Where a sysadmin deletes a company's data, why can't they just restore from backups

Question: As an example, in the UBS Duronio case, Mr. Duronio executed code that deleted everything in its path, but isn't there a backup server? Why was UBS hit by the loss of data? If the backup is available, even if rm command was executed, there would be a way to retrieve the backup data...
Comment: Isn't this question a bit presumptuous?  A lot of businesses don't maintain and/or test their backups as well as they should.  Even with good backups, you've still got the down-time required to retrieve and restore them coupled with the loss of data gathered/created since the last backup.
Comment: For reference, Duronio's attack code is [explained here](https://www.blackhat.com/presentations/bh-usa-07/Belani_and_Jones/Presentation/bh-usa-07-belani_and_jones.pdf). Deadly simple.
Comment: Hi Mark - I have edited to make this question more generally useful Hope that is okay.
Answer: A backup, if there is one, takes time to get restored, if it can be. In other words:

Not every company has good backup practices. Considering that, as noted in the security investigation, UBS had other poor security practices it may not be surprising if they didn't have good backups.
Even if a backup has been made it takes time to restore. During this time the server is not in operation. So if it takes a day to restore, you're down for a day, which can be a devastating loss for the kind of operations UBS does.
Not every backup can be restored. The only way to know for sure is to practice restoration, and this is so time-consuming and expensive that many places never do this.
Comment: +1, a minor point to add: In case of an malicious sysadmin, he might delete the backups, too.
Answer: There's several reasons deletion of production data, especially by a malevolent sysadmin, will have a significant impact on a company - with or without backups:

Many companies don't do backups, or don't do them right.  Without good backups, you may not ever be able to recover data that's been nuked by a sysadmin.
Companies that do have backups don't always test them.  Without regularly testing restoration of your backups, you can never be sure that they'll actually work when needed.  In the middle of an incident response or disaster recovery is the worst time to find out your backups or your restoration process are no good.
The sysadmin may delete the local backups as well.  If the company doesn't also keep off-site backups (and many don't) they could be entirely out of luck in this case.
Backups are a snapshot of the past.  Any data between the time the last backup was made and the time of a total data loss incident is probably lost forever.  If the company has to resort to using an off-site backup, this impact is likely even greater because off-site backups are usually older.
Backups take time to obtain and restore.  In most cases, this means the production environment that relies on the data from that backup is unavailable until the backup is restored.  If restoring from an off-site backup is necessary, that requires even more time.
Loss of data means loss of credibility and confidence.  Any significant security breach such as this, especially if made public, will have an impact on the company's image.  Even if you're able to fully restore data up to the very last minute before the incident, your company will never quite be looked at the same again.

To sum up:  Even if you do have good backups that can be restored, there's still a significant short-term impact while that process is in work.  In the long-term, you'll still suffer the impact of a hit to your company's reputation and will also see some impact due to data that couldn't be recovered.
Comment: I read an article once (can't find it right now) that about 80% of the backups made world wide, do not contain what the sysadmin expects it to contain. These are of course huge numbers. Caused a.o. things not testing backups / worn out media, ...


mixing a project in ProTools with automation is it possible to suspend the automation during playback as if it was automated turned on/off

Question: I'm trying to save DSP on my computer and my current mix session has alot of tracks with automation. Is there any way to set the plugins through automation to suspend during playback on and off?
Answer: I think all ProTools plugins have a master bypass that you can automate to bypass the plugin.  I don't know that it really saves power though.
ProTools 11 has dynamic plugin allocation so the plugs that aren't processing aren't taking up power.
Other options might be thinning the automation more or increasing your playback buffer size.
Comment: you'd have to deactivate the plugin, something i'm not aware of to be automate able.. if you really want to save dsp, reorganise your routing to a more minimalistic style. otherwise you'll simply end up hitting the cpu max...
Answer: If you hit cmd and 4 on the neumeric keypad (ctrl 4 on PC) or go to Window>Automation the automation window will pop up. From there just hit the 'Suspend' button at the top and all automation in the session will be suspended.


PTIJ: I thought one couldn't write a half Torah

Question: The Halacha states that a Sefer Torah isn't valid if it has missing words, or even letters. Then how come each Shabbat after reading the Torah parsha can we read a "halftorah"?

This question is Purim Torah and is not intended to be taken completely seriously. See the Purim Torah policy.
Answer: The Maharal explains that the reason Hashem showed Moshe a half a shekel of fire is because humanly it is impossible to achieve an exact half.
It would appear that the peshat in the Maharal is that exact halves tend to combine, since a whole is a natural state. Therefore an exact half is in a ruchniyosdikly reactive state, since it will seek to combine with another exact half to form a whole.
Similarly, we know that if the Jewish people would observe two Shabassos then Mashiach would come. In other words both Shabassos would combine into a whole, which is me'eyn olam habah.
Therefore each Shabbos after leining we daven that this week's Torah should be considered only half a Torah, which will combine in a fiery manner with our next week's Half Torah, and thus bring mashiach.
Comment: @hayam I am bigger than my wife, but somehow she is my other half. Hashem's calculations are vast
Comment: @hayam The *tzurah* of each Half Torah is equivalent. The length of the Half Torah changes because a different number of *pesukim* are required to express the *tzurah* of the Half Torah according to the influence of that week's *parshah*.
Comment: @RabbiKaii, who says your other half in life is a proper קל וחומר for this case?
Comment: Yeah, but not all the halftotahs are the same length!! How do they combine into one whole then?! Do we have to wait an entire year for each one to combine with itself?!
Answer: The custom to recite Half-Dollar [הבדלה] on Motze Shabbos is in fact based on your very question. On Shabbos everything is anyways half, due to all activities being divided between the soul and the Neshama Yeseirah - so effectively, wholeness has no meaning on Shabbos.
To symbolize this, we perform the Half-Dollar ritual - which, like @theGrapke answered above, it a message from Machatzis Hashekel about halfs becoming whole. This is the reason why Zionists changed the tradition 'Good Shabbos' greeting to 'Shabbat Shalom', hereby blessing that the halves should soon become whole (שלם) once again.

PTIJ: I thought one couldn’t write a half Torah


jenkins version conflict with findbugs

Question: i am getting the following thing every time i start jenkins.i couldn't get hudson findbugs graph even though i activate it.
Manage Old Data
When there are changes in how data is stored on disk, Jenkins uses the following strategy: data is migrated to the new structure when it is loaded, but the file is not resaved in the new format. This allows for downgrading Jenkins if needed. However, it can also leave data on disk in the old format indefinitely. The table below lists files containing such data, and the Jenkins version(s) where the data structure was changed.
Sometimes errors occur while reading data (if a plugin adds some data and that plugin is later disabled, if migration code is not written for structure changes, or if Jenkins is downgraded after it has already written data not readable by the older version). These errors are logged, but the unreadable data is then skipped over, allowing Jenkins to startup and function properly.
Type    Name    Version
The form below may be used to resave these files in the current format. Doing so means a downgrade to a Jenkins release older than the selected version will not be able to read the data stored in the new format. Note that simply using Jenkins to create and configure jobs and run builds can save data that may not be readable by older Jenkins releases, even when this form is not used. Also if any unreadable data errors are reported in the right side of the table above, note that this data will be lost when the file is resaved.
Eventually the code supporting these data migrations may be removed. Compatibility will be retained for at least 150 releases since the structure change. Versions older than this are in bold above, and it is recommended to resave these files.
No old data was found.
Unreadable Data
It is acceptable to leave unreadable data in these files, as Jenkins will safely ignore it. To avoid the log messages at Jenkins startup you can permanently delete the unreadable data by resaving these files using the button below.
Type    Name    Error
hudson.maven.MavenModuleSet nov 7 latest    NonExistentFieldException: No such field hudson.plugins.findbugs.FindBugsReporter.isRankActivated
Discard Unreadable Data
Comment: So what is your question?  Is it causing problems?  Is something not working?
Comment: ya i am not getting hudson findbugs graph.it is showing xmlparser error in console output.couldn't parse findbugs.xml...please refer to my earlier post for error.
Answer: According to the main FindBugs author, this is expected behavior when you downgrade FindBugs from a newer version to an older one:

Once you upgrade to a new version you can't downgrade without getting
  such kind of exceptions (I only ensure backward compatibility). Can't
  you use the "manage old data wizard" in Jenkins to remove these new
  fields from your persisted Jenkins build files?

Nabble discussion.

jenkins version conflict with findbugs


iPad 2 mini with weird battery issue

Question: We have an iPad 2 mini that is several years old with recent issues with the battery.  After charging for extended period of time it will display a dead battery symbol and not boot up.  After plugging charger in and out for a couple of minutes it would finally start to work and when screen comes up it says it is fully charged.  The chargers are same as we are using to charge our iPhones so the chargers are still working fine. When the iPad 2 mini booted it is fully charged and would work fine off charger for hours.  Now we can't get it to boot at all and just get the screen that says the battery is dead.  It also says its charging when not plugged it but not when it is plugged in.  Very confused and need some ideas how to fix this thing.
Answer: The battery is failing/dead, the circuitry inside may be damaged, or both. You need to have this iPad serviced and needs to be opened and checked out by an Apple Tech. If it is out of warranty, any reputable 3rd party Apple Tech fixit shop should be able to help.
There's nothing anybody can do remotely - the device has obvious hardware issues. I've handled enough iPad minis in similar shape to be certain of it.
Your best bet is to get a new (or newer) iPad. If funds are tight, Apple has pretty good refurbished models in the Apple Store (US link).

iPad 2 mini with weird battery issue


Which kernel versions does the udev exploit work?

Question: Which kernel versions does the udev exploit work? Upon googling this, I found articles claiming that it works on Android 2.1 and maybe 2.2, but there is no information about the kernel versions.
Comment: We can't help you find the kernel, as it would be considered a shopping recommendation -- [this](http://android.stackexchange.com/q/17152/1465) may be helpful with that however.
Comment: Fine, can you tell me the  kernel version.
Comment: I am just trying to do some research, for which I need the kernel **version**. I don't want to buy a device. I am not going to *shop* for anything.
Comment: Whether you pay money is irrelevant -- searching for something to acquire (the kernel) is shopping by SE's standards.  We can help you figure out when the exploit was patched / the versions where it is unpatched, but actually finding somewhere to get the kernel is off-topic.  See the [FAQ].
Answer: I'm actually not sure that the kernel version matters for this exploit. It was a bug that was patched in the platform_system_core repository, which I think comprises libraries and system files that live on in the /system directory (the README says as much). The patch was committed on July 19, 2010 (in the Froyo branch, anyway).
I'd wager that any kernel with a build date later than that also has the updated system files, so the system wouldn't be vulnerable. uname -a would tell you the build date of a given device's kernel, but beyond that I don't know that you could really line it up with a specific kernel version, especially on devices from different manufacturers/carriers/etc.
Comment: The patch should be helpful. Now I'll just **unpatch** that patch on the kernel that test the exploit. That should work right?
Comment: @EknathIyer: Sure, if you reversed the diff the code would be exploitable again, I would assume.


