Why does TitaniumBackup not allow me to restore apps after upgrading to 4.3?

Question: After upgrading to 4.3 from a previous version (in my case 4.2), TitaniumBackup might exhibit a behavior where restoring apps does not work and the process just freezes on some devices, in this case a Galaxy Nexus phone. It seems that restoring app settings might work, but when restoring the actual apps this triggers the freeze. Restoring XML data like Wi-Fi hot spots also works.
Comment: This may solve your problem read it carefully: https://forum.xda-developers.com/showpost.php?p=71544556&postcount=22
Answer: To fix this issue, set TitaniumBackup to use the legacy path. The easiest way to do this is to go into TitaniumBackup, press "Menu" and then "Preferences". "Backup folder location" a bit down and click it. Click "DETECT!" and TitaniumBackup will ask you where to scan for backup locations. It's very important that you here choose to scan your whole device and not just the SD card.
After scanning is complete, you might as in my case see that TitaniumBackup presents two paths that seem almost identical (in fact they sort of are). Choose the path that has the string /legacy/ in it, in my case it is /storage/emulated/legacy/TitaniumBackup — which should replace a path similar to /storage/emulated/0/TitaniumBackup.
After TitaniumBackup has been reconfigured to use the legacy path, restoring apps will work as normal. Thanks to necropuppy for this solution.
Comment: Sorry. I didn't make connection between the OP and the person answering.
Comment: This is after you've flashed the 4.3 ROM, correct?
Comment: Yes? Not sure I understand what you're asking, I made it very clear in the first words of the question that this happened after upgrading to 4.3


Interfacing microcontroller and mains via a relay

Question:
I am thinking of starting a project where I will need to interface a microcontroller output and mains for a lighting system. My question is about relays. I have found this one. And I am wondering will it be ok to put 230v through the switch of the relay? Also what am I looking for in the data sheet to tell me what is the maximum voltage that the switch will take?
Answer: The relay is a good one for resistive loads like incandescent lamps. The AgSnO2 contacts can handle higher inrush currents than AgNi.
Note that all given currents refer to cos(\$\phi\$) = 1, i.e. fully resistive loads. If you want to switch reactive loads like fluorescent lamps you're limited to a fraction of the given maximum current. You also want a safety margin for the inrush when switching a cold incandescent lamp when the voltage is maximum.
Your 10 A then become 1 A. Since a 60 W bulb draws 0.25 A at 230 V you should be able to switch up to 4 lamps with 1 relay.
edit
Forget I mentioned incandescent lamps. I was in the supermarket today and I needed a replacement bulb. While in the past there was an offer of at least 30 or 40 different incandescent bulbs in all sizes and shapes today they were all gone! Same variety in CFL (compact fluorescent), so that's no problem, but I didn't think the incandescent effectively would be gone before 1st January 2011.
Anyway, for your relay. Relays like the resistive load of an incandescent bulb much better that the reactive load of a (compact) fluorescent lamp. While in theory you should derate the relay further for the changed load, in practice CFLs are only 20% the power of incandescent lamps, so your load will remain within the limits set earlier: you should still be able to switch 4 CFLs with 1 relay.
Comment: I feel compelled to reinforce the idea that incandescent lamps are NOT resistive loads from a relay standpoint. Given that this is the "accepted" answer, I feel like it shouldn't contain misinformation.
Comment: they fall into their own category - as described in the appnote I linked to my answer (http://cp.literature.agilent.com/litweb/pdf/5988-6917EN.pdf). While they are generally speaking "resistive", they have special temperature-based material properties that must be taken into account.
Comment: Also, it's not *my* suggestion, I provided a reference for that factor, fwiw. I don't think an answer should be accepted on the basis that it tells you what you want to hear.
Comment: @vicatcu: if incandescent lamps are not resistive, can you tell us whether they're capacitive or inductive? And what's their cos phi? My data says cos phi = 1.
Comment: @vicatcu: Exactly, inrush current, I'm not denying that. IMO the people at Agilent are overly cautious; they also recommend a series resistor for the bulb, don't they? Have you ever seen this in an actual installation? My point is that _in my experience_ a factor 4-5 will do.  And I take exception to your insinuation that I tell the OP what he wants to hear.
Comment: @stevenvh: Bell & Howell DJL projector bulbs have two filaments in series, one of which is placed in a location which doesn't provide useful light.  The second filament is longer than the primary one but doesn't glow anywhere near as brightly; my guess would be that it's designed to have a resistance that varies much less between startup and operation, and thus would limit inrush current to the primary filament.
Answer: If you are in any doubt about dealing with mains power - don't do it.
You might want to consider a ready made unit like this one from Adafruit:
https://www.adafruit.com/index.php?main_page=product_info&cPath=44&products_id=268
Comment: @Dean, use a fuse rated for your maximum load + ~10%.
Comment: My main concern was with the relay it melting on me. And im going to mount a plug on a pendant so i can keep my eye on whats happening to it during testing.
Answer: If money is no object, then the first thing I go to is a solid state relay (SSR), instead of the mechanical switch variety.  I've had to switch 120VAC with a DC control voltage many times in the past, and I've alwyas started with Crydom SSRs.  SSRs make interfacing with AC voltage really, really simple.  Crydom has several models that can switch 230VAC.
That said, everything I have used them in is for prototype and R&D automation.  It would be interesting to hear how others here feel about it.
Answer: I've done this kind of thing before, and it worked fine. The relay you've chosen looks about right, and as long as your not switching a huge load it will be fine.
If your unsure about the load, then do a simple calculation, for example if your switching a 100w bulb on and off, then 100w divided by 230v = about 0.4 amps. The datasheet says that the relay is rated at 10A... so its way more than enough.
If your calculations are out, and things go wrong the worst that can happen is it burns out a cheap relay, or blows a fuse or MCB or something... it's not the end of the world.
Comment: On the other hand, if you had 3 100W lightbulbs you should probably be using a relay rated for at least 13amps (Applying 10% derating, one 100W lightbulb should be good with about a 4A relay). Likewise you use conductors and breakers that are adequately rated to that load or you could have a fire hazard on your hands. I would also be cautious in suggesting that all relay failure modes are "safe," as that has a lot to do with the context in which it's used.
Comment: @vicatcu - 400mA not 4A, the relay should be good for 3x100W.
Comment: @Thomas, derating by a factor of 10%, I believe, means you should divide current by 0.1 (i.e. multiply by 10). I got 4A from 400mA * 10...
Comment: @vicatcu, no, that is equivalent to derating by 90%. You should get around 400mA * 1.1 = 440mA for 10% extra (or you could derate the relay to 90%, to get 9A, either works.)
Comment: @Thomas, when switching incandescent loads, it is advisable to derate your relay to *10% of its resistive rating*. So if the relay is rated for 4A resistive loads, you should only use it for 0.4A = 400mA incandescent loads. If you've got a 1.2A incandescent load, you therefore need a relay rated for 12A resistive loads. Read the app note I linked in my answer, I think my reading of it is accurate.
Comment: @vicatcu, That makes some sense. I though incandescents were resistive only? Shows what I know.
Answer: The Max. switching voltage is apparently 277V AC and 30V DC. What you should be asking however, is how much current you need to be rated for. This is not a simple thing to answer because depending on the type of load you are switching, you actually need to derate the current differently to account for inrush current.
I suggest reading through Agilent Application Note 1399 - Maximizing the Life Span
of Your Relays to give you an in depth idea of what I'm talking about. Don't mess around with this stuff without taking appropriate precautions. You will note that for incandescant lighting, you need to derate by a factor of 10%. That means if your lighting draws 5 amps, you better get a relay that can switch 50 amps.
I think the reason that incandescent lighting is derated so much is because when the filaments are cold, they have much lower resistance than when they heat up, and so draw a huge amount of current from a cold start. I'm really just guessing at this though.
Comment: It actually says in the app note you linked to. Quote: "the  resistance of a hot tungsten filament is 10 to 15 times greater than its resistance when it is cold"
Comment: @W5V0 sometimes guesses are just memories in disguise :)


Salesforce CPQ quote Template

Question: I want to display Features and Options related to the product on my Quote template, but I am not sure how to display those records in Salesforce CPQ quote Template without using visualforce as Template Content.
Answer: If a product option is selected, it should show up as a Quote Line that you can conditionally filter.
If you're trying to show all available options, you don't have any other choice than to use the Visualforce sections

Salesforce CPQ quote Template


Perforce - getting email on every checkin

Question: Is there a way to get Perforce to send you an email on every check to a particular depository?
Comment: Are you asking how to configure the perforce server to provide this functionality, or are you just asking as an end user? If the latter Jeff's answer should be sufficient, assuming your admin has setup the review daemon.
Comment: I was asking for the later. And, yup, Jeff's answer works for me. Brian's answer is also good to know.
Answer: Yes. Type "p4 user" to see your user configuration and then under "Reviews:" put the filespec of the area in depot where you'd like to get notified on a check-in, as in:
Reviews:
    //depot/myproject/...

See this section of the P4 command reference for more info.
Comment: I suppose you could create a user that represented the list. I'm not sure of a more efficient way
Comment: What if you want to mail an email list, rather than a particular user?
Answer: In p4v (visual client)

Connection -> Edit Current User
Enter the path to your repository under Reviews

This is correct for OSX & Windows.
Comment: Thanks. Can never remember where to find this feature.
Answer: You want to install the Perforce Review Daemon script on your server. What it does is periodically poll the server for new changelists and sends an e-mail ONLY to the people interested in them. The script is maintained by Perforce and you can get help from the tech support to setup it.
You can download it from the Perforce website from the support site (towards the bottom of the page).
Perforce Support Site: http://www.perforce.com/perforce/loadsupp.html
Direct Link to Script: http://public.perforce.com/public/perforce/utils/reviewd/p4review.py
Once you have it installed you register your that your interested in changinglists by adding the filespec to your user account.
Comment: Is it possible to send the email before committing the changelist, just for review? Via a script of batch file?
Comment: You could write a pre commit hook; I never done that. Also, I've moved on from wanting emails for every commit. I now recommend the pull request work flow to all our clients.
Answer: In the perforce visual client (P4V), go to Connection and Edit current User
Under the user dialog box, go to the reviews tab.
Select and deselect the different trees of the "depot"
Answer: As an admin you can use
p4 triggers

to setup scripts that are executed when various actions are performed (ie: on check in of a changelist).  I've used it to send an email to a distribution list that all of the developers were part of so that they were aware of who was checking in what and when.


