Is it true that all salt is sea salt?

Question: I heard Alton Brown say that on Next Food Network Star. Is it true? What about salt that is mined, or salt from salty lakes?
Answer: In a very real sense, yes, that is a true statement. Virtually all sodium chloride on earth was formed in the ocean. It's a bit of a misnomer to consider "ocean" to be synonymous with "sea"; technically, and according to the National Oceanic and Atmospheric Administration there is a difference:

Many people use the terms "ocean" and "sea" interchangeably when speaking about the ocean, but there is a difference between the two terms when speaking of geography (the study of the Earth's surface).
  Seas are smaller than oceans and are usually located where the land and ocean meet. Typically, seas are partially enclosed by land.

Since many manufacturers of "sea salt" evaporate ocean water independent of any actual "sea", I'll use that small misnomer too, and equate "sea" to "ocean".
Salt (sodium chloride) deposits were born in ancient oceans in a process that started over four billion years ago. At one point in time or another, almost all of the planet (exactly how much and when is still a matter of debate) has been under an ocean. Rivers flow into the oceans, bringing with them minerals from erosion including positively charged sodium. Volcanic eruptions from the ocean floor spew gasses into the ocean including negatively charged chlorine.
Salt lakes share a quality with oceans in that they don't have an outflow, the volume of water is balanced by evaporation and rainfall. Water evaporates, but salt does not. So the salt created (and is still being created, but at a much slower rate) by the oceans concentrates in an ongoing process in salt lakes.
Salt mines are just dried up oceans.
So, marketing sea salt as special because it's from the sea is a bit disingenuous. There are many reasons to choose one type of salt over another, but that it comes from the sea isn't one of them. Other questions here address trace minerals found in certain mined salt, the addition of iodine in some table salt, crystal size and refinement methods; but the original source of all salt is the same.
There is a kind of fun exception: Some salt on earth comes from asteroids and meteorites. Garnish with that, Thomas Keller.
Comment: Technically, all the sodium and the chlorine on our planet were produced inside an exploding star. So all salt is star salt, too.
Comment: "Some salt on earth comes from asteroids and meteorites." And food made with it is out-of-this-world!
Comment: Also, the sodium and chloride ions in [dissolved salt](https://en.wikipedia.org/wiki/Sodium_chloride#Aqueous_solutions) aren't actually bound to each other in any significant way, so the heat of volcanic eruptions surely doesn't have anything to do with that (nonexistent) bonding. The ions only join together when the salt crystallizes out of the water.
Answer: Yes and no.
Sea Salt is salt that is harvested by evaporating natural brine - seawater, typically. Table salt is salt that is mined and processed for purity of color and flavor, and sometimes adulterated with nutrients like iodine and anti-clumping agents. The two will taste very different, as Sea Salt will have trace minerals and even biological elements that affect flavor. The flavor and even texture will often change from one part of the world to another and with harvesting techniques - Brittany Fleur de Sel is very different in taste and texture than the stuff in the paper canister of Morton's Sea Salt.
Salt itself is formed by geological processes that typically involve the oceans - mineral runoff from land will contain sodium ions and volcanoes on the seafloor will contain chlorine ions, and they find each other in the oceans to make sodium chloride. Once water in any given area of the ocean reaches saturation, the excess salt will precipitate out of the water into halide crystals, and these deposits of salt crystals are often vast, and will be buried by other geological processes (sediment accretion, volcanic activity, etc.) These crystals can have different flavor aspects as well - Himalayan salt apparently gets its delicacy and taste from iron deposits!
Halides will also form if seawater, or really any sort of salt in solution - is evaporated. This is how sea-salt is harvested.
Here is an excellent article on the geology of salt.
This is an straightforward overview of the differences between the various types of salt - mined vs. harvested, unprocessed sea-salt vs. kosher salt, etc. - from an online retailer of culinary salt varieties.
Comment: "[Table salt and sea salt] will taste very different". If you say so. I can believe _slightly_ different, but "very different" seems to be a huge exaggeration. Salt has a very strong taste; salt plus traces of not-salt still tastes a whole lot like pure salt.
Comment: @DavidRicherby They're very different in taste to me. I switched to "sea salt" a few years ago, and processed table salt is now far too strong for my tastes. The strength is the major difference to me, though other differences are detected.
Answer: Technically, yes.
Consumers buy sodium chloride from three main sources (in order of increasing rarity/expense): underground mines, evaporation ponds and sea coasts.

Underground mines were formed when salts concentrated in large bodies of water which evaporated over time.  Many of these salt flats (think Great Salt Lake, Bonneville Salt Flats, etc.) wound up underground over centuries and are later mined to produce (usually table) salt.  It's entirely possible that some of these are/were mined while the dried-up lake was still on the surface.
Evaporation ponds are (usually man-made) ponds that let in salty water, then are closed to allow the sun to evaporate the water, leaving the salt behind to be harvested.  Examples include the (former) salt ponds of San Francisco Bay, among others.
The third common source is salt that is manually scraped off of rocks on the sea coasts of several areas.

There are probably also other low-level production salt sources.
What these all have in common is that the salt was at some point concentrated from large bodies of water that evaporated.  The generic term for these large bodies of water being "seas".
Is my salt "Sea Salt"?
Today in the US, the term "Sea Salt" is most commonly a marketing term used to compete with the salts that are hand-scraped from coastal rocks.
By modifying the table salt production process, larger crystals reminiscent of hand-scraped salt can be produced.
Some manufacturers market these larger crystals under the marketing term "Sea Salt", first to indicate the larger crystal size (think Kosher salt) and secondly to capture the higher prices afforded to the hand-scraped (read: labor-intensive) "boutique" salts.
Answer: You could chemically create table salt by literally reacting chlorine and sodium (do not attempt to do so in your kitchen :), or by any number of anorganic reactions, or by burning organic matter and isolating the salt therein - but even here, the sodium and chlorine will have originally come from sea salt. And there would be no likely reason to use such an artificially created salt in food (laboratory uses with special purity requirements are a different matter), it would be more expensive to make.
Comment: Theoretically, you could create the sodium and chlorine through nuclear reactions and get salt that was never part of an ocean or salt lake, but I suspect that would be *quite* cost prohibitive ;-).
Comment: I hope I was not mistaken in the assumption that anybody bothering enough to get hold of these materials as an individual would well know about them being hazardous :)
Comment: @James You remind me of my high school chemistry textbook, which mentioned that the ancient dream of the alchemists (creation of gold) *had* been achieved by particle accelerators -- twice: once to see if it would work, and again to make sure it wasn't a fluke.  And never again, because the yield was microscopic, the cost far more than the gold was worth, and that's not even counting the cost to build the accelerator in the first place.
Comment: @Joe You actually create it with by combining Na+ and Cl- ions, (not the pure elements,) as found in sodium hydroxide and hydrochloric acid, and you can greatly reduce the risk by using baking soda instead of sodium hydroxide.  Baking soda is completely safe, generally speaking--it's a common food ingredient afterall.  HCl is nasty, caustic stuff, but it can be handled safely if you're careful, and when you mix them in the right proportions, you get common table salt.
Comment: Chlorine is a poison (it kills bacteria in small amounts so we use it to treat water ... but it kills humans in larger dosages), and sodium is so highly reactive that it will spontaneously combust if it comes into contact with water ... so really not the sort of thing you want to do in your home.
Comment: @MasonWheeler, or you can do it the exciting way: burn powdered sodium metal in a chlorine atmosphere.
Comment: I like this answer — It proves an exception I hadn't thought about.
Comment: You could create some by just eating some baking soda and letting it react with your stomach acid.

Is it true that all salt is sea salt?


How is a Mesh Collider "performance expensive"?

Question:
Do Mesh Colliders slow down performance simply by existing or only
when they are colliding?
Do they directly impact FPS or do they slow down the in-game physics?
Answer: A moving body near a meshcollider needs to check for collisions against potentially every triangular face of the mesh. So for a detailed or non-convex mesh, or lots of bodies, this can get expensive. And of course, if you have a meshcollider moving near another meshcollider, you pay this cost combinatorically.
These costs hit during the physics update step, as part of its collision resolution. The physics engine doesn't know where to position things for the next frame until it's worked out which objects need to bounce or stop due to these collisions. So in extreme cases, this can make the physics update process take longer and delay rendering of the next frame, impacting the game's frames per second rate.
If your frame runs extremely slow, past the maximum allowed timestep configured in the Time Manager then Unity will start dropping physics steps to try to keep things moving. Only if that happens will your physics slow down relative to realtime, otherwise Unity's decoupled fixed timestep will keep your physics moving consistently even if the rendered FPS drops.
When the meshcollider is not moving, the physics engine can put it to sleep, and only check it when another body comes close enough to potentially hit it, saving quite a lot of computation.
So the cost isn't fixed every frame, it will vary based on the complexity of the physics interactions that need to be checked & resolved in that frame.
To manage this cost, your best bets are:

Favour simpler collider types for dynamic objects, or terrain colliders for environments
Minimize the number of faces in meshes used for collision
When possible, make mesh colliders convex, or break them into convex pieces
(convex meshcolliders can use faster algorithms than an exhaustive face-by-face check, though the worst-case complexity still grows with the face count in the mesh)
Avoid moving big mesh colliders — see if you can keep them static and move things relative to them to create a sense of motion for big environmental collision shapes like a boat/spaceship
Comment: TIL a new word: combinatorically -- of, relating to, or involving combinations
Answer: Unity first uses Axis-Alligned Bounding Boxes (AABB) to check which colliders actually have a chance to collide. Checking two AABB's for intersection is a very cheap operation. Only then does Unity check if the collider-geometries also collide.
That means a mesh-collider only consumes CPU cycles when its bounding box intersects that of another collider. As long as nothing is near it, the collider type doesn't matter much for collision detection performance. Another operation which can cost lots of CPU cycles is rotating, because whenever you rotate an object the engine needs to recalculate the size of its bounding box. By the way, the Unity API exposes the bounding boxes of colliders.
Answer: A Mesh Collider will have to figure out the collisions for every single face of the whole mesh, Therefore It would take Longer (No significant difference most of the time) and would consume more Hardware Resources which would also slow down the performance.
Q -) Do they reduce performance simply by existing or Colliding ?
A -) No they don't reduce performance by just existing, The performance gets a hit when they are colliding.
Q -) Do they directly impact FPS or do they slow down the in-game physics?
A -) Essentially in a Mesh Collider. The more the triangles, The more the performance hit and So on. Most developers actually spend too much time trying to optimize uncritical parts of their projects and This sometimes leads to the poor optimization of the actual critical parts. However to only answer Your question, Yes mesh colliders do actually Impact Fps if they have a lot of faces.
Comment: No. Mesh Colliders for **ALL** Game objects are not acceptable for this purpose, Only the most complex ones. If you want to have 100% correctly placed bullet holes, You can use Mesh Colliders but I am sure there are better options. I am not sure but can't you simply use a raycast and see where It hit on the model without using a physics collider ?

