC, so presumably I don't need to copy it to C:\temp but I did so anyways, taking the 32-bit version because my other DLLs came from Program Files (x86).

I tried running VSDBCMD locally from C:\temp with CMD run as administrator. I have also copied C:\temp to the server and tried running it there.

VSDBCMD /a:Import /cs:"Provider=SQLOLEDB.1;Password=********;Persist Security Info=True;User ID=sa;Initial Catalog=VANILLA_MSCRM;Data Source=********" /dsp:Sql /model:VANILLA_MSCRM.dbschema

I have tried all combinations of Data Sources = {., (local), localhost, the IP address, the machine name, the domain name} with Providers = {SQLOLEDB.1, SQLNCLI10.1, SQLNCLI.1}. All result in the same error. Obviously ., (local) and localhost were only used when ran from the server. I tested my connection strings by building them via UDL files (\http://msdn.microsoft.com/en-us/library/e38h511e%28VS.71%29.aspx). As suggested by this post \http://social.msdn.microsoft.com/Forums/en-US/vstsdb/thread/dabd14fa-a805-4855-b3f1-33b37b16c5b1 I tried sqlcmd and could successfully run it.
How can I troubleshoot this problem? Is my strategy of creating a .dbschema file to reference my CRM database a wrongheaded approach?
Answer: I've tried this too, and found the following worked for me (run from the VS2010 command prompt, and run using an account that has sysadmin priviledges on the database):
<code>vsdbcmd /action:import /connectionstring:"Integrated Security=True;Data Source=<SERVER>;Initial Catalog=<DATABASE>" /modelfile:"<DATABASE>.dbschema"
</code>


Is it bad if my mom comes to a conference with me?

Question: I am going to my first conference and my mom wants to join.  (She can probably get funding from her university to accompany me, even though she is in a different field.)  Will it reflect badly on me if we stick together?
Comment: How do you expect she'll behave at the conference? Will she stand back and let you act independently? Or will she be in the presenters' faces, telling them about her wonderful son and his amazing ideas, all the while interrupting you?
Comment: To me this question can be rephrased as: "Is it bad if my mom comes to work with me?"
Comment: @aparente001 I think it's kind of cute.
Comment: *She can probably get funding from her university to accompany me, even though she is in a different field.* -- this sounds ethically very questionable, I must say.
Comment: I feel like if you have to ask, the answer is obvious. (And if you don't, well, the answer is also obvious.)
Comment: I hope your first name is not Leonard. XD
Comment: How do you feel about it?
Comment: Ah.  Well, if it doesn't bother you, and you would both get more out of the conference in each other's company, then by all means -- go for it.
Comment: Just my two cents here but from a pragmatic point of view this will make you a social pariah, conferences are about meeting people and getting contacts - if you bring your mum you might as well just get the conference papers after the event. Just to be clear, I pass no judgement over yourself or your mother, just the general public (myself included).
Comment: It might reflect poorly on your mother if she uses university funding for a trip taken for personal reasons.
Comment: Choosing between what would be totally awesome and how you'd be viewed by your peers.
Comment: No, academics do this all time. Here is a picture of Landau presenting with his mom, and here is Keller drinks water with his grandmother after the conference. Also a lot of people take their parents to the job interviews.
Answer: You ask about "stick together". This is probably not an ideal idea.
Generally, in a conference, you want freedom of action. Going with your mother may induce you to "talk to the known" person whenever you are unsure; i.e. you talk to her whenever you are not sure how to approach people - the notorious "escape route" - but this is exactly what conferences are not for.
When I went to my first conference, I made a point to talk to as many people as I could. At the beginning, it is quite a leap of faith. But later you find, it is fun, you get to know people, and you get to know new research directions and ideas. Sometimes it feels difficult, but remember: all you people have one thing in common - the topic of the conference. You are very unlikely to go wrong starting a conversation about that.
If you are unsure how to start, start with people which look like they are alone at the conference, and probably a bit lost. They will be grateful to get somebody to talk to; you may meet interesting colleagues (don't think that, because they are alone, they are not good scientists - good scientists may not be good at socialising), and notch up a good deed, to boot.
It is fine to take your mother to social events and the like, but I recommend that, if she joins the conference, say, because she is interested, that she stays mostly in the background and does not send signals of "supervision" to others or - even more importantly - to you. If you can keep that balance, then, by all means, bring her with you.
Comment: +1 for the "escape route". Making yourself meet new people is essential at a conference but can be hard, and it is much harder if there is an easy option available of talking to someone familiar
Answer: A couple of things that come to mind:

It's a bit troubling that you say "my mom wants to join." What do you want?
Also, your first conference is an exciting moment in your academic career that you'll likely remember for a long time. Such an occasion can be a really good opportunity to strike out on your own, be independent, feel free to invent yourself as the person you'd like the world to see you as (and, as others have said, make maximal use of the professional opportunity of being at a conference, though personally I'm less bothered about that). With all respect due to your mom, who I'm sure is an extremely nice lady, it sounds probable to me that her presence will hinder such personal growth on your part, though she may not realize that.

