How to start OpenVPN at boot on Raspbian Jessie

Question: While I can start OpenVPN manually with sudo systemctl start firstname.lastname@example.com ("server" being the name of my config file), trying to get OpenVPN to open automatically after a reboot after having set up the required symlink with the command sudo systemctl enable firstname.lastname@example.com failed.
Answer: TL;DR:
In /etc/openvpn/ your configs must end in .conf and not .ovpn!
Environment
I'm about to make some bold claims that are specific to...
pi@raspberrypi:~ $ uname -a && lsb_release -a
Linux raspberrypi 4.4.50-v7+ #970 SMP Mon Feb 20 19:18:29 GMT 2017 armv7l GNU/Linux
No LSB modules are available.
Distributor ID: Raspbian
Description:    Raspbian GNU/Linux 8.0 (jessie)
Release:        8.0
Codename:       jessie

(imaged from 2017-04-10-raspbian-jessie-lite)
Steps
1. For me it was enough to simply install OpenVPN via:
sudo apt install openvpn

2. Then copied my offsite-client.ovpn to /etc/openvpn
3. Then I enabled the service via:
sudo systemctl enable openvpn

4. This is the initial state of /etc/default/openvpn:
# This is the configuration file for /etc/init.d/openvpn

#
# Start only these VPNs automatically via init script.
# Allowed values are "all", "none" or space separated list of
# names of the VPNs. If empty, "all" is assumed.
# The VPN name refers to the VPN configutation file name.
# i.e. "home" would be /etc/openvpn/home.conf
#
# If you're running systemd, changing this variable will
# require running "systemctl daemon-reload" followed by
# a restart of the openvpn service (if you removed entries
# you may have to stop those manually)
#
#AUTOSTART="all"
#AUTOSTART="none"
#AUTOSTART="home office"
#
# WARNING: If you're running systemd the rest of the
# options in this file are ignored.
#
# Refresh interval (in seconds) of default status files
# located in /var/run/openvpn.$NAME.status
# Defaults to 10, 0 disables status file generation
#
#STATUSREFRESH=10
#STATUSREFRESH=0
# Optional arguments to openvpn's command line
OPTARGS=""
#
# If you need openvpn running after sendsigs, i.e.
# to let umountnfs work over the vpn, set OMIT_SENDSIGS
# to 1 and include umountnfs as Required-Stop: in openvpn's
# init.d script (remember to run insserv after that)
#
OMIT_SENDSIGS=0

I did not need to change anything. (Though I did uncomment AUTOSTART="all" when I was losing my mind, I changed it back and rebooted to confirm the statement If empty, "all" is assumed.)
4. I lost my mind reading 2 dozen articles explaining everything about installing EasyRSA and everything else that was redundant to step #1.
5. I realized that I left the wrong extension on my config and did:
sudo mv /etc/openvpn/offsite-client.ovpn /etc/openvpn/offsite-client.conf
sudo reboot now

And all was well.
Comment: @Rebroad it may not require a reboot. You could probably just do `sudo systemctl stop openvpn` and then `sudo systemctl start openvpn`. But it really depends on what your goal is. I wasn't concerned about uptime. I was concerned with being assured that I could put this RPi in the mail and when my client plugs it in, it will phone home and not need a keyboard and monitor to be connected and not require me to coach them on how to fix it.
Comment: This is fine, but it's a client setup, whereas the OP seems to have been asking about the server.
Comment: Great answer - but it would be even better if it didn't require a full reboot.
Comment: @AtomHeartFather I realize the OP was talking about the server when they asked the question 2 years before I answered it. But, they didn't specify that in the title, and this is where google brings people. SE is much more about the community that comes after, than it is about the person who asks the original question.
Answer: I solved it. It turned out what was blocking OpenVPN from starting at boot was the local IP. The steps I took to make this work were:

Commenting out the local IP address in /etc/openvpn/server.conf
Switching to root with sudo -s
Adding @reboot systemctl start firstname.lastname@example.com to root's crontab
Comment: Hi. I don't understand how the repeated call of `systemctl start` upon boot should improve the behaviour over one `systemctl enable`?
Comment: You may be right. After commenting out the local IP address in the config file, there may be several ways to start OpenVPN automatically after a reboot. Before I discovered that the local IP prevented OpenVPN from starting, all my previous attempts, including `systemctl enable` failed. The problem was OpenVPN trying to bind to it before the network connection was established (see https://bbs.archlinux.org/viewtopic.php?id=183818).
Comment: `@reboot` is the time when the cron daemon starts. Could it be that this might be before some other services are started via `systemd` such as network? In this case the solution would not be robust. (Just guessing here.)
Comment: I don't really know. However, `sudo systemctl enable email@example.com`  (which I tried first) didn't work either. The local IP certainly got in the way also there.
Comment: Using a cron job may get it to start, but it is the wrong way to do it. I'd like to see this get a correct answer. I'll keep searching.
Answer: I manage my Pi 3 jessie with Webmin ( don't ask! ) and I found the removing the "local" line was sufficient to enable the VPN server to start.
Answer: To me openvpn starts well via systemctl only if I configure static IP of eth0 in the /etc/network/interfaces. Unfortunately this causes double routing entries in the table as the new mechanism for configuration of interfaces is via dhcpcd.
Working, but bad solution is to remove manually doubled entries on boot.
I added static configuration in dhcpcd.conf. I changed target of the openvpn init script to network-online instead network but it is still not enough. I checked in logs that dhcpcd set the IP of the eth0 five seconds after openvpn fails.
A working solution is to deactivate dhcpcd:
systemctl disable dhcpcd.service
and edit /etc/network/interfaces
iface eth0 inet static
 address 192.168.0.x
 netmask 255.255.255.0
 gateway 192.168.0.y


Audio playback: part of song is skipped

Question: I am experiencing some problems with music playback after upgrading to Ubuntu 12.10.
Basically some of the songs stop playing after some time as if the song has ended. It's always the same songs and the same time. The weird thing that it happens with Clementine and Totem but VLC doesn't have this problem and it also plays as it should on Windows. I'm guessing there might be a problem with some library that's shared with by the first two applications. I don't know if it's relevant but the file format of the audio files is flac(don't know if the problem affects mp3, because I don't have many of them).
Answer: I still haven't found the reason behind this issue but at least I have found a workaround.
I just decoded the file using flac -d and encoded it again with flac -e and it plays as it should.
As I have said before I'm not sure if this affects mp3's, obviously if it does this workaround wont work since mp3 is a lossy format.
Answer: I've been having the same issue, it seems to be a GStreamer problem, VLC doesn't have an issue since it doesn't use GStreamer, whereas Totem and Clementine do. I've found the command-line program gst-play-1.0 also does this. Here is the output for a song that has this issue. I have reported this as a bug here.

Audio playback: part of song is skipped


Why are rear wheels not placed at the extreme rear of a bus?

Question: In some cars, I have noticed the rear wheels are located at the extreme rear of the vehicle. However, I have noticed that the rear wheels of buses are always located about 1/4th of the way forward from the rear. What is the reason for this?
Comment: I'm sure there are many factors, but a big one is that the further back the wheels are, the larger area the bus needs to turn.
Comment: In quite a few cars, the rear wheels are "always located about 1/4th of the way forward from the rear". Let's just call such cars an estate. Estates are long and have a high payload, just like buses. And now compare again to a car with the rear axle at the end of the vehicle, like an Aygo. See the difference?
Comment: Is the fact that most buses are speed-limited relevant here? I imagine it might not be a good idea to use this on a high speed road vehicle, but I know next to nussing about engineering and physics.
Answer: Some ideas:

Wheel Load Distribution: The load is greater on the rear wheels providing the power; more force on the front ones bring no benefit and would provide less traction.
Better manoeuvrability from having a shorter wheelbase.
Better Ground Clearance in some conditions, especially for bumps and or up a increasing slope for instance.
Better Driving: The front wheels now turn around a point closer to the C.G. than with the rear wheels. Not good with vehicle dynamics but this appears better than the rear end 'trailing' behind.
Structural: As some people have pointed out, it's better to balance the weights on either side of the axle (think beams). You have a (basically) point load for the engine and a distributed load for the rest of the bus. Rather than placing it all on one side, you can distribute it to reduce the ultimate loading.
Comment: The above are great from a physics standpoint, but from an engineering standpoint there are factors constraining the drivetrain overall length.
Comment: @ja72: There are techniques for extending dravetrains to very long runs. After all, we've been building boats with super long drive shafts for ages. The physics makes a shorter drivetrain preferable. Just like all the points above.
Comment: You can have a long hollow shaft of large diameter (for stiffness and low weight) in a ship, but size constraints limit the diameter on a bus. So to get the desired stiffness you need to reduce length.
Comment: The load distribution decreases the wear of tires too. What you say, @mikefoxtrot
Comment: Anyway, people experience more jerk or shock sitting in the back seats.
Comment: I used to work in the transportation industry. in there, most of the time, axle/bogey location is varied to manage the weight distribution over each wheel.
Answer: I think one of the reasons is structural. The bottom on the bus is like a bridge with long steel beam running the length, and if the supports are at the ends the stresses and deflections would be too high. By moving the wheels more towards the center of gravity in reduces the flexure of the center of the bus.
In addition the driveshaft can be shorter which means less flexure and less wear.
Comment: In the UK, buses typically have their engine at the rear, so moving the wheels away from there *increases* the driveshaft length.
Comment: The shorter unsupported spans require less metal, which reduces cost and weight, while retaining structural strength.  This combined with the better handling characteristics (particularly in regards to turning sharp corners and running the side of the bus into people and posts) means that the best position for the rear wheels is well away from the rear, and closer (but not directly under) the center of gravity when loaded with passengers.
Comment: Those brits, with their left hand screws... ;-)
Answer: Front axle load is an important consideration.  It's hard to carry a lot of weight on an axle that steers, as you are effectively limited to single wheels, and you want to minimise the power assistance needed to actually turn the steering wheel.
Answer: The answer is a combination of factors. Weight has a great deal to do with the positioning of the rear axle. If you assume that the bus has a full load of passengers, you'll want the power to the rear wheels closest where there is weight. Larger buses have dual-axles/wheels to accommodate the extra weight, but the positioning of the axles often remains the same. Some heavy-duty dual-wheeled trucks have the rear axle closer to the rear of the vehicle to compensate for the loads they will carry. (trailers, recreational vehicles, etc).  Conventional passenger buses need a shorter wheelbase, and a heavy-duty single rear axle. It's a compromise between weight, ride and fuel economy.
Answer: There are lots of factors but I'd say the two major factors are:

Drive Shaft Length - A very long drive shaft causes various engineering problems so there is some pressure to minimize the length.
Maneuverability - Longer wheelbases cause problems mostly in making turns in tight quarters. The longer the wheelbase the bigger the difference between the track of the front wheels and the rear wheels. So the fronts go around the corner fine but the rear wheels go up over the curb and take out the light pole.
Comment: In the UK, buses usually have the engine at the rear, so moving the rear wheels forwards *increases* the driveshaft length. But the rear wheels are still usually some distance from the back of the bus.
Answer: Think about how you would support a long, flexible beam (or a 30cm ruler, if you prefer). If you put the supports at the ends, the beam will sag in the middle; but if you put the supports at 1/4 and 3/4 of the length, the weight of the beam between the supports will be counterbalanced by the weight of the beam outside the supports.
Of course, there are a lot of other factors involved in designing a vehicle, but the tiny cars with wheels right at the end are the oddities.
Answer: Its most likely a combination of reasons.
Steering behavior and traffic disruption:
Having the axle at the very end of the bus :
Will drastically change the steering behavior or requirements by making the bus' front and rear axles drive along a smaller radius or tighter turn. This can cause more (quantity and/or severity) disruption to other traffic.
The driver must drive way further forward before starting the turn, otherwise the rear wheels will quickly go beyond the lane the bus was in. This can mean drifting over the center of an intersection (possibly in danger of hitting traffic on the other side) if making a left, or hitting curbs (and possibly more damage to street structures, buildings, people, etc.) if making a right at an intersection. Naturally, having to drive further forward will block more lane(s)/traffic in that same direction until completion of the turn.
Having the axle further up:
Will allow the bus' front and rear axles to travel along a bigger radius. This allows the bus to make "smoother" turns, allows the bus to start turning sooner, and allows it to stay more within its own "lane" while turning.

weight distribution and regulations:
I used to work in the transportation industry.
Axle/bogey location is move-able solely to compensate for weight distribution over the wheels. They must make sure that each wheel carries below a certain threshold level of weight in order to be allowed on the streets. If they can't make it work, then they add more axles to distribute it even more. This is enforced with weighing stations and the like.
CalTrans
http://www.dot.ca.gov/
<code>GENERAL RULE

35550. (a) The gross weight on any one axle shall not exceed 20,000 pounds,
and the gross weight upon any one wheel, or wheels, supporting one end of an
axle, shall not exceed 10,500 pounds.
</code>
I believe the streets and freeways can only take so much localized pressure before they start to get damaged.
Answer: Most busses in the U.S. use a rear engine/rear drive layout, with the engine located behind the rear axle for ease of maintenance.  There is no drive shaft per se, because the engine/transmission/rear axle are integrated.


Can a New Zealander get a multi entry visa for Zimbabwe on arival?

Question: I will be landing in Victoria Falls and starting a truck tour which goes through Zambia and back into Zimbabwe. When I called the Zimbabwe embassy in London, they said that I will need to get two single entry visas at the border ($50 each). They didn't want to give me any info on multiple entry visas. Is it possible to get one at the port of entry?
Comment: Apparently there is also a "double entry visa". And one tour site says multi entry are not given at port of entry, but only in the town office. Not sure on either of these.
Comment: I've been doing a lot of reading on this recently and it looks like pot luck. Two singles are only marginally more expensive than the double anyway, it was only really for the convenience of a quicker second entry. I'll post how I get on in October when I get back.
Answer: According to the Zimbabwe Embassy in the US, NZ can get a multi-entry visa on arrival.
Find New Zealand on the list here.
You can find the prices here. Currently it says 95USD for a multi-entry visa.
Comment: If I was crossing three times that would be good value as a single entry is 50USD but hopefully it should make the second crossing nice and speedy.
Answer: When I landed at Vic Falls the options I was given is $30USD for single entry or $45USD for double entry. The prices were the same for the Americans, Swiss and Germans I spoke to in the queue.
A point to note, there was one immigration officer charging people for a double entry and placing a single entry visa in there passport and writing them a receipt for a double so it pays to check the visa as its going in.


How are intersections between two numbered streets named in New York?

Question: There are a number of places in New York—for example, Manhattan, Park Slope, and northwestern Queens—where the streets running in both directions are numbered. What's the convention for which number is given first when you're naming an intersection? For example, is "Third and Fifth" 3rd Street and 5th Avenue or is it 3rd Avenue and 5th Street? Is there a different convention in each of the places where there are intersections like this?
Comment: This question appears to be off-topic because it is not about travel.
Answer: Honestly? There's only a few dozen intersections where this sort of ambiguity is a thing; while Street, Avenue is the most common usage, I've heard the reverse often enough, as have most New Yorkers, that if you're talking about an intersection of two single digit roads, you're going to qualify/classify it.
There are a variety of reasons that this doesn't matter much elsewhere in New York.
In Manhattan, it's because Avenues only go up to 12, and there are some 200 crosstown streets; the West Village and it's peculiar bending of the grid and named streets means that you have very few intersections of numbered Streets with numbered Avenues south of 14th. (Specifically, you have two 'First and Seconds', and a pair of "Third and Sixths". That's it. You can confirm that on a map if you like.)
In Brooklyn, you have several separate street grids. Numbered streets intersect with named streets in Williamsburg and Greenpoint, but be sure to remember the North or South designation. Over in Park Slope, you run into the only real potential source of confusion -  but they're all within a fairly small 5x5 block area - it's not a huge issue. In South Brooklyn, the intersecting streets are numbers and letters, so again, not a problem.
Finally we have Queens. Queens is, to the uninitiated, a total mess. The thing to understand about Queens, is that you can have as many as 5 streets with the same number running in parallel to each other, and another 5 running perpendicular across the entire borough. In Queens, you'll never give a location as number and number, because the suffix (Street, Avenue, Road, Drive, Court, Place, Terrace, Crescent, etc.) is essential information in the address.
To use your own example, there is literally no such place as "Third and Fifth" anywhere in NYC anyway; and most other, similar examples you might contrive don't actually exist to cause the confusion you'd imagine that they could. It generally doesn't matter, because for the vast majority of cases, the numbers themselves imply where the pair meets.
Comment: *Queens is, to the uninitiated, a total mess.* - Amen to that. :)
Comment: @puri but even in those neighborhoods, you have Avenues running parallel to Roads and Streets running parallel to Drives. Unless a named street is involved or a suffix is provided, purely numerical coordinates will always be ambiguous.
Comment: @Karlson In fairness, to the initiated, the scheme makes *a ton of sense* and has a whole lot of charm in it's internal logic and orderliness!
Comment: Personally I hate that scheme in Queens I find it annoying...
Comment: In certain neighborhoods in Queens—such as Woodside, Jackson Heights, or East Elmhurst—the intersection of numbered streets is almost always unambiguous because the street numbers are higher than avenue numbers.
Comment: @LessPop_MoreFizz That's why I said almost always. For example, 35th Road and 37th Road in Jackson Heights are really short so 37th means 37th Ave unless noted. Also local people there do use the numerical coordinates.
Answer: In Brooklyn for example, addresses are designated as follows:
1350 50th St

The 13 designates 13th Avenue, meaning that this location is on 50th street, on the block where it intersects with 13th Avenue.
On the other hand, the corresponding location on 13th Avenue would be:
5050 13th Ave

The 50 designates 50th Street, meaning that this location is on 13th Avenue, on the block where it intersects with 50th Street.
If so, either way would be appropriate, depending on your point of reference: If you're talking about a place on 13th Avenue, you'd say 50th and 13th, but if you're on 50th Street, you'd say 13th and 50th.
Some areas in other parts of NYC have similar addressing schemes - when possible, I'd say let the address be your guide. Unfortunately, as other answers have noted, in certain parts of NYC, particularly Queens, all bets are off...
Comment: Actually, when it comes to building addresses, Queens has the most comprehensive, widespread, useful and consistent scheme in the whole city; however, this question is about designating intersections specifically, which is a whole other ball of wax.
Comment: Yet yourself remarked: _Finally we have Queens. Queens is, to the uninitiated, a total mess_ - and the OP is obviously **uninitiated**, as am I, when it comes to Queens!
Comment: with respect to street *naming?* absolutely! it's Byzantine and confusing. Addresses however, are another matter entirely xxx-yy ZZ St/Ave/Rd/etc., where xxx is the nearest intersecting street, and yy is the number of buildings between the address in question and that street.
Comment: Provided you know if you're talking about street, avenue, road, drive... or whatever else they have out there... :)
Comment: which is why the whole address is so important... And why for the purposes of *this question*, Queens is a mess. :P
Comment: _Queens is a mess_ - I know. And lived there for a while - never did get it straight. Now I just avoid it - I'm afraid I'll go in and never get out... Brooklyn was hard enough, but now I've got it down pretty good - only took me ten years...
Answer: Avenues run uptown and downtown, streets run crosstown. At least that is how it is in Manhattan. So if you were downtown at lets say 1st Ave and 1st street, you can take 1st ave all the way uptown to 100th street. (it goes further than that, but I think you get the point)
In Brooklyn you have the same kind of setup. Main avenues running down the streets. So it would go something like E24th st & Avenue J.
Generally the lingo for NYC streets is dependent on where you are. In my mind, I have always gone street-ave. So I would interpret that as 3rd street and 5th ave, but I can easily see someone like a cab driver getting that messed up if you say third and fifth. Whenever I get in a cab I always give the more specific street first, followed by the intersection. So if I was going to Grand Central, I would say (normally grand central but for these purposes) 42nd & Park.
Edit :
Think about an address, the more specific part comes first, and then the broader location. So you say Albany (specific), New York (non-specific). Apply the same concept to streets. There are only a handful of avenues but there are a lot of streets.
Comment: "42nd and Park" isn't a great example because there's no ambiguity…
Comment: @bdesham right was using an unambiguous example for the format. But like I said if someone told me to meet them at 3rd & 5th I would go to 3rd street and 5th ave. But truthfully most of the time I will probably clarify, because as you can see it is easy to get that mixed up.
Comment: @bdesham updated answer for a better explanation
Comment: @Adjit - I'm a lifelong NY'er, and if someone told me to meet them at 3rd and 5th, I'd think they meant 3rd Avenue and 5th street, but there is no such place - 3rd Avenue doesnt' go down that far. So... :)
Comment: @comeandgo lifelong nyer as well. I guess there is really no right answer to this. Just a matter of who does what
Comment: @Adjit - **Fagettaboutit!**


What happened to Tohorot?