You may want to look into this thread:

http://forum.unity3d.com/threads/14378-Raycast-without-colliders
Comment: "Most developers actually spend too much time trying to optimize uncritical parts of their projects" I want bullet holes and other effects on the surfaces of all objects. Are Mesh Colliders for **ALL** game objects (max 150k tris) acceptable for this purpose? (I will use simple capsule colliders on all moving entities for bumping into objects and a series of box colliders for hit detection only)
Comment: I could make all the colliders ignore the player. So the only thing "colliding" with them would be my raycasts. I'd throw a simple cube in for player collisions. Would that work or would the stationary objects's Mesh colliders interfere with each other / attempt to detect each other's collidion? (Rigidbody and any Physics are disabled, it's just random motionless stuff laying around)
Comment: Experimenting is the best thing that can increase your knowledge. It seems like It would work but Just as I said I've not tried it. You should try it out and post the results here for anyone that may face this problem in the future.
Comment: Honestly, I don't know much about unity. Disabling all MeshColliders doesn't yield any noticeable fps increase. Bulleteffects and muzzleflashes reduce fps from 250 to 150. I will be focusing on the latter...


Stuck in site maintanance mode

Question: I've been trying to update my drupal installation with the security patch from 7.20 to 7.26
using a patch file. Problem is I cannot get out of maintenance mode. I've tried everything indicated in other posts: http://example.com/index.php?q=user, http://example.com/user/login. Also tried to go the DB route, but that does not work either since the variable do not seem to contain anything with the "site_offline" name.
This is very frustrating. I've also backtracked on the changes by reinstalling the DB and site from backup, but unfortunately I had already put the site in maintenance mode when I took the backups. Grrr.
Any help greately appreciated.
Answer: The name entry in variable table is supposed to be maintenance_mode following updates in D7 after which site_offline and site_offline_message were replaced with maintenance_mode and maintenance_mode_message. Refer the inline comments in  update_fix_d7_requirements in update.inc
  // Rename 'site_offline_message' variable to 'maintenance_mode_message'
  // and 'site_offline' variable to 'maintenance_mode'.
  // Old variable is removed in update for system.module, see
  // system_update_7072().

Assuming you have access to the database or drush try updating the variable which is likely set as 1 to 0.
drush vset maintenance_mode 0

or
UPDATE variable SET value = 's:1:"0";' WHERE name= 'maintenance_mode';

You might also want to ensure that this value is not set as 1 with a $conf variable in your site's settings.php.
Many users with similar issue also suggest even clearing the cache table entries named variables for this to work after changing the variable value. If things go well this should bring your site back online.

Stuck in site maintanance mode


Is it logical that file system acls would be corrupted in a way that adds permission for another user?

Question: I was having issues on a shared hosting provider with the host's web server instance not serving some files.  I asked the companies support about the issue and they responded with the results of getfacl on my home directory, and added the necessary line to allow their web server to obtain the necessary permissions.
All is working happily now, but I noticed a line in the getfacl that was for what appeared to be another username to which I had no relation.  I asked them about this and their response was that it was likely some minor corruption and that I could remove the unwanted line with the setfacl -x option.
I know I never added the user to my home directory, and I also find it weird that that could truly happen due to corruption.  So now that it is fixed I'm a little bit weary of whether or not they were trying to cover up a problem they accidentally gave someone permissions to my account, or if this kind of thing can really be corrupted in that way.  Especially when that user is a real user on the same server.
Any thoughts?  Thanks.
Answer: It is possible if you are copying files from one server that has overlapping uids/gids you can end up with the wrong permissions.
Comment: Hmm, thanks James.  I did copy files from another server, but not my home directory itself.  Weird.


Why is SpaceX building the Big Falcon Ship before the Big Falcon Rocket?

Question: I believe that SpaceX is planning on building the BFS (Big Falcon Spacecraft) before the BFR (Big Falcon Rocket), which serves as the first stage for the second-stage BFS. Does anyone know why they are doing things this way round? I would have thought that BFR then BFS would have been more financially viable as BFS is not going to be of much use without BFR, but presumably BFR could be used without the BFS.
Comment: BFS? BFR? Maybe define your acronyms? People come here from the StackExchange "Hot Questions" page, and don't have the relevant context.
Comment: @FakeName See [here](https://www.reddit.com/r/SpaceXLounge/comments/79332s/is_it_called_bfr_or_bfs/) for discussion on the names.  tl;dr: BFR = Big F. Rocket, BFS = Big F. Ship.  Yes, the F originally stood for exactly what you would think, but got changed to "Falcon" for PR reasons.
Comment: Isn't BFR=BFB+BFS? B=Booster aka first stage.
Comment: Where will you put your Ship if you don't have a Rocket to put it on?! Sorry, rocket science is hard and I don't fully understand it.
Comment: Oh, so it wasn't the Big F**king Rocket?
Comment: @immibis Of course it is, they just can't use that name officially. :)
Answer: Neither has much financial purpose without the other. A BFR cannot perform any useful function without an upper stage, and that is the BFS.
Since the whole platform is a major investment in a new architecture, they are starting with the smaller piece - the BFS. Since it uses some of the same engines as the BFR, it can act as a testbed for both BFR and BFS hardware. Since it is smaller, it should be cheaper to construct (moldline, propulsion, fuel, attitude control, avionics -- things like ECLSS will most likely be expensive and time consuming, beginning development now and continuing past the first flights of both vehicles). Since it is more complex, it will likely take longer to get right. Both are good reasons to build first.
The BFR is a much simpler vehicle, mostly using concepts they've established in the Falcon - just updated with technologies that they will field test in the BFS. So it should need less fine tuning after construction, but takes more space and more money to build.
There's also the fact that the BFS is where they are most likely to run into issues getting their mass fractions (and payload capacity) where they want. Changes may be required of the BFS design, which will have impacts with the BFR design. BFR is dependent on the final BFS mass and size.
Comment: +1 for the last paragraph. Heck, anyone who's played enough KSP knows that you start designing a new launch vehicle from the top down, because you need to know how heavy your upper stages are and how much delta-v they have in order to know how powerful your lower stage needs to be. :) (Well, if you're playing with KER, anyway; otherwise it's all just gut instinct and guesswork.)
Comment: @Slarty we crawl before we walk, and walk before we run.  Similarly, did the US build the Saturn V in 1960?  No.  They started small, with the Saturn I, IB and lastly V.
Comment: Musk did say it could SSTO, but I don't recall hearing any mention of payload amounts. An F9 first stage can barely just barely SSTO, but with no usable payload or recovery. In the absence of solid payload claims, it's not safe to assume it's capable.
Comment: BFS can SSTO with approximately zero payload, as noted in this answer: https://space.stackexchange.com/a/25711/195
Comment: It should be noted that the BFS does have potential financial functions. In a crewed or minimal cargo configuration it's supposed to act as a SSTO for LEO missions according to Elon's post FH interview.
Comment: I agree with @IlmariKaronen . Just want to add that **aeroplane development is analogous**: you start building the fuselage, which is a so-called "non-lifting' part. When you know the exact mass of that, you can still do adjustments to the wings ("lifting part") before constructing them. Here, the fuselage corresponds to BFS and the wings to BFR.
Comment: Good answer. But although true that the BFR could not perform any useful function, I would have thought (without any expert background to base it on) that some sort of interim deployment "bus/shroud" would not have been that difficult to engineer
Comment: @RussellBorogove I certainly should have recalled that answer. +1
Answer: Elon Musk stated in a news conference after the Falcon Heavy launch that the BFS will be the focus because they think they understand designing booster rockets pretty well, and thus they decided to focus on the more difficult piece first.
He answers this in response to a question that starts at 20 minutes 52 seconds here, and speaks specifically to starting with the BFS at 22 minutes 18 seconds. The full response has been transcribed here to provide the full comprehensive context of his statement.