Internet connection monitor with logging

Question: We are having intermittent issues with our internet connection in a community house of nine people. It seems to cut out for short intervals so I am looking for an app to test connectivity at regular intervals and log it. For example to ping a host on the internet every minute or so and log the results. What I want is to log when the connection is down and for how long over a period of time. This is not an enterprise issue so I am looking for a free app or script to accomplish this.
Thanks
Comment: Which version of Linux/Ubuntu are you using?
Answer: You can run a simple ping command to accomplish this:
ping -i 60 domain.com > ouput.txt

where 60 is the time between pings. To limit the total count of pings use :
ping -i 60 -c 50 domain.com > ouput.txt

where 50 is the number (count) of pings.
There are many more options to read about on the man page of ping. To access it use:
man ping

If you want more in-depth statistics on all traffic of one machine I recommend to use an application such as wireshark. It is open-source and free.
Wireshark can give you exact statistics on each packet of data sent and/or received by your computer. So if you only want to see if general connectivity is available I would consider this a little much. It can also be hard to figure out what to do with all this output from wireshark.
PS. some suggestions to ping (these are very reliable and fast but don't overdo it or they might ban your IP):
22.214.171.124     (cloudflare DNS)
188.8.131.52     (google DNS)
google.com

Comment: @ColinBondi. You are very welcome. If this answer has solved your question, you can use the ✓ to accept the solution. And mark your problem as solved.


Why do the Stoics Matter?

Question: Aside from overcoming the Fallacy of  Four Terms, what were the major contributions of Stoic syllogisms? What did they provide that Aristotelian syllogisms could not? And, what were their major limitations?
Comment: I don't know about syllogisms - but they developed modal logic more fully
Answer: One of the limitations of the Stoics is that they did not "grasp as clearly as Aristotle the formal nature of invalidity." Ian Mueller pointed this out in a famous article on Stoic Logic. His argument was that they merely provided a framework to settle inferential validity and reveal those questions that fall outside logic (such as soundness questions related to metaphysics implied by the premises).
Comment: Ian Mueller. "An Introduction to Stoic Logic." in John M. Rist (ed.). "The Stoics." University of California Press, 1978.
Comment: Could you at least cite the article?

Why do the Stoics Matter?


Check finished errors found in 1 file

Question: I build custom ISO Ubuntu 20 according to this article.
After the custom ISO is ready, I install the OS from it, and at first, the error appears: Check finished errors found in 1 files.
Could you tell me how to find this error and fix it?
I already checked md5sum, I read about it.
Comment: You've tagged 20.04, but refer to Ubuntu 20 (which doesn't exist, but is closest to Ubuntu Core 20 which is a different product to 20.04).  The wiki page refers to md5sums, which are deprecated & replaced by sha256sums. (you should have noticed that at the download page https://cdimage.ubuntu.com/ubuntu/releases/20.04/release/)  Note: *this is opinion only, if I knew it was fact, I'd correct the wikipage which I believe to be outdated*.
Comment: If errors are reported and you need help solving the problem, it might be useful to include actionable error messages. There are a million reasons for why something might not be working as expected.
Comment: I have been seeing the same error with the xubuntu-20.04.1-desktop-amd64.iso image. There is no actionable error message. This is a check done when you start the boot process - it  reports the error exactly as described (Check finished errors found in 1 files! You might encounter errors.). Otherwise, everything still seems to work. To be clear: I checked the SHA256 checksum, reburned the image to my USB, burned it again with Startup Disk Creator, tried again with dd, tried a different USB, downloaded from a different mirror, downloaded a torrent, and then tried all those things again...
Comment: a related issue (and link to a bug report) is here: https://answers.launchpad.net/ubuntu/+question/691933
Answer: It is mentioned in this bug report that "Windows write System Volume Information on any filesystem it can understand (EFI boot partition in this case) which causes the checksum to fail.". This matches my experience, where the error was reported, repeatably, if the USB stick is inserted into a live Windows system between the time it was created and when it is booted.
Looking closer, a folder System Volume Information is added to the small EFI (Fat-12/16/32) partition.

Advice: Avoid inserting live USB while Windows is running.
Comment: FYI, I successfully created a bootable USB thumb drive (no errors when Windows not involved) using the "Restore Disk Image" feature of 'gnome-disk-utility'.
Answer: Based on what I can discover from looking at this bug report and discussion (Check error with 20.04-desktop ISO)  it appears this is just a built-in limitation of the file checking where the efi.img file is modified when it is loaded and that really means it can't be verified.  I would advise go ahead and ignore this error! That is what I have done with my Xubuntu installation and I have had no problems at all (since then I have also noticed this error when installing Ubuntu Mate and I also ignored it in that case as well!)
Answer:
Press ctrl + c to stop checking or skip this process.
Use "Try Ubuntu".
Then, Install Ubuntu 20.04 lts from inside "Try Ubuntu".
Note: Don't remove your boot-able Pen-drive until it saying to remove it.

I faced same issue like yours and above was helpful.
Comment: you could format your buttons better with  ... .

Check finished errors found in 1 file


navigate images in Fancybox using jquery

Question: On my website, when someone clicks on an image, it gets enlarged I would like a navigation  arrow to appear either side of the photo for people to scroll from photo to another. And photos should get scrolled when navigation arrows are clicked. I've used fancybox to display gallery.
Answer: <code>jQuery("#fancybox-left").show();
jQuery("#fancybox-right").show();
</code>
this will display both side arrows if you have not intiated them while initiating fancybox.


tag names on photo ios

Question: I want to tag names on photos just like in instagram
e.g
before uploading we specify tag name on specific places

after upload when we click on image the name is displace on that places where we specify.

I just want that functionality. The approach which I am thinking that we store x,y position where the tag name appear and embed in the name of image but that approach is not good. any other suggestion?
Answer: Have you considered creating a database table with he following fields?
<code>image_id, /* The image where the tag is in */
person_id, /* The person who is tagged in this image */
x_pos, /* The X Position of the tag */
y_pos /* The Y Position of the tag */
</code>
If yes, what kind of problems did you run into?

tag names on photo ios


Charging a car battery through cigarette lighter

Question: I have an extra car battery that I'd like to charge on a long upcoming drive. I have a spare cigarette lighter plug with ~16 AWG wire. If I use that to connect the battery to the cigarette lighter port, will that charge the battery while the car is running, or am I going to get too many amp flowing through the accessory circuit and blow a fuse?
Comment: Two questions, to clarify: what rating is the battery, and what type of charger are you planning to use (and what is its charge current rating)
Answer: If an adequate length, your 16AWG wire may provide adequate resistance to prevent blown fuse problems.  If 10 feet long, it will be about 0.08 ohm.  Longer may be better for this application.
To experiment, you may want to use an in-line fuse holder with a fuse value less than than of your car's cigarette lighter outlet (usually 15A).  That way, if you do end up blowing a fuse, it's one that is easy to replace.
Answer: This is not really an advised approach for charging the battery. A car battery can demand a lot of charge current if the source can provide it. You will very likely blow out the accessory fuse if there is one in series with the lighter port.
Also the 16 AWG wire is not really a suitable gauge for charging a car battery. You should take a look at the size of the wire that is in your car from the alternator over to the battery and you will get a better idea of the more suitable gauge of wire used for this application.
Finally you have to consider the fact that any battery you attempt to parallel into the car electrical system will also try to feed back into the system when the system demands current draw such as when you try to start the car. Current flow in these conditions could exceed the current when you were attempting to charge the battery.
If you do intend to fix things up to support two batteries at once it is really important that you consider getting an automotive battery splitter (often available at RV supply outlets). These things generally consist of two diodes that feed from a common input terminal to a pair of output terminals. The high current lead from the alternator output feeds the splitter input terminal. One output terminal is used to feed out to the existing battery plus car electrical system. The other output terminal is used to feed to the secondary battery. The installation of such device gives you the basis to install the suitable heavy guage wire to the second battery. The diodes in the splitter solve the problem of back feed from the second battery back into the car main electrical system during cranking or low main battery conditions.
Answer: Depending on how discharged your battery is you either would not have any problems or would blow the fuse.
Use a resistor to limit the maximum current. Something like 0.1Ohm to 0.5Ohm would probably be OK.
Answer: Your battery will charge very nicely this way. But the second your car demands current from the main battery, your charging battery will attempt to provide around 50% of this current backwards through the cigarette socket which could burn out wiring, let alone the fuse. Get a proper battery charging kit as made for trailers and caravans. Leave the cigarette light for light current use only!
Comment: If the instantaneous current under load from the car were enough to blow the fuse, then the instantaneous current to charge the battery would be too.


Graphitic acid-Its structure and properties?