Question: As I understand it, all of Tohorot has been reduced, in modern practice, to Niddah and some hand washing. The entire structure of transmittable 'uncleanliness' is inoperative. Why is it inoperative? Because there's no Temple, and so no ashes of the parah, to get anyone into a definitively tahor state?
Comment: @ba Not sure why it matters where they are written, but Tumah plays an important role in determining [how many times one must wash their hands](http://judaism.stackexchange.com/q/9856/759), what can ruin the washing, for how much bread must one wash, and as you said dipping one's hands into a mikvah.
Comment: By "hand washing," do you mean Mikva'os? (Laws of washing the hands before meals are in Brachos, I think.)
Comment: @DoubleAA I thought he was referring to Seder Taharos.
Comment: @ba I think laws of washing hands before meals are in Chulin
Comment: Actually, looking through the Be'er HaGolah in Shulchan Aruch, I see most are from the eigth chapter of Chulin and Yadayim, with a little scattered in from Brachos.
Answer: It's actually almost entirely still operative. People and utensils transmit and accept impurity just like they always did. What has changed is a lack of impetus to purify one's self in most instances. There are essentially three ways of overcoming a given impurity:

Metzora's Korbanot: A Metzora is impure and he can only become pure again by bringing certain Korbanot in the Beit haMikdash. This latter impurity is the one that is mostly inoperative because no one can become a Metzora without being declared such by a Kohen and this doesn't happen currently both because we aren't so sure who is a Kohen and because we aren't so sure what shades of white qualify.
Parah Adummah (Red Heifer): One who became impure from a corpse can only become pure through being sprinkled with the ashes of the Red Heifer. We currently don't have any of those ashes available.
Mikvah: This works on just about everything else and we still have it. In most cases though it isn't worth using as one will remain impure from the currently unsovable corpse impurity which we assume we all have (a pretty good assumption). It is still utilized to remove a category of impurities called Tumot HaYotz'ot MiGufan (impurities related to bodily discharges) which can be undesirable for other reasons (prohibition of sexual intercourse with a Niddah or Zavah, prohibition on entering the external parts of the Temple Mount for all (with possible exclusion of Keri), possible rabbinic prohibition on learning Torah/praying for a Baal Keri, rabbinic prohibition on Baal Keri Kohanim eating Challah of the Diaspora). Other than that, no one really minds remaining impure from most things, because going to a Mikvah won't change their status practically. (Technically there are different levels of Mikvahs for different things, but they are all possible nowadays.) Without being able to become fully pure and do things like eat Terumah and Challah, offer most Korbanot and enter the inner sections of the Temple Mount, most people are not careful about contracting most impurities. This is not a new phenomenon, see https://judaism.stackexchange.com/a/20280/759 for more.

The laws that accompany Taharot have a number of applications to other areas of Halacha. Sechach for instance can not be a vessel which would accept Tumah. Produce in Yerushalayim must come in contact with a liquid before having Maaser Sheni seperated from it. Kosher Mikvaot are needed for vessels bought from non-Jews (this is not an impurity concern). Hand washing before bread as you mentioned has some related concerns, including what amount of food requires washing. Male Kohanim are prohibited from contracting corpse-related impurity (this has lots of applications). There are likely some other small points which I am not thinking of now.
In the meantime, by learning the Halachot of Taharot it should be considered as if we kept them.
Comment: +1. Note that a Metzora is not the only one who can be [מחוסר כיפורים](http://he.wikipedia.org/wiki/%D7%9E%D7%97%D7%95%D7%A1%D7%A8_%D7%9B%D7%99%D7%A4%D7%95%D7%A8%D7%99%D7%9D).
Comment: Whoa someone discusses it. See Sheilat Yaave"tz 1:136
Comment: @Fred You are right! However, Metzora is the only one of those who can't even get rid of most of his Tumah without a Korban. Though I see I said BHMK specifically in my answer...which makes me wonder: can we perform the birds/bucket procedure nowadays (assuming we had a real kohein and a real metzora)?
Comment: Regarding schach, see http://judaism.stackexchange.com/q/46211/5323 + http://judaism.stackexchange.com/q/20206/5323
Answer: A large part of your answer is already suggested in the question - since the purification process for contact with a corpse is not possible nowadays. Another important point is that even in the time of the Temple, observing a state of purity was only required in order to eat sacrificial/holy foods, and since we don't have these it's not as important to remain ritually pure.
[It's worth noting that even nowadays Cohanim do make sure not to become impure by coming in contact with dead].
Comment: Related: http://judaism.stackexchange.com/questions/10976/can-you-become-more-tamei-if-not-why-do-we-worry-about-it-today

What happened to Tohorot?


Use mean value theorem to prove the following

Question: Use the mean value theorem to prove that:
$$\cos(x)>1-\frac{x^2}{2}$$ for all $$x>0$$
Answer: I thought there may be better way than my answer... But I'll stick on my answer.
apply mean value theorem on $ f(x)= \frac{x^2}{2}+ \cos x $
since $f(0)=1$, we have some $ x_0 \in (0,x)$ such that
$ \frac{\frac{x^2}{2}+ \cos x -1}{x} = x_0 - \sin x_0 >0$
since $x>0$, we get the results.
Answer: okay...so this is my contribution
let $h(x)=cos(x)+((x^2)/2)$
the derivative of $h(x)=x-sin(x)$
for all x>0, the derivative of h is greater than 0.
i.e. $x-sin(x)>0$
let a,b be subsets of x>0, then there exist an number c such that the derivative of c is
$(f(b)-f(a))/b-a.$
let b=x and a=0 from the interval x>0.
hence, we have $(f(x)-f(0))/x-0=(cos(x)+((x^2)/2)-1-0)/x-0=$the derivative of c
but the derivative of c is greater than 0.
therefore, (cos(x)+((x^2)/2)-1)/x>0
           (cos(x)+((x^2)/2)-1)>0
this implies that cos(x)=1-(x^2)/2).PROVED.


Removing spots of tempera paint from rough sawn cedar board ceiling

Question: I've read the thread on removing paint from rough sawn wood but it doesn't exactly address my situation. My daughter painted some designs on the ceiling of her room with some kind of tempera-based (I think) fluorescent paint. the ceiling is rough sawn red cedar and unfinished. I don't plan (or would prefer not to) paint the ceiling as it is a log house and the bare wood look is something I want to keep. I am concerned to find a method of removing these painted spots with minimal impact to the color or texture of the boards. So, for example, if  there were some method of wetting the paint and soaking it out, that would be great. Alternatively, I am considering wire brush, but I think that will make a noticeable difference in color and texture of the wood, which has naturally darkened over the years.
Comment: I'm afraid you're not going to be happy with any solution here. This is one case where prevention most definitely would have been preferable to cure. I think you need to prepare yourself for the inevitable here: either you can't get all traces of the paint out or you will noticeably change the wood. And unfortunately it might be both :-(
Answer: I suspect Graphus may have some insight on this.
Tempura paints are waterbased and should dissolve with soap and water. I would start by wire brushing it to remove as much dried pigment as possible. I would then attempt to remove it by gently wetting it with soapy water repeated several times. You may be able to reduce the risk of pigment soaking in further repeated rinsing and vacuuming it up as you go.  The fact that the surface is upside down on the ceiling may help draining the water away from the board as you go. I suspect however, that some staining will remain and, in the end, the texture of the wood surface will differ from untreated areas. Even if you remove the pigment, the water stains may leave a visual stain on the board.  If so, you may have to wet the entire area to get an even appearance when it dries.
If you are very concerned, you may want to create a test panel duplicating the problem, let it dry for a few days and then test cleaning approaches on it.
Comment: Deep-fried paint hehe (tempura).


Incremental backup of an iPhoto 09 library

Question: I want to backup my 40Gb iPhoto library to an external USB drive.  Due to the large size of the library, copying the whole thing each time is impractical.  As the external drive is rather small, I cannot use time machine.  Is there any easy way of doing of making an incremental backup or mirroring my home drive?  I am using OSX Version 10.6.2.
Answer: Time Machine would be the first choice, I would think. You can browse Time Machine iPhoto backups from within iPhoto '09 itself (File menu).
SuperDuper! or Carbon Copy Cloner would work as well. You could back up your entire drive to the external and boot from it in the event of a disaster.


What is the coolest thing you have done with threads?

Question: Just wondering
Answer: I made them work as I wanted once ! That was cool!
Answer: I don't know if this counts, but for me a working multithreaded software is fascinating in itself, not so much the purpose they achieve. You have like 10, 20, 100 workers working in your program with the same infrastructure (Singletons, files etc.). Having everything work in harmony with mutexes, semaphores, context switches etc. is wonderful to observe, like being a manager and your team is working perfectly together. You read the application log, see the threads cooperate for a common goal, and it's just great. Can anybody relate to this feeling?
Comment: It's like looking at an ant farm that you programmed, just the most addictive thing one can have in terms of programming !!!
Comment: Totally agree with you! It's an addictive feeling!
Answer: I'd love to say that I've cleverly parallelized an algorithm using lock-free data structures in order to get n-fold performance increase on an n-core processor. But I've never had a practical need, especially since most of my professional code has been for single-core systems.
Almost every time I've used more than one thread, in any language, it has been one of two reasons:

the system (or a third party) offers a blocking API and I need an asynchronous one (or at least to let several ops run at once).
to take advantage of pre-emptive priority-based scheduling to keep everything nice and responsive without having to chop all my slow operations into tiny pieces by hand.