Why nmap closed my connection?

Question: I started new connection on port 3333 typing nc -l 3333. Then in other terminal window I typed nmap -sT -O localhost to check if 3333 port is really open. After this command my connection on port 3333 ends. That is each time. Can you explain me why it happens?
Comment: If the existing answer solved your problem, please consider accepting it with the checkmark; thank you!
Answer: Using nc -l 3333 tells netcat to start listening on port 3333. Once nmap -sT (meaning: scan with TCP Connect) connects, it then disconnects, leaving netcat with nothing to do but exit. You may be interested in nc's -k flag, which says:

Forces nc to stay listening for another connection after its current connection is completed. It is an error to use this option without the -l option.
Comment: If the `-sS` (TCP half-open SYN scan) option is given, the connection will not be completed and the listener will still be able to receive a connection.

Why nmap closed my connection?


Google apps timeline inaccurate location

Question: My Google apps timeline says I went to a postcode and stayed there for 3 hours when I never left my house which is 4 miles away from where it says I was it was in the middle of the night when I wasn't even on my phone I was asleep. But on the following date it says I was at my house from 1200am-135pm which was obviously the start on the next day and which means I was at both locations at the same time. Any light shredded on this would be great. Is there anyway to prove I didn't leave my house
Answer: Do you use your Google account on more than one device? Or do you turn off location and your cell data and connect only via wifi? If you were connected to WiFi on your phone, or another WiFi or ethernet connected device logged in with your Google account, Google may have assumed your location was the location of the IP address you were using (which isn't necessarily where the actual WiFi router/access point is). 4 miles away is about the right distance for say a cable broadband hub and the IP address location may have resolved to somewhere near the hub.
If you go to http://whatsmyip.org and click on the "more information" button, it will attempt to locate you via your IP address. That's likely analogous to where your weird Google location came from.


How to install/run windows 8.1 app on Ubuntu?

Question: I'm trying to figure out if it's possible to install and run a Windows 8.1 app on Linux(currently using Ubuntu 16.04, but not opposed to installing a different distro). I know that WINE is supposed to be able to run some Windows programs, but being almost brand new to Linux I don't know if WINE works with Windows 8.1. Also, I'm not sure how to go about getting the program in the first place to even attempt that, since it would appear that you cannot download Windows 8.1 apps from the Windows store unless you have a device with Windows 8.1.
So, My questions is does WINE work with Windows 8.1 apps, and if so, how do I go about getting the app for it to run?
Thanks!
Comment: basically Windows Store is for windows only. Wine emulate the *old* `.exe` API from Windows. Windows Store uses a much different application format and binary and windows store can't be downloaded manually.
Comment: I you really need to run MS-Windows apps, then there is Virtual-box. Install virtual-box, then install MS-Windows 8, then install the app. But be aware, it will suck your freedom.
Answer: Wine does a fine job to run individual Windows programs on Linux and you can find good instructions to use it in Ubuntu's official page on Wine
Qemu provides a good computer emulator which allows to run a separate operating system over your current Linux installation, and is well documented on Ubuntu's official Qemu documentation.
Another commonly used option is to setup virtual machines which are a bit similar to Qemu but instead of emulating everything, they use pass through techniques to access the computer's component's through the host.  VirtualBox is a popular solution for this, also documented on Ubuntu's official VirtualBox documentation.
Comment: Qemu and Virtualbox look like they'd be good solutions, but unless I'm mistaken I'd need a windows 8.1 product key for the virtual machine to set up properly, correct? Also, I still have the problem of getting access to the program from the windows app store on Linux(and if this isn't the right forum for that, please feel free to direct me to the right one. Linux isn't the only thing I'm new to right now. :P ).
Comment: You do need a product key to install Windows 8 on any machine including VMs.  Of course you won't have access to the Windows 8 app store from Linux.  That is like going to your Ford retailer for warranty information about your Toyota.  But you would get access to it from inside the VM though.
Comment: Actually it was more along the lines of I have Windows 7 and Linux already installed, and found an app that looks really cool but only runs on Windows 8 and don't have the money to buy a key to upgrade/dual boot at the moment. :P
Comment: "You do need a product key to install Windows 8 on any machine including VMs" unless you use the 90-days trial versions: https://developer.microsoft.com/en-us/microsoft-edge/tools/vms/
Comment: If you're so stuck on using Windows 8, why did you install Linux?
Comment: I didn't know if there was possibly a way to access the download for the app outside of the Windows store(the thought occurring to me because people have come up with ways to do so with the Android app store).
Comment: Search for that app on Google or if you need help searching for it, you should ask about its name.


Error in UK visa application

Question: Can someone help me out. Someone filled a United Kingdom visit visa online application form for me. He didn't confirm from me if I was refused visa by any country and he put No. He just submitted the form last night. As I was going through the form he sent I saw No. What can I do since the form has been submitted. I need to state that I was refused a United States visa in 2015. Can I write it in the cover letter that I failed to include it. Or what do I advice I do to rectify the mistake. Am so worried right now.
Comment: Be very careful when paying someone to submit a visa application on your behalf. Their errors, carelessness, or deliberate falsehoods will affect you, not them.
Answer: Withdraw your visa application and apply again, this time with the right details.
https://www.gov.uk/cancel-visa
Do not attempt to correct this as part of the cover letter etc - cover letters can get overlooked, separated from your application, misunderstood and so on.  Withdraw your application before its considered.
Comment: @Luvlyspot Please read the information in the supplied link, that answers your first question.
Comment: The moment your application is cancelled, you can apply again.  Pretty sure this is immediate.  Refund might take some time to show up tho.
Comment: If you withdraw before biometrics are taken, you get a refund - so yes, if thats your goal, and your applications are together, then you should withdraw all applications and reapply.
Comment: I applied with my wife and child. Should I withdraw theirs too. Because I want us to get a date for biometric together. And can I get a refund if I withdraw. Can I also apply immediately after withdrawing my application
Comment: Please can I reapply immediately, I withdraw. Or do I need to wait for some certain period. We just submitted and paid we haven't selected a date for biometric.

Error in UK visa application


How to remove port number from url?

Question: My application "XY" running on port 1234 in tomcat server. I'm using HA-Proxy for loadbalancing. So in loadbalancing my front end port is 5678 to access the "XY" application through browser. Right now, I'm accessing htp://abc.game.com:5678/index.html. I want to access the same url but without port number. Because every time I've to remember port number to access application. How I can achieve this?
There are multiple applications running in similar way, and same way it is configured haproxy.conf(centos 6)
Answer: Ports 80 and 443 are the standard ports for http and https, respectively. If you use these ports for your application (instead of port 5678) then you won't need to specify the port number in your URLs.
Comment: There are multiple applications configured in haproxy. Its not possible to run every app in 80 or 443. One more thing is all app dont have public ip's
Comment: If haproxy isn't up to the job then replace it with something that is, such as a BigIP from F5. Re the port numbers, unless you move to port 80 (http) or port 443 (https) you _cannot_ remove the port numbers from your URLs. Re public IP, I don't see the problem: just don't listen on the public IP addresses for those server domains.
Comment: @roaima : I am trying to replace the port number in the url because the redirect works fine only without the url. I have created a backend which points to the IP along with the port number which makes my custom URL not to use the port number. Could you please explain why I cannot remove port number from the URL? here is the better description of my question : https://stackoverflow.com/questions/53418024/haproxy-remove-port-number-from-url

How to remove port number from url?


Transaction Log file size is increasing in my Azure (IAAS) SQL Server 2014 database

Question: Recently we have migrated our application (both web app and database) to Azure (IASS). There we have a VM with SQL Server 2014 installed. Also I have restored all the necessary databases and SQL Server jobs on the server (from the existing On-Premise DB server). All the settings are verified and the application was working fine for a week.
Then we noticed a problem with the log file size (size is increasing  and reached around 42 GB and not able to execute any of the basic query and everything breaks :( ). The same DB and Job ran in on-premise server for a year and  this issue didn't happen.
Some information about the application and DB

The application contains a couple of SQL scheduling jobs which run each 2 hours of a day and the job take maximum of 5-8 minutes to complete.
Application contains less than 200 users and concurrent users are around 20-30.

So please let me know any one of your comments/input on this (Transaction log file size increment) issue. Also please let me know if you need any other information
Answer: Do you ever do a full database backup?  That will zap the log, which is what you're looking for.  See T-SQL BACKUP command for syntax.  Not sure what backups look like on Azure, but that should help.


Why does HPE disable STP by default?

Question: It this certainly true that switches needs STP to avoid loops or broadcasts storms, but recently I saw the configuration of my Hewlett Packard switch and I noticed that it has STP feature disabled by default. Please could you explain this behavior? Answer in Spanish or English.
Comment: HP has spanning tree disabled by default, but you can certainly turn it on. As to why they made that decision, you'll have to ask them.  Speculating on their reasons is off topic here.
Answer: Speculating why HPE does so is off-topic here, but there are a few reasons for disabling STP by factory default:

Ports go through their STP states between physical linking and active forwarding which may cause problems with DHCP and other protocols that expect an interface to actively work once it's up.
STP needs to be configured to work reliably and predictably - you need to select the best and most interoperable variant for your network: MSTP, RSTP, original (obsolete) STP or (R)PVST(+), and also which ones are your root switch and your designated root switch (lowest and second lowest priority values). MSTP instances require careful configuration as well.
The STP parameters themselves may require configuration for some networks, especially when long chains or rings are involved (large tree depth).
A newly configured STP bridge likely requires configuration of its downlink port - features like fast link and BPDU guard need to be disabled before connecting.

Disabling STP by default enables users to connect a new, unconfigured switch to a network like an unmanaged (dumb) one - which may be expected by less proficient users. More competent users configure a switch before integrating it in any case.

Why does HPE disable STP by default?


Differences of get_dummies and labelbinarizer?