Question: What exactly is graphitic acid? I know that it's obtained when you react graphite with concentrated $\ce{HNO3}$ and that its structural formula is $\ce{C11H4O5}$. But I can't find or deduce its structure. And also I am unable to find any of its properties, except that it's a yellow-green liquid insoluble in water.
Comment: $\ce{C4H11O5}$ is not a valid formula for any uncharged-non radical compound.  Perhaps this is the empirical formula?
Comment: Sorry it's C11H4O5
Comment: https://en.wikipedia.org/wiki/Graphite_oxide
Answer: Graphitic acid is a compound derived from graphite.
You may find it named "Graphite oxide" as well: as you see, it is obtained by reacting graphite with an oxidizing agent ($\ce{HNO3}$, for instance).
The structure resembles that of graphite, but it carries several oxygen-containing substituents, such as hydroxyl and carbonyl functions, thus having a less regular geometry, compared to that of graphite.
The exact features of the structure depend a lot on the method used for its preparation, and the layers may show some "defects", not described by this ideally planar model, but the key concept is this.
Here is a simple proposed structure for a single layer (source: Wikipedia)

Note that, just like graphite is made of several layers of graphene, graphite oxide is made of several layers that, upon reaction with a base, become graphene oxide.
Here you can find further information, and a nice image of a single graphene oxide film


discrete convexity arising in a simple discrete optimization problem

Question: Let $S$ be a fixed integer satisfying $S \ge 1$, let $a$ range over the integers between $1$ and $S$ inclusive, and for $i = 1, \dotsc, a$, let each $x_i$ range over the nonnegative integers, such that the $x_1 + \dotsc + x_a = S$ will be a partition of $S$.
Consider the discrete, constrained optimization problem defined by:
$$f(a; S) = \max\limits_{\{ x_i\}}\Bigl[ \ln\big(  \prod\limits_{i = 1}^{a} x_i \bigr)  \colon \;\sum\limits_i^{a} x_i = S \Bigr]$$
It is straightforward to determine the explicit value of $f(a; S)$ in terms of the floor $\lfloor \tfrac{S}{a} \rfloor$. Basically, the $x_i$ have to be as uniform as possible while remaining positive integers summing to $S$.
Intuition and numerical evidence suggest that $f(a;S)$ is discretely concave with respect to $a$, in the sense that
$$
f(a; S) \ge \tfrac{1}{2} f(a-1; S) + \tfrac{1}{2} f(a+1; S)
$$
for all integers $a$ in the range $1 < a <S$.
Can anyone suggest a simple proof of this fact?  It is easy to show via Jensen's inequality that $f(a; S)$ lies below the concave function $a \ln (S/a)$, but that of course is not enough.  Induction on $S$ does not appear terribly promising.
Answer: No sooner did I submit this than I realized that there is indeed a simple answer:
Note that $f(2a; 2S) = 2 f(a;S)$.  But by writing $2S = S + S$ and partitioning one $S$ into a sum of $(a-1)$ terms and the other into a sum of $(a+1)$ terms, because $f(2a,2S)$ is defined as an optimum, we see that
$f(2a, 2S) \ge f(a-1, S) + f(a+1, S)$.


Can I tour Paris during layover time on the way to Germany

Question: I have a single entry Schengen visa, and I transit through Paris where I need to wait for 12.5 hours as layover time. Can I use this time to tour Paris and get back to airport for my connecting flight to Germany?
Answer: Yes you can, legally speaking.
Because Schengen is a single travel area, once you are in it you are free to travel as you wish. You enter the Schengen zone in Paris, go through immigration there, and get admitted. Your flight to Germany is 'domestic', i.e. with no immigration controls.
If you are asking if you have time to do something useful, yes you probably do. At least you will be able to catch the major sights.


Ethernet-over-usb for wifi backhaul, any good?

Question: Is it reliable? I can't seem to find name brand RJ-45 to USB adapters anywhere ...makes me a bit skeptical of the whole thing. Is it just a wire conversion or are there inline resistors/caps/ICs?
Comment: The useful limit of a USB cable length  is much less than an Ethernet cable. I would not consider doing this.
Comment: What do you mean by using it for wifi backhaul, in this case? What devices do you have in mind? Are you planning to run an Ethernet cable and connect it to a USB port, or are you planning to run a USB cable that connects to Ethernet ports?
Comment: Well, I'm going to be using a RPI3B+ as a temporary wifi router and bridge so I need it to have two wired ethernet connections. One is built-in, the other I would have to kludge with a Ethernet-over-USB adapter. Backhaul means taking the packets sent via wifi and sending them up stream on the wire to another router, basically is my understanding. Convert a USB port to an Ethernet port is my plan.
Comment: John, that's good to know, well the device would be within five feet so I think voltage drop wouldn't be an issue.
Comment: If you can find a connecting device, 5 feet will not present any limitation for either length or speed.
Comment: [Ethernet-over-USB](https://en.wikipedia.org/wiki/Ethernet_over_USB) is not the same as using a USB-to-Ethernet adapter (which are readily available).
Answer: There are literally a zillion of these things -- just look on Amazon for "usb ethernet adapter" and you'll have your choice of them.
They are actually very reliable.  If you look at most new thin laptops, you'll find that many do not have ethernet ports anymore.  They use USB Ethernet adapters instead.
Now, some caveats...

The 3B+ only has USB2.  USB 2 is kinda slow.  So, while you can find gigabit usb ethernet adapters, you wont get that speed.
USB on the Rpi3B+ handles everything... ethernet, usb ports, wifi, SDCard, etc.  So, while it will still work, be aware that the USB bus could get saturated.  The ethernet port on the rpi3b+ is actually a usb ethernet adapter built into the rpi.
The rpi CPU may not be beefy enough to handle all of this traffic, especially if you think you'll be trying to shove 100mbit across each interface.
Double-check me on this one, but I think the entire USB bus on the 3b+ is limited to 41MBps or 328mbps.  That really isn't much for 3 network adapters to share, along with everything else crammed onto that bus.

From a reliability standpoint, there's no reason to think it wont be reliable just because it's a usb ethernet adapter.  If there's a reliability problem, it will most likely be in the 3b+'s USB bus capacity.
What you are trying to do, conceptually, is a great idea for an rpi.  But, in all honesty, I'd suggest you use an rpi 4 instead.  It's USB bus is 10x faster (USB3 vs USB2) and it's onboard gig ethernet has been separated from the USB bus. Plus, it has a faster CPU and more memory.
Answer:
Is it just a wire conversion or are there inline resistors/caps/ICs?

It's not anything like a wire conversion – a computer's USB controller is physically incapable of understanding the Ethernet signal.
Instead, these are fully active devices containing a bridge IC which speaks USB on one side and Ethernet on the other. They receive Ethernet data frames and forward the data through a USB endpoint, and the OS has a driver which presents it as a network interface. Fundamentally this works the same way as a PCI-based Ethernet card would.
(In fact, the built-in Ethernet port on older Raspberry Pi versions was internally attached through USB in basically the same way as these external adapters.)

I can't seem to find name brand RJ-45 to USB adapters anywhere ...makes me a bit skeptical of the whole thing.

The adapters are assembled by various brands, but internally they commonly use chips produced by reputable companies such as ASIX (e.g. AX88179) if you're lucky or Realtek (e.g. RTL8153) otherwise. However, their Linux driver support varies.


I purchased the Windows 10 Minecraft for Xbox, can I play it on Windows 7 pc?

Question: I'm trying to get Minecraft on my pc so I can mod. I have paid for it on Xbox, but it's saying I need to buy it again. I am on Windows 7 so I don't know if that is a problem or not.
Comment: You could try to get a refund if you're fast with it. The "Java edition" works on all computers and is generally better.
Answer: No, that is not possible. I tried with the Nintendo Switch and it doesn't work either. You have to buy it separately(I know, what a rip!).
Answer: The problem here is that you're using the "Bedrock Edition", which only works on XBox, Playstation, and Windows10, and also suffers from less support with mods. The cheapest option would be to purchase a copy of Minecraft "Java Edition", which is the main edition for PC, and mod that, as purchasing a copy of Win10 is upwards of $100.
Comment: *Only works on Xbox, Playstation, Mobile, Switch, Windows 10


Where is Pave and why is Festival not being celebrated?

Question: Today I logged on to animal crossing new horizons. I was expecting Isabelle to were a fun hat, confetti flying around, villagers dancing, and Pave in the plaza. Instead I got nothing. I have the latest version. I bought all the furniture and clothing items. There was even a notice on the bulletin board saying Festival was on the 15. Do I have to wait later in the day or is my game glitched?
Comment: you're not alone, I didnt get it either. Upon starting the game today everything went back to "normal", all the lights and decorations around the town center vanished.
Answer: As mentioned in my comment. There was a bug and starting the game from passive sleep had everyone forget about festivale. To fix it, I closed the game down completely and restarted it.
After doing so, Isabelle was back on the announcements to start the event.
Comment: I restarted my switch and it didn't do anything
Comment: Well there's always next year. From now on when I'm done playing I will always turn my switch off instead of on sleep mode.
Comment: that's unfortunate, but to be honest it was a really bad event... so you didnt miss much :)
Answer: this has happened to me but you have to have the upgraded town hall to celebrate festivals.


java.lang.OutOfMemoryError: Java heap space

Question: My result set is too large. If its returning a huge data set which consumes memory, then it displaying OutOfMemory error in server. How can I handle this problem apart from increasing the heap size?
Comment: A resultset isn't normally entirely in memory at once. You're probably keeping what you read somewhere and here's the problem.
Comment: @OmarMEBARKI "apart from inrease heap size"
Comment: use option  -Xmx1024m to increase your heap space
Comment: can not you query with limit option? like in - http://www.tutorialspoint.com/mysql/mysql-select-query.htm ?
Answer: Try don't put so many data per one time, use paginator or something like this.
Comment: When you correctly request a database, the resultset isn't entirely loaded, you may very well iterate over a huge database with small memory.
Answer: Check your query for the resultset is correct/ optimised in the first place.
And in most databases you can restrict the number of rows returned anyway with something like
SELECT top(1000) * FROM mytable;

Answer: Use a paginator pattern: instead of getting everything at once, periodically get only partf of the data. For example, instead of getting 100 results, you can get 20 results 5 times: 0-19, then 20-39, then 40-59, etc...
Answer: If you can't load the entire resultset into memory .... then don't!  I can think of three alternatives, depending on the situation:

Only read part of the resultset at a time; e.g. get it in "pages".
Reduce the resultset as you read it; e.g. by extracting the fields you need, tabulating, or whatever.
Restructure your query so that the data reduction can be done in the database.

If you provided more details of what the resultset contains and what you are doing with it, we may be able to offer concrete suggestions.
Answer: If you can structure your query so that a single query can return everything you need then with result set streaming you can get the database to return results to you one row at a time. Your memory use is then drastically reduced at the expense of increased data traffic between your client software and the database. In my own company we find this very effective when working with result sets with millions of rows returned. This functionality is database dependant, for MySQL it is described at
http://dev.mysql.com/doc/refman/5.0/en/connector-j-reference-implementation-notes.html


Can floor constructions be placed under furniture, or do you have to move it first?