Necessary, but not what you'd call glamorous.
Answer: I'm so useless with threads, I have to get my girlfriend to sew my buttons back on.
Answer: We once wrote a multithreaded application that essentially read a file line by line and did a lookup in an internal database to see if there was a match, appended some data and moved to the next line.  The complexity though was that there could be multiple files processed at the same time, and multiple records per file could be searched. There was a manager class that knew how many threads were available and was responsible for divding out available worker threads to each file (if there was only one file to be processed it would recieve all 40 threads, if there were 5 files, depending on priority, each would recieve a fraction of those 40).  We used Async delegates at first but noticed it would be hard to catch any exceptions that may occur in the async threads so we used the traditional thread start in .net.
The key to this was having a collection of ManualResetEvents in the manager class that was comprised of ManualResentEvents that were public proprties in the worker classes(threads).  When a worker thread would finish it would signal it's ManualResetEvent which would be picked up by the .WaitAny() on the Manager class.  The manager would then know that one of the threads was finished and would start a new one.  In reality it was a little more complex than this but this was the core of what it did.
The hard part was unit testing this to ensure that at any given times the correct number of threads were running.  We had tests that would act as if there was only one file in queue (gets all 40 threads), then another file was introduced and the allocation of threads would have to cycle down to 20 a piece for the two files.  We had "Mock Objects" that essentially had a thread sleep parameter that we would pass a value for (in ms) to control how long each thread would take to process so we would have a good idea of when to do our assertion or interrogate the file processor to see how many threads, records, it was currently processing.  There were also tests that would have two files running with 20 threads a piece, then one file would finish and as all the record threads would finish on the first file they would be reallocated to the second file to help it finish faster.
I'm sure this isn't the clearest explanation of what we actually did, I really need to write a blog post about it.  If anyone needs more information on it please contact me, I'll try to answer as best I can.
Answer: I have recently been hired to help with a quite large and complicated multithreaded application running on Microsoft Windows systems, with reader/writer locking objects. That made it difficult to search for deadlocks, so I wrote a deadlock detection object executing in its own thread that was sent information messages (with PostThreadMessage) from the locking objects whenever they were attempting to lock, succeeded or failed to lock, and unlocked.
By looking up the different threads and the shared locks and their state in a truth table it was then possible to without any doubt pinpoint the cause and location of the deadlocks.
Answer: I figured out that I can create a FIFO, with ONLY ONE WRITER AND ONLY ONE READER, without using any synchronization instruments.
( so a master-slave with 2*n FIFO .. without any mutex / semaphone !! )
If you have a long linked list, you don't need to synchronize for inserting at one end and removing at other end.
The trick is to keep always one element in the list (-;
the code is really small
My pride was 'dented' when a hardware guy told me ..that's obvious (-:
Answer: One of the most interesting things I have done with threads was write a multi-threaded application to solve a maze.
While it's nothing ground breaking, it was definitely interesting.
Answer: I create a windows service to consult a bunch of RSS feeds and store the information retrieved in a database. Since the application can contain a lot of RSS feeds, a pool of threads queries every n times packets of RSS. Like Thorsten79 comented, the most exciting part is watching your threads cooperate and work together as a team.
Answer: Distributed link checking system for a web crawler.  Since web crawling is a very easily threaded solution I don't know if that counts...
I did write an algorithm to crack DES when I was in college that ran on a custom 256 CPU machine at the University.  That was pretty neat, but was really just a divide and conquer type of problem.
Comment: Totally agree - crawlers are probably the simplest (and IMHO at least) most fun to write as threaded applications - it balances perfectly the I/O bound nature of each request with the ability to dramatically increase throughput.
Answer: Ian P, Mind to elaborate? AFAIK you don't need to use threading to solve a maze, unless, of course the maze is so complicated that the wait time becomes so unbearable that you have to add in status bar so that the users would not get bored and thought that your program hangs.
Answer: Oh -- they were not complicated mazes.
The mazes were defined in an array, similar to this:
String[] MazeArray = new String[5];

MazeArray[0] = "---X---X-------XF";
MazeArray[0] = "-X-X-X---XXXXXXX-";
MazeArray[0] = "-X-X-X-X-X---X---";
MazeArray[0] = "-X-X-X-XXX-X-X-X-";
MazeArray[0] = "SX---X-----X---X-";

I'd spawn a new worker thread when there is a fork in the path, and have that thread investigate that path. Then, through some basic logic, I could determine the shortest path, longest path, etc.
The example listed is obviously over simplified, but it should illustrate the point. It's a fun exercise, you should try it if you have a few minutes to spare.
Ian
Comment: So how did the other four rows of MazeArray look like? :) (ie. check your indices)
Comment: haha -- sorry, copy/paste won that one.
Comment: Hummm, quite interesting. Solving a problem that would be a typical recursion problem with threads. Quite amazing !!
Answer: Well this is really vanilla, but it's a nice stepping stone toward more creative threading:
In upload-new-data-and-process-it-for-me type requests, the request thread accepts the data and throws it in a queue, and the user goes on their merry way.  One or more background threads continually dequeues items and processes them in some way.
Answer: I wrote a small fcgi servlet model in C++ which allocated a new thread instantly for each new request.
If you don't think thats cool, you should see what happened when i pumped 3K req/s through it. I accidentally forgot to clean them up, and even thou they all self terminated and stopped actually using memory, they still consumed addressing and I had the app quicky reseve more memory than I had and cease to create threads.
( I was on 32bit at the time and it literally stopped after creating 2^32 threads. Goodness knows what it would do with 64bits )
Also, I created a multi-threaded ( well, forking ) breadth-first fork-on-directory replacement for the famous command rm -rf . Mainly I was frustrated with rm -rf seeming to wait for IO to respond with a yay/nay response, which made it slow on some directory structures ( such as squid caches ). The only real caveat of this code is it only had entertainment value, and if ever used on a whole filesystem, it would be a race between 2 scenarios:

Disk being wiped making it unusable, and possibly erasing the commands that permitted you to tell it to die.
The system "Fork Bombing" due to the massive fork rate and making it so highly operation intensive it no longer even responds to commands.

And in the case of "fork bombing" the massive spawn rate could result in the recursive rm stopping itself ( or hit the Ulimit if any )
Answer: A simple client server with asynchronous input/output.
Answer: I guess implementing multi-threading for dos was a coolest thing i done with threads ..
Answer: I created a threading library with lock-free intertask communication to simplify multithreading programming. Delphi only: OmniThreadLibrary.
(To give credit where it is due - I didn't write the lock-free structures, GJ did.)
Answer: I wrote a multi-threading library for HDOS. HDOS was an 8-bit OS that ran on HeathKit systems. I intercepted the system clock tick (Every 55 millseconds, if I remember correctly) and had a scheduler that would decide which thread to run next in a round-robin fashion. Of course since the OS itself was not multi-threading, only one thread was allowed to be in the OS at any given time.
I never did anything useful with it. It was just a fun project I decided to tackle to see if I could do it.
Answer: I wrote an image filtering framework in Java that uses thread pools.
I was surprised how much faster the filters run in multiple parallel threads even on a single processor single core machine. When I find some free time, I want to actually figure out why that is; all I'm doing is accessing memory and mathematical computation.
Threads rock (as long as they don't lock.)
Kudos to Java thread pools, too.
Answer: I wrote a lock-free cache that's 10x faster than the most common, lock-based, caching library. It was really interesting to figure out how to do complex CASing logic and come up with an alternative to LRU that didn't suffer suffer locking overhead.
I also wrote a distributed master-worker framework, which I later prototyped abstractions to support fork-join and map-reduce. I need to redo those at some point, as they weren't production quality, but it was quite a fun diversion.
I'd really love to write a SkipList data structure, just to learn how. There's already a core implementation, but its such a cool and simple idea I'd love to dig into it. It would be purely throw away code, but educational.
Answer: This isn't an application of multi-threading, but a small snippet that shows off C# 3.0 features including lambdas and object initializers. Not what you had in mind, I'm sure—but the "cooleset thing [I've] done with threads" nonetheless.
new Thread(() =>
{
    // do stuff in a new thread's context
})
{
    Name = "Thread " + GetHashCode().ToString(),
    Priority = this.threadPriority
}
.Start();

Answer: I made an implementation for quick sort where the left and right sides of the partition are sorted concurrently.  It was almost twice as fast as the same code using only 1 thread.
Answer: I wrote an implementation of actors/message passing for multithreading in C#, ever since I wrote that multithreading has been so easy! Writing that in itself was pretty fun, lockless data structures for message queues. There isn't a thread for each actor but instead a pool of threads which loops through the actors and runs each of them.
Since multithreading is so easy now that I have this system to play with I've written several cool things:
A simple socket server/client demo app
A multithreaded webcrawler (I'm going to go back to that one)
A procedural content generator for games
and some other things, but they're all small and boring
Answer: Multi-threaded calls to a (third party application) which does not support simultaneous calls from different apps or threads?  Although multiple instances could be executed (and this is how I eventually implemented it), certain applications operations could not be executed simultaneously on different app instances.
Answer: See this parallel N-puzzle solver. It solves the Npuzzle problem by iterative deepening searching forking grains to implement the search.  This is done in a parallel programming language I designed which makes it easy to fork grains; almost the whole magic in program is hiding in the "fork parallel" operator (|| ... )   You have to look for it in the code.


Continue the Pattern

Question: Another one of my puzzles to promote our school's webpage that has no answer yet after a week:
Answer: Not very solid logic but I would say:

 Answer C.