Q: So... the potential to go to the moon or mars, what's your timeline there?
Elon: There are a lot of uncertainties on this program, but it is going to be our focus now that we're almost done with Falcon 9 and Falcon Heavy. We're gonna level off as I said at block 5 or version 5 as there won't be any more major versions of Falcon 9 or Falcon Heavy. Dragon is also going to level off at dragon version 2. There might be point releases, like 5.1 or dragon 2.1 or something like that but most of our engineering resources will be devoted to BFR and so I think that will make things go quite quickly.
The ship part is by far the hardest, because that's going to come in from super-orbital velocities, like interplanetary, Mars transfer velocities, Earth-Moon transport velocities. These are way harder than coming in from low-earth orbit. There's some of the heating things that scale to the 8th power. I didn't realise there was anything that scaled to the 8th power, but it turns out certain elements of re-entry heating scale to the 8th. So testing that ship out is the real tricky part. The booster, I don't want to get, you know, complacent, but I think we understand reusable boosters. Reusable spaceships that can land propulsively, that's harder, so we're starting with the hard part first.
I think it's conceivable that we do our first test flight in 3 or 4 years of a full-up orbital test flight including the booster. We'd go to low-earth orbit first, but it would be capable of going to the moon shortly thereafter. It's designed to do that.
Comment: WOG, best possible answer.
Comment: @doppelgreener nice work!
Answer: Straightforward. SpaceX is Goal-oriented.
Better to know your needs up-front and plan around them than the other way around.
You start with the intended payload requirements because if you build a Big Rocket and try and cram your payload into it, you soon find you've built a rocket that isn't big enough for what you need, or is inefficient at carrying it, then you have to break up your payload into multiple launches (so much more expensive!) or redesign your Big Rocket again and then you might as well have started with the payload in the first place.
Answer: As with all orbital rockets, you have essentially two parts - upper stage & payload (BFS) and the means to boost it to orbit (BFR).
If you finalize the design of your booster first, that will set limits on what sort of upper stage/payload you can launch with it. Finalize the design of your payload first, and you then get to design a booster that gets it to orbit with enough performance margin to be reliable and not too much margin to be wasteful.
Going about it the other way round would be putting the cart before the horse.
Just my two layman's cents.
Comment: @Racheet, in those terms, yes. If they got the horse first then they'd be limited by it's ability, and if then they wanted a bigger cart they'd have to find another, stronger horse. You do know that cart before a horse is an idiom, right? :)
Comment: isn't that exactly what they're doing though? Building the cart before they go and buy the right horses to pull it?
Comment: absolutely, I just thought it was funny that the idiom could be reversed in this case.


Does the sentence "His confident visage hid insecurity" make sense?

Question: I was wondering if this sentence makes sense, and if it does, is the meaning of visage in this sentence metaphoric?

His confident visage hid insecurity.
Answer: It is correct, although I'd suggest a minor edit along the lines of:

His confident visage hid (or masked) his insecurity (or insecurities).
Comment: I'd probably stick to a continuous form *was hiding* too, unless the context calls for this use.
Answer: Yes, it is an acceptable sentence according to me at least.
Visage is appearance. Appearance is not the truth, it is a mask, a mere skin over something we cannot perceive. The perception of insecurity behind a confident mask is common phenomenon amongst those who consider appearance to be the final word; observe most movie stars and the half-sentient populace who follow them, then you would know this aspect of appearance being supreme to be true.
Cornbread-ninja suggests a minor edit which I think is unnecessary because i) visage or appearance does connote a mask too and ii) 'his' is not required because there is no ambiguity over subject in the sentence fragment provided. If there were other subjects in play within a larger sentence or context then Cornbread-ninja's suggestions would be valid.
Anyway, my first comment around here..please do guide if am missing the spirit of this site!
Answer: The sentence makes perfect sense.  Whether visage here is metaphorical kind of depends on how you look at things.  This word is borrowed from French; and in French, visage means face.  Usually in English it means appearance or bearing, as indeed it does here.  So yes, it's absolutely a metaphor.  It's rare to find it not as a metaphor.


Any wallet that support cancellation of transaction?

Question: Does anyone know what free bitcoin wallet can support the cancellation of unconfirmed transactions?
Answer: Yes. Most software wallets will have this feature. It's called double spending with a higher fee.
There is not really a thing as "cancelling" a transaction, once it is broadcasted, it is unstoppable, unless you double-spend it. (The first tx will get cancelled)
Comment: Can you name some of them? I have a transaction sent from blockchain.info wallet (it seems that it does not have this feature) and have set the fee too low accidentally and the transaction is get stuck. Can I recover the whole wallet without another brandname of wallet and double spent the transaction to effectively cancel the previous transaction?
Comment: Blockchain.info is notorious for making it hard to export your private keys. Electrum is a good light-weigt wallet which offers all of these functions.
Answer: Most Bitcoin wallets, including Bitcoin Core, have the feature to help get an unconfirmed transaction that is still in the mempool be more likely to get included in a block by "re-sending" to another address with an added transaction fee.  This new address can be one that you own, so you'd be sending the bitcoin to yourself.  This feature is called "Child Pays For Parent", or CPFP.
A good guide for how to determine the proper fee is here: https://themerkle.com/what-is-child-pay-for-parent/


What was the last release of OS/400 to support CISC hardware?

Question: What was the last release of OS/400 to support CISC (i.e IMPI) hardware? And when was it released?
Comment: @chthon OS/400 has two components – the part that lives on top of the virtual machine, and the part that runs under it. The part that runs on top is (internally within IBM) called "XPF". The part that lives under the VM and actually implements it – in CISC times that was called HLIC and VLIC (Horizontal/Vertical Licensed Internal Code), in RISC times renamed to SLIC (System Licensed Internal Code).
Comment: @chthon The virtual architecture is to my knowledge part of OS/400.  There was a major "you must recompile your programs now" hubbub around V5R3 IIRC.
Comment: Isn't OS/400 an operating system that completely runs on a virtual architecture, so it doesn't matter if the underlying processor micro-architecture is CISC or RISC?
Answer: I run a 9404 F10 which has V3R2 installed. That is the last OS that can be run on IMPI machines. When IBM moved to power they had to rewrite vast amounts of OS/400 as lots of little things such as even the disk geometry changed. As such it is also true of the fact that power machines cannot run anything below V3R6. V3R2 is also quite a stretch for my machine. I will not call it slow but I will not call it fast. V3R2 was announced in 1996.
Answer: There was a little overlap of CISC and RISC.  V3R6 was the first release to support RISC and had similar function to the CISC release V3R1.  This was followed by V3R2 for CISC and V3R7 for RISC.  From then on, it was RISC only so V3R2 was the last CISC release.
Most programs could be carried across but the hardware independence did not work like Java today.  The programs contain hardware specific code but the hardware independent intermediate code was also stored in the program object.  When a program is restored to incompatible hardware, the hardware specific code is dropped and the second stage compile reruns.  This also happened in the transition from the S/38 to the AS/400 and again later on.
Long ago, even back on the S/38, there were third party space saving products which would drop the intermediate code.  They would often boast of doubling your disk capacity.  Programs did drop to about half their size but you would only double your capacity if you had only programs and no data (unlikely for these machines).  Later, IBM supported this procedure which they called "removiving observability".  I don't think that they ever intended to support this but when the third party products appeared, they may have decided that it is better that they do it than others.  A cost of removing observability is that you will not be able to restore the program to new hardware.
A while ago, I asked whether it is possible to restore a program from the S/38 (the predecessor of the AS/400) to an IBM i (its latest form).  I expect that it would be possible for the reasons described above but there would be a practical problem of finding a common storage format.  It is conceivable that an S/38 program may have lingered unused through numerous updates or a save file (online save) might have lingered.  Can I restore an S/38 program to a current IBM i?


How would I generate random falling objects

Question: I'm creating a game using libgdx on Eclipse that is similar to Ragdoll Avalanche.  I'm looking for a way to generate falling objects like the triangles of Ragdoll Avalanche.  All I know that i have to use an array but i dont know how to do it.
Comment: You'll want to use some kind of random number generator (or something like perlin noise). Sounds to me like you need a little more programming experience, though, before anyone here can help you much.
Comment: I know how to create sprites, but i do not know how to make sprites   appear in a random order
Answer: If all your objects are the same shape, all you have to do is pick a location to drop them from at the top of the screen and then lower them each update either by a fixed amount or by a velocity that increases via downward acceleration (gravity)
I haven't done any android development so this will be a little generic.
The easiest way to handle the objects is to create them at the top at a random position.  Once you've done that add it to your collection.  Each update move the objects downward via the logic you prefer(as mentioned above), and when an object gets past the bottom of the screen, remove it from the collection.
Now this is by far not the most efficient solution, but it's a good starting point.  If you end up needing more efficiency, consider doing things like not removing from the collection and instead marking ones that pass the bottom as "dead".  That way when you go to make a new one, you can first see if you have a dead one to recycle.
Remember though that everything in programming is a trade, the above example adds look-up time to creation while saving you on allocation and collection resizing.  Don't solve for problems you don't have.
Also I would recommend looking up information about various collection types for your language to see how they are used and what their limitations are.  You likely will want something dynamic that you can add to easily, but others may be able to call out specific implementation details.
Answer: In addition to Lunin's answer:
If you're looking to use a library instead of writing you're own collision detection/physics then you should use Box2D (its what Angry Birds uses). In fact, LibGDX has a port for Box2D physics engine.  It handles collision detection, and physics simulation like the ragdoll body parts and falling triangles. You can search up some Box2D tutorials and look at Box2D tests in libgdx source or the VectorPinball demo.
Note that Box2D was originally written in C++. If you learn how to use Box2D for this game,I think it will be very trivial and much easier to do.
Answer: The items spawned want to be objects with intrinsic position properties and a move method that can be called every frame or every set update to change the objects position downwards. As these are instantiated you can set up the y position such that they start just above the viable screen, and use a RandomNumber*screenwidth to determine the random x positions.
Using a loop that runs though the array you can check collisions and run the moveDown method for each object - you can also then check the positions of the objects to see if they are out of the screen to remove them, and count them up to see if you need to add more.