Question: Is it possible in Dwarf Fortress to add floor constructions without having to move furniture that is already occupying the same space? How should I do that?
Comment: I'm not sure what you mean by "add floor" and "move furniture" here. Are you asking about how to build a ceiling, or if furnitures can support floors without them caving in?
Comment: @YiJiang'sEvilClone You can build floor constructions, sort of laminating over the existing natural floors. It's not obvious in-game that it's even possible, but this question makes a lot more sense once you've discovered that you can do that.
Answer: No, if you've already built furniture you can't then build a floor tile underneath it.
You'll need to dismantle the furniture first, build the floor, then rebuild the furniture. Also don't bother engraving the stone first if you're going to floor over it, building a floor (or furniture) over an engraving destroys the engraving, which can lead to unhappy thoughts if you accidentally deface someone's masterwork.
On the other hand, smoothing out the stone beforehand is useful as free practice for your engravers.
Comment: Building furniture won't destroy engravings. Constructions replace the floor on a tile, but the floor still exists under furniture, and the engraving can be examined. A simple example is the door, where you can still see that the floor is engraved.


Difficulty creating Spdlog asynchronous file logger

Question: I am trying to make a logger for my application which doesn't run in the main thread. I am using a wrapper class, Logger, around spdlog. The class has a private static data member of type std::shared_ptr<spdlog::logger> which gets initialized in an init() function. I am able to successfully create a spdlog::sinks::basic_file_sink_mt but when I try to use spd::async_factory it won't compile.
Logger.h
class Logger {
public:
  static void init();
private:
  static std::shared_ptr<spdlog:::logger> my_logger;
}

Logger.cpp
std::shared_ptr<spdlog::logger> Logger::my_logger;

void Logger::init() {
  spdlog::sink_ptr my_sink = std::make_shared<spdlog::sinks::basic_file_sink_mt>("myfile.log", true);
  my_logger = std::make_shared<spdlog::logger>("Application", my_sink);
}

This solution seems to work. It logs to the file, but the issue is that it is in the main thread. I try updating the logger to be asynchronous by changing the line std::make_shared<spdlog::sinks::basic_file_sink_mt> to be std::make_shared<spdlog::sinks::basic_file_sink_mt<spdlog::async_factory>> as follows:
void Logger::init() {
  spdlog::sink_ptr my_sink = std::make_shared<spdlog::sinks::basic_file_sink_mt<spdlog::async_factory>>("myfile.log", true);
  my_logger = std::make_shared<spdlog::logger>("Application", my_sink);
}

When I try this I get compilation errors. What can I do to set my member variable to be an async logger?
Thanks for reading all of this, and thanks for the help.
Answer: Try this:
auto my_logger = spdlog::create_async<spdlog::sinks::basic_file_sink_mt>("async_file_logger", "myfile.log");


Is there a relation between the words "import" (trade) and "important" (valuable)?

Question: Is there a relation between the words import (in a trade sense) and important (special, etc)? It seems to me that there is, or rather that there should be, but I was wondering if anyone can give some proper clarification.
Comment: *Important* means *of import*. But I suppose you're asking about *import* as an antonym of export. I'd make it clear in your question if I were you.
Answer: The etymology of the two terms shows that they have the same origin, the Latin 'importare' (bring in):
Import (v.):

early 15c., "convey information, express, make known, signify," from Latin importare "bring in, convey," from assimilated form of in- "into, in" (see in- (2)) + portare "to carry" (see port (n.1)). Sense of "bring in goods from abroad" first recorded c.1500.

Important(adj.):

mid-15c., from Middle French important and directly from Medieval Latin importantem (nominative importans), present participle of importare "be significant in," from Latin importare "bring in" (see import).


changing android package name

Question: I want to change the package name for an app which is not yet published in the Market. Is there a way to use the new package name as the uniqueId on Market/Play and while still using the old package name in my code?
Comment: `R` is always generated in the package that is defined in `package="your.package.here"` in the manifest. Your java files can use a different package though. You may need to fix the import of `R` manually if you change the manifest.
Answer: Changing the package name in the manifest will change how Google Play reads your package name.  You don't need to change the package name anywhere else to accomplish that.  In Eclipse, the package name for classes can be changed independently (directly under src).
As zapl mentions, you may need to handle a few manual items if your application package name differs from that of the classes within (shortcuts that assume everything is in the same package don't always work in that case).  For example, using ".classname" may need to change to a fully qualified classname in the manifest and elsewhere.
If you're looking for a way to change the package name to be different in Google Play than it is in the manifest, then no you can't (it wouldn't be a good idea anyway).  You can, however, use library projects to create a new app with the new package name without changing the original code or manifest.  Minimal code/xml would need to be written.

changing android package name


What does the Bible mean in Exodus 20:4 when it speaks of "the waters under the earth"

Question: What does the Bible mean by "in the waters under the earth" ? What is found in the waters under the earth? Fish, gold, silver, and other creatures and precious stones, metals, and minerals in the waters under the earth?
Comment: Welcome to BHSX.  Thanks for your question.  Please remember to take the tour (link below) to better understand how this site works and what sort of question are appropriate.
Comment: @Dottard  Given that the tags the asker has chosen are "Genesis, Hebrew, Jesus, Luke, contradiction," and given that this forum is ostensibly for the interpretation of these scriptures, and given that the expression in question, "the waters under the earth," appear in the Bible--in the Ten Commandments, even--it seems clear that this question _is_ addressing a Biblical topic.  Add the fact that the asker is a "New contributor" here and may not understand all of what is generally expected, and I would urge a little clemency, courtesy, and Christian spirit.
Comment: @Polyhat - except for the following: The OP does not mention (1) commandments (2) any specific Bible passage; but that the OP does ask about a mythical creature not in the Bible, there is little that Biblical therapeutics can offer this question.  Further, neither the 10 commandments nor "waters under the earth" appear in Genesis.
Comment: @Polyhat The rules are quite specific. And without those rules the site would quickly descend into chaos.
Comment: @Dottard  If the asker is knowledgeable of all the facts before asking, then there were no reason to ask.
Answer: In the creation account of Genesis 1, God created the firmament to divide the waters.  Following this, they are divided into the waters under the firmament, named "Heaven," and the waters which were above the firmament.

And God said, Let there be a firmament in the midst of the waters,
and let it divide the waters from the waters. (Genesis 1:6, KJV)
And God made the firmament, and divided the waters which were under
the firmament from the waters which were above the firmament: and it
was so. (Genesis 1:7, KJV)
And God called the firmament Heaven. And the evening and the morning
were the second day. (Genesis 1:8, KJV)
And God said, Let the waters under the heaven be gathered together
unto one place, and let the dry land appear: and it was so. (Genesis
1:9, KJV)
And God called the dry land Earth; and the gathering together of the
waters called he Seas: and God saw that it was good. (Genesis 1:10,
KJV)

In the Ten Commandments, these waters which were under the firmament, and which had been separated from the dry land (Earth), are also said to be "under the earth."

Thou shalt not make unto thee any graven image, or any likeness of any
thing that is in heaven above, or that is in the earth beneath, or
that is in the water under the earth. (Exodus 20:4, KJV)
For in six days the LORD made heaven and earth, the sea, and all that
in them is, and rested the seventh day: wherefore the LORD blessed the
sabbath day, and hallowed it. (Exodus 20:11, KJV)

These waters, then, were those that included all of the sea life that God had created on the fifth day of creation.
NOTE: The waters are below the level of the land, which is why they do not overflow the land.  In this sense, they are truly "under" the earth.  The Hebrew word here could also be translated as "beneath."
Conclusion
The fish, whales, and other sea life that God created in the sea are those things which are in the "waters under the earth."
Answer: The Bible informs us that the pre-flood environment was different from what we experience today.  Between the waters on the surface of the earth and the waters above, there was an expanse (Genesis 1:6-7).  Genesis 2:6 says that a mist went up from the land and this watered the whole face of the ground.
During the lifetime of Noah and his family, there was a global flood, and Genesis 7:11 tells us where  the water came from:

In the six hundredth year of Noah's life, on the seventeenth day of the second month – on that day all the springs of the great deep burst forth and the floodgates of the heavens were opened.

This suggests that great quantities of water came from below the earth as well as from above.  Although the Bible does not tell us any more about the waters that were below the surface of the earth, science does.  One view is that there may be an underground ocean three times greater than what we see on the surface of the earth.

Some scientists think Earth's oceans formed when icy comets hit the planet. But new research suggests a different origin for the oceans: they simply seeped out of the center of the Earth.  The finding, published in Science, suggests that a reservoir of water is hidden in the Earth's mantle, more than 400 miles below the surface. Try to refrain from imagining expanses of underground seas: all this water, three times the volume of water on the surface, is trapped inside rocks.  https://ssec.si.edu/stemvisions-blog/there-ocean-below-your-feet

This 2020 article suggests that he water stored in the inner layers of Earth may be more plentiful — and important — than scientists previously thought.

Under the extreme temperatures and pressures existing far underground, water breaks down into its constituent elements, hydrogen and oxygen, which are chemically bound to the rock's crystal structure. But to geophysicists, it's still water, regardless of the form it takes.  This begs the question: How much of this water is buried beneath the surface? The answer could help explain our planet's suitability for life and tell us how all this water got here in the first place.  Source: https://www.discovermagazine.com/planet-earth/the-search-for-earths-underground-oceans