Question: Are there any differences between get_dummies and labelbinarizer in terms of what they want to achieve? It seems to be both will somehow do a one-hot encoding.
Answer: A couple of things comes to mind.
get_dummies can transform a dataframe with many columns, whereas LabelBinarizer will only do one column.
get_dummies outputs a dataframe (if the input is a dataframe) with a nicely formatted columns, whereas LabelBinarizer outputs a numpy array, so if you want to attach labels to them, you'd need to get them from the fitted instance of the LabelBinarizer.
Inverse transform is more intuitive with LabelBinarizer, it has a method named inverse_transform, whereas with get_dummies you would need to do something like dummies.idxmax(axis=1)
So overall, get_dummies seems to be a better choice


Detect open or closed circuit via USB sensor

Question: I have a relay which I need to detect the state of (similar to this question but no current flow) and would like know what the easiest method would be to detect the state via USB and Raspberry-pi. I assume the simplest method would be to detect the resistance, but my lack of knowledge of what's available out there makes it hard to even know what it is that I'm looking for.
Comment: Lots of details needed: what is the voltage of the relay coil and is it AC or DC? What is the relay contacts switching? Are there extra relay contacts available?
Comment: The Pi has GPIOs which can be used to detect the state of a relay contact, so why do you want to use USB? You say there is no current flow - does that mean the relay contacts are not connected to anything? (or if they are, what circuit are they connected to?).
Comment: USB because I have a USB hub already setup where I need it and the GPIO would add additional wiring. The relay is 5v, but from an educational perspective, if it were a switch that only had an open and closed state, how what could be used to detect the state? Essentially a USB ohmmeter, but I'm not familiar with anything like that?
Comment: @BruceAbbott the relay isn't connected to anything. It's there only to signal a change in state.
Answer: A relay is effectively an electrically operated push-button, so you can use a similar circuit to detect relay contact closure as for a push-button being pressed.
Connect a resistor in series with the relay contacts and apply voltage to the circuit. When the relay contacts are open no current flows, so there will be no voltage across the resistor and full voltage across the contacts. When the contacts are closed they apply full voltage to the resistor and current flows (limited by the resistance) while voltage across the contacts drops to zero. This voltage change can easily be detected by digital logic.
The circuit can produce either a logic '1' or logic '0' when the relay closes, depending on the whether it switches to the positive or negative side of the supply voltage. Switching to ground may be safer and require fewer wires. The resistor then pulls the input voltage up (producing logic '1') when the relay contacts are open.

simulate this circuit – Schematic created using CircuitLab
The Raspberry Pi's GPIO port has pull-up resistors built in, so you would only need to connect two wires to the relay. Unfortunately it is not quite so simple for USB. You cannot connect relay contacts directly to it. USB is a complex serial protocol which requires an intelligent device to convert the voltage change into a signal that can be transmitted over USB.
You could make a special USB device just for your purpose (and write a device driver to interface with it) but it may be easier to just use an existing USB device which has general purpose I/O (eg. TTL serial or parallel adapter) or even take apart a USB mouse or joystick and connect the relay contacts across one of its buttons.


Docker + NGINX + SSL

Question: I have a trivial NGINX proxy config (below) that uses my new SSL cert (first time I'm trying this).
I've deployed this via Docker extending the standard "nginx" image. I'm reasonably sure my InstantSSL cert file is valid, but the server isn't returning a valid SSL connection.
I'm getting the following error:
<code>$ openssl s_client -connect MY_DOMAIN.com:443
CONNECTED(00000003)
22489:error:140790E5:SSL routines:SSL23_WRITE:ssl handshake
</code>
I've tried other tools too:
<code>$ ./cipherscan -v https://MY_DOMAIN.com
handshake failed, no ciphersuite was returned
</code>
And finally, https://www.ssllabs.com/ssltest/analyze.html returns "No secure protocols supported"
I've tried various combinations of ssl_protocols and ssl_ciphers settings, but the nginx docs say the defaults should be fine.
NGINX works fine on port 80 (i.e., with my standard virtual host setting listening on 80), so general server set-up seems OK.
Anyone have anything else I can try?
<code>  server {
    listen 443 ssl;

    server_name MY_DOMAIN.com;

    ssl on;
    ssl_certificate       /etc/ssl/ssl-bundle.crt;
    ssl_certificate_key   /etc/ssl/MY_DOMAIN.key;

    ssl_prefer_server_ciphers on;

    ssl_stapling on;
    ssl_stapling_verify on;

    location / {
      proxy_pass http://frontend;

      proxy_redirect http:// https://;

      proxy_http_version 1.1;
      proxy_set_header Host $host;
      proxy_set_header Upgrade $http_upgrade;
      proxy_set_header Connection 'upgrade';
      proxy_set_header X-Real-IP $remote_addr;
      proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
      proxy_set_header X-Forwarded-Proto $scheme;
      proxy_cache_bypass $http_upgrade;
    }
  }
</code>
Answer: User Error:
I had 443 exposed in my Dockerfile, but not in my Docker Cloud stackfile (so the hosted containers port was blocked).
I figured this out by testing nginx locally (adding an /etc/hosts entry to "fake" my prod server) and it worked correctly (outside of docker).

Docker + NGINX + SSL


How could I check if my pc is accepting traffic from specified IP?

Question: I need to check if a server is accepting incoming traffic from a specified IP.
Isn't enough to check only if a port is listening, because for example, even if I have port 22 open I don't know if it accept traffic from another server.
I saw nmap and netstat but seems that they can't help me.
Do you know a command to do this?
Answer: I use netstat to answer questions like this. I'm not sure why you say netstat can't help you, because it is certainly possible to determine whether or not your PC is currently receiving traffic from a specific IP using netstat.
Assuming you are on a current version of Windows: go to the Command Prompt, and type netstat -n to see all connections to/from your PC. Leave out the -n to see hostname (where your PC can determine it) instead of the IP address.
If the issue with using netstat to get what you want is that the amount of output is the issue (too many lines) then consider either copy/pasting the output to a good text editor, or using netstat in Windows PowerShell (hit the Windows key and type 'PowerShell', then select 'Windows PowerShell') in conjunction with Select-String to filter only for the IP you're interested in.
PS C:\> netstat -n | Select-String 10.11.15.41

TCP    192.168.1.1:22    10.11.15.41:62352       ESTABLISHED
TCP    192.168.1.1:22    10.11.15.41:63782       ESTABLISHED
TCP    192.168.1.1:22    10.11.15.41:60185       ESTABLISHED

If that's still showing too much information, you could use a second Select-String to filter only for lines including the string ":22":
netstat -n | Select-String 10.11.15.41 | Select-String :22

Similar results may be achieved on other operating systems (e.g. Linux, OSX) using netstat and grep.
If you need to set up monitoring, then this probably won't meet your needs, but for a quick answer to the question "Is X connecting to me?", netstat is both practical and useful. I use variations of this every day.
On the other hand, if you are asking "How can I tell if a particular host B is capable of making a connection to my host A on port 22?" - determining that routing is in place from B to A, and no firewall would block the connection attempt - then I don't think there's any way of knowing for sure from A. You'd have to access B, and conduct a test from B to A.
Comment: Even plain Windows CMD can do `netstat | findstr` or `netstat | find` (`findstr` does _much_ of what Unix `grep` does but not all; `find` is closer to `fgrep` but that is enough here)
Answer: Netstat should indeed work for what you asked using the techniques FosseWay suggested, but one limitation is that its only going to show a point in time.  An alternative if you want to check for traffic over a period of time would be to use WireShark.  It might be overkill is some ways, since it has the ability to capture packets and even replay them, but its easy to use and has the ability to filter the traffic and only record it say from a specifc IP.  this way you can see not just if traffic came from an IP but what the traffic was.
A good tutorial for installing and using WireShark can be found here.  Feel free to post back if you have any questions on its function.
https://www.howtogeek.com/104278/how-to-use-wireshark-to-capture-filter-and-inspect-packets/


Looking for a term that describes a system that favors rich over poor

Question: What term describes a system that favors rich over poor?
Comment: @CookieMonster "Oligarchy" is simply government by a small elite group. Government by the wealthy is **"plutocracy"**. Though that is not exactly what the OP asked. I can't think of a term which means government favouring the wealthy, but I think "plutocracy" gets close.
Comment: What do you think of the term **oligarchy**?
Comment: Possible. You make me realize I'm looking for something that describes a system that leads to an oligarchy.
Comment: @WS2 Right, but, while technically incorrect, these days *oligarchy* has come to mean pretty much the same thing as *plutocracy*.
Comment: @CookieMonster But you could have a left-wing oligarchy, which conducted wholesale redistribution of wealth.
Answer: In contemporary English, one sees the expression: the system is rigged against the poor; a rigged system.
This was a term used by Bernie Sanders in the US election: rigged economy.
But "a rigged system" can apply to many things, including voting.
It's such an interesting term as it dates back to the rigging of ship's sails. Elections are also said to be rigged.
All dictionaries give the two meanings: re ships and how something can be set up dishonestly to benefit the few. When you look at a tall ship, fully rigged, you can see how the term came to mean what it does:
full-rigged sailing vessel
Here's the Merriam Webster's definition: rig
rigged economy
On sailing ships (tall ships), it is the captain who orders sailors to set the rigging (all the lines to sails and which sails are furled or unfurled) to his (or her!) own liking.  As such, they control the ship and how it is sails through the sea(s). One can say that captains have total say over the rigging. And in the literal sense, it does not mean what it has come to mean today in politics, economics, etc. where such a negative connotation remains of what is actually a beautiful thing. [There are many tall ship events around the world and its an amazing sight to see these old vessels sailing  into a harbor. In fact, you can go on some of them and they will teach you how to rig the sails!]


