signal is a sequence of states in a communication system that encodes a message.

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24 views

What's the soonest I can send a signal to a background process (trap)?

I have a script from which I run a second script in a subshell. What's the soonest that can send a signal to the second script? script1: ./script2 & kill -SIGCONT $! script2: echo "~~ ENTRY" ...
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1answer
53 views

How do I pinpoint why wifi access is dropping

I am in a public building (ie. library) with wifi. I am trying to to pinpoint why a wifi signal keeps dropping...or find a why to work around it. My boss often uses the wifi and recently she has ...
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0answers
19 views

Abort Printing of Huge Amounts of Text in Terminal

This has happened to me in a variety of instances: Sometimes I accidentally copy/paste the wrong thing into vim, and then I have to wait around 10 minutes for it to print through all that text. I ...
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1answer
80 views

wavwrite function usage, Octave

Hey just to continue the thread would like to ask you something about wavwrite. I am trying to get a mat file (T01DATA.mat) to be played. Tryed with sound() with no actual solution; thanks to you I ...
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1answer
12 views

Can cables affect Wlan connection?

Do different cables (One coax, 5-6 power cables, one HDMI, two Ethernet CAT 5e) effect a WLAN signal? Im asking because my wlan throughput rate is jumping between a poor signal and optimum, where the ...
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1answer
38 views

SIGUSR1 is getting ignored when starting binary from system() command

I try to use SIGUSR1 with timer. It works fine when starting binary from command line. But if i start same binary from system() command from other application then SIGUSR1 is getting ignored. I don't ...
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0answers
46 views

When is SIGSTOP/SIGCONT safe?

I often find myself wanting to pause a long-running operation so I can quickly do something that needs computer power. I find myself scared of using SIGSTOP/SIGCONT. One alternative would be to use ...
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1answer
159 views

Stopped process doesn't continue to work after sending SIGCONT

I start cat in terminal: $ cat Then in second terminal I send stop signal: $ kill -SIGSTOP $(pgrep cat) And that works - cat is stopped. Now I want to wake up this cat process by sending ...
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2answers
321 views

enable on-board graphics after separated graphics card broken

My separated graphics card broke so I want to enable on-board graphics. Problem is I can't do anything in the Bios because my monitor has no signal. What should I do?
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2answers
59 views

How to submit a external signal to my computer in a simple way?

I have an electrical wire that have two states: 1/0. `1' means there is current while `0' means there is no current. How can I put these two states into a file of my computer in a simple way? I know ...
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0answers
378 views

how to kill a tcp connection in solaris operating system?

A client program connects to my server program written in JAVA via TCP connection (ServerSocket). I want to close the TCP connection between these two programs with a Solaris command or tool for ...
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2answers
230 views

Internet and Satellite sharing same coax

I have searched for this question online and I've seen a variety of answers, most of which are non-technical and simply this is a bad idea and I would never do this without any rational to back it up. ...
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1answer
197 views

How an unprivileged user could kill a process she didn't start?

I stumbled upon something very surprising which I cannot understand on a Red Hat EL 5.6 box : the user hri (which is in the group dba) is able to kill processes owned by user oracle (which is also in ...
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1answer
325 views

wifi usb dongle tricks and upload speed

Some people use a DIY parabolic foil around a wifi dongle to get better signal from a weak public WiFi hotspot, and some people buy a wifi dongle with an antenna that looks like a long vertical stick. ...
0
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1answer
60 views

What is the name of things that focus wifi signal (from the receiving side)?

I remember a year ago seeing a lot of ideas on the net about how to get better wifi signal from the receiving side, that is, you place Pringles or a round metal mesh near your laptop to receive better ...
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1answer
111 views

Logging signal strength in router logs?

Is it possible to to log signal strength of devices connected to Wi-Fi access point? Actually not even just connected devices, but would it be possible to intercept all wireless traffic and record the ...
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3answers
329 views

Router in a box

I want to put my router in a box for security reasons (it's in a common area of the building) and I was wondering in what ways would the box's material affect the signal's strength. It'll be either ...
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1answer
291 views

GNU screen quitting — sigterm to running process

I want to quit screen session. For this, I use screen -S session_name -X quit. This works well, but not like I would. The program running in screen has a handler for SIGTERM, and I really need this ...
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3answers
14k views

Which Wifi Channel should I use? [closed]

Very confused. I'm using inSSiDer, WiFi Overview 360 and Wifi Analyzer apps to try to determine the best wifi channel to use. Assuming all channels are in use and there are about 20 different users ...
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1answer
857 views

Python doesn't dump core files

I have a problem where a Python process is hitting a segmentation fault but not producing a core file. The following is a toy example that does not produce a core file on the following distros: ...
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1answer
276 views

Is it possible to read signal strength of USB mouse to detect its proximity in Linux?

Similar to the idea of detecting proximity via Bluetooth signal strength, I was wondering if it is possible to read such information for USB wireless mousein a linux system.
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1answer
222 views

ssh: propagate signal to remote process

This is the general version of: Send SIGTERM signal to a process running inside ssh It is possible to send Ctrl-C to the remote process if the process gets a pty (-tt): # Runs for 5 seconds (sleep ...
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1answer
637 views

What are likely causes of this wifi signal noise that could be causing dropped connections?

Seeing a reverse sawtooth-shaped noise spike in OS X Wi-fi Diagnostics that is associated with wireless connection drops. My wireless router is old, so it might just be dying. It seems to be somewhat ...
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1answer
2k views

How can I kill a parent process only?