Just my two cents based on the very small amount of information you've provided. In any case good luck, and have fun!
Edit: I also want to add, just in case you or anybody else reading this care, that I think "will it reflect badly on me" is the wrong question to ask. What I mean more precisely is this: if you happen to be a mature, strong-willed, independent person who just happens to get along fabulously with your mom and think you'll enjoy having her around, I'd say bring her along, and it doesn't matter what other people will think; life's too short to care too much about that (or, as Steve Jobs said, "Don't let the noise of others' opinions drown out your own inner voice"). On the other hand, the advice I wrote above is a way of helping you reflect on whether by letting your mom come to the conference with you, you may in fact be holding yourself back from becoming a mature, strong-willed, and independent person. If that is the case, then although having your mom at the conference may indeed reflect badly on you in the eyes of some people, that is not the reason why you shouldn't bring her -- rather, you shouldn't bring her but for a different reason, because of the more intrinsic fact that having her be such a dominant presence in your professional and social life is simply not good for you.
Comment: @RobertGrant [this Steve Jobs quote](https://www.macstories.net/news/steve-jobs-what-have-you-done-thats-so-great/) seems like a good response to your question.
Comment: Curious to know whether Steve Jobs would've wanted his employees to not let his screaming at them drown out their inner voices :)
Comment: Foolish as I am to debate with the Faithful :) 1) that quote is an [argument of the excluded middle](http://www.carlsagan.com/index_ideascontent.htm); I don't *just* belittle others, as evidenced by my not doing so here. I just applied Jobs' own quote in a way it should withstand without ad hominem responses. 2) It's an obvious inconsistency that Jobs said that while yelling orders at others. Except it's not inconsistent, because he *didn't believe that*. He wanted to do whatever *he* wanted, including shout at others, and dressed it in feelgood language.
Comment: And 3) Direct answer, as though Jobs were asking: I wasn't a terrible father and husband and didn't overshadow my much brainier and more talented colleague to the extent my tat gets rebleated online, so I've got that going for me :)
Comment: @DanRomik I think, as Steve can't defend himself, it would be fair to point out what he might say in response to such allegations by our friend Robert Grant: "While I was yelling orders at my employees, I didn't want them to let me drown out their inner voice, I wanted them to fight for it." (And if you fight, make sure you're right about what you're fighting for.) His employees were employees because they needed a leader to look up to, because they didnt have the aptitude to be the one yelling orders whilst changing the world.
Comment: @RobertGrant Perhaps he wasn't drowning out his employees' inner voice, but only making up for the lack thereof. I didn't know the guy, but I doubt you did either. Lets not shroud the reputations of great men who earned their places in history whilst improving the world.
Answer: Would your mother attend the conference even if you didn't? If so, then sure -- but make sure not just to follow her to the talks she is interested in. If not (and the question makes me think that's the case), I think it would be a bad idea for her to join you.

Conferences are professional events where your goal should be to meet and share ideas with others in your field. You will have something to talk about with them, but your mother won't.
How would her being there impact your ability to socialize? This is going to depend on the conference, but people generally like to get drinks in the evenings. It would be odd if you went out with a few graduate students and she came along.
Irrespective of how independent you can be, you should think about the signal it sends to your potential employers (i.e. people on search committees). Think about job applicants who bring their mothers to an interview and ask yourself whether that hurts their chances of getting the job.
Comment: +1 for _Would your mother attend the conference even if you didn't?_
Comment: @dwoz Parents should be honored and celebrated... at the appropriate place and time. And by the same token, children and their independence should also be honored, celebrated and respected -- something that too many helicopter parents don't appreciate.
Comment: Good answer, but as for _Would your mother attend ... even if you didn't?_ I think you're making a rather utopian assumption that an academic's decision of whether to attend a conference should depend purely on professional interest and never be influenced by any other factor. E.g., no one should ever choose to go to a conference in Hawaii and skip a different conference in Cleveland that's slightly more relevant to their academic interests. (Yeah, I bet that _never_ happens, right? ;-)). If humans were robots that might make sense, but they're not. I agree with the other things you wrote.
Comment: @DanRomik The answer to "Would your mother attend... even if you didn't?" isn't necessarily binary. If the answer is "Hell, no!" then she shouldn't go; if the answer is "Of course she would", then she probably should go. If the answer is somewhere between, then that's more information to base a decision on.
Comment: I downvoted because I think the point raised is entirely ridiculous.  Not just moot...ridiculous.  Parents should be honored and celebrated.
Answer: I have seen non academic mothers accompany their children, or more accurately their grandchildren, to conference and there is absolutely nothing wrong with this. Even in the absence of grandchildren, it would be fine. For example, lots of conferences have time for an afternoon of site seeing and people often add on a couple of days of vacation.
As your mother is an academic in a related field (presumably since you said she can get funding). It makes perfect sense. As for sticking together, within reason that is fine. This is especially true if she can introduce you to people. Just make sure you keep the relationship professional.
Comment: The first answer mentioning the relevance of "academic mother"
Answer: Remember that a conference is first and foremost a major professional opportunity for you.  So long as you will meet as many other conference participants as you would otherwise, and it wouldn't affect your performance giving the talk, then I see no reason not to bring her.
My mother sometimes asked to come to conferences with me, but I didn't let her, because I was afraid seeing her in the audience during my talk would put me off and I wouldn't do as good of a job giving it, which would negate the entire purpose of attending the conference.  My mother could be very critical.  Unfortunately she didn't live long enough to get to the point where academic talks got put on YouTube all the time, but she did read my papers. My father enjoys watching some of my talks on line now.
On the other hand, my partner is also an academic, and we often attend each other's meetings, and even go to different talks in parallel sessions and learn from each other at the meeting.  My partner is very supportive and I love seeing their smile in my talks.  If your mother is a good academic, I could believe that having her at a conference might be similar to that.
Comment: with all due respect, Joanna...your relationship with your mom might not have been all that it could be.  who knows why that happened.  Not me, certainly.  Parents that are also academics can be celebrated without the least problem.
Comment: @dwoz What does "celebration" — whatever it means in this context — have to do with this? Me (or whoever else) giving a talk has nothing to do with my mother, and all to do with me and my work. If I feel that my mother's presence in the audience would hinder in a noticeable way my ability to give a talk to the best of my abilities, then I should feel obliged to tell her so and ask her no to come.
Answer: It's unlikely anyone would notice or care.  Anyway, how would they know you are parent and child?
Having said that, in the UK a lot of conferences are funded by EPSRC or similar agencies, which in turn are funded by tax payers.  As a tax payer, I have to say the folks who go on jollies to unrelated conferences can grate.
Overall it seems unnecessary and while I don't think it would necessarily look "bad", it would likely be a missed opportunity to talk to other people.
Comment: I downvoted because I don't like the idea that relatives are any different from any other non-expert attendee.  If a conference wants diversity in its audience, then the organisers probably value that source of innovation.  if it's a small workshop for experts, then how would a family member get in?  I don't see how either strategy wastes tax-payer resources.  Unless you are complaining about people who sign up to attend the meeting but then skip talks to be a tourist, in which case yes I hate that, but I don't see how that relates to family members.
Comment: OP says "mom [...] in a different field" and answer is based on that.  Nepotism != just family and nothing else in answer restricts to family (albeit all examples are family).  By your logic, doesn't it make sense for OP to edit their question to "acquaintance ... in a difference field"?  Also nothing mentioned in answer about it being a small workshop for experts.  No idea how "[s]he can probably get funding from her university" or "get in", that's not the question.  Anyway thanks for the comment.
Comment: "Anyway, how would they know you are parent and child?" By reading the name badges?
Comment: But (in my experience) few people bother with name badges.  Also many women use their original name.
Answer: I would chime in that if she wants to come to celebrate your success(es) and witness you if it's something you are publicly participating in, sounds great.  I would say terrific.
However, if she is coming to overtly - overly - mother you when you are an adult?  I recently learned terrific actually means terrifying by definition.   So maybe it is terrific.  So in that case... hmm
Was hard to tell from what you wrote, in that case, time to cut the ole umbilical cord, probably was time some time ago, in fact, not being sarcastic, I'd argue that cord was cut a long time ago.
That said, I'd welcome her to come and celebrate your participatory role in the conference, sure, bring grandma Esralda too,  your family is likely proud of you and wants to support you.
If the former, go for it- if the latter?  I'd politely state you are now an adult, and would prefer if she only came to witness the conference but did not bring any unnecessary focus during your academic responsibility post conference.
Best to you and her.
Tim Miltz
Answer: There are at least three issues here: conference funding, conference participation, and joint travel.
It is theoretically possible, but unlikely, that your mother's department has so much travel and conference money that every researcher gets to every conference they want. It is also possible that the conference is one your mother should be attending, and your participation is only a tie-breaker among conferences.
If neither of those cases applies, consider the following scenario:

There is a conference you should attend.
Your department regrets to inform you that there is insufficient travel budget for you to go.
You find out they funded another department member going to an off-topic conference primarily to hang out with a relative.

How would you feel? Unless it is a conference she should be attending for her own research, I think your mother should either not attend or pay for it herself.
As others have pointed out, to get the full benefit of the conference you need to get into casual conversations with other participants. Having someone with you who is not a specialist in your research area could be a hindrance. On the other hand, if she is attending primarily for your company, telling her you can't have lunch with her today because you want to continue a discussion over lunch would be unfair to her.
If the purpose in her going is spending time together in a different location, consider extending your stay for a few days after the conference and having her join you for that time as a vacation. That way you can concentrate on the conference while it is running, and give your mother your full attention during your joint vacation.
Comment: In my experience, faculty tend to go to conferences on their own grant money. Assuming the asker's mother is faculty, her spending her grant money on going to this conference doesn't affect whether anybody else in her department can go to a conference: they couldn't travel on her grant money anyway.
Answer: The obvious answer is a RESOUNDING "yes."  Invite your mom to come on her own dime and credentials.
When you present your paper, stop, point her out to the seven people in attendance at your session, and acknowledge her, calling her out as a beloved colleague in the unrelated field of xyz.  Blow her a kiss, say "thanks, mom!" and go on with your paper.
Spend MOST of your time at the conference schmoozing with colleagues.


How to decipher an ADFGVX cipher?

Question: I got introduced to the ADFGVX cipher, and it seems very tedious to decipher such ciphertexts. If I do not have access to the key square and the keyword, and I am just given the ciphertext and a string of numbers, how do you decipher it? The columnar transposition is another thing that makes it even more difficult to break. (I am assuming that ADFGVX comes with a columnar transposition). I am planning on making a code that can break it. A complete brute force seems possible, just too tiresome.
Comment: This was a general question. It's weird how people can down vote it but not write a reason in the comment section below. Also I don't see a reason for the down-vote.
Comment: Classical crypto like this is trivially breakable by computer. https://web.archive.org/web/20100503103848/http://www.vectorsite.net/ttcode_04.html#m3 talks about how it was broken in 1918.
Comment: @tomtomtom This cipher has been broken for some time. You are asking for a general method to break the cipher, without going into detail what you've tried or even what search terms you have used to try and find out what techniques are out there.
Comment: @tomtomtom  As one of the moderators just said, please go into detail and show the effort that you have made.  Then we can help you more.
Answer: As you must know, ADFGVX is a German cipher from World War I. It was broken by the French (Painvin) during that war, but not without a major effort, and only on certain days.
It uses fractionation and a Polybius square, followed by a columnar transposition based on a keyword.
In Milton F. Friedman's Military Cryptanalysis, Part IV, pp. 103-149, he goes into detail about how to break this cipher.
There is also a useful paper from 1984, Konheim, A. G. (n.d.). Cryptanalysis of Adfgvx Encipherment Systems. Lecture Notes in Computer Science, 339–341. doi:10.1007/3-540-39568-7_26 (an extended abstract)
Konheim presents a four-step cryptanalytic technique to break ADFGVX.