Identity Management with ActiveDirectory

Question: What is the best, or most reliable, way to manage my Unix/Linux user accounts with ActiveDirectory? Or, is this even feasible?
Answer: I highly highly highly (highly) recommend using Likewise Open to do this. Every time I talk about them, I sound like a paid shill, but I'm not. It's just really that good.
Essentially, you install the software (painless, there's an RPM and DEB intaller), run "domainjoin-cli domain.com adminuser", type the password for "adminuser", and then your machine is part of the AD domain.
The one thing that I do change is in the configuration, I turn on the the assume default domain setting, because I don't want my users to have to type their domain every time they connect to the machine.
The benefits are huge. When you log in with AD credentials, your UID and GIDs are assigned based on a hash, which means that they're the same across the entire infrastructure. This means that things like NFS work. In addition, it's simple to get things like Samba and Apache to authenticate, since Likewise configures PAM.
Thanks to Likewise Open, there is not a single network-based service that I offer that isn't authenticated against AD.
Comment: Any Kerberos-enabled network service - from NFS to Apache and from SSH to FTP - will work just fine with any Kerberos implementation. For this functionality it does not matter whether you use stock Winbind, Likewise's version of Winbind, pam_krb5 with MIT Kerberos or Heimdal, Vintella, Centrify, it's all the same: Kerberos single sign-on.

Using a hashed SID as the basis for UID's and GID's (I think that is what they do) has it's downside too: I don't think cross-realm trusts work very well with this.

What *is* cool about this, is that it transparant: AD does not have to be changed for this.
Comment: Thank you for that excellent answer. On a side question, have you ever heard of, or used, this http://www.quest.com/authentication-services/ ?
Comment: I haven't, though several people have recommended their powershell CLI commands to me.
Answer: Because we are talking about AD, I am going to assume an enterprise environment here.
I have a couple of hundred RHEL3, 4 and 5 boxes running with Active Directory based user-accounts. All of them run the same configuration, using nss_ldap and pam_krb5. It works brilliantly, it is supported by all commercial Linux vendors in the standard support option, because it uses out-of-the-box tools and it is rock solid. In the end, AD is just Kerberos and LDAP and and to vendors, those are standardized, easily supportable protocols.
I have yet to run into a problem with this way of using AD that I cannot solve. Scott Lowe's documentation here helped me quite a bit when initially designing our solution. It's not perfect, but it'll help you get underway. Scott's idea is to create a bind account for LDAP, which I'm not that fond of. A machine that is joined in AD can do LDAP queries with its own credentials, which is a lot saner, if you ask me.
Depending on your requirements, you might want to take a step back and consider whether you need a supported solution or not. Because nice as Likewise may be, it is fairly expensive. Using the tools that come with every Linux distro by default and are thus supported, might be a tiny bit more complicated (but that shouldn't scare off a good Linux admin) but is just as good (or maybe better, depending on your requirements).
I could write up in a bit more detail about how I did this, but I don't have time for that right now. Would that be of help?
Answer: Not exactly AD, but I got a nice answer to a similar question over here:

What is the equivalent of Active Directory on Linux
Answer: PAM LDAP against Active Directory should work fine.
Answer: It's quite feasible, and already done.
As someone has already mentioned, Likewise will give you direct integration.  However...
If you want to take the plunge, you could also install winbind from the Samba project, which would give you the same experience.  Using winbind, your machine will become a domain member...and user accounts in Active Directory can be transparently mapped and assigned UID/GID settings.
Answer: I'll spare you the marketing speak, but try Centrify Express. It's a free tool to join your Linux and Macs to AD. http://www.centrify.com/express/download-centrify-express.asp


Can I still wear socks for each prayer?

Question: If I'm suffering from farts continuously and if I'm wearing socks, do i have to take off my socks every time I make wudu and wear it again or can I just wipe over it like how you would normally do when you wanna make wudu with socks on even if you feel sometime during the wudu or after the wudu?
Answer: In Islamic tradition, there is a concept known as masah, which refers to the act of wiping over certain types of footwear during wudu, instead of washing the feet. This practice is based on certain Hadith, or sayings attributed to the Prophet Muhammad. However, there is considerable variation and disagreement among Muslim scholars about the specifics of this practice, including when it can be done, what types of footwear it applies to, and under what circumstances it is valid.
Some scholars hold that masah can only be done if the socks (or other footwear) were put on after a complete wudu, and that one must remove and wash the feet in the event of a major impurity (such as passing gas), while others are more lenient.
However, in my opinion, one of the fundamental values of any religious or moral system should be compassion and consideration for human needs and limitations. If you're suffering from a medical condition that makes it difficult or uncomfortable to remove your socks for wudu, I would hope that any reasonable interpretation of Islamic law would take that into account.

Can I still wear socks for each prayer?


Flex - including a host component class that is in a sibling folder

Question: I have a FLEX project, in the 'default' folder of which I have 2 sub-folders - "skins" and "scripts". My custom skins and actionscript classes (all defined in "scripts" package namespace) are stored in these sub-folders respectively.
Now, in one of the skins I refer to a AS class that is in the "scripts" folder, say, like this:
[HostComponent("MyCustomButtonClass")]
This obviously reports the error:
1046: Type was not found or was not a compile-time constant: MyCustomButtonClass.
How do I make the class reference in host-component work?
(If it helps, there is main.mxml in the default package where all these components are used)
Answer: Just add both folders to the source path and use package structures.


How can i use _module.less in custom module

Question: I'm writing a custom module and i need to add styles. So i'm trying to follow magento's way with using _module.less file.
i've created a file Namespace/Module/view/frontend/web/css/source/_module.less. When i change this file, i see, that grunt watch see those changes and recompiles my styles. But changes from my _module.less file never gets into result files. Any help?
Answer: I think, i've found an answer. I worked on the admin part of a module before. So it somehow generated a code without frontend part. So what i did to get it work:

Disable module with clear content: php bin/magento module:disable Namespace_Module --clear-static-content
Clear cache php bin/magento cache:clean
Enable module back with clear content php bin/magento module:enable Namespace_Module --clear-static-content
Comment: This worked for me! Accept this answer (:
Answer: Run below commands
- php bin/magento cache:clean
- php bin/magento setup:static-content:deploy

Comment: Allready tried. More than that: i'm in developer mode - so, as i know, i don't need do deploy static content


UiAutomator dump for Lollipop Lost WebView View Hierarchy

Question: In KitKat we were able to get webview view hierarchy from a UIAutomator dump if focus was placed on the webview. I was wondering if there was substitute functionality for getting webview view hierarchy with the lollipop release, or if that functionality was lost in the release?
Answer: Took me a while to work this out, but basically, for practical purposes, yes this functionality was lost in this release.
There are some kludgy work-arounds but they aren't reliable.
Your best bet is to write an actual unit test that is run by uiautomator, and use the dumpWindowHierarchy API to extract it yourself. If you are doing this it is important to ensure the WebView you wish to extract is created after uiautomator has started (but obviously before you make the call to dumpWindowHierarchy). The best way to achieve that will be depend on your exact circumstances.
I wrote up more speculation on why this may have changed in Lollipop in a blog post.
Answer: I'm not sure about what you need to do, but maybe setWebContentsDebuggingEnabled() could help. Enabling this will allow you to debug the content of your WebView using Chrome, it may also affect the behavior of the UiAutomator so give it a chance!
<code>WebView web = ...
web.setWebContentsDebuggingEnabled(true);
</code>
A more detailed docs about remote debugging on webviews can be found here.
Comment: Thanks for taking a look! I am familiar with setWebContentsDebuggingEnabled, and Chrome Debugging Webviews. Unfortunately this is for 3rd party applications that I can't repackage.
Answer: This appears to have been fixed in Android System Webview v44 upwards for Android Lollipop. Just had a go this morning and dump now appears to give me the view hierarchy. Try upgrading webview and having another go :-)


Apple Monitor Thunderbolt adapter

Question: I have a Mac Screen that doest have any ports, instead having only a thunderbolt 1 cable coming out of the back. i have a non-apple pc that doest have a thunderbolt. i do not want to spend $70 on a good adaptor. Help?
Comment: I do not know what kind of help you want from us? you will still need to purchase something to get the thunderbolt I assume to HDMI or VGA? usually these cables here in uk are like 10pounds. (Thunderbold to HDMI)
Comment: Do you need help finding a serial number? Or manual?
Comment: There is no Thunderbolt monitor with "no ports on the back", can you get the model number (found on the back or bottom) so we can identify the model you're working with?  Also, please clarify what you want.
Answer: Presumably, this is the Apple 27" Thunderbolt Display (the only Apple-branded display 'with Thunderbolt 1 cable coming out of the back').
Unfortunately, that display will not work with anything other than a Thunderbolt connection.
Will Thunderbolt Cinema displays work with Mini DisplayPort equipped macs?
Are there adapters to use Thunderbolt Display with non-Thunderbolt computers?
Fortunately, these are not made anymore, so you may be able to find a buyer that has more cash than displays and you can have fewer displays and more cash.

Apple Monitor Thunderbolt adapter


Measuring output optical power of an LED

Question: How do I measure the optical power output of a LED? I have a detector that measures the output power of a laser incident on a small opening. The problem with using the LED with the same detector is that its light is dispersed and I don't have a model that quantifies the distribution of the LED light in space, with which I can calculate the total power based on information of power incident on the small opening.
Comment: converging lens?
Comment: Google "integrating sphere".
Answer:
If you want to measure the total power of a LED in Lab, you can place it in a focal point of a concave mirror and after collimating beam focus it to your detector with a lens:

note that the loss for an uncoated lens is about 9% of total power and mirror loss is negligible.

simpler way is, of course, find the part number of the LED and see the catalog. because solid state diode emits light in term of a sophisticated function and it is not simple to find the angular distribution with a number of measurements.
Answer: If your LED has decent power and your power meter is sensitive and if you know the area of the aperture you could make an estimate but it might take a few measurements at different angles. A LED's light distribution is called Lambertian and the formula is available online. You would need to assume your power meter is calibrated and that it performs well over its known area surface.
Answer: In order to not to have any estimations on the radiation pattern you can use an integrating sphere. Just like in the following link, for exemple. https://www.led-professional.com/resources-1/articles/using-integrating-spheres-correctly-to-measure-leds-by-gl-optic-and-just-normlicht-gmbh


Eurodollar futures volatility

Question: Considering each point is 2500, how can I get the volatility of the jun 24 contract? On tastyworks I'm seeing a 0.7% iv for the contract, how can I translate it to standard deviation? Ex:sp500 15%stdev, gold 20% stdev
Comment: Have you asked the brokerages what their IV quotes represent? Neither 0.7% nor 0.07% seems remotely correct. See, for example, https://www.cmegroup.com/tools-information/quikstrike/volatility-term-structure.html#
Comment: S&P Emini point value is 50, current price is 4400 (approx), notional is 220,000. 15% of this is 33,000 dollars. This is annualized standard deviation for a 1 contract position. Eurodollar: 1 point is 2500, 100 points (hypothetical current price, just for ex.) is 250000 notional, 0.7% is 1750 dollars.
Comment: Thank you for adding context. Do you know why brokerages have different iv? Tastyworks has 0.7% and I'm seeing ibkr tell me it's at 0.07%
Comment: How can I see the back months on this tool to check the Jun '24 expiration volatility? This is showing that the market is pricing in a 25 bps volatility for EDM2?
Comment: Does the volatility in the quikstrike tool in bps? for example 15 vol= 15bps=15*$25=$375
Answer: For the purpose of calculating the option vol of Eurodollars you need to convert the underlying to basis points of interest. Subtract the price from 100 to determine that level. Sep Euros settled at 99.53. 100-99.53 is .47  .47 is the underlying. Additionally, strikes are 100-strike. The 99.50 strike is really the .5 strike.