My explanation below:

 First and last column seem to be opposite sides of the dice and no other sides have the exactly same orientation (the 2's and the 3's are turned 90 degrees). So pretty much builds the pattern between 1st and 3rd column and use the 2nd one to not match the orientation of any single die.
Comment: I think you are essentially correct in your deduction, although OP probably was thinking about rolling the same, slightly non-standard dice on each row.
Answer: I would say that the correct answer is

 C

Explanation :

 The set seems to be a collection of all the different patterns you can get on the faces of a 6-face dice, allowing center rotations.
 Thus, you can have only one representation of 1, 4 and 5 as they remain identical when you rotate them, but 2 versions of 2, 3 and 6.
 The one that is missing from the set is therefore C
Comment: Hello, that is pretty much my answer though I saw another pattern that reaffirms it
Comment: Well, I only read the beginning of your answer (the part where you mention opposing sides) before posting my answer, so I didn't noticed they were similar (though " no other sides have the exactly same orientation" misled me because for me, every side has 4 orientation, which may share the same pattern, thus, it did not struck me of any similarity)
Answer: Current Answer (looks correct):
It is

The following explanation reveals why some faces of each die are rotated... it took me a while to come up with a plausible answer, so thanks OP for the puzzle. It was great! :D
$$$$
Explanation:
We will look at the faces below,

and compare it with a net of a single die; i.e.,

Look at the rows of the faces. The first row is

In the net...

 ...when drawing a line from the $4$ Face to the $2$ Face in the net, you want to then draw a symmetrical line from the last met Face (i.e. the $2$ Face). This will mean you have to draw a line from the $2$ Face to the $3$ Face, thus making the $3$ Face come last in the row.

Let's rotate the net $90^\circ$ clockwise ($90$ degrees to the right):

And look at the second row in the given faces.

In the net,

 ...when drawing a line from the $2$ Face to the $6$ Face in the net, you want to then draw a symmetrical line from the last met Face (i.e. the $6$ face). This will mean you have to draw a line from the $6$ Face to the $5$ Face, thus making the $5$ Face come last in the row.

Now we rotate the net once more, $90^\circ$ clockwise:

And look at the third row in the given faces.

Oh no!

There are only two faces in that row. So what is the last one?

Well,

 Using the same rules, we look at the net...   ...when drawing a line from the $1$ Face to the $3$ Face in the net, you want to then draw a symmetrical line from the last met Face (i.e. the $3$ face). This will mean you have to draw a line from the $3$ Face to the $6$ Face.

This means,

 The $6$ face finishes off the incomplete row. But it is rotated because we rotated the net!

Therefore,

 The answer is $C$.

Original Answer (probably incorrect):
The answer could be...

...either $B$ or $E$

$$$$
Original Thought:
Convert the numbers of dots on each die to, well, numbers.

$$\begin{matrix}\boxed4 & \boxed2 & \boxed3 \\ \boxed2 & \boxed6 & \boxed5 \\ \boxed1 & \boxed3 & \boxed? \\ \end{matrix}$$

Now we carry out the following calculations:

 $$\begin{align}4\times (2+1)\tag{for the leftmost column}&= 12 \\ 2\times (6+3)&=18\tag{for the middle column}\end{align}$$ so we have the pattern $12, 18, 24$ such that $3\times (5\,+\,?)=24$ (for the rightmost column).

That leaves the answer to be,

 $$\begin{align}?&= (24\div 3)-5 \\ &= 8 - 5 \\ &= 3.\end{align}$$

So now we know,

 The answer is either $B$ or $E$, because they each have three dots.
Comment: (+1) Wow! How long did you spend on typing this?
Comment: @TheSimpliFire hahah, I don't know — but it was long. I am convinced this answer is correct... well, I am hoping ;)
Answer: The answer is

 E

Explanation:

 Add the values of the first row: $4+2+3=9$ is odd.

 Add the values of the second row: $2+6+5=13$ is odd.

 This means that the total of the third row must also be odd, which eliminates A, C, D and F.

 For the first column, every single one has dots on the top-right and bottom-left, except for the bottom square.

 For the second column, every single one has dots on the top-left and bottom-right, except for the bottom square.

 For the third column, the top two squares have dots on the top-left and bottom-right, so the bottom square must not have these properties. Hence B is eliminated.
Comment: @user477343 I'm the total opposite. I don't know anything about blockquotes ;)
Comment: @user477343 Just realised that SE changed the colour of the comment upvoting button and the editing sign...
Comment: I have not looked at the other answer, but I am gonna have a go at this problem. With number problems like these, there seem to always be more than one solution :D
Comment: I didn't know you could write ``. I thought you could only write `` and some other block-quote command I don't remember :)
Comment: I think the upvoting button for comments is blue, now. The normal upvoting system (for questions and answers) use to be red, I think, once upon a time :)
Comment: Took a while, but I finally gave a plausible answer! ....I'm gonna listen to music and work on a riddle...
Answer: I think the answer is:

 F

Explanation:

 If you take a regular 6-faces dice and you begin with the first face of each row and you follow the path created by the second face from that row, you'll get the the third face:
 For example, the first row creates this pattern: 4 -> 2 -> 3 -> 5 -> 4 -> ...
 To explain it more, make 4 face up. Now rotate the dice to make 2 face up. Perform the exact same rotation again, and now 3 is facing up. Et voilà!
 Same works for the second row. And for the third row, that yields a standing 6, i.e. F.

 If you don't have a real dice, try to wrap your head arround this image.
Comment: This answer looks pretty good as well, though my answer is similar to yours. $(+1)$

Continue the Pattern


Can you be a Christian and serve in the Military?

Question: Can you serve in a military service and not violate the will of God?
Comment: @Sven If you look at the history you will see that this was already closed and reopened once as a duplicate.  The edits have made it a separate question.
Comment: @Nick - some folks would have an issue with the kind of submitting to the authority of the Government that the military involves (perhaps something about serving 2 masters).
Comment: [If the Ten Commandments say "thou shalt not kill" how can a Christian fight in a war?](http://christianity.stackexchange.com/q/49)
Comment: Didn't God ask the Hebrew people to destroy other nations?
Answer: This is a question on which Christians are divided. The vast majority adhere to the belief that fighting in a war is entirely justifiable for a Christian. They draw on several biblical sources for this, including Paul's writings in Romans that the State is a legitimate authority charged with preserving order, that Christians should submit to; and also the fact that Jesus interacted with several soldiers and yet never commanded them to leave their profession. Most Christians would place limits on what kind of war is allowable, and what conduct is allowable within war, gathered together under the Just War theory.
A significant minority of Christians believe that fighting and killing are entirely incompatible with Christianity. Their basis is that commands such as "love your neighbour as yourself" and "turn the other cheek" cannot be compatible with attempting to kill your neighbour. While acknowleging that the State has the right and power to defend itself, they would say that Christians should play no part in such a war. Denominations that espouse this belief includes the Quakers and the Mennonites. Many of these have refused the draft and gone to jail for their beliefs; others have volunteered for non-combatant (but often still dangerous) war tasks such as stretcher bearers.
Answer: Yes, absolutely. In fact, in countries that have National Service, it is precisely the will of God that we do so (see other questions about obeying national laws). Military service does not always involve killing. In the instances where it does, your issue is addressed in this question:
If the Ten Commandments say "thou shalt not kill" how can a Christian fight in a war?
In my country (the UK), search-and-rescue helicopter services are run by the military, occasionally people are given military titles and membership as honorary rights, military personnel work in our civilian healthcare system, and until recently the army stepped in when our civilian firefighters went on strike - so there are many roles in the military that are little to do with armed conflict.
Finally, there's another scenario to consider. Often when joining the military one does so for a fixed period of time, and "belongs" to the service until that time expires, unless they buy themselves out. It's arguably a voluntary form of slavery, and the Bible specifically deals with what to happen when you become a Christian while a slave in 1 Corinthians 7:20-21 - you stay a slave until you can become free.
Comment: Last paragraph is a little interesting. Are you saying that if I voluntarily hire myself out to a murderer, that it becomes OK to commit murder if he tells me to?
Comment: This answer only gives one point of view.
Comment: @DJClayworth I think there's a whole separate question in there, but the short answer is no, it wouldn't be ok to commit murder.
Comment: Then if it's not OK to kill people in battle, then it's not OK to join an organization which will order you to kill people in battle.
Comment: Killing in battle is different from murder. And not every military role involves conflict, as my answer clearly says.
Comment: -1 because: This is an issue on which Christians disagree, and to say " it is precisely the will of God that we [fight]" is somewhat presumptuous.
Comment: @DJClayworth I think my answer makes it clear that "military service" and "fighting" are two very different things.
Comment: I don't know of any country that allows you to *volunteer* for the military but refuse to fight. A S&R pilot might well be transferred to fighting duties.
Comment: @djclayworth but the sentence you're objecting to isn't about volunteering, it's about national service. - a synonym for conscription.
Answer: There is no consensus among pacifist Christians about whether particular actions in support of the military are unacceptable. As Wolf Mendl notes in Prophets and Reconcilers: Reflections on the Quaker Peace Testimony (1974):

The emphasis on personal action, which in the case of war means abstention, inevitably raises the problem of where one draws the line. In the total wars of the first half of this century, Quakers accepted non-combatant service with the armed forces, served in an independent but uniformed Friends Ambulance Unit, relieved the sufferings of civilian war victims, did alternative civilian service of 'national importance' at home, went to prison for refusing any service which might assist the war effort, even fire-watching. Some refused to pay taxes. There are no formal rules laid down for Quaker conduct in such circumstances, other than to follow the Light of Christ.

He does not mention that some Quakers actually did decide to serve in the armed forces, but that happened too.
In general, most Christians have found no conflict between their faith and active military service. Those who would not be soldiers may still find it acceptable to be involved in some other way (the classic example being service in the medical corps) though other Christians hold that any kind of participation in warlike activity is wrong, including even paying taxes that will go towards the armed forces.
Comment: I would add that the Bible is not conclusive on this issue. If it were, then a lot more people would agree. As it is, there are several Biblically-based reasons to support a range of positions, and the practical difference comes down to emphasis, interpretation and local circumstances.
Comment: Not really an answer to the question.
Answer: Yes you can serve in the military
How many times did God send Israel to war? Could anybody say that those men are not men of God? Sure Israel has many times, fallen away from God's love, but when have you not?