Specific electron energy gap values $E_{i+1}-E_i$ vs. photons with arbitrary energy $\hbar \omega$

Question: The energy levels of electrons in an atom are quantized $E_i$. A photon of a specific momentum $\vec p$ and energy $$\omega=(E_{i+1}-E_i)/\hbar$$ hits an atom and gets absorbed. Okay now say the energy of the photon is $$\omega'=(E_{i+1}-E_i)/\hbar+\Delta E/\hbar,$$ where the value $\Delta E$ is some energy, which is not even near the value of any electron state gap energy. hence the quantity $\Delta E$ cannot be absorbed by means of excitation of the other particle. What happens in this case? Does this energy-wise non-fitting photon just go through the material? Does the photon "spit" in a way that the part $E_{i+1}-E_i$ of the photon energy gets absorbed and a new photon with energy $\Delta E$ will move away? Microscopically, has this anything to do with soft radiation?
Okay well, if we model the atom as only being able to suck up energy by changing it's energy levels, this would violate momentum conservation. I guess the atom must start to move too, or if we view it as part of a bigger solid state system, the photon will make the thing wobble a little. From that perspective, we'd have to consider the kinetic energy distribution of the particles composing the material and this would be able to suck up any real energy or momentum value.
If we leave the microscopic description (in terms of which I'd like to see an answer to the first question - after all, I'm speaking of the behaviour of a single photon here) and go on and view this as a "gray body" problem, and in case the answer really is that after the photoelectric effect the rest energy gets termalized, then I'd like to know the relation (for a class of materials) between the absorption per frequency and material characterizing parameters like (electron/atom density? emissivity? ...).
Comment: *"if we view [the atom] as part of a bigger solid state system, the photon will make the thing wobble a little"* You are rapidly setting up the preconditions for the [Mössbauer effect](http://en.wikipedia.org/wiki/M%C3%B6ssbauer_effect).
Answer: There is nothing that requires a reaction like
$$ \gamma + A \to A^{*}$$
as opposed to
$$ \gamma + A \to A^* + \gamma'$$
were the emitted photon carries off the excess energy.


Infinite strike rate

Question: Debut match of the player, he faces the last ball of the inning when his team requires 6 runs to win. He hits the last ball for a six, its called a no-ball by the umpire. What will be the strike rate of that player, as per statistics, after the match?
Answer: No-ball is also included for calculating strike rate and in the above case since he has hit 6 in the no-ball, his strike rate will be 600.
Here is a sample score card which says that the ball faced by Yagnik is 24. If you check the commentary, you can see that he has faced 24 balls out of which 2 were no balls(both of them are shown as 11.3).
Comment: 6 runs in 1 ball. No-ball just gives an extra run and bowler has to bowl extra ball. For batsman it is still a ball he faced. Check the sample score card link. You can understand from that how they calculated it.
Comment: So how many legal deliveries has he faced ? What will be his personal score ? 6 runs in 1 ball or 6 runs in 0 balls ?

Infinite strike rate


A grid system (Photoshop/Pixelmator) for designing for the iPad

Question: I am designing an iPad app, so I could really use a grid template. I could probably just work with the 960 grid system; however, I'd love to find a solution that is tailor-made for the purpose (that is, takes into account such things as the iPad's resolution and suggested (by Xcode's Interface Builder) screen margins). Any suggestions? How do you approach iPad interface design?
Comment: This is more of a User Interface issue than a Graphic Design issue, thus no `ios` tag. Please read the FAQ for more information. Migrating now...
Comment: Are you creating an iOS app or a web site?
Comment: I'm creating an app.
Comment: but is it an native app with native controls or a html5 app with phonegap or something similar?
Comment: It's a native app, and its interface is going to be custom-made (i.e., I am mostly _not_ going to use default iOS interface elements). Thus, I need some sort of a grid to guide me. The simplest example of that: you know how when you use Interface Builder, the software shows gridlines suggesting that you should not put stuff any closer to the edge? Well, I'd like to have a gridline there in Photoshop.
Answer: You can find a list of iPad stencils here:
http://emilychang.com/2010/03/ipad-templates-and-stencils/
most are in PSD format bit I did not used them myself.
Answer: I've been experimenting with grid layouts for the iPad/iPhone and I've started a collection of PSD templates on GitHub. They're intended for web design but they could also work for designing native app comps.
https://github.com/robflaherty/photoshop-grids
Comment: Great work Rob, I was looking for some Ps mobile grids for a while and never found them.
Answer: There aren't any grid systems for native iOS development. You have to do your own grids in photoshop.

I am mostly not going to use default iOS interface elements

The most common way of doing your own components is to extend iOS components with your own skins and behaviors.
If you go for full custom components then you extend the UIView and build your elements on top of that, but IMHO for most components it is a costly approach, i.e., lot of development work that you need to do yourself.
Also from a ux perpective it is a good practice to follow the OS UI Guidelines so it is good to use or extend native components.
I'm not saying you have to do exactly what the guidelines say or to use native components for everything, but it is a good place to start.
Guidelines are recommendations that were tested (at least we hope so) and that users get to know and get accustomed to, they are not unbreakable rules.


My professor did not write my name in the inventor list although I am the lead author on the publication that claim the product

Question: I am current graduate (international) student in a chemistry lab in USA which filed a provisional patent. I just discovered a few days ago that I am not the inventor on the patent although I solely made the product (compound) that we filed patent for. I am the first author on the publication and everyone acknowledges that I did that work. When I asked my professor about it he said we filed that patent long long ago and had no satisfactory answer that why I am not on the inventor list. How could he file a patent without making the product that he is claiming in the patent. I have all the data and experiment properly written in my log book. He included the names of two other students which have minor contribution on that work.
I am finishing up my 3rd year but I have 2 more years to work with him. What options I have to get the corrections on the inventors names?
Thanks!
Comment: Do you know if a non-provisional was ever filed or any other application filed other than the U.S? A provisional application filed longer than 1 year ago is no longer anything.
Comment: The provisional was filed in somewhere in May 2019. They definitely filed non-provisional later but they never disclosed anything to me. I only became aware of it when professor contacted me to find some answers about the product when a company showed interest in buying the product and asked some questions.
Comment: I am not sure if they filed any application other than US. I believe they tried to hide these things from me and never talked about it in group meetings.
Answer: I can't determine whether or not you should be listed as an inventor based on your description of your activities. The criteria for inventorship is not at all based on how much effort and time you put into the project. The criteria is based on whether you were responsible for the inventive element that is captured in a claim.
To give an example, let's assume a professor has an inspiration for a novel compound. He determines the synthesis steps and then asks one of his students to perform the experiment. The student spends weeks successfully synthesizing the new compound and weeks more characterizing the performance of the compound. In this scenario, the student would not be an inventor as he/she did not contribute an inventive step. However, let's say the student had to overcome a problem with the synthesis with a clever solution. If the clever synthesis fix ends up in a claim, the student should be named as an inventor.
The point I'm making, is the fact that you worked long and hard on the project isn't relevant to the determination of inventorship. Neither is being first author on a paper. If claims were drafted as part of the provisional application, I'd ask to review the application. If there is some inventive element for which you are responsible then you should be listed as an inventor.
As for you other question:

How could he file a patent without making the product that he is
claiming in the patent.

Perhaps surprisingly, there is no requirement to actually make a product or even prove that the invention works to pursue a patent.
Comment: Thanks Eric for the clear explanation. I agree that I should look at the application first and find the innovative points that I am responsible for.
Comment: "Solely" is nit part of the law. An inventor is one who makes "a" conceptual contribution to something that is claimed.
Comment: @GeorgeWhite Yeah, I was debating that bit. I removed the "solely" and also addressed the second question the OP had.
Comment: @Imran Please be advised that there is no requirement to have claims in a provisional application. It is the non-provisional application which is required to have claims.


Pontiac Grand Prix 2007 engine hot at idle

Question: I noticed lately that on my dash engine heat goes close to hot but never really gets there. That usually happens when i am in idle.
When i start driving it goes back to normal and only sometimes goes close to hot.
I hope this is not water pump which might get pricey.
Any suggestions?

This is what the top of the radiator looks like.
Comment: Welcome to Motor Vehicle Maintenance & Repair! First, ensure your coolant level is up to snuff. Second, ensure your fans are kicking on. This is usually a cause of overheating when stopped. Next, is the cooling system due for new Dexcool (150k miles/5 years old)?
Comment: Coolant level looks ok in the white tank.  Fans are definitely kicking in.  I noticed that needle goes to borderline between normal and red but never goes into red. I know 2.5 years ago my engine was overheating amd timing cover was changed as well as coolant.  I just opened the radiator cover and took a pic
Comment: @StriborK did you ever get this figured out?  My first guess would be the (mechanical) thermostat (generally between the radiator and the water pump).  Second guess for me would be the water pump.
Comment: I got 07 had same problem one of my fans wasn't turning on it was a problem in my circuit panel by the batt , after i bought after market fans from auto part store that aint crap but i change the radiator cause dexicool clogged it after a while especially if you aint using it right new water pump and thermo stat if yoi replace them with both fans running that should fix you problem ill start with radiator.
Answer: Ive owned 3 3800 powered vehicles. First thing you need to do is get rid of dexcool. Completely flush it out and refill with distilled water and add some preston cleaner or TSP  drive the car for about 3 days then drain then refill with water idle until warm cool down drain. Then refill with green antifreeze and don't forget to bleed the system there is a small 8 mil bolt on top of the thermostat housing. Once you have this done change your thermostat to a 180 degree thermostat. You should see a cooler running car unless in stop in go traffic during this time it will still climb to 190. Also 04+ grand prixs do not have coolant temp sensors located on the radiator.
Comment: Thanks for the info here.  Could you explain why the green is better than the orange?  I hadn't heard that before.  My first guess would be the thermostat as well.
Answer: This is perfectly normal in cars that actually idle (my last two vehicles have had idle stop/start system, and a hybrid system, respectively, so I haven't seen this behaviour in the last two vehicles).
When idling, there is no air current on the radiator. Thus, the system continuously heats up, until the radiator fan(s) kick in. The thermostat opens at usually bit below 90 degrees Celsius or so, which is the normal temperature of the engine when driving. However, the fan(s) kick in at much higher temperature, probably around 100 degrees Celsius or so.
Thus, you are close to the hot red zone when idling, but you never reach the hot red zone if everything is working properly.
When driving, the air current in the radiator ensures that radiator is adequately cooled even without fans rotating, and thus, the thermostat opening temperature (usually bit below 90 degrees Celsius or so) dictates the engine temperature.
If your engine temperature stays normal when driving at highway speeds for extended periods, your water pump and thermostat are probably working just fine. The engine temperature when driving at highway speeds fo extended periods should stay constant. If there's variation in the engine temperature (apart from asymptotically reaching the steady-state level), something's not right. A bouncing temperature reading at these speeds would be a cause of concern.
I would check the coolant level (please don't open the radiator cap when engine is hot!) and the tightness of the radiator cap (again, don't loosen it when engine is hot!), though. It buys you peace of mind to do this check, but it costs you practically nothing apart from few minutes of your time.
Comment: I would not say it is "normal" - it all depends on the accuracy (or lack of) of the temperature gauge, they are only an indicator and, quite often, are designed to exhibit a large movement for as small temperature rise above about 85 deg C while only a relatively small movement for 5 degrees to 80... the only way to be sure of what the temperature is is to use an accurate thermometer...
Answer: yeah sometimes it's your coolant temperature sensor that's on the outside of the radiator maybe you could unscrew it clean it off and put it back in don't forget to put the white pipe dope around the threads additionally I think your coolant looks pretty funky it doesn't look very clear looking looks kind of cloudy you might want to change your coolant but it could just be that your temp sensors clogged with a bunch of junk around it so it's not very accurate?