Eurodollar futures volatility


Will I break my Dahon Mu Uno?

Question: I weigh around 220 pounds, the weight limit for the bike is 230 pounds, part of my regular ride is a long stretch of compacted gravel, I tend to thrash along being used to riding a mountain bike and the less than a year old Mu Uno has already developed a squeak. Am I going to break it?
Comment: Down vote with no comment, why?
Comment: Squeaks are a part of life. If you can find and fix the source of the squeak, great; if not, just learn to live with it. No, you won't break your bike.
Comment: Keep riding and you'll soon be far from the limit.
Comment: Check the spokes, crank arms, wheel and pedal hubs.
Answer: Weight limits are usually based on what the wheels can take rather than the frame. Also like with most things nowadays the manufacturers build in a margin of error so you can likely ride it safely 10-15 lbs above the actual limit.
Riding on compact gravel should not bother the bike so long as you keep it clean - make sure dust isn't getting into the hinges. To rule out any issues with the hinges clean them thoroughly and apply a light coat of quality lube something like Dumonde or Finishline. Then ride the bike and see if the creak gets any better. If it does, there may be some play in your hinges. A good bike shop should be able to adjust that play for you. If it does not get better the culprit is likely somewhere else. Possible sources could be the saddle mount or bottom bracket area.
Answer: Depends on the frame material. I can speak only about aluminum.
A cracked aluminum tube produces a weird type of squeak - you recognize it once your break you first frame. Before that, just inspect your bike for cracks at the welds.
Another thing is how you ride. Fellow 60kg MTB'ers claim they can break a DH bike in 10 drops to flat from 1 meter if they want to. I don't know if that's true, but am sure MTB skills can help safely ride a road bike through off-road terrain.
Keeping your ass off the saddle, keeping knees and elbows properly preloaded but relaxed, reacting to impacts progressively (slight impact - be limp; harsh impact - push back exactly as much as to exhaust your whole preload), line selection, hopping over sharp edges etc.

Will I break my Dahon Mu Uno?


Data plotting iOS - CSV file

Question: I have a csv file that is updated every second on a client. This file is synced with a server which holds the file. An iOS application reads this file using 'contentofURL'. Instead of reading is it possible to store the file data - like receive only the updated values instead reading the whole file? These values are later plotted using core plot API
Answer: You need your server to be able to provide the updates of your data.
If your CSV file only grows by appending new values, you can make a service that would accept an index as a parameter and return all elements starting from that index.
Then in your client you request that service with the index equal to the number of elements already retrieved by the client, and then append the returned elements to the stored ones.
If your CSV file changes in more complicated ways then you will need some kind of version numbers and a service that accepts a version number and returns a diff between that version and the latest one, together with the latest version number.

Data plotting iOS - CSV file


Android Action sheet

Question: In iPhone, there is the concept of Action Sheet. I want to use the same functionality on a button click in Android, but Android doesn't have Action Sheet. Can anyone tell me the equivalent of Action Sheet in Android?
Comment: `Context Menu` is the solution in Android.
Comment: possible duplicate of [implement actionsheet in android](http://stackoverflow.com/questions/6342180/implement-actionsheet-in-android)
Comment: no Paresh,it's not working dude.
Comment: please have a look of this image,i want to create the ame thing in android on a button click.http://www.mobile.safilsunny.com/wp-content/uploads/2012/01/UIActionSheet-2.png
Comment: **Google** may be your friend !!
Comment: anybody want that effect refer that link  http://horribile.blogspot.in/2012/01/options-menu-like-actionsheet.html
Answer: You may use Popup Menu in Android
A popup menu displays a list of items in a vertical list that's anchored to the view that invoked the menu. It's good for providing an overflow of actions that relate to specific content or to provide options for a second part of a command. Actions in a popup menu should not directly affect the corresponding content—that's what contextual actions are for. Rather, the popup menu is for extended actions that relate to regions of content in your activity.
Comment: Hay Aziz,but context menu uses instance of menu inflator,so it will work only when i clicked menu button, however my actual requirement is that i have a button on an image,and when i clicked on that button then Action sheet with four buttons appear in foreground.for more clear concept please have a look of an Action sheet image on google.
Comment: Do you think Popup menus serve you better in this case?
Comment: no,my client requirement is that when i click on button then a four buttons comes in foreground from bottom of the screen(Same as action sheet in iPhone,it is very easy in iPhone) and that button goes to background,out of these four buttons one is cancel button,when we click on cancel button then all four buttons again went to the bottom of the screen and background button comes in foreground again.and this thing is only achieved by Action sheet in iPhone, that's why  i m looking for a same thing in android.if you have any idea then please help me out?
Comment: on that sheet i have four buttons like,MMS,EMAIL,FACEBOOK and cancel.
Comment: Now its more clear, sorry no idea about this. Seems like you would have go out of the way to implement it.
Comment: Aziz please have a look on this image,i have to create same thing in android on a button click.http://www.mobile.safilsunny.com/wp-content/uploads/2012/01/UIActionSheet-2.png
Comment: ok,buddy thanx for help,it was nice tacking to you.

Android Action sheet


Should I block visitors who seem to be probing my site?

Question: I have detected some attempts to probe the security of my site.  Should I blacklist their IP address?  What are the considerations or tradeoffs to use in deciding when to block their IP address and when not to?
Comment: Funny, I've been wanting to ask the exact same question and also post an answer myself like you did. Just checked the comment where I thought this question might have come from, and indeed you commented below me ^^ Will answer later, 5:47am here.
Comment: I would be very careful at deciding what is _probing the site_. Some interpretations would ban legitimate users, which is much worse than the slight. Think for instance a user manually changing the date in the url (and failing a checksumming token), a POP3 denial of access to the user of a webmail-only plan or grandpa attempting to remember his password. So unless it is a **very clear attempt** (and beware of automated tools like mod_security, they **have** false positives) require a good number of attempts, and be conservative with the ban duration.
Answer: As a rule, the returns on this type of defense are nearly zero. There are exceptions, but even then this technique may offer only a small amount of security.
Exhaustive vulnerability scans of randomly-chosen hosts offer extremely low returns on scanning resources. Instead, successful attackers generally choose one of the following two options to increase their odds:

Check for a very small number of vulnerabilities over a large number of hosts
This includes bad passwords for common services such as SSH, POP3, cPanel, Wordpress, Joomla, and the like. If your root password is "root" or your site admin password is "admin", you can expect to get caught in one of these drift nets surprisingly quickly.
Starting with a single known vulnerability, use a search technique to narrow down your target list to only the most likely victims.
Usually this starts on one of the common vulnerability databases. He finds a recent candidate and identifies some string that would be common on vulnerable hosts. This is often a "Powered by" line or a login link or a specific URL pattern. Then, using his favorite search engine he retrieves a list of sites that follow that pattern.

The important point is that in neither of these cases does the attacker make more than a few attempts at a given site. Either they're successful immediately, or they move on.
That's not to say that you won't see the occasional persistent attacker. There's always some misguidedly optimistic individual running Nessus against a /16, but such attacks are by their very nature self-limiting and very rarely successful, since the vast majority of the attacks target software that a given server doesn't even run.
Could such an attack be successful? Yes. Does it ever happen? I deal on the average with several compromised servers per day, and so far I have yet to see even one come from nessus-style full-spectrum scans. But the probability isn't exactly zero. And in the world of random attacks, statistics and probability matter quite a great deal.
The exception is when the attack is not random. If you run a high-value or high-visibility site, you'll attract a lot of direct attacks against you in particular. Sites like Facebook, Twitter, Hotmail, etc., see an extraordinary amount of attack traffic. If you deal in this type of site, you probably already take security very seriously and aren't looking for advice.
A note about SQL injection: This type of attack does take some refinement; after catching an SQL error message in a cursory scan, an attacker may send several dozen queries to a given server to get the bits centered right. So theoretically a clamp-down response may prevent such an attack... but probably not, since he'll probably just return using a different IP. Since he's already alerted on your server, he won't be deterred by a blacklist. Better advice is don't run crappy software. There's no excuse for using non-parameterized queries today.
Answer: Arguments in favor of blacklisting: Might as well make the attacker's life harder.  While this is not a strong defense, it might give a little bit of additional time to investigate the attack and put in place stronger defenses.
Arguments against blacklisting: In the case dynamic IP addresses, blacklisting them may end up blocking other benign users.  You might never know that you are blocking other benign users, or it might lead to hard-to-diagnose errors in the future.  In addition, there is some potential configuration complexity to managing a blacklist.
If the attacker is attempting to disrupt the site by overloading it (to mount a denial-of-service attack), then blocking the IP address might be the right answer.  A temporary block might be enough.
If the attacker is just probing or scanning, I would be less inclined to blacklist their IP address, but you can take the tradeoffs into account in each situation and make an informed decision about what makes the most sense.
Answer: Edit: This answer does not consider login brute-forcing, just attacks which attempt to exploit system vulnerabilities. Of course it seems legit to me to temporarily ban an IP which attempts 30 logins in 5 minutes. /edit.
If you don't have an automatic system in place to check and block requests, don't ban IP addresses that attempt to hack your service. If you block them, they can't make anymore requests, and you won't know if there is a leak. Attacks are going on day and night, and more often than not, you won't be watching the log while an attack is attempted. Block an attack now, and some day someone else will find the leak.
Of course, blocking attacking IPs is a precautionary measure which will help your security. It is not real security, but it might just ward of an attack while giving you early warning.
Doing this in an automated manner might have an advantage when you give a default response back (like a HTTP-200 response) so that automated tools won't detect the block. If you keep logging the requests, you can later check if any of the attempts would have been successful.
There are some problems with this though:

Attacks may come from a botnet, hacked server, or dynamic IP. Sooner or later, you're going to block a benign user. At least just temporarily ban the IP until you've made sure that the attack would not have been successful.
It is a lot of work to check all requests from detected attacks, especially since there are so many automated attack tools that make hundreds of requests.
You will probably start to rely on the detection system in some way. This kind of precaution will make you feel safer, and thus make you think less about security while configuring the system (or writing code).
You still have to check log files from time to time to make sure your detection system didn't miss anything.
False positives may occur. A simple example is when detecting apostrophes in POST-data (which an attack tool might attempt to detect SQL-injections), you could block a user who is trying to use an apostrophe in their password. This may be solved with a captcha, but targeted attacks will also solve the captcha.