To answer your question, what does the Bible mean by "in the waters under the earth", the Bible is not specific.  However science indicates that there are no "seas" that contain fish or other living creatures.  The water may contain traces of minerals, metals and diamonds, but not in a form that could be extracted and instantly recognised.
We do not need to know the details.  After all, the Genesis account of creation and the flood is not meant to be a scientific paper.  Rather than looking into the bowels of the earth, we do better to lift our eyes to heaven to the creator of time, space, matter and all life and give Him our thanks.
P.S. Jesus Christ believed in the universal flood and took it as the type of the coming destruction of the world when He returns (Matthew 24:37-39; Luke 17:26-27). Hebrews 11:7 also refers to the flood during the time of Noah.
Comment: @Marshall - Do you have any research material/sources that might be used as an answer to this question?  I liked your question about red hair/scarlet thread and twins in the O.T.
Comment: I don't interpret "water" so literally. Water in the Bible is most often used symbolically. Usually its associated with "words" or "speech". God is described as having a voice of "many waters". Jesus and Paul say believers are "washed with water" through the word. Jesus the word gives "living water". Attacks describe water in a negative way. The serpent "spews water out of its mouth" at the woman in revelation. King David says the floods and seas have "lifted their voices" against him in psalm 93. My understanding is it's talking about people/voices under the earth. That would be Sheol/Hell
Comment: @Marshall - I am aware that some people do not think the global flood was a literal event, but I do not share the view that "water" (in this instance) is symbolic. Your interpretation of people/voices under the earth being a reference to Sheol is one I have never heard before. Interesting.
Comment: Recently I have been doing a lot of study / prayer to understand specific key symbols of scripture and their meaning based on how they are used throughout the whole bible.
Water is really one of the trickier ones and I'm still considering and meditating on it. So this post was really kind of thinking out loud while pondering the question and your response :)  Some of the symbols are easier to understand.
Trees = A person/being or group of people
Fire / Cloud = the holy spirt
So things like burning bush = being filled with the holy spirit (Jesus/God)
Water and its usage is trickier
Comment: Also despite the above I don't automatically believe there wasn't a global flood. God speaks in parable - but in the old testament he seemed to like to have the spiritual symbology of the parable - literally acted out. So I think its possible for potentially the symbolic meaning and literal meaning to both be true. But what happened physically is representing something else on a spiritual level. The water was real - but it represents something else. Just like later the wells they dug or met wives at were real - but they represented something else.
Comment: I will try and put something together with scriptural references. :) I think I might need a few days to do so as like I said - my post on your answer was really me thinking out loud over the scriptures I had been studying on water while I pondered the question and your answer.  Think I will need to put my own thoughts together properly before I can gather the referrences and answer :)
Answer: The phrase "in the waters under the earth" is used in context of forbidding idol worship and making graven images for idol worship.  In addition to the prohibition of Ex. 20:4 we find -

"16 lest ye do corruptly, and have made to you a graven image, a similitude of any figure, a form of male or female --

17 a form of any beast which [is] in the earth -- a form of any winged bird which flieth in the heavens --

18 a form of any creeping thing on the ground -- a form of any fish which [is] in the waters under the earth;  (Deu. 4:16-18, YLT)

also see:

"`Thou dost not make to thee a graven image, any similitude which [is] in the heavens above, and which [is] in the earth beneath, and which [is] in the waters under the earth;"  (Deu. 5:8, YLT)

Therefore, as they were forbidden to make graven images of either men or women, or any creature or object they could see in the heavens above, or in the waters under the earth, then the context has to include the objects or creatures they could see in the waters under the earth, ie: whales, fish, corals, dolphins, starfish, eels, etc.
We do know that some forms of life have become extinct due either to Noah's flood, or to excessive hunting by mankind, so some of the creatures that may have appeared very large or fearsome as to inspire awe are no longer with us.  But, the context was concerning making images of things they could see.
The implication of "the waters under the earth" is very interesting when examined more thoroughly.  If interested you might read my post "Is the Earth Hanging Upon Nothing>" here: ShreddingTheVeil


Cancel SQL Job execution make automatic rollback

Question: I have a SQL SP which has a set a transaction. All the statements handled inside the TRY CATCH block. If we explicitly cancel the job by close the button in the JOb execution window, will it get into the catch block and automaticall rollback all the transaction tried in the TRY block ?
Answer: No, it probably won't. I can't say for sure, but client "aborts" normally don't rollback if the connection is returned to the connection pool
Add SET XACT_ABORT ON to your code or stored procedure
See (SO) https://stackoverflow.com/questions/917773/do-i-really-need-to-use-set-xact-abort-on/919279#919279 and SQL Server Transaction Timeout
Answer: I would say no. Assuming that pressing close button sends "stop notification" then here is what msdn says:
"When SQL Server Agent receives the stop notification, it waits for the job step that is currently running to finish before it processes the cancel request. Some long-running Transact-SQL statements such as BACKUP, RESTORE, and some DBCC commands can take a long time to finish."


Why are healthcare costs so inflated in the USA?

Question: I have seen much more inexpensive non-socialized medicine in places such as Puerto Rico, with equal or greater standards of care and outcomes. I would like to understand why the USA is not like that.
Comment: This question is political and might be on topic for Politics.SE, but it's definitely not about medical science and thus off topic here.
Comment: I'm closing this question because it's a political question, not medical.
Answer: There are several reason actually, I will try to sum it for you:

Doctors in USA is very careful when dealing with patient. They may require several test and check before make the decision about the treat that patient need to take.
High administrative cost. Government in most of the developed countries play roles to rule the cost of medicare, but medical care in USA is different due to lack of political support for the government taking a larger role in controlling healthcare costs.
Comment: Welcome to the site and thanks for the answer, but as you can see the question is off topic here. Your second point highlighted that it's a political question with your link to investopedia.


What are the names of the Summer Getaway Badge levels on Steam?

Question: After crafting the Summer Getaway Badge I noticed that it had multiple levels. What are the names of the various levels?
Comment: It's the same as every other badge out there, so I don't understand what's the point of this question.  All normal cards can be crafted up to Level 5, and Foils can be crafted up to Level 1.
Comment: Your first edit was a little ambiguous, but your edit actually made it a lot clearer. I posted that comment because the question was so vague 'what are the levels for the badge?"
Comment: Retrosaur, the question isn't about the number of levels. It is a question of the names. Still, thanks for the info on the foils, that was a little obscure to me.
Answer:
Steam Sightseer
Digital Day-Tripper
Virtual Voyager
Joystick Jester
Vacation Veteran

I have first hand confirmation of levels 1 through 5. According members in the Steam forums there exist a Foil badge, Gaming Globetrotter. I have yet to confirm its existence as I have no foil badges.


Sun's corona is so much hotter than Chromosphere

Question: What makes Sun's corona so hot? I tried to google it but can't find satisfactory answer.
Answer: This has been a puzzle for many years, here is what's thought to be at work in this situation:
The Sun has a powerful magnetic field that extends a significant distance from the edge of the photosphere, which represents what we see as the "surface" of the sun.
The atmosphere of the Sun (by this I mean the gases that exist outside of the photosphere) are at least partially ionized and as such are electrically conductive.
Since the Sun revolves, its magnetic field sweeps through that atmosphere and induces eddy currents in the ionized gas out there.
This in turn causes significant amounts of I-squared-R power dissipation in that part of the sun's atmosphere, which heats it up.
I invite the experts here to weigh in with their perspectives on this.
Comment: there's plenty of magnetic field out there to do the work, and only a tiny amount of mass to apply it to.
Comment: Also note that the corona has a low density, around $10^{-16} g/cm^3$, so a given volume of corona material contains much less heat than the same volume of material at the photosphere.
Comment: Okay..but by this concept chromosphere should be hotter than photosphere which the case is. But corona is farther than surface of sun then how can you explain that?

Sun’s corona is so much hotter than Chromosphere


In UML class diagrams, what are Boundary Classes, Control Classes, and Entity Classes?

Question: I'm now using NetBeans as my IDE-of-choice, and it has a plugin for UML modeling. In the class diagram, there are model elements known as Boundary Class, Control Class, and Entity Class. However, I can't find a good definition of them, but I did find this site on UML Class Diagrams.
Comment: Wikipedia explains all you need to know about the [Entity-Boundary-Control pattern](https://en.wikipedia.org/wiki/Entity-control-boundary) and related concepts.  It provides lots of sources for additional reading, if you need to know more.
Answer: Robustness diagrams are written after use cases and before class diagrams. They help to identify the roles of use case steps. You can use them to ensure your use cases are sufficiently robust to represent usage requirements for the system you're building.
They involve:

Actors
Use Cases
Entities
Boundaries
Controls

Whereas the Model-View-Controller pattern is used for user interfaces, the Entity-Control-Boundary Pattern (ECB) is used for systems. The following aspects of ECB can be likened to an abstract version of MVC, if that's helpful:

Entities (model)
Objects representing system data, often from the domain model.
Boundaries (view/service collaborator)
Objects that interface with system actors (e.g. a user or external service). Windows, screens and menus are examples of boundaries that interface with users.
Controls (controller)
Objects that mediate between boundaries and entities. These serve as the glue between boundary elements and entity elements, implementing the logic required to manage the various elements and their interactions. It is important to understand that you may decide to implement controllers within your design as something other than objects – many controllers are simple enough to be implemented as a method of an entity or boundary class for example.
Four rules apply to their communication:

Actors can only talk to boundary objects.
Boundary objects can only talk to controllers and actors.
Entity objects can only talk to controllers.
Controllers can talk to boundary objects and entity objects, and to other controllers, but not to actors

Communication allowed:
         Entity    Boundary   Control
Entity     X                     X
Boundary                         X
Control    X          X          X

Comment: Judging by the comments, this answer isn't helping people appreciate the difference between "Entity Boundary Control" and MVC. One of them is that a Boundary is not a View; it's an element of the system that manages communication with elements outside the area under design, whatever that area might be. For example, a PayPal REST API facade inside your system might be a boundary element. Furthermore, your subsystems may have boundaries of their own. Compare this to a View, which is always a View from any perspective, and is always user-facing.
Comment: This answer does include say the same thing, really: "Boundary: Objects that interface with system actors (e.g. a user **or external service**)". Anyhow, my point is that they are different: ECB is not a "simplification" of MVC.
Comment: A point, these stereotype do not seem to be define in UML specification ...
Answer: Often used with/as a part of OOAD and business modeling.  The definition by Neil is correct, but it is basically identical to MVC, but just abstracted for the business.  The "Good summary" is well done so I will not copy it here as it is not my work, more detailed but inline with Neil's bullet points.
Good summary - Conceito: Entity-Control-Boundary Pattern
OOAD
Comment: But MVC is only for view layer.
Comment: The answer should contain information and not only link to it. Unfortunately the link is dead.
Comment: @ted-johnson Any chance for an updated link? Thanks!
Comment: Updated link to similar site that had content.
Answer: These are class stereotypes used in analysis.

boundary classes are ones at the boundary of the system - the classes that you or other systems interact with
entity classes classes are your typical business entities like "person" and "bank account"
control classes implement some business logic or other
Answer: Actually, the Robustness Diagrams (or Analysis Diagrams, as they are sometimes called) are just specialized Class Diagrams.  They are a part of UML, and have been from the beginning (see Jacobson's book, The Unified Software Development Process - part of the "Three Amigos" series of books).  The aforementioned book has a good definition of these three classes on pp 183-185.
Answer: Boundary Control Entity pattern have two versions:
- old structural, described at 127 (entity as an data model elements, control as an functions, boundary as an application interface)
- new object pattern

As an object pattern:
- Boundary is an interface for "other world"
- Control in an any internal logic (like a service in DDD pattern)
- Entity is an an persistence serwis for objects (like a repository in DDD pattern).
All classes have operations (see Fowler anemic domain model anti-pattern)

All of them is an Model component in MVC pattern. The rules:
- Only Boundary provide services for the "other world"
- Boundary can call only to Controll
- Control can call anybody
- Entity can't call anybody (!), only be called.
jz
Answer: For the records, the Entity-Boundary-Control pattern comes from use-case driven software development and is much older than Scott Ambler's robustness diagrams who only reused the concept.
The pattern is not part of UML, but is closely related to it because it was promoted by Ivar Jacobson (who initiated it in 1992), Grady Booch and Jim Rumbaugh, the founding fathers of UML... and of the Unified process (UP, RUP). In UML it's just stereotypes like any others.
The Wikipedia explains it best, but Control classes correspond to Use Cases,  Boundary classes correspond to the association between a Use-Case and an Actor, and Entities correspond to domain objects identified as being involved in the use-case.
The circulars symbols that most UML tools use with predefined BCE stereotypes are also from Jacobson.  The robustness rules are just the transposition of the use-case mapping explained above.