Determine which column vectors are adjacent in the array.
Determine the relative order of the pairs of column vectors.
Recover the substitution.
Recover the transposition order of the columns in the array.

One thing that could be looked at first is this: perhaps the Polybius square is not a mixed alphabet after all, but alphabetical.

Edit:
The cryptanalysis of ADFGVX is given extensive step-by-step treatment in a fascinating book called Secret History:  The Story of Cryptology, by Craig T. Bauer, CRC Press, 2021. pp. 168-182.
Further reading:
Childs, J. Rives, General Solution of the ADFGVX Cipher System, War Department, Office of the Chief
Signal Officer, United States Government Printing Office, Washington, DC, 1934.
Hitt, Parker, Manual for the Solution of Military Ciphers, Army Service Schools Press, Fort Leavenworth, Kansas, 1916, second edition 1918, reprinted by Aegean Park Press, Laguna Hills, California, 1976. Can be found here.
Lasry, George, Ingo Niebel, Nils Kopal, and Arno Wacker, "Deciphering ADFGVX Messages from the
Eastern Front of World War I," Cryptologia, Vol. 41, No. 2, March 2017, pp. 101–136.
Pergent, Jacques, "Une figure extraordinaire du chiffre français de 1914 à 1918: le capitaine Georges
Painvin," Armée et Défense, Vol. 47, No. 4, April 1968, pp. 4–8.
Answer: There is also more modern research in order to attack complete ADFGVX ciphertexts (both partly-known-plaintext attacks and ciphertext-only-attacks).
See chapter 6 of the following PhD thesis: Lasry, G.: A Methodology for the Cryptanalysis of Classical Ciphers with Search Metaheuristics, Kassel University Press. kassel university press (2018) at https://d-nb.info/1153797542/34.
These new results are implemented e.g. in the free, open-source e-learning program CrypTool 2. In ready-to-run templates you can try an ADFGVX dictionary attack or an  ADFGVX heuristic analysis with simulated annealing. See the two attached screenshots:
,

As you said -- if you plan writing code that can break ADFGVX, you might even try to improve the results from Lasry and in CrypTool and share your findings again with the open-source community.

How to decipher an ADFGVX cipher?


H2o flow automl temporary sample frame

Question: I have a large frame and used h2o flow run automl with a deep learning algo. However, the training metrics are calculated on a "temporary sample frame". I could not find any info to this. I am not sure if the automl has been run on the full frame or just thus temp frame. Can someone help to understand or give a pointer? BTW, I don't find this feature convenient.
Comment: Where did you read that the metrics are calculated on a "temporary sample frame"?  That's not the case.  By default the leaderboard returns 5-fold CV metrics.
Comment: Thanks for your quick response Erin! I have updated my original post with a screenshot. It happens when I click any of the models in the autoML process. If you take a look at the "frame" part and from the name, it downsampled my frame by 0.05%. The "description" part indicates that only 9993 samples wan used for the metrics. However in my original frame, I have tens of millions of records. Thanks for your help!
Comment: More information: I don't have the "automl_training_###_hex_temporary_sample.0.05%" frame. It should be created by H2O flow at some stage. I used versions 18.104.22.168 and 188.8.131.52 and saw this on both versions.
Answer: This is a special case for Deep Learning models and is not the case for any other models produced by the AutoML process.  For efficiency reasons (and since H2O is designed for very large datasets), the training metrics in Deep Learning models are calculated on a subset of the original training frame.
There is a parameter in the H2O Deep Learning algorithm called score_training_samples that defaults to 10,000 rows (and since we do approximate sampling, also for efficiency reasons, it makes sense that the actual subset size is 9,993).
This should be a good approximation for training error.  The only way to change this in Flow would be to train a Deep Learning model manually (outside the AutoML process).
Comment: @XWen Make sure to download the nightly release as this has not been in a stable release yet. http://h2o-release.s3.amazonaws.com/h2o/master/latest.html
Comment: Thanks! It would be useful to let user to take control of it.
Comment: I don't know if this helps you, but it's possible to override algorithm parameters via the H2O AutoML Python API via a recently added hidden argument called `algo_parameters` (for reference). Example: https://github.com/h2oai/h2o-3/blob/97d757c3fee81a2bbc8c18d7821bfe15013c961f/h2o-py/tests/testdir_algos/automl/pyunit_automl_model_selection.py#L252
Comment: Definitely will try it. Thanks for sharing!

H2o flow automl temporary sample frame


WSL Linux - Kali SET Package Install issue

Question: I'm fairly new to kali-linux, so I apologize for my lack of expertise.
I had installed Kali-Linux and Ubuntu successfully and updated everything. However, when installing Packages for Kali (only had the bare minimum of Kali installed) I came upon an issue, in every successive package un-met dependencies kept popping up that wouldn't be installed, no matter the package they would lead back to a package called 'set' that wouldn't install (its part of the kali-linux-headless package install). Working in root.
When trying to fix the install of 'set' this happens below.
It LOOKS like an issue with the archive not being in Debian format, but I'm honestly not sure what the actual issue is or how to fix it.

I've tried re-installing 'headless' and associated packages.
Searched online for the issue but came up with this issue happening for custom-packages in the file being 'broken'.
Also have tried getting a new Key for the archive signature error.