Judges 3:1-2 (New International Version)
1 These are the nations the LORD left to test all those Israelites who
had not experienced any of the wars in Canaan
2 (he did this only to teach warfare to the descendants of the
Israelites who had not had previous battle experience):

Did you catch that? God left nations near Israel to teach the Israelites about war. God is not a weak God, His will is that wicked people are put to shame. If you go to war then you are doing His will, in one way or another.
See my answer here as well.
If the Ten Commandments say "thou shalt not kill" how can a Christian fight in a war?
Comment: The New Testament way is not necessarily the Old Testament way.
Answer: John the Baptist, when asked effectively the same question by a group of soldiers during the transition from Old to New Covenants, answered in the following way (Luke 3:14):

Some soldiers were questioning him, saying, "And what about us, what shall we do?" And he said to them, "Do not take money from anyone by force, or accuse anyone falsely, and be content with your wages."

He did not tell them to quit their jobs - he told them to be content and not abuse their positions of authority/power.
Jesus told his disciples to make sure they had a sword (they had two) before they went to the Garden of Gethsemane (immediately following the establishment of the New Covenant in the upper room) (Luke 22:35-38):

And He said to them, "When I sent you out without money belt and bag and sandals, you did not lack anything, did you?" They said, "No, nothing." And He said to them, "But now, whoever has a money belt is to take it along, likewise also a bag, and whoever has no sword is to sell his coat and buy one. For I tell you that this which is written must be fulfilled in Me, 'AND HE WAS NUMBERED WITH TRANSGRESSORS'; for that which refers to Me has its fulfillment." They said, "Lord, look, here are two swords." And He said to them, "It is enough."
Answer: I've personally gone through a year of military service. National service is compulsory here for every male citizen. There's an alternative, non-military service that's also available for those that have ethical or religious objections to military service. So I definitely had to think a lot about this.
A credible defense is important for probably any country, but especially mine. We cannot prevent an invasion no matter what, but we can make it too costly to be practical. The only effective way for a small country to do that is to have a large proportion of the population receive some basic military training. If someone marched in, they'd get all over the country in no time. But then there'd be a million armed men in the forests, just waiting to rid the new overlords of their lives, and to get their fatherland back.
Having a system that actually prevents war is a good thing, even the will of God. I would not fight a war outside our borders. I wouldn't have enlisted to any non-compulsory army. But I certainly am glad to be one of the millions of trained men that make any prospective enemy think twice.

Jeremiah 29:7 (NIV)
  Also, seek the peace and prosperity of the city to which I have carried you into exile. Pray to the LORD for it, because if it prospers, you too will prosper."

Take the circumstances I describe as a case study of how a person can practically seek the peace. Note that circumstances vary, and this idea doesn't fit with a war-waging military.
I do understand if someone feels being a soldier is wrong. Any possible enemy still consists of human beings, created and loved by God. But there's a great difference between a soldier that fights on a distant front and one that only exists in order not to fight at all.

Background: I live in Finland, a small country neighboring Sweden, Norway, Estonia and Russia. Finland's only been independent since 1917, and was attacked in WWII -- but my grandfather and other Finnish men of that time fought back, and Finland kept its independence. That, I think, was a miracle of God (seriously). They say that each and every man prayed in the trenches. Finland certainly was quite a Christian country back then; nowadays it's very secular.
The Cold War was politically a difficult time for us, too. Maybe you can imagine.

Map by NuclearVacuum. CC-BY-SA 3.0
Comment: This answer is a really interesting essay, but frankly nothing to do with Christianity and barely anything to do with the question.
Answer: SALVATION FOR THE MILITARY, PARAMILITARY AND OTHER AGENCIES WORLDWIDE
Christians should serve in the military.
Today many people (worldwide) totally condemned the activities of this agencies, the Lord Jesus the not condemned them.
National duties must be separated from religious sentiments.
Matthew 8:8-10
Before reading verses 8-10, this is a little summary from verses 5-7, a centurion (a Roman soldier, may be a group captain) was begging Jesus to come and heal his servant, from palsy. When Jesus decided to come and heal his servant, the centurion said;
Matthew 8:8-10
The centurion replied "Lord, I do not deserve to have you come under my roof, but just say the word, and my servant will be healed.
Verse 9 for I my self am a man under authority with soldiers under me. I tell this one "Go" and he goes; and that "Come" and he comes. I said to my servant do this and he does it".
Verse 10 when Jesus heard this, he was astonished and said to those following him "I tell you the truth, I have not found any one in Israel with such great faith.
Jesus recommended this soldier as the man with great faith.
I need salvation, police need salvation, soldier need salvation, so as Christians all we need to do is to preach the word and not condemn people and we must not mix National duties with religious sentiments.
Therefore, as a Christian, we need to pray for this group of people worldwide, we all knew that the security and live of people is in the hands of God. Yet this people volunteered themselves to render National services to their nations worldwide.
Comment: Welcome to the site. As a new visitor, I'd recommend checking out the following posts, which are meant to help newcomers "learn the ropes": [help page](http://christianity.stackexchange.com/help), [How we are different than other sites?](http://meta.christianity.stackexchange.com/questions/1808/how-we-are-different-than-other-sites)


Can i add an animation from crazy talk 7 into a whole keynote presentation?

Question: I want to do a presentation with keynote and with Crazy talk 7, but i would like to know how to lay the animation over the entire keynote presentation, how can i do that?
Answer: With CrazyTalk7 you can output your creations as videos or images in different sizes, resolutions and file formats. You can convert your work to an AVI file in DVD, HD, iPad and iPhone quality. You may also convert it into sequenced image (BMP/JPG/TGA/PNG) files to broadcast on a web server.
If you wish to import a photo or movie into Keynote the most convenient way to do it is by dragging the file directly into Keynote. Just drop it onto you slide.
You can also import media by choosing Insert > Choose from the top menu.
Hope this helps answer your question.
If you have any further questions please contact Reallusion Customer Support directly using the link below. The support team will gladly help you.
http://www.reallusion.com/CustomerSupport/User/QForm.aspx


What are the differences between different releases of Ubuntu?

Question: For example, what is the difference between Ubuntu 11.10 and 12.04 LTS? What are some major/minor changes between the two versions?
Answer: I'd recommend consulting the release notes page which can be found here:
http://www.ubuntu.com/getubuntu/releasenotes
Answer: Besides the official release notes in Histo's answer, Wikipedia also has an article listing all of the different Ubuntu releases, screenshots of each, mentions of major new features and changes, and tables listing each release's life span and certain package version numbers. This can be useful for seeing more of Ubuntu's historical highlights at a glance.
The article can be found here: http://en.wikipedia.org/wiki/List_of_Ubuntu_releases
Answer: This doesn't quite answer the question, but in future I'd recommending reading OMG!Ubuntu because all the major changes are written about before the next release, and the articles are very well written. The articles about specific releases are tagged using the release codename, for example http://www.omgubuntu.co.uk/tag/quantal has news about
Answer: I think the main difference is in support and stability. Ubuntu 12.04 is more stable than Ubuntu 11.04 and 11.10 because it received several bug fix. Ubuntu 12.04 is a Long Term Support (LTS) release (until 2017-04) but Ubuntu 11.04 and 11.10 support is finished soon (2012-10 and 2013-04)


Modern HDD replacement for an old laptop

Question: What is the modern solution I could use in Commodore C386SX-LT? It requires selection of disk type in bios, otherwise it won't work. Max setting allows up to 63MB, so would a 64MB CF with IDE adapter work?
Comment: I can't speak for your exact computer, but if you're able to manually set CHS in your bios rather than picking a type number, there's a program called 'whatide' that can report the geometry of the hard drive / cf present. I'd expect this approach would work with a 64mb CF (or set the cylinders lower if 64mb doesn't work).
Answer: Modern hard drives tend to list a CHS geometry of some large number of cylinders, 16 heads, 63 sectors.  I'm reading the label on an 18GB IBM Travelstar for that; as CHS only goes up to about 8GB, the listed settings wouldn't cover the entire capacity of the drive.
I think it's better to have the correct number of heads and sectors.  It may then be possible to have the operating system use a large number of cylinders than the BIOS supports, while still having compatible geometry otherwise.
Comment: @DarkDust There are still PATA drives being sold in 2.5" form factor, including SSDs.  I have one in an old ThinkPad right now.
Comment: Apart from the PC only being able to use about 0,35% of its capacity, how would you connect such a disk? That's the main part of the question, I guess: you can't hook up a SATA disk to this thing.
Answer: CF should work. I guess this may help you:

Connect the CF to your computer, no BIOS settings needed.
Boot from floppy to the DOS
Use utilities like WhatIDE or IDEInfo. They tell you how the system "see" the CF card (if so)

You can find more details here or here.


Reposts of answer-chaining challenges

Question: The reason that we don't allow reposts is because the same answers will be copied from the first challenge and the original can still be answered. But what about answer-chaining challenges? Those are inherently different if they were run multiple times. Imagine if the challenge Add a language to a polyglot started with LISP, it could have ended up being a completely different challenge. (that might not have been the best example). The point is, do you lot think it could be acceptable to repost such challenges, provided we don't spam them over and over? It would enable languages that at this point can no longer be reasonably inserted to compete, and could provide different kinds of challenges.
Comment: I'm torn on this. On the one hand, different initial conditions would lead to different, interesting variations on the challenge. On the other hand, we don't want dozens of challenges that are all the same except for their initial conditions.
Answer: Yes, under specific circumstances:
I think that DJMcMayhem made some really good points as to why we don't like duplicates.  I'll address the two he felt were still relevant to answer-chaining:

A challenge becomes less interesting when it's been done before. Even challenges around a theme become boring after being repeated too many times. (For example, flag challenges, "Print the alphabet in this pattern" challenges)
Taking credit for the creativity of another user who wrote the original challenge is not OK.

I believe that the following measures would solve both point 3 and 4:

Require that reposts be posted by the challenge author, or with their permission.