ASP.NET MVC - Model in Web project

Question: I'm new to ASP.NET MVC and inherited a project that uses the technology.
Such Web project contains three folders: Views, Controllers and Model. As I understand it, the Model contains in fact your domain / business logic and is called by your controllers. The controllers themselves act as delegators between Views and Model.
Now, in a typical layered architecture, there should be no references in any project to the Web/UI project.
I find this quite confusing:
-> The UI contains the Model, which is - in an ideal world - based on "Domain Driven Design"-principles.
-> The layers on top of the UI (Services and DataAccess) cannot have a reference to the UI
How can you write efficient services and dataaccess layers if they do not know your model?
What am I missing here? Is the Web.Model different from "DDD" and should I still have a separate BL project? If that is the case, then what is the Web.Model supposed to contain?
Answer: I view the Model as a concept. You can have a completely separate project containing your Domain (your entities, your services etc.) and reference that in your "UI" project. In this scenario this will be your "Model".
This is what I typically do, In my Models folder I keep "ViewModels", which I use for Binding/Validation (for the UI).
For example, If I have an Employee but I don't necessary want to use all its properties (or for that matter different properties), I will create an EmployeeViewModel adjust it the way I want, I'll add validation (if required) and I'll pass it to my View.
This is by no means, "the right way"/"only way", but It worked for me in the past, and I thought I'll share (also, I'm pretty terrible in explanations, so I really hope this post makes sense, in case it doesn't or clarifications are needed - please let me know).
Answer: You necessarily do not need to have your model in the same project. You can ofcourse have those in different layers.
This is how i usually setup my projects
1) UI Project - This is an MVC Web application type project where i will have my controllers and it's views and other UI related stuff
2) Business Entities - This will be a class library type project where i will define my domain objects ( Ex : Customer). This mostly looks similar to how my DB schema looks like. These are usually just POCO's which represent my domain modal ( I use this for the CodeFirst Database generation).
3) Data Access - This will be another class library type project which has the data access classes. Usually my repository class/interfaces, my DBContext class and other data access classes will be in this project.
4) Tests - Unit tests for the project

Business Entities project has been added as a reference to the Data Access Project so that i can use those classes in my Data access code.
Business Entities and Data Access Projects are added as references in UI Project. I would call the data access methods from my Controllers/ Service classes.
You may also add a Service/Business logic layer between your controller's and Data access layer as needed.
I have few ViewModel classes also inside my UI project ViewModels folder. I use this for some screens where i have to show data from multiple domain objects. I have a mapping/service class which maps the domain object to view model object. If your project is bifg, you may keep this as a serperate project under the same solution
Answer:
Views Contain your HTML Layouts
Controllers do the heavy lifting of getting data from the models or the models themselves and passing them to the Views.
Models are used to do actions for your BL or fetch data.

Tip : You can use a EntityFramework ( i'm recommending it because it's easy to get started with ) to fetch your data and it's dead simple to setup thus eliminating your DAL and saving you time from writing everything yourself.
Services : you can have controllers that return XML/JSON (other format?) by converting the data you have got from the DB to XML/JSON and returning that instead of a view.
Take a look at MVC 4 WebApi for more details,Note that you can pretty much the same thing with mvc 3 too
Also refer to asp.net/mvc site for tutorials to get you started, they are really useful.

ASP.NET MVC - Model in Web project


Photoshop Save for web batch not saving the right "Save For Web" size

Question: I am using Photoshop CS4 Version 11.0.2.  I make an action called Resize to 388px. I record the action as follows:
Start Recording
Image
Image Size
Adjust size of image down to 388px.
File
Save for web and devices
I choose JPEG Low
I check Optimized
Hit Save
Direct the save to the "Resized to 388px For Web" folder.
Save the file in the "Resized to 388px For Web" folder.
Stop recording

The size of the resulting jpeg file is 8k and the file dimensions are 388x388
When I run it in batch, the resulting file dimensions are correct, but the file size is much larger at 209k which is the same as when I simply change the file size and use "Save As" manually.
Here is How I run the batch:
File
Automate Batch
Source
Folder
Choose (Choose my source folder)
Check off Suppress File Open Options dialogs and Suppress Color Profile Warnings.
Destination
Choose (Choose my destination folder)
ok.

Can you explain what I am doing wrong or is this the normal result.
Thanks,
Bruce
Comment: what about resaving as 72dpi though?
Answer: I don't immediately see a problem there without testing it, but your simplest solution is to use the Image Processor script that comes with Photoshop and Bridge. I don't recall off-hand, but I'm pretty sure it's been around since CS2.

Select all the images in Bridge that you want to resize
Choose Tools > Photoshop > Image Processor. Bridge will open Photoshop if it's not already running and run the script, which starts with a dialog box.
Fill in the dialog with size, destination and any renaming you want to do
Click OK

You can also run this from inside Photoshop, with the extra step of selecting the images once the script starts running. It's simpler to start in Bridge.


Trying to make a solid shape out of this, but can't figure out how! (Adobe Illustrator 27.7)

Question: I'm trying to figure out how to make the red lines (selection, not drawn) into a single form. Does anybody have any idea how to do that in Adobe Illustrator? Because right now, as the tree said to the lumberjack, I'm stumped.
Comment: vector art is not like drawing. Its more like cutting with scissors so tryin to make that fill works just as well as expecting that path to cut one thing on paper. You need to rebuild this to only include the outermost lines. Should be quite easy with shapebuilder.
Comment: Hi. I'm not sure what you are actually trying to do here, but if you want a solid custom shape, then use the Pen Tool to make a closed path, then apply a fill to it. [see example here](https://imgur.com/a/0y7G9a1)
Comment: What's the "shape" supposed to be??? It looks just like a random scribble. Just add a fill color... or... click the `Unite` button on the Pathfinder Panel.. then adjust the fill color.
Answer:
Select it - Expand appearance (in object menu)

if you want just the outside line - you can release the compound path (Alt-sht-ctr-8) and use the first button in the pathfinder to have just the outside stroke


Why should we only keep the private key secret, why not the public key?

Question: If I am not wrong, both private key and public key are the same since communication is possible only if both keys are matching. So, why we should only keep the private key secret, why not public key? When I generate a key by ssh-keygen command, and save it on a directory, is it a public key or private key?
Comment: "both private key and public key are the same" -- citation needed
Comment: See [How does public/private key encryption work?](https://security.stackexchange.com/q/174599)
Answer:
If I am not wrong, both private key and public key are the same

Unfortunately, you are wrong. The private key and the public key are not the same.
The entire idea of public key cryptography depends on this difference. The public key is public, it can be published, it can be widely disseminated. The private key is private, it must be kept secret.
In practice, the form of the public key data may be similar to the form of the private key data, but the data is different and their function is very different. For example, the public key might be a large integer N and a small "encryption exponent" e whereas the private key might be that same large integer N and a "decryption exponent" d. Nevertheless, d and e are different (e is often well known whereas d is not).

since communication is possible only if both keys are matching. So, why we should only kept the private key secret, why not public key? When I generate a key by ssh-keygen command, and save it on a directory, is it a public key or private key?

In SSH, you use the private key to log into an ssh server. This server keeps your public key in the "authorized keys" directory. This DIRECTORY must also be protected--not necessarily the public keys in the directory. If anyone is allowed to put their public key in this directory then anyone will be able to login. So the authorized keys directory must be protected.
In this SSH use case, you probably just so happen to keep the public key secret too, but it doesn't necessarily have to be kept secret.
If you use the "ssh-keygen" command, it generates both the public and private key. The private key will probably be called something like "id_rsa" and the public key will probably be called something like "id_rsa.pub".
Comment: @MartinPrikryl I don't think that's true. I just created one to test, and the private key file contains a single base64-encoded block, delimited by "BEGIN RSA PRIVATE KEY" and "END RSA PRIVATE KEY"; if the public key is in there explicitly, it's not in a format that's trivial to extract. It is however true that you can _derive_ the public key from the private key, which may be what you're thinking of?
Comment: can I use `chmod 400 authorized keys` command to protect the authorized keys directory.
Comment: Many tutorials that I've seen on setting up an ssh server suggest `chmod 600 authorized_keys` rather than `chmod 400`
Comment: I've never tried `chmod 400` on that directory, but `chmod 600` should be fine.
Comment: @MartinPrikryl You *can* derive the public key from the private key in many cases. You can *not* derive the private key from the public key. For example, In RSA the public key is (N,e) where e is usually a well-known small prime (e.g., 0x10001). OTOH, in RSA the *private* key is (N,d) where d is *not* well-known. Therefore you can derive public from private in this case, but not private from public.
Comment: Not that this matters much, since the private key data structure usually already also contains the public exponent (since it is public). But clearly the public key data structure must not contain the private exponent.
Answer: A common analogy for asymmetric cryptography is a padlock and key. Like most analogies, it will fall down if taken too far, but I think it serves as a good top level explanation for questions like this.
The analogy goes something like this:

Alice wants to put something in a locked box, and let Bob open it, but she's worried someone will make a copy of the key if she sends it to Bob in the post.
Bob has a padlock which can be closed without the key, but only he has the key to open it. He doesn't mind if anyone makes identical padlocks, because that won't help them open anything, so he makes it available to anyone who wants it.
Alice takes Bob's padlock, and uses it to lock her box. Bob is now the only person who can unlock the box - not even Alice herself can do that.