Power motor with Uno

Question: I am trying to power a small peristaltic pump using an UNO R3. I have it powered using usb, and I tried running the blink program to see if I could power it using digital write, and extended the delay to troubleshoot voltages using a multimeter. The motor doesn't do anything connected to the digital pins even when the digital write is set to high. If I connect the motor to the 5 V power pin the motor turns on so I know 5 V is enough voltage. I've looked at tutorials for DC motors and they explain how to set it up with motor reversing using components I don't have, and I don't need it to reverse. How can I get the motor to turn for a specific length of time?
Answer: Most likely the motor you are trying to drive requires much higher current than what the UNO can provide through its digital outputs.
Check out this summary to find out detailed specs for the I/O ports.
What you could do is to draw power from the 5V line provided by the Arduino. If that can drive your motor, then use the line to power an output stage, driven by the digital I/O. See this example.
In general, the idea is that the digital I/O provides the control logic, while the output stage provides the power required by the specific load.
The typical loads that can be driven directly by GPIOs are low power LEDs.
Anything that involves moving parts is generally out of reach, power-wise.
Comment: Thank you for your reply, I managed to get it working using your information coupled with a tutorial from youtube found here: https://www.youtube.com/watch?v=sOz41WQF7wE . Instead of a mosfet I used an NPN transistor, but ran too much current and blew up the motor, oops. Next time I'll use use your 5v suggestion since it is indeed able to be run well on that voltage. Thanks again!
Comment: Driving motors in a safe way is a problem on its own. Especially if you want to implement more sophisticated control, like variable speed and/or direction. During some transients the motor can start acting like a generator and pump current back into your driving stage, which might result in damage of either of both of them.

Power motor with Uno


Candle Lighting Time: Why Then?

Question: Why 18 minutes (or other minhagim). Where did these numbers come from?
Answer: There's an article on the subject at Hirhurim, by Rabbi Ari Enkin. He cites two reasons that are given for the 18-minute figure:

It's based on a Gemara in Shabbos (35b), where it says that six shofar blasts were blown to announce that Shabbos will be starting soon; the third one is the signal for lighting candles, then "he waits as much time as it takes to roast a small fish," blows the last three blasts, and Shabbos begins. This amount of time is elsewhere stated to be 18 minutes.
It's in deference to the opinion of Sefer Yereim (by R' Eliezer of Metz, one of the Tosafists), who says that the halachic day ends (and thus Shabbos begins) a 1-mil walk before sunset. There are various opinions as to how long a 1-mil walk is, ranging from 18-24 minutes, but 18 minutes is the most widespread (in connection with other laws such as the amount of time that it takes for dough to become chametz), and therefore it was adopted here too.
Comment: 18 is simply the most Machmir by Chametz so it is used there. Here it's the most Meikil, but even caring about the Yereim's position at all here is already a Chumra.

Candle Lighting Time: Why Then?


Who owns the project timeline?

Question: On a large, fully staffed, project team, under ideal situations, who would you expect to own the project timeline?
Answer: At the company I work for the Project Manager owns the timeline, but everyone on a project has access to it and is responsible for making sure their tasks are completed within the time slot allocated.  Having the timeline in a shared location means that everyone can see task dependencies both upstream and downstream of their own pieces of the project, and give feedback to the PM when changes need to be made.
In short, everyone has access to the timeline, but if a change needs to be made it's the PM's responsibility.  If the entire schedule is going to slip, then I'm sure the PM will get input from the business owners as well as from the project team members.
Comment: +1 - @Bill, what software do you use to maintain a schedule?
Comment: @jmort253, We use MS Project to create the schedule and upload it to a project Sharepoint.
Answer: Its the project manager's responsibility to "own" it from an accountability standpoint.
Importantly, the PM also owns the expectations management that comes with managing the project timeline. This flows upstream to project sponsors and clients, downstream to team members and across the stream to accounting.
Answer: According to PMBOK the PM is the only person who owns Schedule (timeline, as you call it).

Who owns the project timeline?


Best Practises in Android Resources Naming

Question: There are a lot of android resources types: layouts, strings, drawables and so on. I understand that readability of it's names is important but can not create a table of rules how to name them in the best way.
Are there any best practices on that?
Comment: I don't think this is a particularly constructive question. I'll monitor the answers to see if anything useful comes out, but it's likely to be closed fairly soon.
Answer: I never came accross an "official" good practice for naming resource. Each type of resource is kinda located in a specific directory (layouts in "res/layout", etc., so I think common sense is enough here.
Answer: I think a good practice is to name the resources uniting the  the activity name (if exists), object type or object name, and property name, using all chars in lower case. I believe that if the resources exists, it'll be used, so I would name my resources like below:
If I have a object used in a Activity:

mainactivity_button_id - using the type of object
mainactivity_button_ok_id - using the name of object
If the object isn't been used in a Activity or is used in various locals:
global_string_messagetext


What transportation is available from Costa Rica to Nicaragua?

Question: We will be flying in to San Jose Costa Rica in January for 3 weeks, and would like to spend part of that time in Nicaragua. What is the easiest, least expensive way to get to Lake Nicaragua area?
Comment: Easiest and least expensive are rarely the same.
Answer: Bus it, Man
Rome2rio says there are three bus services from San Jose, Costa Rica to somewhere near Lake Nicaragua (Peñas Blancas, Costa Rica or Rivas, Nicaragua). Indeed following up on the bus company websites one finds the information below. Note that ticket costs often don't include immigration taxes to enter/exit Costa Rica and Nicaragua. At the time of writing these are as follows (according to the Trans Nica FAQ page):

Costa Rica: Salida $7USD y entrada $2USD.
Nicaragua: Salida $2 y entrada si es extranjero $14USD, si es nicaragüense $1.

1. Trans Nica
Trans Nica buses depart from San Jose and stop in Rivas. At the time of writing there are three economy and one executive departures per day. The economy fare is 54USD return, and the executive fare is 76USD return.
For more information here is the FAQ page of Trans Nica (in Spanish). Below is a screenshot taken from the linked page, showing detailed information on the bus service:

2. Marvelus Travels
Marvelus Travels operates a bus from San Jose to Rivas. At the time of writing there are two departures per day. The fare is 37USD one-way. The journey duration is advertised as 7 hours. Below is a screenshot of the Marvelus Travels website:

3. Bus 505
According to this unofficial website, there seems to be a mysterious bus n. 505 which serves the route from San Jose to Peñas Blancas. There are six departures per day, of which two are express buses. In this case you are looking at 6 hours to cover 293km (not sure if this is the express service or not). Quoting from the linked website:

505 SANTA ROSA AND PEÑAS BLANCAS (from San José)

DEP. ev. day from 100 mts north of Terminal Coca Cola at 4:30, 5:00, 7:00, 7:45, 13:20, 16:10; RET. 5:00, 7:15, 10:30, 10:40, 13:30, 14:45, 15:30.
Only DEP. 4:30 , 7:00 and RET: 10:30, 13:30 are express buses.
293 km, 6:00 hrs.
Answer: You can take a bus from San Jose or any major city (Transnica, Nicabus and other big companies have good deals with comfortable buses).
You can fly from any airport for around $100, give or take.
Or you can boat it.
Source: a Costa Rican
Answer: Take a national bus to Penas blancas, walk over the border and the take a national bus to your final destination, on the way back you can take a boat and cross over to Los Chiles (Costa Rica). I did it when I was visiting Nicaragua after arriving by plane to Costa Rica


Why doesn't the same miner always win?