Require that a repost be posted at least 6 months after the original post, maximum 3 times.

Both measures would act as a natural limiter to ensure that reposts are high-quality.  It doesn't eliminate the problem of low-quality reposts, but I think that the benefit outweighs the cost.
Comment: 1 month seems a bit short, especially if you're limiting it to three times. Make it a year or at least half a year. That also allows more interesting languages to be created that can change how the challenge plays out.
Comment: @NathanMerrill I don't think losing interest is relevant. It'll get attention when it's reposted and if the time between is longer then it's actually likely that it will get *more* interest.
Comment: If the original author no longer used the site, can we say that if they don't respond in a month, they give permission?
Comment: @Pavel I'm on the fence on that.  I'll leave that up to another meta post if it becomes an issue
Comment: @MartinEnder the challenge in question (Add a language to a polyglot) is just about to turn 1 month old, and has pretty much finished.  If you make it much longer, I think you'd lose interest in it.  However, I'll take upvotes on your suggestion into consideration, and change it if enough support it.
Comment: Random idea: instead of having a set time limit and max number of reposts, we could have a thread similar to the sandbox where there could be "repost requests", and in order for a challenge to get the thumbs up for reposting, it must reach (insert ratio here) upvotes to downvotes
Comment: @ConorO'Brien that's not a bad idea.  Perhaps post it as a separate idea here?
Comment: @NathanMerrill Done.
Comment: Why have a maximum of 3 times? Have a good, long wait period sure, but PPCGers 100 years from now may be mad that they can't redo historic challenges.
Comment: Also, I'd say an author's permission is not required if the don't respond to questions about their challenge within a month. Not all authors still frequent SE.
Answer: Yes, but the reposting of a challenge must be voted on
Instead of having a set time limit and max number of reposts, we could have a thread similar to the sandbox where there could be "repost requests", and in order for a challenge to get the thumbs up for reposting, it must reach a certain ratio of upvotes to downvotes. A request might look like this:
# [challenge](link/to/it)

<Citation of eligibility for the user wishing to repost>

<Any additional information>

Comment: @Pavel I do like that idea, but that's beyond the scope of this question
Comment: This could also include reposting old challenges with unclear specifications.
Comment: @DLosc I think this would warrant a separate thread.
Comment: Do we need a separate thread, or could this use the existing sandbox?
Answer: This should not be allowed, but we could lower the threshold for these challenges to be considered a "duplicate".

The reason that we don't allow reposts is because the same answers will be copied from the first challenge and the original can still be answered.

That's certainly not the only reason. There are four reasons I can think of to not allow duplicate challenges.

Like you mentioned, answers from the first can be copied and posted on the new one,

The old challenge can usually still accept answers,

A challenge becomes less interesting when it's been done before. Even challenges around a theme become boring after being repeated too many times. (For example, flag challenges, "Print the alphabet in this pattern" challenges)

Taking credit for the creativity of another user who wrote the original challenge is not OK.

Now you are right, answer-chaining challenges address most of these points. 1 is moot because a tiny change in the first post could drastically change future answers. 2 is addressed somewhat, because lots of answer-chaining challenges have a deadline, or are impossibly hard to add a new answer to. (For example, 95 movie-quotes)
But that still leaves points 3 and 4. Reposting answer-chaining challenges is still taking credit for someone else's creative challenge idea, and still gets old if done too often.
So I think that we should not allow directly copying an old answer-chaining challenge, but I think it's perfectly reasonable to be slightly more lenient about what we consider to be a duplicate.
Comment: You said "be more lenient", but you haven't said how.
Comment: Side note: That particular challenge has an incredible amount of participation, and the community's response has been overwhelmingly positive, with lots of fantastic answers. Personally, I wouldn't mind making an exception and reposting it much later once the opportunity for new answers is all gone. It would probably need to be a community wiki, and we'd definitely want full community consensus before posting it. Of course, this is completely tangential to my answer.
Answer: Please note that, even if this technically works, it actually lets you post dupes one after the other. That loophole should be eventually fixed. Any feedback for that instead of just downvotes is appreciated.
Yes, allow reposting, but:

Make sure that you cannot solve the original challenge or any of its already existing reposts. If you can, there is no reason to repost, as solving at least one of them isn't impossible.
Adding to the above bullet-point, if an answer is posted to a repost older than yours or the original challenge, and your challenge didn't have answers at the time the new answer was posted, your repost is subject to closing as a dupe of that repost. Please keep up with the spirit of answer-chaining. Answering such a repost is extremely discouraged, although there is no easy way of determining whether a newer answer to an older repost or the original challenge has been posted. The only way is to look through each older repost and see if an answer has been posted there later than the posting of the repost question. Note that if the question poster is the only answer poster, it still counts as a dupe.
Credit the original author, not subsequent reposters, and link to the original challenge. Linking to the original challenge will add the repost to the original challenge's "Linked questions", thus marking the existence of your repost. If your repost is closed as a dupe, the link is subject to be removed, or replaced with a no-ad URL-shortened link (such as goo.gl or bit.ly), so as to not clutter the original question's "Linked" list.
Self-contain the original challenge AS-IS, do not just give a link to the old challenge which might have been deleted, so that users without moderator privileges can still read the challenge's spec.
If the original challenge has been closed, do not repost it yourself. Doing such a thing means your challenge will most probably be closed too, as the content is AS-IS.
Follow the exact formatting described below.

Format as:
Title: <original title> (Repost <repost number>). Replace <original title> with the original post's title, and <repost number> with the number of your repost (first repost is 1, second is 2, etc.)
Content:
**Note that this is a repost of the original challenge linked [here](<link>).**

---
<original challenge>

Replace <link> with a link to the original challenge (not URL-shortened unless repost is closed) and <original challenge> with the contents of the last revision of the original challenge where no answer was accepted. The link must be in the form of /q/<id>, where <id> is the original question's ID.
Tags must be the same as in the original challenge. No added or removed tags please.
Comment: I don't really like this answer because it doesn't address the problems with duplicates that I mentioned. IMO Nathan's answer is a better `Yes this is OK` answer because it doesn't have any loopholes, addresses the issues with duplicates, and is a little more restrictive about when it would be OK to repost a challenge.
Comment: @DJMcMayhem Nathan's answer has a too restrictive "at most 3 times", which I generally disagree with. About the loophole, it does not really have a good fix, unless someone goes through all of the older reposts of the original challenge and the original challenge itself, and checks whether an answer has been posted there at least a second after the repost was posted, and that the repost has no answers or only has answers posted by OP. Also, if OP has a second account, they might post a starting answer with that, and then the challenge goes on. That's why I have stated such a loophole.
Comment: I really debated about the "3 times", but I think its a good limit before the community gets sick of a particular style of challenge (I believe we started getting sick of alphabet challenges at around 3-4 of them).
Comment: That said, my biggest problem with this method is that its *really* hard to determine if a challenge can't be answered anymore.  The entire point of [tag:answer-chaining] problems is that they get progressively more difficult, and just because I can't figure out the next link in the chain doesn't mean nobody can.  Either the requirement will scare reposters away, or they will just ignore it.
Comment: @NathanMerrill I don't think there is any method making it easier. Maybe we should agree with DJMcMayhem's answer then.
Comment: Right, but I'm personally ok if there are two "active" answer-chaining challenges.  The likelyhood of it happening with my method is low, but even if it is occurring, that's fine to me.  They'd be drastically different challenges after a month.
Comment: @NathanMerrill Well, I was actually of the opinion that the [tag:answer-chaining] tag should be obsoleted once and for all, and I can't think of a better way of solving [tag:answer-chaining]'s issue. Yes, the biggest problem is the tag's spirit, which is that the challenge itself is to try to create an answer based on the challenge's rules and the existing last answer.

Reposts of answer-chaining challenges


Is starting a group with 5 newbies (DM included) possible?

Question: Some friends and I want to start playing D&D (5e), but none of us, DM included (not me) have played before to any great extent. The DM and I have some cursory experience with 4e, but have never been able to play to any great extent. Is this advisable, or should we play with existing groups first? We live in a relatively remote area, making it hard to find experienced players.
Comment: The great thing about living in the 21st century is that even if none of you had any idea of the rules or how the game is played, you can [watch people play it on youtube](https://www.youtube.com/watch?v=zFTmmZaD9GI&list=PLSANAnKYkJY2-LhFRPZyb4rMVB8pFUFRC).
Comment: Reminder: comments are for clarifying content, not posting small or incomplete answers. Please use answer posts to submit answers instead. Prior comments containing answers have been purged.
Answer: I had a quick look around because I felt sure this would have been asked before but I can't find anything that would qualify as a duplicate.
Short answer - go for it.
I started playing in 1980 with a group of friends none of whom had ever seen or heard of a game anything like D&D. We made it up as we went along, had lots of fun and some of us still do. Oh, and there was no internet with sites like this one!
Its your game - you can't play it wrong!
Read the rules, make an adventure  or buy the Starter Set, play it, do things wrong, realise you did them wrong, work out if you like your wrong way better than the official right way, decide how you will play them in the future, check that you are having fun, if so, keep going.
Comment: As a rookie DM for a rookie group, I wish I had read this when we started out. A shame I can't +2.
Answer: this is advisable!
The adventure included in the boxed 5e "Starter Set"--the Lost Mine of Phandelver--is for you. In fact, the whole starter set is designed with you in mind. The rulebook is a coherent subset of the PHB (and thus simpler to wrap your heads around), the pregenerated characters' sheets nicely explain features, and the adventure has lots of notes to the DM. (Things like: in the next encounter surprise may be a factor; be sure to review the surprise rules on p.xx.)
On a personal note, I'd not played since the 80's and had never GMed when I picked the starter set up and got three other complete newbies to try it. At lunch the other day one of the group asked about starting up a third concurrent campaign so that we-all (and the half-dozen other newbs who've joined us) can 'get our fix.' the starter set works!
Then, while you're GMing or playing, keep a running tally of things to ask about here or in chat. At the beginning of each session you can go over all the questions, and you'll all learn together.
Answer: Go for it, absolutely.
Many of the very greatest experiences that are told and re-told come from groups who were completely "green", simply because they didn't know "how it was done properly", and thus experienced things in their own, genuine, unique way.
(Some of the greatest moments in my RPG / LARP career only happened because we were unexperienced.)
Moreover, being on a "common ground" experience-wise is a boon as well. Newbies in an experienced group can work, but can also experience disconnection, or just "following around" because they're overawed by the more experienced players.
This is a game about discovering. Discover what style you want to play, not what style others could teach you. (You can do that later on.)
Have fun.

