Help: Grammar Without Context – Computer Science Stack Exchange

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ports – nmap gives different results in two shells on the same computer

I run kali and metasploitable2 in Virtualbox, and I have them connect via host-only network mode. I can ping and ssh from kali to metasploitable and have assigned the following IP addresses: (kali) and (metasploitable). For some reason, I was not able to see most open ports during a simple scan:

kali $ nmap -sV
Start Nmap 7.70 ( on ​​2019-06-16 09:04 CEST
Nmap analysis report for
The host is up (latency of 0.011 s).
Not shown: 997 filtered ports
80 / tcp open http?
443 / tcp open https?
8080 / tcp open http-proxy?

But if I open another shell and run the same command, the result is very different:

kali $ nmap -sV
Starting Nmap 7.70 ( on ​​2019-06-16 09:05 CEST
Nmap analysis report for
The host is active (0.00029 latency).
Not shown: 977 closed ports
21 / tcp open ftp vsftpd 2.3.4
22 / tcp open ssh OpenSSH 4.7p1 Debian 8ubuntu1 (protocol 2.0)
23 / tcp open telnet Linux telnetd
25 / tcp open smtp Postfix smtpd
53 / tcp open domain ISC BIND 9.4.2
80 / TCP open http Apache httpd 2.2.8 ((Ubuntu) DAV / 2)
111 / tcp open rpcbind 2 (RPC # 100000)
139 / tcp open netbios-ssn Samba smbd 3.X - 4.X (working group: WORKGROUP)
445 / tcp open netbios-ssn Samba smbd 3.X - 4.X (working group: WORKGROUP)
512 / tcp open exec netkit-rsh rexecd
--- snip ----

This is a potentially very new question, but what could these differences between seashells give? The env variables were identical in both cases.

computer geometry – Condition to check if two flat surfaces form the boundary of the same object

I'm trying to find an algorithm to determine if the plans detected by a depth sensor can be considered part of the same 3D object.

I was reading an article entitled "Optimizing Geometry and Texture by Plane for RGB-D Reconstruction of Interior Scenes" by C. Wang and X. Guo, in which they present a new approach to adaptive plans. They basically use 3 conditions: 1. The angle between the normals between two planes is small: 2. The average distance between two planes is small: 3. The angle between the radius connecting two centers of the plane and each normal plane is as close as possible to 90 °

I have come with the following two conditions: 1. Normals for both planes should be perpendicular to each other. (I guess here the 3D object is a cuboid). 2. The average distance between two planes is small. (from the paper)

What other conditions might be necessary and sufficient to conclude this? Any other research document or documentation on this subject would be very useful.enter the description of the image here

I am in the Windows Insider program and I was wondering if I would reset my computer (without deleting the personal files), would I be on a public version?

Some antecedents:

I joined the Windows Insider program to be able to run Android emulators while developing Android apps. Unfortunately, I can not play games with BattlEye because it is not supported with Preview versions, so I have to make a decision. I can play my favorite games or use Android emulators to continue developing my apps.

Yes, I know that I can connect my physical device but I prefer to run


If I reset my computer without deleting any personal files, will I go back to a public version of Windows and if so, does it take me out of the Insider program? I would like to leave.

Also a bit unrelated: do we know when Microsoft will fix the problem of the Android emulator?

computation – Higher function composition derivatives using a computer

I am interested in calculating feature composition derivatives analytically using a computer, in order to avoid calculation errors.

Some of the calculations I have to deal with are:
Let $ g (x) = F ^ {- 1} ( Phi (x)) $ or $ F $ is a function then $ Phi $ is the cdf of a standard normal distribution. In calculating derivatives, I strongly prefer to keep $ F $ as such, so the expression I receive is valid for everything $ F $ instead of a concrete one.

I need to calculate derivatives such as $ g & # 39; (x) $ and evaluate it at $ x = Phi ^ {- 1} (F (y)) $ and after that, if $ h (y) = g & # 39; (x) $ evaluated at $ x = Phi ^ {- 1} (F (y)) $I need to calculate $ frac {d} {dy} h (y) $.

As you can imagine, doing it by hand becomes a computer nightmare. Is it possible to do this effectively using symbolic differentiation tools? Can any one give me an example to do it? I hope this is the right forum to ask!

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The same email test failed on VPS but was successful on my own computer

I'm using v13.64 on both VPS and on my own computer, I've tried using a Yahoo email account in SER, all the security settings have been set correctly and I'm testing the mail account via SER on my own computer, it worked, then I tested it in SER on my VPS, it failed … the error message is:
Last Error: + OK 8462 Message (s) ..

Please advise, thank you in advance.

networking – How do you share a website running on my computer (localhost- with other people connected to the same wifi network?

I run a dashboard locally on my computer on port 8080. I wish to be able to share this dashboard with other people at work. I have tried to use these services:
But none of them worked for me. They all do the same thing, I will execute the command, it will work for a little while, then nothing will happen. No URLs are displayed. Could this be because I'm doing it at work and a network firewall is preventing this from happening? If this is the case, does anyone know that there is a way around the problem?

Any help would be appreciated!