Would love any advice anyone could provide or direct me to for this
sudo apt install set
Reading package lists... Done
Building dependency tree... Done
Reading state information... Done
Suggested packages:
  sendmail-bin
The following NEW packages will be installed:
  set
0 upgraded, 1 newly installed, 0 to remove and 0 not upgraded.
1393 not fully installed or removed.
Need to get 0 B/39.4 MB of archives.
After this operation, 50.9 MB of additional disk space will be used.
E: Invalid archive signature
E: Internal error, could not locate member control.tar{.zst,.lz4,.gz,.xz,.bz2,.lzma,}
E: Prior errors apply to /var/cache/apt/archives/set_8.0.3+git20200609-0kali2_all.deb
debconf: apt-extracttemplates failed: No such file or directory
dpkg-deb: error: '/var/cache/apt/archives/set_8.0.3+git20200609-0kali2_all.deb' is not a Debian format archive
dpkg: error processing archive /var/cache/apt/archives/set_8.0.3+git20200609-0kali2_all.deb (--unpack):
 dpkg-deb --control subprocess returned error exit status 2
Errors were encountered while processing:
 /var/cache/apt/archives/set_8.0.3+git20200609-0kali2_all.deb
E: Sub-process /usr/bin/dpkg returned an error code (1)

Answer: It seems the downloaded set package is corrupted (probably incomplete) on your system. The file in the repository is fine, so delete your cached version and try again:
sudo apt clean
sudo apt install set

Comment: Thanks, I tried what you suggested to sadly no avail; same error. Also I tried `dpkg -r set` which yielded `dpkg: warning: ignoring request to remove set which isn't installed` and then `apt -f install` giving the same error


RDP access to domain controllers ("Allow Logon through Terminal Services" GPO)

Question: I have a problem. I set GPO on the "Domain Controllers" OU with "Allow Logon through Terminal Services", where I set one user group. I wanted to assign RDP access to group of technicians. But after that, I lost RDP access to all DCs with accounts in the Administrators group and even with the Domain admin accounts. When I deleted this GPO, it's not how it used to be. I still can't log in with these accounts. I have to specify them in this GPO to get the access there. But it's not set like that with the default Domain Controllers Policy. How can I set it how it was? Thank you...
Comment: What is the scenario where you would want to allow a group of non-Domain Admin accounts RDP access to the Domain Controllers?
Answer: User Rights settings remain even when the GPO that configured them no longer applies.
By default, Domain Controllers have the user right of "Allow log on through Remote Desktop Services" assigned to the Builtin Administrators group. What you did with your GPO was effectively remove the Builtin Administrators group from that user right and you replaced it with your technicians group. Removing or deleting the GPO will not "reset" this user rights assignment back to it's default setting.
There are two ways to fix this:

Apply a Group Policy Object that sets this user right back to the Builtin Administrators group.
Log on to every Domain Controller and set this user right back to it's default setting in local Group Policy (secpol.msc).

In the future, if you want to grant this user right to a group of technicians for the Domain Controllers either do it in local Group Policy on each Domain Controller or do it with domain based Group Policy but make sure to include the Builtin Administrators group in the policy in addition to your technicians group.
Comment: Oh, I forgot about local GPOs. Everything makes sense now. Thank you!


Google Sheets: Arrays: using ARRAYFORMULA() v. { }

Question: Why does this work: =ARRAYFORMULA(LEFT(A2:A13,1)),
but this doesn't: ={LEFT(A2:A13,1)}
ie, using ARRAYFORMULA returns the array: J
F
M
A
M
J
J
A
S
O
N
D, while using the braces instead of the formula, only returns the J in January.
Answer: In Google sheets you need to wrap a function in ARRAYFORMULA if you want to feed an array (in your example the range A1:A12) into an argument of the many functions which by default only accept single values for their arguments (in your example the 'string' argument of the LEFT function) and only output a single value. When you use ARRAYFORMULA in this way the input array is processed element-by-element through the requested function and an output array is generated which has the same dimensions as the input array.
The 'braces' you describe in your example (proper name 'array literals') look like they correspond to the array formula syntax from older versions of Excel, where the array formulas have to be entered using Ctrl+Shift+Enter which wraps the function in the brace characters as shown. Array literals are used in a different way in Google Sheets (to effectively 'glue' different arrays together into one). A full discussion of the complexities of array formulas and array literals (and how their implementations differ in Google Sheets vs old Excel Vs new Excel) would take several pages...
Answer: The curly brackets are meant for generating arrays by referring cells, rows, columns, but not to convert formulas into array ones. I understand it's different in Microsoft Excel.
For formulas like that you can use ARRAYFORMULA, BYROW, BYCOL, MAP and INDEX among others in order to process arrays in the order and sequence you need at each opportunity.
Can't give you an exact explanation of why it's like this, but I think it has its logic too. It allows you to have in between curly brackets different kind of processing arrays depending on your needs. Maybe the first column is processed with MAP, and the next ones with BYROW, just for mentioning an example. You can be more specific in the way you need the calculations to be done.
I hope it's useful in some way!


Why do CDO's have a reinvestment period?

Question: If CDO's collect all the cashflows from their underlying assets and then pay them out to the CDO investors whats the need for a reinvestment period? and where is the principal that is being reinvested coming from?
Answer: Let's say a CDO invests in bonds and runs for 10 years. Not all the assets e.g. bonds it buys initially will have a lifetime of 10 years, many will have shorter durations. While the assets are paying interest that is used to pay the investors in the CDO.
At some point prior to the end of the duration of the CDO though, some of the assets will end their duration, at that point those assets repay their principal. The CDO manager must then reinvest that principal payment into other assets so that the CDOs cashflow continues to be generated.
The reinvestment period will be shorter than the entire lifetime of the CDO because at some point it won't make sense to buy assets as they will need to be shorter and shorter dated so they don't overrun the CDO lifetime.
Comment: No, as I said, they would use the proceeds to buy new assets that would themselves pay interest, unless the reinvestment period has ended.
Comment: does the CDO manager use the reinvestment proceeds to make up the loss in interest payments from the maturing assets?
Comment: during the reinvestment period are the investors receiving only coupon payments or are they receiving principal pay-downs as well?