Overall, I would not block any attempted attacks. There may be situations where this is a good idea (perhaps in high-security environments, like for a bank or website with millions of visitors), but in general I don't think it will really help, or may even give you a false sense of security.
The only exception is a DoS attack. Here is no security risk, the only thing being exploited is processing time or bandwidth, so there is no reason not to block this. Though even then, only temporarily ratelimit or ban: these attacks are likely done from a botnet, thus making you block user's IPs.
Answer: It obviously depends on what your site does, the downside of blocking IPs (could you inadvertantly block real non-attacking customers), and the risk that something could be compromised (is it likely that some users have weak guessable passwords on the site?)
Short term blocks seem perfectly reasonable varying from anywhere from 5 minutes to a day.  This may allow an attacker to try ~1000 attempts a day, versus a ~1000 per second in an online attack.  Granted, you need to be sure that you do not block legitimate users who forgot their password.
Personally, for example, I block large ranges of IP addresses from China/Russia on a website I run for a local business.  I observed that the ssh server for the website had a couple thousand attempted logins with non-existent usernames.  While they weren't close to guessing my username, let alone my random high-entropy passphrase, I  wasn't comfortable with the attempts and so no reason to let them continue.  So I installed fail2ban with loose settings (five failed logins = 30 minutes ban; whitelist for my static IPs -- so I can still login if needed -- also I login 95% of the time with a RSA key so a single failed login is rare).  I also changed the ssh port from 22, yes this is only security by obscurity that's easily defeated by a port scan (though I could setup a honeypot for that; but didn't), but that's ok if its part of defense-in-depth.  Implementing these changes caused the number of attacks to go down to zero in the past month (as far back as the logs go).
Comment: Login brute-forcing is not really what is meant here, but yes that would (imo) be a legitimate reason to resort to temporarily banning IPs.
Comment: @Luc - I understand what's generally meant by probing--mapping out the server (e.g.,port scan), tests for SQLi, etc.  But for my stuff, the servers sit behind a firewall blocking unnecessary ports (the server doesn't log port scanning) and I use a mature framework that always uses bound parameters.  I could setup a rule to block an IP if it tried an unused port, but that could backfire (if I try the wrong port once while setting something up or have to let a colleague in and they try the wrong port; it could be a major hassle) as well as being easily circumvented by determined attackers.
Comment: My main fears are 0-day vulnerabilities in ssh/my web servers or someone using a weak password that gets brute forced.  So the one thing I temporarily block is brute-forcing of passwords to limit attempts (this is also partially just to reduce the unintentional DoS effect of trying an online attack). Also, its worthwhile to disable host info (don't advertise apache/nginx version numbers) in case 0-days come out that only affect certain versions; no reason to clearly advertise your vulnerability to the world -- make them work to find what's running (by feature set or seeing if it has a vuln).
Answer: I would monitor the situation a bit more before moving on with blacklisting an IP, even temporarily. Besides the cons mentioned by D.W., I don't think a serious attempt at attacking your site would employ the same IP more than a couple of times; it's not very hard to spoof it after all. If, however, after a short time spent monitoring, I were to observe repeated probes from that specific IP, I would definitely consider blocking it.
Another thing I might be in the lookout for is the nature of the probes. If the range of offending IPs all share common characteristics in a given window of time, there is a good chance they have been made by the same attacker.
Finally, if the attacks were persisting and / or I had some time to spare, I would attempt to get an idea of what the attacker sees by repeating the probes myself. At the very least, I would get more information about my site 's security.
Answer: This is an "it depends" tradeoff.
1 - what is the priority of accessibility vs. obstruction of attackers?
For any block, you want to determine whether you are blocking legitimate usage as well as attackers.  For example, if the IP comes from your customer and one of their machines has been hacked to scan you - you may want to alert the customer and work with their security team rather than shooting off your own foot.
2 - what is the impact?
Do you have the helpful protocols that expose your network turned off?  What can the attacker see when they port scan you?  Scanning yourself on a regular basis is a good practice, so you can know what you're vulnerable to.  If you've locked things down fairly well, your risk here is minor.
Also - what damage is the scan doing?  Is it slowing down legitimate usage?
3 - what is the nature of the risk?  What is your capability to manage it?
The typical classics - availability, compromise of assets or information, reputation of the organization.  What can you loose from the port scan, what can you loose if they find something and how frequently is it occurring?
And what is your staffing and your capability to address it?  In some networks, putting in a block is fast and easy, in others it takes a significant degree of due diligence.  If you put it in incorrectly, what is the harm?
Answer: The most reasonable thing right now is to follow that scan and make sure that attacker didn't find anything vulnerable in your application. Secondly you should check that IP. Blocking someone's IP address isn't always the best solution. The attacker could be hidden behind the NAT. So if he shares his IP with a lot of different users, you will lose visitors (they will be also blocked). The scan could be also started from the innocent victim (his PC could be a part of the botnet). However you should make sure that:

this IP doesn't belong to any bots/web-crawlers (which are scanning the Web almost all the time)
the traffic generates by this scanning doesn't generate huge bandwith (or doesn't affect the performance of your server).
Comment: Crawlers != attackers. If they get themselves banned by overloading the service it's their problem, but that's another discussion.
Answer: I suggest a different approach to the problem rather than banning ip addresses or fail2ban, which can be fragile and ineffective. Instead I recommend changing the configuration of your webserver so all request to unknown server names or locations return 404. I wrote about this technique for nginx here:
https://medium.com/quiq-blog/harden-nginx-from-malicious-scanners-5bd1ca9c5a5c
Answer: If you have annoying visitors, site scrapers, or spammers, you may find it useful to block these users from accessing your website content. You can block bad visitors by IP address or blocks of IP addresses using a .htaccess file.
Read more some useful examples: http://kb.mediatemple.net/questions/1699/Block+a+specific+IP+address+from+accessing+your+website#gs
Comment: First, D.W. doesn't actually say it's http traffic, secondly there are a number of issues with htaccess files regarding policy management and performance, thirdly, any serious probing / attack is more likely to use multiple protocols and fourthly temporary bans avoid most of the negative impact while delivering most of the benefits - but this means pro-actively managing te block list. Fail2ban does a very good job of this and works for a range of protocols / applications.


Wiring a light switched fan to a remote only fan

Question: I am replacing an older pull chain fan that is also controlled with two light switches, One controls the lights and the the other the fan. The new fan I have has no pull chains and has a remote module in the mounting bracket. The old wiring coming out of the ceiling has a red wire, black wire, white wire and copper wire (ground). The new fan only has 3 wires. A black, a white and ground. How would I wire the new fan to work with only the remote control. The red wire is what is confusing me. How do I know if the black or red wire is the hot wire. I Assume it is the black but what does the red do? Can that one just be capped off and disregarded. Any input is appreciated. Thank you
Answer: To have the fan work with the remote only, wire up the black to black, white to white and grounds. Cap the red wire. ( the black and the red are hot only with their respective switches in the "on" position.)
The fan will run only with remote input, HOWEVER, you need to be sure that the switch that controls the black wire remains "ON", or there will be no power to the fan.
You can also opt to remove the switch that powers the black wire and tie the 2 black wires from the switch together, making that black to the fan always hot.
You can remove the switch powering the red wire and cap them also., covering the boxes with blank plate covers.


running ASP on a linux machine

Question: My testing environment for coding is currently a LAMP setup on an internal server running Linux Gnome. We've recently gained 2 or so sites to do maintenance for that were written in ASP. I'm now aware I don't have a testing environment for ASP and as I know so little about what I need to do, is it possible to run ASP on a linux machine (much like you can use WAMP to run PHP on windows)?
Comment: Are you meaning "classic" ASP or ASP.NET? The two are very different kettles of fish.
Comment: unfortunately, i don't know how to tell. My ASP skills are very very low end - the website has .asp files as part of the structue. Looking at them, i'm not sure how to tell?
Comment: You can't tell just by looking at filenames. ASP.NET usually uses the file extension .aspx rather than .asp, but this is not always the case. I would avoid being responsible for an ASP testing environment, especially away from its native OS, without much/any knowledge in the area - you could be volunteering yourself for quite a lot of hassle/confusion and complaints from the users when it doesn't work how they'd expect.
Comment: thanks for the advice david. unfortunately i don't have a choice in the matter. :( fortunately its a small team and so there's lots of lee-way for the learning curve. and it's just for one client, so it's not too massive yet. besides - gotta learn sometime! :)
Answer: Check out Apache-ASP: http://www.apache-asp.org/ It's a port of ASP to an Apache module
Not used it myself but looks OK, not sure about performance in live but should be good enough for testing/dev.

running ASP on a linux machine


Using SATA drives with SAS shared backplane?

Question: Is it possible to use SATA drives when you have a SAS shared backplane to be able to address the drives?
Comment: What type of server, hardware, controller and/or JBOD enclosure are you using?
Answer: Yes. It's definitely not ideal, but yes, you can.
Scenarios...