Question: If the miner with the strongest ability to solve the block wins, why doesn't the same miner win every time?  Wouldn't that miner still have the strongest ability to perform the proof of work on the next block and thus win every block?
Answer: Mining is not won by the miner with the "strongest ability to solve the block". Mining is a random progress-free process. Each block candidate independently has a tiny chance to be a valid block.
Each miner is working on a separate, non-overlapping block candidate set. Block candidates assign the block reward to their author with an output in the Coinbase transactions and therefore each miner has their own transaction set differing to that of other miners. As everyone is working on a separate set of work, and every piece of work has an tiny chance of winning (independently of what else was tried!), mining is a Poisson process, rather than a linear stack of work that needs to be powered through. Therefore, the miner with the most hashing power has the greatest chance to win the block, but only probabilistically so.
Think of mining as buying a lottery ticket for each block candidate hashed. Only a fraction of the tickets in the pot are winning tickets, but somebody might draw a winner on their second try, while another has bought fifty losing tickets already. However, when you buy more tickets more quickly, your chance of winning is higher.
For a better overview what mining is, you can have a look at "What exactly is mining?".
Comment: Each hash is a lottery ticket. Hashes per second (hashrate) are lottery tickets per second. If you do more hashes per second then you will find blocks more often.
Comment: Thanks Murch. So the stronger hash power allows you to enter into the pot more often?
Answer: Every miner is working a on different block. While they share some of the same data, there are several parts of a block which are completely up to the miner to decide, and those differences make the blocks different. This also means that they have different hashes so every miner is searching a different part of the SHA256d search space.
Although each of the blocks every miner is working on will share the same height and parent block, they will have different transactions, and may have different block version numbers, and timestamps.
But the most obvious thing is going to be the transactions, which are hashed into the merkle root. Just one transaction being different, or just one transaction in a different position, is going to cause the merkle root to change, which causes the block header to change, which thus makes the hash different. And every miner is going to have at least their coinbase transaction be different from everyone else's. This is because the coinbase transaction contains the output that pays the miner, so obviously every miner is going to make their coinbase transaction pay themselves, not someone else. From this simple fact, the transactions in the blocks that miners are working on are going to be different in at least the coinbase.
So because miners are all working on different blocks, every nonce that they try is going to result in a block hash that no other miner has seen yet. Thus a small miner could be lucky enough that the block they are trying has a nonce that makes the hash meet the PoW requirement before a larger miner finds such a nonce for their block.
Comment: Ah, now I get it. This was the missing piece for me: "Yes they "restart", but they restart after each and every nonce tried. Updating to the next block is no different than trying the a new nonce." I pictured that once a block is being mined, transactions in it are frozen until the correct nonce is found. That's not the case. Each nonce is tried on a "fresh" block of transactions, header of which points at the top of the current longest block chain. Thank you, Andrew!
Comment: Does this mean that whenever a miner meets the PoW requirement and therefore his/her block is added to the blockchain, all the other miners have to throw away the work on their currently mined blocks because the parent block to append the next block to changed, therefore the hash of the next block will change? I hope this makes sense.
Comment: So say a miner A and B mine blocks. Miner A finishes PoW first, so his/her block is added to the top of the blockchain. That means that the next block to be added will have to contain the hash of the miner A's block as its parent block, right (because that's the new top of the blockchain)? But the miner A's block wasn't known when miner B started mining the last block, so he/she will have to restart the process so that he/she starts with the correct parent block hash at the header of the next block to be mined, no? I know I am missing something, just can't figure out what it is.
Comment: @pkout Yes, but they aren't really throwing away work. Mining is a progressless process, so all previous work done has no bearing on whether the miner would have found the block if someone else hadn't.
Comment: @pkout Yes, that is what will happen. Miner B will change the header they work on to have a new previous block and to have new transactions (as the original transactions are likely to have been confirmed in A's block). However this doesn't cost B anything because mining is progress-less. All of the work that B had done previously did not make it more or less likely that the next block header B tries will be valid. Yes they "restart", but they restart after each and every nonce tried. Updating to the next block is no different than trying the a new nonce.

Why doesn't the same miner always win?


Is there a minimum of notes and chords i need to determine the key of a song?

Question: Just by curiosity. What is the minimum of notes and chords i need to determine the key of a song?
Comment: If you can find the 2 half-note steps you can find out the key.
Comment: Did a test this week on 100 songs at random. 40% were started on the key chord (not including anacruces).95% probably represents the LAST chord.
Comment: @Caleb - so that's 4 notes minimum?
Comment: @Tim Yes. It's what I usually do if I'm trying to play by ear.
Comment: 95% of the time the first chord will tell you what key the song is in
Comment: @tim: I think this may vary strongly with the kind of music you're into. The figure in my collection is 72%, but 95%, while clearly an estimate, does sound plausible.
Comment: @MarcksThomas - I grabbed a busker's book with 101 numbers in it, at random.There's certainly less chance of a piece starting on tonic than finishing on it.
Answer: There isn't any hard and fast rule.  The first thing is that the key signature narrows it down to two keys.  So, for example, if there are no sharps or flats in the key signature, the key is either C major or A minor.  Most of the time, the first few measures in the piece will establish whether you're in the major or minor key.
Beethoven's 5th symphony is a famous example of an intentionally ambiguous opening.  There are three flats in the key signature, so it's either Eb major or C minor, but it's impossible to tell which from the first four bars.  The first four notes could be either the top two notes of a Cm chord or the bottom two notes of an Eb chord.  The next four notes are no help; they could be either the middle two notes of a Bb7 chord (and therefore the V7 chord in Eb) or the top two notes of the G7 chord (and therefore the V7 chord in Cm).  Then, the next four notes end on a Cm chord, leading up to a strong cadence on the G7 chord.  This establishes the piece firmly in C minor.  So sometimes, you have to dig into the piece a bit before you know.
One way to tell whether a piece (at least in classical music) is in the major or minor key associated with the key signature is to look for an accidental that raises the 7th note of the scale.  That's usually a dead giveaway that the piece is in the minor key.  This accidental will be a natural in keys with three or more flats, a double-sharp in keys with five or more sharps, and a sharp in every other key.
Comment: @supercat - Arthur's theme modulates like crazy. Whatever key it may be written in, there's going to be accidentals everywhere.Then it effectively goes into another key. El Shaddai really stays in the same key all through.I've played stuff where I've asked at the end "Why was it written in that key?" as a different one would have been easier to write, and read.
Comment: that's not fair !! OP never mentioned key sigs!!! Obviously with that as a given the choice is 2 - unless someone's written modally, properly...
Comment: A song's key signature doesn't always relate to its tonality.  If Arthur's Theme ("Best that you can do") and "El Shaddai" are transposed so that the first chord is Dm, both would start with the chord sequence "Dm G7 C F Bb E7..."; and both melodies have the same tonality (one could sing them simultaneously and they'd fit) but the key signature of the former would be A major (I think) and the latter, C major.
Comment: @Tim, if it's in a weird key, it's usually the singer's fault. :-) I have one song I sing in Cm. The fiddler hates soloing on it.
Comment: @KevinJohnsrude - it's a perennial nightmare with singers insisting that they can only sing a particular song in one key. Tessitura often says they're wrong !But my beef was that you could,for instance, write a song in, say, F, with a Bb, and naturalise any subsequent Bbs in the piece. So, in fact, it wouldn't really be in F.Or maybe there aren't any Bbs in the piece.Why? gets asked : the answer is rarely forthcoming.If a piece modulates a lot, strictly, it should be written in the key it'll end in,but it isn't always.Hence,accidentals everywhere, which would happen anyway,so why not minimise?
Comment: @Tim, for some songs I'm one of those singers. And yes, it's tessitura . Not my full range but my strongest range for the phrasing of the song. I only have an octave and a half to work with, you see.
Comment: @Tim: The OP didn't say not to use them, either.  :)
Answer: It depends on how many different chords there are in the song.  For jazz, the traditions of chord substitution, use of ii-V progressions, possible polytonality and shifting key centers may mean you have to look at a dozen chords and grok the chord movement to understand the key.
But for the overwhelming majority of songs you only need one chord, the final one.  The last chord almost always resolves to the tonic.
As for the number of notes, I have a hunch that the overwhelming majority of songs end on a half or full bar of the tonic.
So let's assume that we're listening to a tune and there's no polytonality and no shifting of key centers and no modality.  If the time signature is 4/4 then to determine the key by the notes I would either

collect all the notes that play on the 1 and 3 of each bar and eliminate the obvious passing tones or
collect all the notes that appear to be chord tones: This is difficult for me to explain but easy to do.  I look for notes that fit one of these combinations: 135, 351, 513 where 3 could be natural or flatted.  In jazz it's a little more complicated but you get the idea.

This collection of notes will give me either the full scale or the strong notes. The strong notes for major keys are usually the pentatonic major scale, and for minor keys usually the  pentatonic minor.  With these notes plus the tonic in the last bar I've got the key.
So if we ignore the note harvesting and assume no modality, it's 2 notes: the 1 and the 3.  If our collection of notes indicates either modality or an exotic scale then it could be up to 7 notes.
If we include the note harvesting then for a 32 bar song it's somewhere between 5 notes (chord tones) and 64 notes (1&3).
Although honestly, if I was listening to a song and wanted to find the key, I'd comp along until I gathered all the skeleton chords.
Comment: What's the difference between a blues band and a jazz band? A blues band plays 3 chords in front of 100 people, and a jazz band plays 100 chords in front of 3 people.
Comment: (Good answer, by the way, I just couldn't resist making the joke!)
Answer: Chords, I'd say two. One will be the tonic, and the other, usually, the dominant. There are songs that use tonic and sub-dominant, which, funnily enough, is the same relationship, but the other way round.Given a minor key, the dominant may well be major, so it's easier to determine.Obviously, the more the merrier.Working through a song, three could be enough to be accurate, but start at the end chord, which OFTEN is the tonic, you maybe don't need more than just the one ! This could turn out to be not the simple question it appears.
Note-wise, hope someone else will reason that out.Given some underlying harmony, there will be a simple answer,but I wonder whether you mean notes/chords separately or together...


When transiting between two flights, will my luggage be automatically transferred?