Check file is present and it is not empty

Question: I want to check the file xx_x__x.log is present in the location or the file size is 0 at every Sunday 2:30am. I have a script to check file size and to check that it exists but I don't know how to check at a particular time.
Comment: This is pretty straight forward with `test` (`[`). What have you tried?
Comment: please accept @the_velour_fog' answer, which actually answer the whole question, not just part of it.
Answer: From man bash | less '+/^\s*CONDITIONAL'

-s file
  True if file exists and has a size greater than zero.

To get the script to run at a pre-defined time, put your code into an executable scipt and load it into a cronjob.
I suspect you possibly could put your command into a one liner and load it into a crobtab?  ( I would be interested to know if anyone else has done this successfully)
But the problem with cron commands is that

they are not connected to a terminal - that I know of {although you could probably check with lsof or something} - so you don't get any debug output / feedback about what went wrong as you build up your cron command
You have to wait a some time before you can test your cron command

for those reasons I would recommend just put your commands into an executable script, so that you can write your code in a coder friendly environment - i.e. a terminal, then when your are satisfied its behaviour is correct then load a command to call it into a crontab
so say this is your script /tmp/checksize.sh
#!/bin/bash

if [[ -s /tmp/xx_x__x.log  ]]
then
        printf "\n\n%s\n\n\n" true > /tmp/sizelog.log
else
        printf "\n\n%s\n\n\n" false > /tmp/sizelog.log
fi

just run crontab -e and add the command
5 0 * * * /tmp/checksize.sh

which means: # run five minutes after midnight, every day
about getting the timing right
from man 5 crontab
Commands  are  executed by cron(8) when the minute, hour, and month of
       year fields match the current time, and when at least one  of  the  two
       day  fields  (day of month, or day of week) match the current time (see
       ``Note'' below).  cron(8) examines cron entries once every minute.  The
       time and date fields are:

          field      allowed values
          -----      --------------
          minute         0-59
          hour       0-23
          day of month   1-31
          month      1-12 (or names, see below)
          day of week    0-7 (0 or 7 is Sun, or use names)

[...]

EXAMPLE CRON FILE
       The following lists an example of a user crontab file.

       # use /bin/bash to run commands, instead of the default /bin/sh
       SHELL=/bin/bash
       # mail any output to `paul', no matter whose crontab this is
       MAILTO=paul
       #
       # run five minutes after midnight, every day
       5 0 * * *       $HOME/bin/daily.job >> $HOME/tmp/out 2>&1
       # run at 2:15pm on the first of every month -- output mailed to paul
       15 14 1 * *     $HOME/bin/monthly
       # run at 10 pm on weekdays, annoy Joe
       0 22 * * 1-5    mail -s "It's 10pm" joe%Joe,%%Where are your kids?%
       23 0-23/2 * * * echo "run 23 minutes after midn, 2am, 4am ..., everyday"
       5 4 * * sun     echo "run at 5 after 4 every sunday"
       # Run on every second Saturday of the month
       0 4 8-14 * *    test $(date +\%u) -eq 6 && echo "2nd Saturday"

Answer: To check if a file is present in a location you can use the -f test in an if statement.
if [ -f "$FILE" ]; then

(As the_velour_fog said, the expression will return True even if the file is empty)
Comment: you can use `[[ -s $FILE ]]` which will return `1` (false) if the file is present but empty
Comment: `[ $FILE -f ]` this will also return true even if the file is empty


To disable button or to not disable button?

Question: Simple question, should a button be disabled if the form is not finished, i.e. still missing some input of mandatory fields?
Why/Why not?
Answer: It depends on what you're working on. You can have multiple approaches here such as

It can be disabled until completion if you're instantly validating every form field and also showing him the validation status of each field instantly.
Show a message beside the disabled button that says "form can be submitted only upon completion" or similar.
Comment: what about a login or signup form?