Java Lottery Program – Computer Science Stack Exchange

Hi, I have a problem with writing a Java program that gives 3 random lottery rows and writes the result using JOptionPane.showMessageDialog (); in the following format.

Row 1: [ 23, 7, 10, 31, 27, 11, 3]
Row 2: [ 12, 3, 25, 9, 35, 6, 20]
Row: 3: [ 31, 27, 19, 1, 12, 32, 19]

In addition, lines 1, 2 and 3 can have different values ​​and two values ​​can not be identical in the same line.

The problem is that I can not generate rows and get impressions of the Line 1 form: [ 23, 7, 10, 31, 27, 11, 3,]that is, I want to get rid of the last comma.

Here is my code. I will appreciate very much the help that I will be able to get.

lotteri of packaging;
import javax.swing. *;
/ **
* @author torbjornolsson
* /
public class Lotteri {

/ **
* @param args the arguments of the command line
* /
public static void main (String[] args) {

for (int j = 1; j <= 3; j ++) {

String out = ""

String out2 = ""

int lottery = 0;
int randomNum = 0;

for (int i = 0; i <6; i ++) {
randomNum = (int) (Math.random () * 99); // Random number created here.
for (int x = 0; x <i; x ++) {
if (lottery == randomNum) // Here, the code checks if the same random number was generated before.
randomNum = (Math.random () * 99); // If the random number is the same, another number is generated.
x = -1; // restart the loop

lottery = randomNum;

out2 = out + lottery + ",";

out2 = "Row" + j + ": ["+ out + "]"+"  n ";

JOptionPane.showMessageDialog (null, out);



Disk Utility – Froze from the computer, the raid on iSCSI (APFS format) is no longer mountable. GPT / MBR not present

I was exporting video in Premiere and the computer stopped working, so I had to restart. When rebooting, I noticed that the RAID drive I connected to via iSCSI did not appear on my desktop. However, it appeared in Disk Utility. The physical disk and the container were opaque, but the volume (CC-SYN 1) was grayed out.

The container in the Disk Utility displays the indications "1 unassembled, 63.74 TB" and "Free, 32.22 TB". Its physical stores are disk3s2. The device is disk4. The volume is disk4s1, displays a capacity of 95.96 TB, Zero KB available, and – for use. Said not mounted. When I try to climb it is gives the error:

Can not mount "CC-SYN1". (Error 49225.

Running first aid on the container and the volume generates the following error lines in the details:

error: (oid 0x407) root apfs: btn: invalid o_oid (0x403)
error: (oid 0x407) root apfs: btn: invalid byte type (0xd)
error: (oid 0x407) pfs_root: btn: invalid o subtype (0)
fsroot tree is invalid.
The volume / dev / rdisk4s1 could not be verified completely.

Running First Aid on the physical disk does not produce any errors.

list of disk utilities Displays the following information for the RAID drive:

+ - Container disk4 6B51753E-274F-48BB-A0C2-89600A5B5DFF
APFS Container Reference: disk4
Size (ceiling capacity): 95959023288320 B (96.0 TB)
Capacity used by volumes: 63742597726208 B (63.7 TB) (66.4% used)
Unallocated capacity: 32216425562112 B (32.2 TB) (33.6% free)
+ -< Physical Store disk3s2 1E687745-0C0C-499E-BE56-6734C2909458
    |   -----------------------------------------------------------
    |   APFS Physical Store Disk:   disk3s2
    |   Size:                       95959023312896 B (96.0 TB)
    +-> Volume disk4s1 1BEFAA45-80CC-36F6-A360-C3B645F4687E
-------------------------------------------------- -
APFS volume disk (role): disk4s1 (no specific role)
Name: CC-SYN1 (case insensitive)
Mounting point: not mounted
Consumed capacity: 63740357574656 B (63.7 TB)
FileVault: No

sudo gpt -r show disk4
start of the contents of the size index
0 23427495926
sudo gpt -r show disk3s2
start of the contents of the size index
0 187419967408
sudo gpt -r show disk4s1
gpt show: can not open the device & # 39; disk4s1: permission denied

I have installed gdisk (from a previous bug to increase the size of the RAID storage) and I noticed the following problem when running the command – sudo gdisk / dev / disk4

GPT fdisk (gdisk) version 1.0.4

Analysis of the partition table:
MBR: not present
BSD: not present
APM: not present
TPG: not present

The partition table prints:

Disk / dev / disk4: 23427495926 sectors, 87.3 TiB
Sector size (logic): 4096 bytes
Disk Identifier (GUID): A8A7FBD2-665F-4081-BACC-6CB2D4FB8F18
The partition table can contain up to 128 entries
Main partition table starts at sector 2 and ends at sector 5
The first usable area is 6, the last usable area is 23427495920
The partitions will be aligned on boundaries of 256 sectors
The total headroom is 23427495915 sectors (87.3 Tb)

It seems that when the computer froze, it basically destroyed the GPT / MBR and that the computer does not know how to mount it anymore. I'm not 100% sure if gdisk has a viable solution to get the recognized volume again without losing any data. I've tried to read as much as I could, but I've never had the confidence to press some of the commands that could lead to potential data loss. Is there a way to fix that?