Question: I have flight where I need to move from airplane to another. Do I need to check out my luggage and then check it in again, or will it be automatically transferred to another plane?
Comment: It is often termed "being in transit"
Answer: That depends. If you booked the flights together at the same time, luggage will usually be "checked through" to your final destination. If you booked them separately, especially if it's different airlines, you'll probably have to pick up your luggage and check it in again.
In any case, the airline employee at your original checkin can tell you whether your luggage is checked through - they'll often ask you themselves to confirm whether you want that.
Comment: This is missing important information. For example, when connecting from an international flight to a domestic flight in the US, you must collect your luggage and take it through customs yourself; you then hand it back and it's put on your connecting flight.
Comment: @Malvolio: The attendant was _wrong_ in this case, but be careful with throwing "idiot" about. One might be tempted to use the same kind of language about you sweeping and completely wrong claim about "every country, every route, every passenger": For arrivals into the EU, the standard procedure is to clear customs at one's eventual destination, not the first point of landing.
Comment: I ran into this problem in October (rechecking bags) when fyling from Britain to the US. I was flying from London Heathrow to Dallas and then onto Portland (OR). Tickets were booked through British AIrways as Heathrow -> Portland, and when checking in I asked "Will these bags be transferred automatically?", I was told "yes" by the BA attendant but when I arrived in Portland my bags were still in Dallas (though thankfully these were put on the next flight and brought to us the next day).
Comment: @MistaGiggles -- the attendant was an idiot.  Did he think that the Dallas-Portland flight was going to pull up to the International terminal to let you and your bags go through customs?  Every country, every route, every passenger, you must carry your own bags through customs at the very first stop in your destination country.
Answer: Usually, an airline checks luggage to the final desination when transfers occurs. On a same booking, as already said, there are many chances your luggage goes on through to the next plane.
Exceptions :

Separate reservations on different airlines
Airport change during a transfer : you will need to bring the luggage with you during the required ground transportation
Transfer from an international inbound flight to a domestic outbound flight : since this is your entry point into the country, you will have to pick your bags, clear the customs then re-check them right after. This is the case at least in the USA, and depends on the countries. In Europe Schengen space, it did not happen when flying MIA -> FRA -> CDG although FRA is the entry point into Schengen space.
Comment: In Schengen customs will be cleared at your final destination. Even small airports have customs officers (at least on call). Immigration is different as you need to go through it in your first point of entry.
Comment: That is not a Schengen thing; it's an EU thing.
Comment: Also note customs != immigration.
Comment: @HenningMakholm Except in Scandinavia of course
Comment: @Calchas: What do you say is different in Scandinavia?
Comment: Sweden and (albeit not an EU member but is an EEA member...) Norway do not have customs stations at many of their smaller airports. Norway always does customs at first entry if going to a domestic flight. For Sweden, it depends on your final destination, and customs are always done at first entry if you don't go through Stockholm or Gothenburg.


Plugin Derivatives For Queue and Migration Plugins

Question: I've created a custom Content Entity and a custom Content Entity Type, basically I'm mirroring the Node module but the purpose of this is to have external data to be synced with this setup(not using node and the content types because I want the content not to have any canonical pages, and at the same time, I am supposed to have content with landing pages).
Content Sync - this link provides a good example of setting up a sync process using the Migrate module. I would need a set of plugins to define the migration process for a custom entity, but since I have multiple types of my custom entity, can it be possible to use derivatives for any types of plugins(Migrate module - source, process, destination and Queue plugins like QueueWorker) to handle each type of custom entity dynamically?
This might be a huge question to dig into, but I'm more interested in a yes/no type of answer, because I can do the investigation myself afterwards, just need to know if it's worth it.
Answer: The annotation cannot be derviated, but the class itself yes.


Can I connect two Linux systems via USB?

Question: I would like to hook up my new Raspberry Pi A+ to an older B model without having to connect the A+ to WiFi.  Can I connect them somehow via USB? Can I do it with a hub in between?
Comment: And anyway, you can't connect *any two systems* with a direct USB cable. USB just doesn't work that way. It's host-to-device, not host-to-host.
Comment: @Massimo Unless you are using USB3, specifications allow it, though no-one bothered yet to implement it.
Comment: Yes, but you need to use a **[special cable](http://en.wikipedia.org/wiki/Direct_cable_connection#DCC_with_USB)**.  As implied there, they're probably all propriety; the usbnet driver on linux apparently supports a limited set of them, so before you buy a cable, check around to see if it will work.  Presumably you could do it through a hub *on one side*.  You can't simply do it with a normal cable, or two normal cables through a hub; as per the wikipedia bit that can potentially cause damage and will never work.  There must be additional hardware in the middle.
Comment: _Why_ do you want to connect them ? What data do you want to transfer ? A simple serial connection using two GPIO pins on each (and two cables + 1 for `GND` maybe) could be sufficient if you want to transfer data at low speed.
Comment: We've got five answers now that adress mostly the same issues. But to get the most of it, it would be more than helpful to give additional details of what you are trying to achieve here. So please be more specific about the purpose of that connection.
Answer: I wanted to expand upon Chisight's helpful answer.
I lack a keyboard/monitor that can connect to a Pi, so I followed gbaman's "quick route" instructions linked from the first Gist.
I connected a Pi Zero to a Pi 3 B+ in this way. I could use ping and ssh to access the link-local name raspberrypi.local with no problem, I think this is thanks to avahi-daemon. I also verified this using the command getent hosts -s mdns4_minimal raspberrypi.local which I had learned about from this serverfault question. However, when the Pi Zero was connected to my Arch Linux machine I did not have a working raspberrypi.local and so had to discover the IP of the connected device using arp-scan as described here.
Being able to ssh into the Zero was great, but not the end of the road. At this point the Zero did not have network access, and in fact its presence as a USB network device caused the Pi 3 to lose outgoing wireless access. (This was due to a usb0 link-local entry which appeared in the Pi 3 routing table with higher priority than the wireless gateway) To give access to the Pi Zero, I configured a static IP for both ends of the USB device, and set up NAT on the Pi 3 to forward connections from the Zero. This was according to instructions from BurtyB on Freenode's #raspberrypi:
## Pi Zero add to /etc/dhcpcd.conf

profile fb_usb0
static ip_address=172.19.180.1/24
static routers=172.19.180.254
static domain_name_servers=188.8.131.52 126.96.36.199

interface usb0
fallback fb_usb0

## Pi 3 add to /etc/dhcpcd.conf

profile fb_usb0
static ip_address=172.19.180.254/24

interface usb0
fallback fb_usb0

## Pi 3 setup NAT

sudo sh -c "echo 'net.ipv4.ip_forward=1' >> /etc/sysctl.conf"
sudo sysctl -p /etc/sysctl.conf

sudo iptables -t nat -A POSTROUTING -s 172.19.180.0/24 ! -o usb0 -j MASQUERADE
sudo iptables -A FORWARD -i usb0 ! -o usb0 -j ACCEPT
sudo iptables -A FORWARD -o usb0 -m conntrack --ctstate RELATED,ESTABLISHED -j ACCEPT
sudo sh -c "iptables-save > /etc/iptables/rules.v4"

# ^ first you need to
# apt-get install iptables-persistent

These instructions could be easily adapted to give the Pi Zero network access via a laptop or other computer. Once I followed them, I was able to run apt-get on the Zero and finish configuring it to my liking. Before BurtyB told me to use NAT, I had gotten sidetracked trying to set up a bridge with brctl, which doesn't work between ethernet and wireless devices - so don't do that...
(Strangely, after I did these things I no longer had an issue with the routing table on the Pi 3. It had been suggested earlier that I configure metric values in /etc/dhcpcd.conf to fix the routing priority table issue but the problem persisted, which was a mystery. This is from the Pi 3
$ ip route
default dev usb0 scope link
default via 192.168.1.1 dev wlan0 src 192.168.1.123 metric 200
169.254.0.0/16 dev usb0 proto kernel scope link src 169.254.38.33 metric 300
192.168.1.0/24 dev wlan0 proto kernel scope link src 192.168.1.123 metric 200

whose dhcpcd.conf still has the metric values:
interface wlan0
metric 200

# from BurtyB at #raspberrypi
profile fb_usb0
static ip_address=172.19.180.254/24

interface usb0
fallback fb_usb0
metric 300

...)
Answer: You can't use USB to connect to computers to each other. Use a crossover ethernet cable! Make sure to configure the IPs.
edit: a+ doesn't have ethernet cable. Consider using USB ethernet adapter.
Comment: The A+ as the A does not have Ethernet,..
Comment: @LarsPötter you can always use an USB ethernet adapter.
Answer: Connect them via UART! You will have them talking in no time.
Here is a link to get you started:http://www.raspberry-projects.com/pi/programming-in-c/uart-serial-port/using-the-uart
just connect tx to the other rx and rx to the other tx.
Comment: I'll definitely try this option, even if i'm not a question asker....
Answer: Yes!
The Pi A, A+ and Zero are special, they each support USB OTG and can connect directly to other computers via USB.
These models alone are special and this feature does not exist on any Pi that has more than one USB data connector like the B, B+ 2B, 3B and likely not any bigger Pi in the future.
The basic steps are in this gist https://gist.github.com/gbaman/50b6cca61dd1c3f88f41
Note that the command including BRANCH=next should not be used, it no longer works and isn't even available anymore, you just update your Pi the usual way and you'll get the updates needed.
Answer: There are two options:
1.) A special USB Cable with USB-A Plugs on each end. They have a chip inside that tels both sides that this would be an USB Stick or something. So you will need a special software and that software for ARM to use it. So this is the hard way.
2.) Just use a Ethernet Cable and two USB-Ethernet Adapters. This will be supported by the Kernel and you now have a LAN connection between the two. Only issue is that at least one of the USB-Ethernet Adapters has to support Auto-MDI. If they both do not support it then you need a Cross-Over Cable. A cross over Cable is a special LAN cable that has a special pin layout so that two host can be connected with each other. In the normal case you connect a host to a switch. The Auto-MDI feature automatically detects if a normal cable or a cross over cable is needed and can do the cross over part automatically if needed.
Answer: As others have pointed out you can't do this via USB (at least without writing your own drivers).
There are 3 simple options (without any additional hardware); serial, SPI or I²C.
You first have to define what you are trying to achieve.
Serial is the time honoured solution; indeed once all UNIX machines did this, before IP was invented. There is a lot of support built into any Linux system to support this.
The other protocols are more suitable to using one device as a slave.
Answer: The only thing that comes close is to access one Pi over the Serial Console using a serial USB adapter

These are the same used to programme Arduino 3.3v boards. basically it gives you a Console over USB on Pi, and a Serial on the other.
You asked for USB, but you may just connect the two directly RX to TX and TX to RX.  The problem with this is that 2 is the max. There are ways to get more but it get more complicated than needed.
Comment: You did not connect your USB to UART to the ground pin. This might work as long as your raspberry pi is powered from the same USB host device but will fail if you power the Raspberry Pi from a USB phone charger or such.