Synthesis of branched alkanes

Question: The question might seem kind of trivial, although it is even harder than I've thought. How can we synthesise branched alkanes from linear one? For example, I want to obtain 3,4,7,8-tetramethyldecane from n-decane. I've already found Stille coupling, but I guess I'm searching for easier method. I'm just a high school student, studying chemistry by myself as well.
Comment: If this is a homework problem, it is an exercise in futility. No knowledgable chemist would consider n-decane as a starting material to obtain your tetradecane, stereochemistry notwithstanding. A better question is to prepare the tetradecane from commercially available compounds --possibly with some restrictions-- with no regard for stereochemistry.
Comment: You have to functionalise first, introduce a substituent that you can manipulate e.g. halide
Comment: There is an odd photochemical route to many hard-to-get branched alkanes described by [Crabtree](https://pubs.acs.org/doi/pdf/10.1021/ed065p290). It is unclear how much it is used (https://chemistry.stackexchange.com/q/84777/81).
Comment: Yeah, that's what I know, but what methylating agents should I use?
Comment: The easiest way is to make the Grignard from the halide then react with MeI
Comment: It's not a homework problem, I am just interesed in method (doesn't have to be easy) that can branch a linear alkane.
Comment: Homework or not, @user55119 is right, alkanes are not a sensible starting point to synthesise alkanes.
Comment: I did add my educational background @Karl
Comment: Hmm, on this level, you may not realise the difference between lab synthesis and industrial process. I think answer for you should be about isomerisation, like one used for better fuel.
Answer: @Radi: Critical changes to original post! I will guide you through a reasonable approach. You have to realize that you have not specified the stereochemistry of 11 -- of which there are 16 possible stereoisomers (8 racemates) -- but I will ignore the issue. You will recognize the symmetry in 3,4,7,8-tetramethyldecane (11), so we will look for a coupling reaction of two 7-carbon entities. (E)-2-Buten-1-ol (crotyl alcohol) (4) and triethylorthopropionate 5 are commercially available. The reaction of 4 and 5 is a Johnson-type Claisen rearrangement (Google it!) which produces racemic esters 7 via transition state 6. Reduction of the double bond of unsaturated esters 7 leads to saturated esters 8. Reduction of the ester group to an alcohol followed by conversion to a bromide gives structure 9. The Wurtz reaction (9 --> 11) is rarely used but here is an opportunity.
Alternatively, esters 8 under the same conditions of the Wurtz reaction produces the α-hydroxyketones 10 (acyloin condensation). While the Clemmensen reduction (10 --> 11) of aliphatic ketones does not work as well as with aromatic ketones, under these conditions you would lose both oxygens. If the ketone is produced (structure 10 less the hydroxyl group), a Wolff-Kishner reduction would lead to the tetradecanes (plural) 11.Read about these name reactions which will be of more value to you than your original proposal. Good luck!
Comment: Thank you for guiding me through really interesing synthesis, but the question was  if there is a general method (simpler that Stille's reaction) that allows us to obtain branched alkanes from linear. Synthesis of 3,4,7,8-tetramethyldecane from n-decane was just an example since they both have 10-carbon chain.
Comment: No, there are no general methods. Waylander suggested a coupling -- like your thought of the Stille -- between an organometallic and halide. The organometallic would be better as the methyl unit. To halogenate (Cl or Br) n-decane at the 3,4,7,8 positions, the yield calculated is 0.02% of all tetrahaloisomers. And this is optimistic amid  a myriad of other polyhalogenated compounds. Absolutely impractical.
Answer: This problem has two parts: One is industrial chemistry. You typically halogenate alkanes, which gives you a wild mixture, and then fractionate and purify the products. You want to make a lot of different chemicals, so you can use most of the products, and you try to fine-tune the process so the composition matches your customers' demands, more or less.
Now you sell these n- and sec-haloalkanes (and other relatively simple, functionalised compounds)  to a chemical laboratory. They now make some fancy metal-organic coupling reaction(s) like Stille (after perhaps making alcohols or ketones out of your haloalkanes) with some specific pair of compounds, possibly a following reduction step, and get a defined, branched alkane. A straightforward example is the https://en.wikipedia.org/wiki/McMurry_reaction .
There are a lot more possibilities for both parts, but the guy making the end product will always buy pre-products that each already contain sizeable parts of the structure he aims for. To plan such a sequence of reaction for a certain target is called retrosynthesis.
OR
If you don't want some specific compound, but just more branching,  https://en.wikipedia.org/wiki/Catalytic_reforming would be your horse. You also get some aromats then, or cracking, depending on hydrogen pressure. This is also an industrial process, hard to and sort of pointless to do in the lab unless you are developing catalysts. I've visited a lab doing that, and it looked like a shrunk-down refinery with a roof and three outside walls, not at all like a chemistry lab.

Synthesis of branched alkanes


How to distinguish attached monitors?

Question: To automatically change the display layout of the Xserver when I dock my laptop I need not only detect that this event actually happened but also which monitors are connected to be able to distinguish between multiple docking station setups, i.e. there are multiple docking stations with different connected monitors. How is this possible on Linux (preferable in POSIX shell code)?
Answer: If you are actually looking for a way to set up your displays automatically when (un)docking I suggest that you are looking at autorandr before starting something alike on your own (unlike me ;).
To detect if a certain display output is connected to a monitor or not there exist good answers in this question. The most intriguing seems to be to look at /sys/class/drm/card0-*-*/status which reads connected or disconnected.
This does not solve the problem stated in this very question though but a very similar approach can be taken since there exist /sys/class/drm/card0-*-*/edid with the (cached) EDID aka DDC information of the respective monitors. If you are somewhat lucky this data does even contain the serial number of the monitor and thus can distinguish even between setups of identical monitor types (you can check with edid-decode /sys/class/drm/.../edid).
So for the purpose of distinguishing sets of attached monitors I am using the following shell function that is heavily based on a function with a similar functionality in autorandr.
# hash_sysfs_edid() simply concatenates the md5 hashes of all connected
# monitors and hashes them again so that the output is always 32 characters long.
hash_sysfs_edid () {
  edid_hash=""
    for DEVICE in /sys/class/drm/card*-*; do
        [ -e "${DEVICE}/status" ] && grep -q "^connected$" "${DEVICE}/status" || continue
      edid_hash="${edid_hash}"$(md5sum "${DEVICE}/edid" | awk '{print $1}')
    done
  echo $(echo "$edid_hash" | md5sum | awk '{print $1}')
}

How to distinguish attached monitors?


Samsung galaxy S4 Blacked out Screen need to retreive files

Question: Anyone know how to get photos/files from a galaxy 4 that has a broken / blacked out screen - Ive tried every method possible ive read online and im getting no-were and ready to scream ...I cant seem to unlock the screen to allow a computer to extract files - Ive pluged the phone into multiple computers it wont read the phone...ive tried the Kies Program...the Samsung recovery system - can I plug the phone into something and see the screen separate from the phone?
Answer: Your phone can be turned on and off? Your pc recognize your phone by making any sound?
You don't say what caused your phone screen to break but anyway you can try to do an ADB recovery or an nand backup just google for if and you find many tutorials
Comment: I can hear it turn on and off ...I dropped the phone and the LCD broke Im not sure if a ADB recovery would work....does the technology exist to plug into the phone ...mirror the screen and get what I need
Comment: The ADB recovery will work since it does not require you to do anything on your screen just your device turned on...google for "adb recovery s4" for detailed steps
Comment: And yes you can easily mirror the screen of your phone to your tv using and hdmi cable but still need to use the touch of the phone to click and etc