Anecdotes:
We played Talislanta once, in a huge group of 12 or more players, with no-one in the room -- GM included -- having any previous experience with the game world, or the game mechanics. The "thing" about Talislanta is that there is nothing "classic" in it. No human cleric, dwarven warrior, or elven ranger. Everyone is completely alien. After a truly enjoyable evening of serious character play, the GM looked at us in a funny way, asking us if we actually realized she hadn't said a word for the last couple of hours... We hadn't. One of the best RPG sessions ever.
My very first LARP (and that's >20 years since) was the first for everybody else in the group as well, except the GM who had played once (!) before. After the first day, well over a dozen players crammed into a single room, keeping a three-man watch at the only door the whole night, because we never even considered that the NPCs would need (or want) sleep as well. I have never since experienced another LARP with that feeling of intense, real, immediate threat, which came from literally no-one knowing what to expect. (Actually we were ambushed in the middle of the night, simply because the GM thought she couldn't all that guarding go to waste.)
Answer: Perfectly Fine to Play
You can definitely run the game as a new DM with inexperienced players! Assuming you run the starter set (or any of the other published adventures) I'd strongly recommend reading online for how other groups have played through the adventures. Doing so will help you teeth out any scenarios in the adventure that don't quite make sense or are confusing, while also exposing you to the range of actions that characters could undertake. Knowing those actions will help for at least three reasons:

so you understand the kinds of things that players might do that deviate from the explicit advice/guidance in the adventure itself, and how to possibly respond;
so you can give a wider range of suggestions for possible actions if your players are 'stuck';
so you can see how/why/when other DMs modified the adventure in order to understand, for yourself, when/why/how you might want to modify the adventure.

In effect, by seeing how other groups have played the adventure you'll get the advantage of learning from more experienced DMs while simultaneously preparing yourself for running the game yourself for the first time.
Answer: The other answers are very good, but I would add one word of advice:
Don't get hung up on the rules right now.
Rules are great once you've established a good understanding of them, but right now the form of role-playing is much more important than getting bogged down in every little nuance of whether a given skill governs a particular task.
You'll be looking in the rules a lot, but I would suggest if you can't find the answer in 30 seconds or less, just wing it and look it up later. Maybe each player who has a question you couldn't answer can jot the question on a piece of paper, then everybody looks up the answers between sessions and reports back later.
My gaming group many moons ago started with zero understanding of tabletop RPGs and this was probably our biggest issue. Some of us *cough* me *cough* were treating it too much like a board game where the rules are critical to understanding the game, and had trouble recognizing that it's not about rolling dice and crunching numbers -- it's about smashing some bad guys and saving the hapless villagers and rolling around in the loot afterwards.
Note this mainly applies during gameplay -- the DM should spend as much time as they can reading the rules right now and getting as familiar as possible with the nuances. But they can't learn everything in a week (or a lifetime, really), so they should just do what they can once you're playing to keep things running smoothly.
I would also recommend not spending too much time in the first character creation session. Some of your players may want to get every detail right, but remind them the character sheet is just an interface. The real character is in their head, waiting to come out during the gaming session.
Comment: +1 for "the real character is in your head, the sheet is just an interface."
Answer: Acceptable And Recommendable
Although DND has a depth that can make playing the game daunting, among a small group of people just starting out, you're not likely to run into that depth, and will find the simpler end of DND isn't too difficult to get the hang of - provided at least one of your group is at least moderately good at math, since adding up die rolls and HP and various other character stats is still required.  Since you and the DM have cursory 4E experience, you should already be familiar with that type of math, so you'll be fine.
As previously suggested, the Starter Set is a good place to start for new players, though any pre-packaged campaign should be good for new players too (as long as it's not explicitly marked for more experienced players).  The pre-generated characters should help get things going.
If you decide not to use the starter set, you can still have fun - though you'll need to guide your players through character creation to help set up a party that can do what they want.  This can be fun and enjoyable, but if you plan to go this route, you should dedicate a whole session, or even some one-on-one time with each individual player, to decide how their character should be (And try to get plenty of input from them - players, even new ones, will be more invested in characters they've had a hand in building).
Be prepared to be patient though - new players tend to need to look up the rules, or flat-out forget them in the middle of their turn, and may need a little hand-holding to keep things moving along.  But my all means, it is an enjoyable experience, and a good way to get new players into gaming.
Answer: Yes, but the GM and players should do some reading online of good practice and the kinds of behaviour that kill games.  If these are the only people you've got to play with locally be careful not to screw that relationship up with a beginner mistake.  Start out by playing some short scenarios with throw-away characters to get a feel for how everyone plays and what you have in common.
I agree with MichaelS that playing well is more important that getting the rules exactly right.
Make sure that you all agree on how you want to play.  It's easy for a beginning GM to over-control the game or under-control player behaviour.  It's a partnership that's easy to get wrong but truly magic if you get it right.  There's a good chance that you'll have people who want different things out of the game - every group has people that love debating the rules, people who just want to get more powerful and don't care how, people for whom the integrity of the character and the story is everything.  Those differences are going to cause friction so you need to recognise them early and agree on how you're going to manage it.
Some example of behaviour rules that I enforced to keep the game from bogging down (you'll find variations of these online - go look for them):

All rules can be changed but not while playing.  The groups I played with routinely wrote new rules to handle things we wanted our characters to be able to do, and re-wrote those rules when they didn't work.  But once the game started there were no rule debates allowed - the GM makes a quick ruling that's as balanced as possible and then you get on with the game (this is the "The GM's word is final" rule).  After the play session work out how the rule should really work and write it down for next time.  Work out if anyone was disadvantaged by the GM's quick ruling and work out how to correct that.
The GM doesn't own the world.  He's the referee, not the owner.  He's got to play by the rules the same as every one else and can't just rip out part of the world or rewrite something if it would mess up someone's character.  It's easy to forget that every player invests in the richness and depth of the world and deserves some say in how it changes.
The GM's word is final.  This is the person that's going to put twice the hours in that anyone else will (if you can build a group where everyone contributes world content, plot lines, etc and take turns GMing that's awesome, but it's rare).  From time to time you're going to get disagreements that can't be resolved and someone has to make a call.  That's what the GM is there for so both the players and the GM need to respect the authority, use it wisely and abide by it.
If you can't trust the GM don't play in the world.  This one you'll learn over time and unfortunately some people make awesome players but just can't resisting cheating as GMs.  Don't step into those games.  If you're one of those people don't GM.  I  sometimes worked with someone like that who would write scenarios and get me to GM them.
Don't marginalise characters.  Some people build characters that have a different roles.  They might be protectors of the truth in a party of "bash and loot" warriors or druidic mystics in a party of bandits.  Try to give those characters the focus sometimes and let them have the impact they deserve.  This is a message to the players as much as to the GM: sometimes the story isn't about you.

That's not all but I'm meant to be working and there are other people who write this stuff better than I do, just make sure that you focus on eliminating stuff that's not fun.


How much do I charge?

Question: I'm doing a freelance gig for a doughnut shop that has 3 locations and is about to open up a 4th making an android and iOS app. They want me to show all locations, have the app link to the nearest location based on your location, set up per-orders through square,  show the menu and other information about the business and offer coopons as well as a few more things. But this is my first freelance job for apps, and I'm not sure how much I should charge for this. Can anyone give me a quote?
Comment: Given that a mobile friendly website would be a lot better option than an app, I think you should not be charging them…….  Being a professional includes refusing to do work that is not of benefit to the client.
Comment: I already did a website for them and now they want me to do the app. I also explained that I don't think it would be if it them be he said he doesn't care, he wants an app. So I'm going with the customer is always right motto here.
Comment: Possible Duplicate: http://freelancing.stackexchange.com/questions/1710/how-do-i-estimate-the-cost-of-building-an-mobile-app?rq=1
Comment: My dad told me that you should take the hourly rate that you make at a company and times it by 3. That way you are covered for the time that you aren't working.
Answer: First off, charge by the hour. Without knowing a great many details about your expectations for payment, level of skill, customer expectations, graphics, whatever, it's impossible to come up with an accurate estimate that is going to make you happy.
Here's the deal though...you are in the same position. Fixed price gigs almost always (in my 30 years of freelance experience) have hidden expectations associated with them. When you charge a fixed price, you are essentially charging for a product that the client assumes will match what is in his or her head. You are estimating based on what is in your head and most of the time you end up spending more time with fussy details or surprise requirements that you aren't being paid for but essentially agreed to do when you took on the project.
At some point, you will have to have the conversation with the client where you both decide when you are done, or where to draw the line between work that is part of the fixed price estimate and work that is over and above. Those aren't usually fun meetings.
If you charge by the hour, then it really doesn't matter as much...the client can keep generating requests and you keep building. They'll stop generating requests when development reaches their budget limit. Be sure to negotiate a regular invoicing and payment schedule while you are at it.
Answer: There might be instances where the client may need an hourly based contract or a fixed-price one. I would suggest going by the hourly method.
In order to quote for the project, you need to make the timeline sheet on your side first. Include all the features and modules and list down the number of hours it will take you to get them done.
Be sure to include buffer time in it as well. Otherwise, it will come back and bite you later, if you get any of the modules delayed. It is a safe practice to have buffer time.
After you do this, share the doc/sheet with the client and get their approval. Make sure they checked the whole doc and made sure nothing was missing or was extra.
Once that is done, you are good to go.You have the estimated timeframe in front of you and you have to do whatever it takes to stick to it and give the best quality delivery possible.

How much do I charge?