What are the main improvements in suspension technology in the last 10 years?

Question: How much has bicycle suspension technology evolved in the last 10 years? I am thinking about both rear and front suspension. What have been the major breakthroughs that all bicycle manufacturers are now using, and what sort of improvements have there been to suspension forks from 2002 vs. 2012 as an example?
Comment: Better marketing.
Answer: I'd say the biggest change is the shift from coil and oil shocks to air springs. Even at the cheaper end of the market most bikes designed to go uphill will be using air shock suspension. Air suspension is lighter but in the past has performed less well and been more expensive. Over the years price has fallen and performance has improved.
The other big change is the amount of adjustment that can be achieved just by turning a dial. In 2002 I had to adjust the travel of my forks by taking them apart and moving spacers about. To change the rebound I had to use a different spring and to change the damping I had to use a different weight of oil. Now I have dials to adjust all three.
Lockouts that stop the suspension moving for more efficient climbing have also become widespread and much more reliable. Initially applying too much pressure to the shock while it was locked would break it. Now it will 'blow out' and switch back into non locked mode. Cannondale are taking this a step further in some of their new bikes which offer remotely adjustable travel on the fly from the handlebar.
Ps. this a great question and would be interesting for other parts of the bike. Bikes has changed massively since the birth of the sport.
Comment: Cost reduction,shocks for the masses!!
Answer: To me (and for others, I think) the greatest paradigm shift (that should become widespread in the near future, my opinion) is the inertial-controlled compression-lockout valve (Fox Terralogic, Specialized BRAIN).
These work as automatic lockouts, which make the bike stable if the rider pushes it down (like pedalling hard on a smoot uphill, or sprinting on road), but allow the suspension to work when some force is applied from below, by means of a moving mass inside the system, which closes or opens the oil valves when it moves.
Of course there have been advances in compression/rebound valve design, the "full range in half a turn" adjustment dials are great, and some extra-plush, low-stiction anodized coat on stanchions make huge difference, although they are more of quantitative improvements than real game changers.
At last, it is a pity that all these achievements of technology are focused primarily in high-end, performance oriented, racing sports market. But the fact is: every vehicle deserves some suspension system. Commuter bikes suffer badly due to the lack of dedicated suspension systems, be them forks or transport-oriented suspension-equipped frames.
Either for commuting, transporting cargo or even going around with a child seat attached, not every road is smooth (in my city, most of the streets are definitely NOT smooth), but if you want to put a good suspension fork on a commuter, you end up spending too much, having a part that needs constant maintenance, and having serious compatibility problems with fenders, racks, etc. That could be the NEXT revolution: designing suspension systems with the utilitarian bicycle culture in mind.
Comment: +1 for the suspenssion for the commuter concept! I (try to) commute in a very hilly city with completely busted streets, a tipical commuter here has nothing to do, it would not stand the "offroad" streets and it doesn't have the gearing, but a MTB that has the wheels and suspension can not take the fenders nor panniers required.
Comment: @Jahaziel Also, I had serious problems already with rear-rack/pannier combination SHAKING LIKE HELL because of road bumps, and sooner or later breaking (real exemples from my current setup: both eyelets broken/rewelded near the rear axle, three weld points in the rack, two plastic hooks in the pannier, one ripped/broken handlebar bag). With a transport-oriented full-suspension frame (of some sort), perhaps the problems would be fewer and less severe.
Comment: your comment makes me rethink a simple design of mine: I've been thinking of building a custom rear rack for my hardtail-front suspension only MTB commuter. I will have to add some sort of suspension or change the materials used... Who knows, maybe there I make the next breaktrhough... heheh.
Comment: @Jahaziel a 4-bar linkage REAR RACK!   ;o)


Program Preferences no longer recognizes Desktop webmail

Question: Until today, I had desktop-webmail as my preferred e-mail client. Today, I clicked on an e-mail link, and up popped an Evolution window.
I do not know of any changes that I deliberately made to desktop-webmail or the preferred applications settings.
When I opened the preferred applications settings, I did not have the option to select desktop-webmail, nor did I have custom command entries available for either the web browser or the e-mail client settings, although I did still have the custom command entry available for other program preferences.
1) Does this indicate some deeper misconfiguration in my system that I need to try to fix?
2) What is the command line for resetting my default e-mail client?
Answer: I made a new desktop-webmail release and uploaded new packages for Ubuntu to my PPA.


Did the witches know that the Wizard of Oz was a fraud?

Question: I'm not familiar with Baum's Oz universe enough to know for sure, but it seems to me that in most cases, true experts in any field can spot a fraud.  So I'm simply wondering if there is anything mentioning that the witches (any of them) know that the Wizard was a fraud, but chose not to expose him for some reason, or were they truly fooled?
Comment: FYI, If you would like to read them, their age has long since put them into public domain; to read online, try [Wikisource](http://en.wikisource.org/wiki/Author:Lyman_Frank_Baum#Oz_books), or Project Gutenberg has [LFB's works](http://www.gutenberg.org/ebooks/author/42) in formats for the various readers (kindle, nook, etc.)
Answer: In the opening chapter of "Glinda of Oz", the fourteenth (and last written by Baum himself) of the series, the audience is introduced to "Glinda's Great Book of Records". The book is described thus:

on the pages of which are constantly being printed a record of every
  event that happens in any part of the world, at exactly the moment it happens.
  And the records are always truthful, although sometimes they do not give
  as many details as one could wish.

So it seems entirely likely that Glinda, using the Book of Records, would know the origins of the Wizard and his actual magic abilities (none).
On the other hand, it is a virtual certainty that none of the wicked witches knew. If they had known, they would certainly have attempted to kill him (they were, after all, wicked). Their ability to succeed in killing him would not necessarily have been a sure thing. While the Wizard had no magic abilities, he exemplified some of the better qualities of stage magicians including creativity, resourcefulness, dedication, attention to detail plus a better than average understanding of people.
There is an interesting thing about the Wizard.

 In the fourth book of the series the Wizard returns to Oz and eventually
 becomes an apprentice of Glinda's. By the seventh book he was capable of
 performing significant (real) magic of his own.
Comment: Greetings from 2022! Holy Cow, that Book of Records sounds like one of the very earliest computer technology/internet predictions. Just a brilliant idea from well over a century ago!
Answer: In the original book, the witches definitely don't know about the true nature of Oz: the wicked witch of the East feared Oz enough to use one of the precious uses (out of 3) of the winged monkeys against him.
Edit: It is very likely that the good witch of the North also didn't know who Oz really is, because she suggested Dorothy to travel and seek his help.
Comment: Well, that addresses the Witch of the East... But doesn't say anything of the other witches.. Especially Glinda and her all-seeing book. And, things between them being what they were, I doubt the Good Witches shared info with the Wicked Witches...  LFB may have back-filled it later, but the book is still part of the canon.


Is it a good idea to use Normalize.CSS in every website?

Question: For tablet and other mobile devices, new browsers are popping out like mushrooms, and it's practically becoming very difficult to test the rendering of every website we design on all such browsers. Is it a good idea to use Normalize.CSS on every website?
Answer: It's just a tool. You need to evaluate whether or not it's appropriate to use for yourself. For any given project, you might be using some other elements that conflict with it, for all we know. It's a handy library, but nobody can really make a blanket statement that you should/not use it for every project you do.
Answer: I like to use Normalize.css whenever I possibly can on a new project. It's better than Eric Meyer's CSS Reset in that it actually provides "standardized" styles for elements, as opposed to removing all styles.
So yes, it's a great starting point for a new project. You'll want to ensure that the framework or CMS your using won't conflict with it, but it's a great resource.


Is there an alternative to MySQL?

Question: I'd like a lightweight database for my lightweight RaspPi.  MySQL seems a bit of overkill and involves too much administration.  I'll need one with a perl API.
Comment: Do you think that answers to this question will be completely subjective?
Comment: @Jivings I'm not sure what you're asking.  Do I believe that people will give only opinions and not facts? If others give preferences in their answers, who cares?  As long as they are factual and to the point, I'm interested.
Comment: I'm saying that the answer to this question could be based quite heavily on personal preference. All that means is that we need to keep an closer eye on it to make sure that answers are supported by facts.
Answer: You're in luck!  You should try SQLite.  SQLite is very lightweight and implements a large subset of SQL.  Your entire database is stored on a single file.  And there is a perl API.  Here's a link to SQLite's homepage ...
SQLite
To install only SQLite ...
sudo apt-get install sqlite

To install the perl API and SQLite (no need for the above) ...
sudo apt-get install libdbd-sqlite3-perl

You might want to consider DBD::CSV instead (or also) ...
sudo apt-get install libdbd-csv-perl

Comment: I think this answer should list more than just SQLite. There are many solutions.
Comment: Some comments about SQLite limitations when compared to MySQL would also be great.

Is there an alternative to MySQL?