For an SSH login, this corresponds to this:

Alice want to make a server secure, and let Bob log into it, but she's worried someone will make a copy of the password if she send it to Bob over the internet.
Bob has a public key which can be used to encrypt things, and only he has the private key to decrypt them. He doesn't mind if anyone copies the public key, because that won't help them decrypt anything, so he makes it available to anyone who wants it.
Alice takes Bob's public key, and marks it as the trusted key for an SSH user. Bob is now the only person who can log in as that user.

(As I said, the analogy soon falls down - in this case, you can authorise multiple public keys for the same SSH user. I guess you could say that there's a row of boxes locked with different people's padlocks, or something.)
Asymmetric keys always come in pairs, by definition. The ssh-keygen command will generate two files: one is the public key (the "padlock") which you can share however you like; the other is the private key (the "key") which you must keep secret.


Sharing one HDD and Printer in home

Question: I have two questions
-- I have 3 pc, two xp sp3 and one win 7. Now I have couple of external hard drive and printer and I want them to be accessible to all 3 pcs I have. Can somebody tell me how can I setup this network?
-- My second question is about installing a monitor driver properly. My current setup is I have on desktop with win 7 and two latptop with xp 3. All 3 pcs are connected to KVM switch so that I can switch between diff pcs. Now problem is when I use my desktop on my 25" HP HD monitor it just works, I dont have to change the resolution but when I switch to laptop(xp) then I have to manually change the resolution everytime I switch. Can somebody tell me how can I resolve this issue?
THanks
Answer: You can attach to printer and the drives to a computer and the enable Windows' File and Printer Sharing on all of them. This can get complicated because you're mixing versions of Windows, but can be done. There are numerous web tutorials available that have step-by-step instructions for setting up File and Printer Sharing on Windows. Windows 7 may even have a built-in "Wizard" to help you set it up.
As for your second question (which really should have been posted separately), what exactly do you mean by "I have to manually change the resolution everytime I switch"? Change the resolution of WHAT? Most monitors these days will auto-sync to the signal being sent to them.

Sharing one HDD and Printer in home


Is there a way to sync Xcode preferences and keyboard shortcuts across computers?

Question: I'd like to avoid having to do tweaking the keyboard bindings repeatedly for each machine I use Xcode on.
Sort of like copy the settings file to a particular location in the target computer's filesystem; doesn't need Dropbox.
Answer: Yes, at least for key bindings.  I'm assuming you're using Xcode4.  If that's the case, your Key Bindings are stored here...
~/Library/Developer/Xcode/UserData/KeyBindings
Just copy the 'sets' you want from one machine to the other and there you go.
Note that unlike Xcode3, Xcode4 now respects global bindings as well.  Global bindings are stored here...
~/Library/KeyBindings/DefaultKeyBindings.dict
Global bindings are for instance, if like me, you prefer the way cursor movement is handled in Windows (e.g. Home/End work on the line, CTRL Left/Right jump a word at a time, etc.) you can remap the keys for the overall system, and Xcode4 respects that.  In Xcode3, such changes had to be duplicated in its own key bindings file.
Also note that if the same key is defined in both the defaults and the Xcode4 file, the latter 'wins'.
Additionally, you can unmap a system-wide key when using Xcode.  This will disable that key when using Xcode, but leave it enabled elsewhere.
(If you open the actual key bindings file in say TextEdit or a PList editor (that's all these files are) then you'll see it still defines the command, but leaves the key itself cleared out.
Something else that may be of interest is KeyBindingsEditor.  It's a great editor for creating system-wide shortcuts.  While it claims to support Xcode, it doesn't (or rather Xcode 3 and 4 it doesn't.  I can't speak to earlier.)
However since again Xcode 4 can utilize system-wide shortcuts now, you can use this indirectly with Xcode.  I personally am very happy about that as now, no matter where I am, including Xcode, my keyboard shortcuts are unified across the entire system.
HTH, Mark
Answer: Adding to Mark's answer, setup dropbox to point that file to ~/nameofyourchoice on all of your machines, and viola, everything should be synced.  You'll need to test it out to see if other machines don't overwrite etc.


Upgrade Solidity contract

Question: i am upgrading my contract to a new implementation.
I was wondering if i mistakenly put wrong positions of variables in my new implementation and get my data corrupted, can i upgrade back to original implementation again, and would that fix my issue?
Answer: You can, but it depends on what you mess up.  If you accidentally change the total supply or some balances, you'll have to change them back.  If you just upgrade to the zero address for instance and don't change anything else, you can just switch back just fine.
Answer: If the storage gets messed up because of updating to a contract that has different positioning of old variables, you can easily update your contract again to old version, and no data will be lost.

Upgrade Solidity contract


"connect to address x.x.x.x port nnnnn Connection refused"

Question: When I ssh ( Openssh (7.2p2 ) to (Ubuntu 16.04) server from the (Ubuntu 18.04) workstation for the first time I get the following message "connect to address x.x.x.x port nnnnn Connection refused" (port 22 is not being used ) and ufw has been set to allow the port number being used.
Answer: Make sure your sshd.service is running:
$ systemctl status sshd

If it is not running, run it:
$ sudo systemctl start sshd

Connection refused could be because of the service is not running, the port is wrong or firewall could block it.
You could allow ssh by the next command:
$ sudo ufw allow ssh

Check if your service is actually running on specified port (replace 22 to your own specified port):
$ sudo lsof -i -n -P | grep "22 "
cupsd       791            root    7u  IPv4  27822      0t0  TCP 127.0.0.1:631 (LISTEN)
sshd      10927            root    3u  IPv4 135947      0t0  TCP *:22 (LISTEN)
sshd      10927            root    4u  IPv6 135949      0t0  TCP *:22 (LISTEN)

Check if you could connect to localhost first:
$ ssh user@localhost -p 22
Welcome to Ubuntu 20.04 LTS (GNU/Linux 5.4.0-29-generic x86_64)

Comment: Thanks for the tips which will become useful later on. I had to purge the installation using apt-get purge openssh-server  and then re-install. Purging seemed to work better than re-installing although I think your comments would have helped had I known about them at the time. I seem to be getting another problem and that of the system appearing to login Ok but defaults to the client installation. Any ideas? Thanks again..


Bogoliubov transformation for fermion (exercise in Piers Coleman)

Question: I am trying to solve the exercise 3.2 in Piers Coleman's Introduction to many body physics. It's about fermionic Bogoliubov transformation with only 2 fermion operators $a_{1}^{\dagger}$, $a_{2}^{\dagger}$, $a_{1}$, $a_{2}$.
The canonical transformation is
\begin{align}
& c_{1} = u a_{1} + va_{2}^{\dagger} \\
&c_{2}^{\dagger} = -va_{1} + ua_{2}^{\dagger}
\end{align}
The starting Hamiltonian is
\begin{equation}
H = \epsilon(a_{1}^{\dagger}a_{1} - a_{2}a_{2}^{\dagger}) + \Delta(a_{1}^{\dagger}a_{2}^{\dagger} + H.C.)
\end{equation}
I have already successfully transformed the above $H$ into
\begin{equation}
H = \sqrt{\epsilon^{2} + \Delta^{2}} (c_{1}^{\dagger}c_{1} + c_{2}^{\dagger}c_{2} - 1)
\end{equation}
where $u=cos\theta$ and $v=sin\theta$ with $\theta$ satisfies $tan2\theta = \frac{\Delta}{\epsilon}$.
I am now struggling with finding the ground state of the Hamiltonian in terms of (1) vacuum state of $a_{1}$ and $a_{2}$ (2) $a_{1}^{\dagger}$ and (3) $a_{2}^{\dagger}$.
I know that the ground state energy is $-\sqrt{\epsilon^{2} + \Delta^{2}}$ and the ground state should also satisfies
\begin{align}
& c_{1}\left| {G} \right\rangle = 0\\
& c_{2}\left| {G} \right\rangle = 0
\end{align}
I have browsed some website and it seems that it is possible that I assume the ground state as
\begin{equation}
\left| {G} \right\rangle  = x \left| {0,0} \right\rangle + y \left| {1,1} \right\rangle
\end{equation}
where
\begin{align}
& a_{1} \left| {0,0} \right\rangle = 0\\
& a_{2} \left| {0,0} \right\rangle = 0\\
& a_{1}^{\dagger} a_{2}^{\dagger} \left| {0,0} \right\rangle = \left| {1,1} \right\rangle
\end{align}
But I found that I can not get a proper $\{x,y\}$ coefficients to make
\begin{equation}
\left| {G} \right\rangle  = x \left| {0,0} \right\rangle + y \left| {1,1} \right\rangle
\end{equation}
well-defined.
I think this is a rather easy exercise but I just can not find the ground state haha. I will be extremely grateful for any suggestion! :)
Edit :
It turns out that I find that answer and it is rather easy, as follow.
We want to find a state $\left| {G} \right\rangle$ that satisfies
\begin{align}
& c_{1} \left| {G} \right\rangle = 0\\
& c_{2} \left| {G} \right\rangle = 0
\end{align}
The key properties are $\{ c_{1},c_{1}\} = 0$ & $\{ c_{2},c_{2}\} = 0$.
We now construct a state $\left| {\psi} \right\rangle = c_{1}c_{2} \left| {0} \right\rangle$
where $a_{1}\left| {0} \right\rangle = a_{2} \left| {0} \right\rangle = 0$, meaning that $\left| {0} \right\rangle$ is the vaccum w.r.t the original fermionic operators $a_{1}$ & $a_{2}$.
Let's see whether this trial $\left| {\psi} \right\rangle$ can satisfy what we require for the ground state.
First, we apply $c_{1}$ on $\left| {\psi} \right\rangle$ and we have $c_{1}c_{1}c_{2} \left| {0} \right\rangle = 0$ according to $\{ c_{1},c_{1}\} = 0$.
Similarly we apply $c_{2}$ on $\left| {\psi} \right\rangle$ and we again get $0$.
This proves that $\left| {\psi} \right\rangle = c_{1}c_{2} \left| {0} \right\rangle$ is the $\left| {G} \right\rangle$ we are searching for.
So, if we write $\left| {G} \right\rangle$ explicitly, it will be
\begin{align}
 c_{1}c_{2} \left| {0} \right\rangle &= (u a_{1} + va_{2}^{\dagger})(-va_{1}^{\dagger} + ua_{2}) \left| {0} \right\rangle \\
& = ( -uva_{1}a_{1}^{\dagger} + u^{2} a_{1}a_{2} -v^{2} a_{2}^{\dagger}a_{1}^{\dagger}+uva_{2}^{\dagger}a_{2} ) \left| {0} \right\rangle\\
& =  (-uv - v^{2}a_{2}^{\dagger}a_{1}^{\dagger} )\left| {0} \right\rangle \\
&  \propto (u + va_{2}^{\dagger}a_{1}^{\dagger} )\left| {0} \right\rangle
\end{align}
By acting the Hamiltonian on the $\left| {G} \right\rangle$ we can easily confirm the ground state energy is exactly $-\sqrt{\epsilon^{2} + \Delta^{2}}$
I think the reason that I can not get the correct coefficient is because I view the $a_{2}^{\dagger}a_{1}^{\dagger} \left| {0} \right\rangle$ as $\left| {1,1} \right\rangle$. However, because of the anticommute properties for fermion, the arrangement of the operator, and the $+$ or $-$ sign become very important. So it will be safer to write $a_{2}^{\dagger}a_{1}^{\dagger} \left| {0} \right\rangle$ rather than $\left| {1,1} \right\rangle$.
Answer: Take $\psi=x \psi_{00}+w \psi_{01}+z\psi_{10}+y\psi_{11}$ then apply $c_1, c_2$ set equal zero. Then you get $w=z=0$ and one of $x,y$, and remember you need normalization condition to determine the last one.


