Wikipedia:Reference desk/Archives/Computing/2017 April 12

= April 12 =

calculate angle on image
Is there a way to calculate the (approximate) angle at which these two thick black lines meet? Doesn't have to be precise, plus minus 2 or 3 degrees is fine. ECS LIVA Z (talk) 00:19, 12 April 2017 (UTC)


 * Slap a protractor on it and read the answer. StuRat (talk) 01:06, 12 April 2017 (UTC)


 * The upper line is 45.48 degrees. The lower line is 74.41 degrees. Open the image in a photo editor (I used Gimp) and use a measuring tool to calculate the angles. The angle between them is 28.93 degrees. 71.85.51.150 (talk) 01:07, 12 April 2017 (UTC)
 * Uh wait, the angle between them is clearly more than 90deg.
 * Sturat's "slap a protractor on the screen" method gives me roughly 140deg (Perhaps you subtracted when you should have added?) ApLundell (talk) 02:06, 12 April 2017 (UTC)
 * The IP just gave the outside angle, while you got the inside. I checked both ways (inside and outside) and got 29&deg; and 151&deg;. ᛗᛁᛟᛚᚾᛁᚱPants   Tell me all about it.  02:15, 12 April 2017 (UTC)
 * They will add up to 180° so if you measure one you can calculate the other. If your measuring tool doesn't do angles, you can still possibly get the pixel coordinates and then figure out the angles with trigonometry. 50.0.136.56 (talk) 16:35, 12 April 2017 (UTC)

Local machine IP extended to a virtual machine cause conflict?
I have a local machine with Win10 from which I mean to run a Linux virtual machine (LVM) with an OpenSSH server (there is a reason why I consider an LVM instead of WSL, in this case). Now, here's what I want to ask:

I have my IP address which is permanent. As far as I know, this IP comes from my ISP, and due to that, if I'll install an LVM on my local it will have the same IP as the host machine.

Let's assume I have the same IP both on the host machine and LVM: How then could I SSH tunnel into both without creating some kind of conflict? That is, both has the same ISP-provided IP address, so how could I avoid conflict? Ben-Yeudith (talk) 04:53, 12 April 2017 (UTC)
 * You can not have the same IP address on both of them. Your LVM will have a different IP probably in a 192.168.*.* range. Then either the host OS or your wi-fi router (if you use one) will translate it into the external provider assigned IP. Ruslik_ Zero 08:42, 12 April 2017 (UTC)
 * In terms of enabling remote SSH, these easiest thing to do is probably to choose different ports for the SSH in each computer and make sure you set up port forwarding correctly. I'm assumign you're not behind CGNAT or anything else that will make things difficult and either your router or host OS (whichever is reponsible, or both) supports forwarding properly. Nil Einne (talk) 09:44, 12 April 2017 (UTC)
 * Yes, port forwarding is the answer. Your LVM will configure a virtual network interface that will listen for traffic on your host machine's localhost and forward it as appropriate. On VirtualBox, you can do this with the Network Address Translation option on the guest machine: I like to set it up to forward an otherwise-unused port such as 2222 for my OpenSSH server on the guest.OldTimeNESter (talk) 13:11, 12 April 2017 (UTC)

ǂ
ǂ is a redirect to Palatal click, a kind of sound in some click languages that's typically transcribed with this character. What other uses does this character have? In MARC records, it's used to set off subfields, e.g. the standard LCSH for crime in Providence RI might be Crime ǂz Rhode Island ǂz Providence, and substituting other characters, e.g. ‡, will confuse the relevant software. Given these two radically different usages (and the fact that it's not a standard keyboard character, with no "normal" meaning), I'm wondering if it might be the standard character for other purposes as well, but aside from palatal clicks and MARC references, all I'm finding with Google are mojibake and idiosyncratic uses, e.g. this person's Twitter page. Nyttend (talk) 22:35, 12 April 2017 (UTC)


 * The Unicode name for that character (U+01C2) is LATIN LETTER ALVEOLAR CLICK . So it seems the click is the intended normal meaning for the character.  CodeTalker (talk) 15:45, 13 April 2017 (UTC)
 * Thank you. Nyttend (talk) 00:08, 14 April 2017 (UTC)
 * I don't think that's a normal MARC thing, even. Maybe some specific software uses it.  MARC codes usually look like $a, $b, etc.  The character is also called "double-barred pipe" and almost all the ghits are about the Unicode or IPA phonetic usage. 50.0.136.56 (talk) 23:51, 13 April 2017 (UTC)
 * Interesting. Where have you seen $ used as the subfield indicator?  ǂ is the indicator in OCLC Connexion, and I think it's the indicator in Voyager Cataloging; I can't figure out how to get MARC details from WorldCat, and many libraries just use | to separate subfields in the public-facing sides of their catalogues, e.g.,  (those first two links might not persist), and .  Nyttend (talk) 00:08, 14 April 2017 (UTC)
 * See for example here unless I'm confusing something. Web version of that record is here 50.0.136.56 (talk) 19:41, 16 April 2017 (UTC)
 * No, you're definitely not confusing anything; 245 subfield a is the main section of the title, and subfield b is a subtitle, so clearly this is just what you said it was. Thank you for the pointer!  Nyttend (talk) 17:08, 17 April 2017 (UTC)