Shared backplane behind a SAS expander. Not good.
Shared backplane with dedicated 4-lane SAS connectors (e.g. a Dell or HP server's internal drive bays with 1:1 port controller port to disk bay mapping). Okay.

I tell people to just use nearline SAS instead of SATA these days, just to avoid any issues. Expanders tend to cause more problems in these mixed scenarios.
Technical explanation in detail.
It's when you add SAS expanders (and SATA Tunneling Protocol) to the mix that you start encountering weird errors with misbehaving SATA disks. SATA simply isn't designed with a switching fabric in mind, and it looks like firmwares still aren't robust enough to deal with command tunneling reliably in the presence of errors.
Answer: SIMPLE answer: yes.
COMPLEX answer: Yes, IF the SATA drives actually behave correctly - some do not. Too few checks, so you get issues.
I run a 24 slow SA backplane full with SATA drives (SSD, Velociraptors) and I DID have a share of Problems under load. SSD Firmwareupdates got them under control.
http://www.adaptec.com/blog/?p=1951
isa blog post about a similar experience ;)
Answer: It's depend of SAS architecture. If your backplane have connector type SFF 8482 it is compatible.
See: http://en.wikipedia.org/wiki/Serial_attached_SCSI#Architecture


Cannot access my wordpress website

Question: My WP website which I have been using for several months and working well, but suddenly today I cannot login to my admin area. I got some error message like attached. Even some regular pages of the website are displaying such texts.
Answer: It looks your website has been 'hacked'. Use FTP (or some other way to access the files) and try to open index.php (and some other PHP files) in the root folder with a text editor like Notepad+.
If it contains large strings with strange characters like your screenshot, someone has been editing your files. If this is the case, you better do a fresh install of Wordpress and update all your themes and plugins to the latest version.
I hope the cause is something different.

Cannot access my wordpress website


What is the "lowest energy"?

Question: In many textbooks I come across the term lowest energy. For example in atomic structures, electrons are placed in orbitals in order for the atom to have the lowest energy. But what is this energy? Potential- or kinetic energy or the sum of the two?
Comment: The sum of the two, usually the eigenvalue of the Hamiltonian operator.
Answer: The lowest energy of a quantum system is the minimum eigenvalue of the Hamiltonian of the system. The Hamiltonian is the operator which corresponds to the total energy of the system, so it is the sum of the kinetic and potential energy. This is often also referred to as the ground state energy of the system.

but what is this energy?

Heuristically, the ground state energy is the energy which the system has simply by existing. Normally, this doesn't make any sense: If I just make the system do nothing, just sit there, then it would have zero energy. We wouldn't need the fancy name.
But it turns out that this is impossible. We can never "pin down" a system and make it completely still, due to the famous Heisenberg uncertainty principle,
$$\Delta x \Delta p \geq \hbar/2.$$
The system must have some momentum, to satisfy the inequality. In turn, it will also have some energy. This is why we can never reach absolute zero! No matter how hard we try, there always remains the jiggling of the ground state.
Comment: What wikipedia says is that the uncertainty principle may help to understand why, when the system gets the minimum of energy there is still some irreducible kinetic energy. But this has nothing to do with absolute zero. Things go the other way round: at absolute zero the system has to get the minimum energy. Due to quantum mechanics such minimum energy state is not the state with zero kinetic energy. what is wrong is to add the implication no zero energy -> no zero temperature. The thermodynamic temperature is not proportional to the kinetic energy at low temperatures.
Comment: Writing that it is not possible to get absolute zero because the system has to satisfy the uncertainty principle is completely wrong. Absolute zero does correspond to the minumum of energy whatever it is. It has nothing to do with energy being zero. One very good reason is that the energy is always definite within an arbitrary constant.
Comment: @GiorgioP Thank you for pointing out my mistake. Unfortunately, I always thought that this was the case, and I don't understand why it shouldn't be. Is it _completely_ wrong, absolutely and utterly? Could you enlighten me?
Comment: Think of a particle of mass $m$ in a potential well which could be approximated, close to the minimum, by a harmonic potential $\frac{1}{2}( m \omega^2 x^2 - \hbar \omega)$. By construction its lowest eigenvalue is zero. The corresponding eigenstate is a minimum uncertainty wavefunction . Moreover, since the system is in an eigenstate, the variance of the energy vanishes, Therefore, all the measurements of energy will return zero. The argument you are citing is usually used to justify a value of the minimum energy higher than the minimum of the potential energy.
Comment: I am using it to justify exactly that. My intent was to make it clear that there is a difference between the classical minimum and the quantum minimum, which is why we give it a name. Also, I still don't understand why the uncertainty principle doesn't prevent a system from reaching absolute zero. [Wikipedia](https://en.wikipedia.org/wiki/Zero-point_energy#CITEREFSciama1991) seems to agree with me.
Answer: The sum of the two.
An electronic state like an orbital is an exact or approximate solution of some time independent  Schrödinger equation, i.e. an eigenstate of the hamiltonian made by a kinetic and a potential energy term. The corresponding eigenvalue is the expectation value of such hamiltonian, evaluated on the state described by the orbital.
The expectation value of the hamiltonian  can always be written as the sum of the expectation value of kinetic and potential energy. The lowest energy, is the eigenvalue of the hamiltonian with the minimum value.
Answer: In QM the Schrödinger Equation gives you the solutions for the wavefunction of a particle with a given potential. Because the energy is quantized you usually find several possible values for the energy that are given by an integer number $ n $ called the Principal Quantum Number. The lowest value of $ E_n $, normally when $ n=0 $ or $ n=1 $, is the Groud-State. This means that the energy of the particle is the lowest and it is a combination of the potential energy and the kinetic energy.

What is the "lowest energy"?


What is the purpose of these grey balls on the drone?

Question: Are these used for position tracking? Are there any papers
Comment: "Unfortunately, it won't solve existing problems but create new ones" Sorry, but that is wrong. It perfectly solves the problem of exactly knowing where your drone is. What you do with the data afterwards is not a problem of the Mocap. It's like saying drones create the huge problem of having to control a flying object.
Comment: According to a drone enthusiasts forum, grey balls are utilized as a tracking marker. Unfortunately, it won't solve existing problems but create new ones. If the high speed camera has recognized the position of the drone, the next step is parse the data on a semantic level for example to recognize if the pilot has flown a left curve or a right one.
Answer: These are markers for a visual Motion Capture system. Buy some markers here
Most MoCap systems work by setting up multiple cameras with strong IR-Flashes and IR-Cameras and the surface of the balls are optimized to reflect the specific wavelength. The cameras then almost only see the markers and can use triangulation to compute their position.
As at least the last image was capture at ETH Zurich (specifically the Polyterasse), they likely used their Vicon tracking system. Note that they captured the data on a cloudy day as direct sunlight also contains IR and could compromise the MoCap. However, you normally set up the MoCap cameras in a full circle around your working area to improve accuracy and have a lower probability of occluded markers. So it's also possible that there was no MoCap and just a photo session.


Delete/Remove Material Library VX

Question: Anyone know how to delete/remove a "Library" under Material Library? There is a "New Library" button to add your own new library - but what if you want to remove one?
Answer: You have to work directly on the asset blender file placed in your BlenderAssets/ directory (Pref/File Path).

Delete/Remove Material Library VX


Divorce, tax lien on house but liability is for one spouse because of Married Filing Separately. What happens when sold?

Question: 26 years marriage. Wife stayed home for 20 of 26 years. Husband owned S-Corp that flowed to their personal taxes, always filed in October after an extension, and never paid the liability. Once the last lien was paid, wife got a job and started filing Married Filing Separately. She doesn't owe, receives a refund, and is in good standing. Husband owes over $550K to the IRS. They placed a lien on the marital home. Home has over $700K in equity. Wife filed for divorce, and they're near the end. Judge orders a 50/50 split of remaining equity, $350K to each. When sold, what will the IRS do? Can or will they take all the equity to satisfy only the husband's back tax liability or will wife get her 350K, husband gets $0 and will still owe the IRS $200K?
Answer:
When sold, what will the IRS do? Can or will they take all the equity to satisfy only the husband's back tax liability or will wife get her 350K, husband gets $0 and will still owe the IRS $200K?

That's a question to your attorney. The IRS put the lien on the house before the judge gave the order, and it's not entirely sure why the judge's order didn't address the lien.
As an "innocent spouse" (at least for the MFS years) you got some recourse, but it's not a DIY situation, you got to talk your attorney. If your family law attorney doesn't know - ask them for a referral to a tax attorney.
Comment: @TWilson It can't, but the IRS *usually* wouldn't go against a family court judgement as long as the debt was considered and attributed to one person. You may end up in a Federal court against the IRS on this, or back in the Family court against your ex, demanding either refund from the IRS or from the ex, depending on what your lawyers would suggest to be the better shot.
Comment: Thanks. I've done all of the above. No one seems to have an answer and that astonishes me. A family law judge is governing at the county level. The IRS is federal and their laws override county and state laws in the U.S. (in case you're not a US based person). Innocent spouse provision only applies to joint returns. We are MFS, so not applicable. I don't owe it but there's enough equity in the house to pay it. Even the tax attorney doesn't know. My sense is there is no one way they handle this situation but I'm asking here just in case. A family law judge can't dictate IRS actions though.
Comment: Yeah, that's what I'm trying to avoid by getting clear on IRS collection law or procedure. To no avail so far. Who wants to sue the IRS? I don't. The divorce is enough.


Different keystrokes to hide

Question: I noticed that sometimes ctrl-L selects all and sometimes A works instead.  What is the difference between the two?
Answer: A will select all geometry.
⎈ CtrlL will select all geometry that is connected to your current selection.
For example, from this state in edit mode:

Pressing A will result in this:

Pressing ⎈ CtrlL will result in this:
Answer: In edit mode Ctrl+L selects all geometry that is linked to the geometry you have selected.
So if you have a mesh with two (or more) 'loose parts', and you select one face of one of those partes, hitting ctrl+L will select all the faces in that part, but not the other one(s). While A will select every face in the mesh regardless of being in another part.
That's why Ctrl+L doesn't do anything unless you already have something selected.
Answer: A selects all geometry.
ctrlL selects linked geometry. In edit mode, if you have geometry selected, it would let you select all of the geometry connected. Here is a quote from docs.blender.org:

Select geometry connected to already selected elements. This is often useful when a mesh has disconnected, overlapping parts, where isolating it any other way would be tedious.
Comment: No, invert selection is ctrl+i.
ctrl+L is "select all linked".
Comment: @Alexandre Marcati I edited my response.