Empty response on mutual likes graph explorer when user is not app admin

Question: I'm developing an Android app, based on facebook android SDK.
My app asks user_likes, user_friends, and read_friendlists permissions.
I'm trying to get mutual likes between two users with fql query (I can post it if you need but since it don't even work with graph explorer, fql is not the problem).
My fql request is  :
SELECT page_id from page_fan WHERE uid = 'uid1' and page_id IN ( SELECT page_id from page_fan WHERE uid = 'uid2').
Both uid1 and uid2 are registered app user, which have granted all permisions
If I execute this fql query from graph explorer on my account, the app administrator account, it works => I get the mutual likes ids
But if I execute this query from my test user, an account I created to test my app and wich have a test user role, I get an empty array.
I think my user access token is not enough to access other registered user's data, excepted my administrator user token.
But how could I get the results I need ?
The app access token don't seem made for that, so what I'm missing ?
Answer: user_likes and read_friendlists need to get approved by Facebook or they will only be available to App Admins.

Changelog: https://developers.facebook.com/docs/apps/changelog
App Review Guidelines: https://developers.facebook.com/docs/apps/review


02 Honda civic LX battery drain

Question: Put a new alternator in and it's charging I believe I took the negative cable off and it said running but while driving is sputters dies out and then especially when the Sun goes down when it's evening time and it doesn't hold a charge or it's charging I believe but it's not want to start back up like battery is dead
Comment: Welcome to Motor Vehicle Maintenance & Repair!
Answer: I think your problem is the battery isn't charged up like it should be. Take the battery out of the car and fully charge it. Once you're done, put it in the car, start it, then check the voltage at the battery with a multimeter. If it's 13+ vdc and steady, you're in pretty good shape. If it's 13+ volts or less and dropping, then the alternator is still at fault.
Also, once the battery is fully charged, install the battery and turn the lights on for a few seconds. Once this is done, check the voltage on the battery. If it is not above 12 vdc, then you have a battery issue. You'd need to get it load tested.
As a side note, do NOT disconnect the battery while the engine is running. This is a good way ruin electronics in your vehicle. This USED to be a way to check generators, but doing it in a vehicle with an alternator can cause issues.

02 Honda civic LX battery drain


ODE45 speed up and for loops

Question: I have a coupled first order ODE to solve of the form
<code>dy = f(t, x)
dx = d(f, x)
</code>
which depend on a common parameter which I have to solve for over some range. I can solve the system using ODE45 and a for loops which increments the parameter of interest at each loop, however, this is very slow. Can I avoid solving this problem in loops? Or what is best practice with problems of this type.
Answer: Wanted to post a comment but I can't until I get 50 reputation.
What do you need to solve the parameter in each range?
Can't you create a function for solving the parameter and put the function handle in the second argument for ode45?

ODE45 speed up and for loops


What is the mother-site for the Raspberry Pi?

Question: I need a website that has many Raspberry Pi projects! In particular for electrical projects for kids, especially projects that will impress the kids.
I will be mainly working with the GPIO pins.
Answer: It must be raspberrypi.org
Have a look at https://www.raspberrypi.org/help/physical-computing/ for GPIO and https://www.raspberrypi.org/community/
Answer: The official website is https://www.raspberrypi.org/
I really like Adafruit for kits and projects here: https://learn.adafruit.com/
Instuctables also has a lot of projects: http://www.instructables.com/id/Raspberry-Pi-Projects/
Hope this helps!
Answer: In my opinion, make has the funnest electronics projects for kids.


Should I be calling a plumber or someone from my water supply company to test for contaminents in my water?

Question: I have one bathroom where the hot shower water has a sulfur-like odor to it on most days and I'd like to have someone come and check it out but I'm not positive on who to call.
Comment: What do you think they are going to do? Import water from the Greenland ice cap so you can have a pure shower? Best case scenario is the guy comes and say, "Yep, smells like sulfur. Glad I don't live in your town." Worst case scenario is he says, "I don't smell anything." and then winks at you.
Comment: BTW it's probably not the water, it's the drain. You are smelling your own sewage. The tub probably does not have a trap.
Comment: @TylerDurden - If there's a problem in the pipes and/or water heater, I'd expect them to say "You have corroded pipes and/or water heater, to get rid of the smell, replace them". Since he said it's "one" bathroom, it's likely not a problem with his water supply, no need to import water from Greenland.
Answer: If you are on a public water supply, there may be water test results already published on a quarterly basis.
If you are doing your own testing, generally an environmental testing company or consultant (rather than a plumber) - in many cases you can save money if you can follow directions carefully and take the samples yourself, for testing at their laboratory, rather than having a consultant come and take the samples for you.
If it's ONLY the one bathroom, it's more likely something in your pipes than in the general water supply.
Answer: As @tyler durden comments, this may be an issue with the drain, but it is very unlikely that there is no trap. A more likely scenario is that a partial blockage or obstruction of either the drain line or a vent line is causing a siphon action that is preventing the trap from maintaining a water seal. Another possibility is that one or more drains have been added (or the drain configuration has been changed), causing inadequate venting and/or siphoning.
Comment: There might be no trap. Without knowing how long he's been having the problem and where he lives, who knows what is and isn't there? But I do agree a blockage is more likely.
Comment: I think it may be a combination of what Jimmy Fix-it and Exnerwal said.  The shower in question had severe draining issues last summer so I had a plumber replace the pipes that led from the shower drain to the main stack that led the water out of the house; but he didn't replace the trap (which would have caused a lot more work and $$).  I've been noticing the stench for the last month or so and over the last week or so I"m noticing the water is draining a lot slower than it used to.  So this may answer my question, if we go on this assumption should I be calling a plumber?
Comment: Yes - a plumber is the first person to call in this situation.
Answer: Sulfur smell is often caused by degradation of the sacrificial anodes in the hot water heating system.
Comment: The OP said it was only occurring in one bathroom shower. If the water heater anode rods were the root cause, would not all the hot water exhibit the same foul smell? Hydrogen sulfide (H2S) gas is often present in sewer systems, smells like rotten eggs...or sulfur.


What could be causing my new GFCI receptacle to keep tripping?

Question: An electrician installed an outlet on a circuit inside my garage that is connected to an exterior spotlight. The spotlight has a sensor that automatically turns it on at dusk and off at dawn. There is an interior switch between the outlet and the light that controls the light only. The switch has to be on for the spotlight to respond to the sensor. I was told it would be a good idea replace the regular outlet with a GFI outlet before the Holidays since I connect the Christmas lights there. Everything was fine until I removed the Christmas lights. Now when I turn on the interior switch (it was off to allow the Christmas lights to be worked with a timer plugged into the outlet) to allow the spotlight to work with the light sensor, the GFI outlet goes off! Possibly of note: prior to putting in the GFI outlet there were no problems and the washer/dryer are on the same circuit. Is it possible the circuit is overloaded? The outdoor spotlight is 10 years old. Could replacing it with a modern light that requires less power make a difference?
Answer: The washer and dryer are on the same circuit? It must be a gas dryer?
I'd think that you would want to see about splitting this out on its own circuit if you can. The drum motors in the washer or dryer could be the culprit. GFCI only requires a 0.005A difference in current between the hot and neutral legs to trip.
Your GFCI outlet might be defective or over-sensitive.
There could be a small/intermittent short to ground in your outdoor spotlight fixture? Maybe the lamp itself is defective and causing enough fluctuation to trip the GFCI.
Do you have a moisture problem in the outdoor spotlight, perhaps?
Answer: The circuit might be overloaded, but that could not be tripping the GFCI. I assume the GFCI outlet was installed downstream from the washer/dryer so that they are not protected by the GFCI. You can confirm this by pressing TEST on the GFCI and see if the washer/dryer still have power.
The outdoor spotlight is probably damp, causing enough current leakage to trip the GFCI. If it was switched off for a few weeks over Christmas, moisture might have accumulated.

Remove the spotlight bulb. Does it still trip?
With the bulb still out, dry the socket and surrounding area with a hairdryer. Does it still trip?
With the breaker off, remove the spotlight fixture from its box, disconnect the black wire, and wrap some tape around the exposed conductor on the "power" side. Turn on the breaker. Does the GFCI still trip? If YES, call the electrician. If NO, remove the spotlight unit, take it indoors and put it in a warm place to dry out for a day. Then reinstall and try again.
Answer: GFCI's can easily be wired incorrectly, even by an electrician. It's quite possible that the wiring going to the outside light (which would be an "additional circuit" you want to protect) is wired to the "line" terminals instead of the "load" terminals, and the power to the GFCI is wired to the "line" terminals. IF wired correctly it won't do this.
It's also possible to bypass the GFCI for the light outside, BEFORE the GFCI, or the feed to the light simply connected to the "line" terminals (but this will give no ground fault protection to the outside light.)
I've seen this repeatedly.
See the diagram below "Here are the instructions for connecting in a 2-wire scenario." in the following post:
How do I install a GFCI receptacle with two hot wires and common neutral?