Memory reserved for hardware

Question: Can somebody explain why some amount of memory always reserved for hardware?
How is this related to memory addressing?
Comment: The most common use of main memory for hardware is for on-board graphics. Modern CPUs provide graphics handling within the chip, but there is no on-board memory for this, so some main memory is reserved as graphics memory. The amount allocated can generally be controlled within the BIOS, where you should find information on any other reserved memory.
Comment: I don't know enough to write up an answer, nor can I easily find anything that isn't a forum post with dubious conflicting answers and statements, but I believe that this is a "symptom" of what is called "memory mapped IO." Without BIOS support/workarounds, some of this memory is actually unused, since the basic design requires a specific range to be open for hardware use.
Comment: post some hardware details
Comment: @Yorik so it means that memory unavailable to use just because address range is ised by CPU to communicate with some hardware?
Answer: <code>why some amount of memory always reserved for hardware?
</code>
Because this is a part of contemporary personal computer architecture, called "PCI", Peripheral Component Interconnect. This architecture was originally developed in early 1990s to make a progress in configuration and performance of expanding number of PC add-on devices, to provide also Plug-And-Play functionality (to eliminate awkward explicit configuration process and allocate peripheral resources automatically)
Each peripheral device needs means to communicate with CPU, to transfer data back and forth. So the PCI architecture provides the legacy I/O access space (an outdated form of peripheral communication in X86 architecture, which is less and less utilized nowadays), and a MEMORY-MAPPED space, which provides much faster access and data exchange. Obviously, if some window of communication is mapped to common memory space, it gets excluded from the address area of regular RAM. Although this resource allocation schema is flexible, there are some achitectural restictions (I believe at OS level as well) on how to decode and map this space, so some portion of upper memory is "reserved".
Answer: A great deal depends on whether this is a 32 or 64 bit OS.
With a 64 bit OS the biggest user of hardware reserved memory is typically the video system. For reasons of economy many video systems have no or very little memory of their own but rely on system memory for it's needs. This is particularly common in laptops. This memory would be reserved by the BIOS for video use before Windows even starts.
All of the above applies to a 32 bit OS but there is an additional factor. A 32 bit OS has a fixed 4 GB physical address space. RAM is the biggest user of this address space but it is not the only one. For performance reasons a substantial portion of this space is used for memory mapped IO. This allows the CPU to quickly communicate with hardware devices by reading and writing to them the same as it does with memory. Typically this would require about 500 MB and more address space. There are other methods available but they are much too slow for high performance devices like video.
Memory mapped IO appears in the same address space as RAM. That introduces a problem. You can't have 4 GB RAM and 500 MB+ of memory mapped devices in a 4 GB address space. It just won't fit. Thus, whatever space is used for memory mapped devices is unavailable for use by RAM. Typically about 500 to 750 MB is lost but the exact amount depends on the hardware.
64 bit operating systems have a physical address space measured in terabytes so there is plenty of room for RAM and memory mapped IO.
Comment: and one more question please. For example I have GPU with 2 GB memory and RAM 8 GB. Does it mean that available RAM for Windows will be 8-2 = 6 GB ?
Comment: @Gleb Voronchikhin
Comment: @Gleb Voronchikhin
Comment: @LMiller7 You wrote _"A 32 bit OS has a fixed 4 GB physical address space._" While this is true of 32-bit Windows "client" (i.e. not Server) editions it is not true in general. The "bitness" of an x86 or x64 OS or CPU limits the size of virtual address space, but not of physical address space (RAM). Windows 32-bit Server versions can... well, _could,_ since there are no current ones any longer... address far more than 4 GB RAM via PAE. So can many other OSs. That 32-bit Windows client editions refuse to look at RAM addresses above 0xFFFFFFFF limit wired into the OS. It is not architectural.
Comment: @GlebVoronchikhin > _"For example I have GPU with 2 GB memory and RAM 8 GB. Does it mean that available RAM for Windows will be 8-2 = 6 GB ?"_ No, you'll be fine. x64 CPUs have a minimum of 40 bits of physical address, theoretically enough for 1 TiB of RAM, though most platforms don't support that much. (Check the max RAM your motherboard allows. If it's more than 8 GB, you're fine.) Also, a "GPU with 2 GB memory" almost never needs 2 GB of address space. Instead they present a much smaller "window" to the host CPU which the host can then "map" into various pieces of the card's full RAM.

Memory reserved for hardware


What is the purpose of DHIS2's "aggregation type" when "editing data element"?

Question: I can't find details about "aggregation type" in "editing data element" in DHIS2.
What is its purpose and what should the value inside be?
Answer: The aggregation type defines how the data for a data element is aggregated in analytics, meaning in the pivot table, visualizer and maps apps. As an example, if you set the aggregation type to "Sum" for a data element, when using that data element as part of a pivot table, the data values for that data element will be summarized and presented as an aggregated value. The "sum" type is the most common. Make sure to chose the type which best fits your data element and the data you are aggregating.
Answer: It depends on what you're measuring; the other approach you can take is to consider what it is you're trying to assess. Most often DHIS2 is used to input counts of people visiting clinic A in a month with a particular condition (or accessing a specific health service, depending on your HMIS data sets). The analytics generated from this input data requires an operator in order to construct a meaningful result for use in analysis phase. You also need to understand the hierarchical nature of its data model: facilities > county > district > state > country.
It's designed to aggregate data upwards from lowest reporting level (usually facility) up to a national level. If you were interested in counting the number of facilities reporting data for a specific element you would use COUNT. If you're interested in summing together the values captured across all facilities in your country - you use SUM. Obviously there are other operators designed with specific cases in mind...