Different keystrokes to hide


Is it possible to to use same frequency band and same frequency blocks for two adjacent/near telecom circles

Question: As shown in the Screen-Shot, TRAI (Telecom Regulatory authority of India) in the pre-auction recommendation manual to DoT(Department of telecommunication) mentions 770 MHz of the spectrum ( 35 MHz for all 22 telecom circles in India) up for auction. But using the same frequency band in all telecom circles or two adjacent circles leads to interference. Even then they are being recommended for auctioning what am I missing? Please help me understand. I am using telecom circle for LSA (licensed service area)in the screenshot.
Comment: Can you justify this: *But using the same frequency band in all telecom circles or two adjacent circles leads to interference.*
Answer: A "licensed service area" is a licensing fee division, not a technical division. "Andhra Pradesh" is a LSA. You may compare to "France" and "Germany".  France and Germany are adjacent, and both use the same Bands for mobile telecommunications.  That doesn't "lead to interference".
Using the same bands for adjacent mobile towers (a much much smaller area) doesn't "lead to interference". Thousands or millions of mobile phones may use the same bands in the same LSA. That doesn't "lead to interference". because interference is a technical problem, addressed by things like antenna direction and signal coding.


Local stability + global attractivity = global asymptotic stability?

Question: I was wondering how could I prove such a property stated in [Angeli, 2004]. For instance, consider the system $\dot{x}=f(x)$, where $f:\mathbb{R}^n\to\mathbb{R}^n$ is Lipschitz continuous.
Claim. Suppose that the system is locally stable and globally attractive. Then, it is globally asymptotically stable.
Proof. I was trying to prove it as follows. From local stability definition, there exists neighborhood $N$ of the origin for which,
$$\forall\varepsilon>0, \exists\delta>0:|\xi|<\delta\Rightarrow|\phi(t,\xi)|<\varepsilon,\forall t\geq0,\forall \xi\in N,$$
and
\begin{equation*}
\lim_{t\to\infty}\phi(t,\xi)=0,\quad\forall \xi\in N.
\end{equation*}
where $\phi$ is a solution for the system.
Let $\tilde{\xi}\notin N$ be an initial condition for a solution $\phi$ of the system. From the global attracvity, $$\lim_{t\to\infty}\phi(t,\tilde{\xi})=0.$$
From the local asymptotic stability of the origin, there exists $T<\infty$ such that, $\forall t>T$, $\phi(T,\tilde{\xi})\in N$. Moreover,
\begin{equation*}
\forall\varepsilon>0, \exists\delta>0:|\phi(T,\tilde{\xi})|<\delta\Rightarrow|\phi(t,\phi(T,\tilde{\xi}))|<\varepsilon,\forall t\geq0.
\end{equation*}
From the time-invariance property and unicity of solutions, $$\forall t\geq0,\quad\phi(t,\phi(T,\tilde{\xi}))=\phi(t+T,\tilde{\xi}).$$
Thus, $\forall\xi\in\mathbb{R}^n$,
\begin{equation*}
 \forall\varepsilon>0,\exists\delta>0:|\xi|<\delta\Rightarrow|\phi(t,\xi)|<\varepsilon
\end{equation*}
and
\begin{equation*}
\lim_{t\to\infty}\phi(t,\xi)=0.
\end{equation*}
Hence, the origin of the system is globally asymptotically stable.$\square$
Is this proof correct?
References:
[Angeli, 2004] Angeli, D. (2004). An Almost Global Notion of Input-to-State Stability. IEEE Trans. Aut. Control, 49(6):866–874.
Answer: I think you misunderstood the paper. The property "global asymptotic stability" is defined to be the combination of local stability and global attractivity. There is nothing to prove here; it's a definition. Here is the relevant part:
Answer: No, the proof is not correct. Because
$\phi(t+T,\tilde \xi) < \epsilon \not \Rightarrow \phi(t,\xi) < \epsilon$


How can I test a COM VHF antenna?

Question: I have an older VAL 760 TSO COM radio. Twice now the radio has blown an internal radio fuse on transmit. VAL has tested and certified the radio as "Good", but advice that the cable or antenna could be faulty. How does one test that the antenna or cable is adequate? Can one use an ohm meter to check for resistance or continuity? Any other advice is appreciated. I have a newer VHF antenna. It may be a CI-101, although not positive.
Comment: Just a suggestion: If the cable/antenna was wrong, the fuse would probably have no time to blow, that would be the power amplifier transistors. In addition if they are protected against impedance mismatch, nothing should happen except a bad reception and bad transmission. So, as the unit has been checked, I would now check the other connections, specially any existing DC output (to power external devices or switch), as this could be a short-circuit between +Vcc and the ground.
Answer: Your radio shop may be able to test the SWR of the antenna working with the COM radio.  That would be my starting point.  However, sometimes problems like these are intermittent and difficult to isolate.
You can test the antenna with an ohm meter but that will not measure the impedance at transmit frequencies.  An SWR meter will.
Unfortunately, unless your other hobby is ham radio, you may not have the equipment on hand to check out transmitter operation.  But your radio shop will.
They will also have a dummy load for testing the transmitter.
I have to say that I am surprised that the unit blew a fuse.  Most aviation radios I have experience with (I am not an avionics tech only a ham) have protection against shorts or opens on the output of the transmitter, which usually shut down the power of the transmitter, for example when a high reflected signal comes back. So blowing fuses is normally extremely rare.

How can I test a COM VHF antenna?


Why is SQL AG sync commit mode classified as no data-loss HA solution even when the session timeout can make the mode async?

Question: Assuming the SQL AG is in sync commit mode. Suppose the secondary becomes unresponsive or has secondary has network issues, then upon the session timeout expiry the AG will automatically get converted into async mode.
So, why is SQL AG sync commit mode classified as no data-loss HA solution even when the session timeout can make the mode async?
Answer:
upon the session timeout expiry the AG will automatically get converted into async mode

It's been a while since I've worked with AlwaysOn Availability Groups, so I'm not sure that statement is entirely accurate. The secondary replica in your example will however leave the Healthy state and enter a Disconnected state, whereby allowing the primary replica to continue to transact without waiting to synchronize to it (similar to how an asynchronous replica works).
I think it's still fair to call synchronous AlwaysOn Availability Groups a valid HA/DR solution with minimal chance of data loss (no solution in the world offers 100% guarantee of 0 data loss) despite its session timeout functionality. The situation where a replica is unresponsive is an error situation you would want to be aware of, and therefore it's fair for it to be marked as Disconnected.
It would be worse if everything carried on as normal, and a days worth of transactions just continued to build up on the primary replica waiting to be committed but couldn't because the secondary is unresponsive. There's a lot of risk for data loss in such a situation. And we'd be none the wiser without any indication that the secondary is in a bad state. Even scarier of a situation would be if the primary became unresponsive. The secondaries should have a way to acknowledge that there's some sort of a failure occuring on the primary, and the session timeout is one way of doing so.
The session timeout is configured for 10 seconds by default, such that one can be alerted and respond to an unresponsive replica situation rather quickly. But it can be adjusted to the needs of your use case, and increased if a longer timeout time is necessary (due to normal anomalies, etc).


After you deploy your token, do people who want to buy your token do a transfer with you as the owner of the total supply of the contract?

Question: I understand there are a list of required functions to deploy in an ERC-20 or BEP-20 token, but do I need buy and sell functions in my code or do I just need the transfer function? I am assuming that the buyers will buy from my wallet as the owner of the total supply. However, people would be buying from an exchange, so does the exchange have liquidity pool providers buy a bunch of tokens from me at first in an IEO? Thanks!
Answer: This completely depends on how you want to distribute your token.
Often this is separated between different components. E.g. you deploy your token and mint the initial supply to and distributor address. This distributor could be a contract that is used for an ICO, by selling the token for a specific price. Another way would be to use a MultiSig wallet, such as the Safe and sell the token via a platform like Gnosis Auction. Additionally you can distribute tokens by performing airdrops (e.g. a MerkleDrop).
Often many of these are combined to archive the best result. An example for this can be seen in an early proposal for a SAFE token on the Gnosis Forum.


Xubuntu Alt+Tab behavior

Question: I'm using Xubuntu 14.04 and I want to change the Alt+Tab behavior. In Xubuntu, it just has the option to alternate between applications, but I prefer something like Gnome Shell or Unity, that have the Alt+` to change between windows of the same instance. This is possible?
Answer: I found that option among commands that you can assign the shortcut to in Window Manager Settings via Whisker menu → Window Manager → Keyboard → Switching between windows of the same program. (Translation mine, so official one may vary.)
In my case it's Super+Tab, but I think it was empty by default.

Xubuntu Alt+Tab behavior


FLOUR tortillas as a crust?

Question: I am making a chili cheese tater tot casserole and would like to know could I use flour tortillas on the bottom or would that be a bad idea since I am baking it at 350 for 45 minutes
Comment: Hi Joel. Welcome to Seasoned Advice! It would be helpful if you would include your entire recipe here so folks can give you an informed response. For example, if this casserole is soupy in consistency flour tortillas on the bottom might sog out and make a goopy mess. It's hard to say without details.
Comment: @Preston : they don't sog out, but they're somewhere between what you'd get with a dried lasagna noodle and a fresh lasagna noodle.  (I use them in an enchilada casserole recipe that calls for dipping each one in water before placing it in the dish ... and it's always on top of a layer of sauce)
Answer: Yes, you absolutely can use flour tortillas on the bottom of your casserole. I disagree with @Rob's answer as I've never found the need to pre-heat the tortillas whether used as you intend, or when rolled. And I've never seen a recipe calling for that step. (Except when there is no further cooking.)
Answer: Many casseroles and dishes use rolled up tortillas containing meat and cheese, placed in a pan, and baked in the oven. You should be able to do the same but I would be sure to pre-heat the shells just as you would with any tortilla wrapped serving.

FLOUR tortillas as a crust?