I have the following processes. ParentProcess -- ChildProcess -- ChildProcess -- ChildProcess How can I kill the parent process only? I want the children processes not to be killed. If I try to ...
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0answers
180 views

Router in repeater mode

We have a Buffalo AirStation WHR-HP-G300N as the main router. We also have an Asus RT-N53 router located one floor higher. I've set the Asus router to act as a repeater for the Buffalo. There is a ...
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1answer
54 views

Signal Loss over Length

This is in regards to coaxial cable... I'm looking at low loss Cable to run a wireless receiving antenna to an outdoor wireless bridge rated to handle extreme cold. So far, what I'm trying to decide ...
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0answers
47 views

Is it possible to make a stopped process survive a shutdown?

I know that a program can receive a STOP signal and just sit there until it receives a CONT signal. Now knowing exactly how this works, I'm curious whether whether there's any way to have a STOPped ...
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1answer
58 views

Signals: Kernel-generated only?

Can processes really "generate" signals or they just request the kernel to send the signal on their behalf? And what about hardware interrupts? Do they get translated to software interrupts? Like, ...
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1answer
734 views

Wifi signal changes over time

I have a trouble about my wireless router signal. My laptop is 25-30 feet (~8 meters) away from the router. There are two walls between them. Windows reports signal strength is two bars, and inSSIDer ...
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1answer
325 views

Way to produce “constant” SPDIF audio signal to receiver? After 5 minutes of no audio signal, receiver switches from 5.1 to 2.1 surround

I have a specific problem with my receiver that I have hooked up to my PC. I have the receiver hooked up to my PC using SPDIF digital audio, and the receiver defaults to 2.1 surround mode when playing ...
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1answer
210 views

Can temperature change affect graphic card or monitor to change analog signal and cause blurry image?

My computer is located near the window, and I noticed that when I open my window, after a minute or two the picture on the screen often gets blurry and I have to press "auto" to make it sharp again. ...
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1answer
744 views

Inserting gpu in motherboard makes video signal of motherboard dissapear?

Is it normal that when you connect a GPU to a motherboard, the video output from the motherboard connectors disappear, and only the GPU connectors give the video output? This is relevant to me ...
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1answer
286 views

Samsung S23A750D 23" 120Hz get no signal

I have a few days ago received this monitor. Samsung S23A750D 23" 120Hz I am using it with a Gainward Nvidia GTX570 Phantom GPU via DisplayPort cabling. The trouble I am having is that the monitor ...
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7answers
4k views

Can a huge coiled LAN cable have some trouble for transmitting a signal?

Let's say I have a long (> 30m) LAN cable, that connect two (very close) devices. Could some of the unused wire, disposed as a huge coil, cause any issue ? I'm thinking about the special wire layout ...
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0answers
61 views

reading a trigger signal

I have a data acquisition card (Matrox Solios) which uses an input trigger signal to trigger a connected camera. This card is connected into the computer through a PCIe port. The device came with a ...
0
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1answer
421 views

HDMI Screen loosing signal in Safemode

I recently got a ransomeware at my computer so i decided to start up in safe mode to do a recovery but when I choose safemode my screen turns and the message "No HDMI Signal" appears. I've tried ...
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2answers
5k views

Asus monitor does not get HDMI signal after “Starting Windows” screen

I have an Asus 247H monitor which I hooked up to a Gigabyte motherboard's (GA-Z77-D3H) on-board VGA port at first. Soon after I got my hands on an HDMI cable, I tried to replace the VGA one with it. ...
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1answer
7k views

Meaning of line-bars in wifi signal strength, dB and negative values?

If I connect to wifi AP with 1 line of strength, does it mean that I will get only 1/5 of AP's bandwidth? I mean, do these lines tell me whether I will receive a full bandwidth or only a part of it? ...
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1answer
3k views

Video “no signal” but computer still running

Update Not doing anything in particular during these blackouts... Usually just when im doing nothing, sometimes im watching a video, sometimes playing a game... but mostly just whenever. I mostly ...
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1answer
1k views

Wireless repeater shows 54 mbps G when configured for 300 mbps N

I have an Encore ENHWI-2AN34D as a wireless repeater in my WLAN. The router is a TP-LINK TL-WR1043ND 300 mbps N and the repeater is 300 mbps N too, but when I check signal strength with inSSIDer or ...
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1answer
631 views

Loss of net access seemingly due to WiFi signal clash with repeater

The apartment I live in has a single corridor opening into rooms A,B,C,D adjacent to each other. The WAN ethernet terminates in room C where I have a Netgear WGR614v7 router installed. This router has ...
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0answers
190 views

After leaving display on overnight, I cannot get the Windows login screen up on the display, via the DVI cable alone, no matter what I try

When I come back to my computer, after leaving it on overnight, the display gives me a no signal message. I cannot get the Windows login screen up on the display, via the DVI cable alone, no matter ...
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votes
2answers
5k views

How do I troubleshoot low wireless signal strength on my Dell Studio XPS?

My Dell Studio xps laptop has just started experiencing extremely low signal strength. I did set up a wireless printer the other day, so maybe I screwed something up in the process. Here's what I ...
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1answer
1k views

no DVI signal during bootup 'till OS loaded

I connected a new display (ASUS VS229-H) to my computer using the DVI-cable which came with the display. I only see "no signal" on screen until the OS log-in screen is loaded. The previous display ...
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0answers
175 views

How can I reverse my router to boost wifi

I have a Linksys N Router model E3200. I do NOT have the internet, but use WiFi on my laptop a MAC Book Pro running Lion. Since my wifi goes in and out all the time. I was wondering how to use this ...
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1answer
105 views

Why does Unix deliver signals this way?

In Unix, when signals are posted, and the receiving process is running more than one thread, at first a thread is chosen to carry out the signal handling routine. I don't understand why that is ...
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620 views

How to make a Shell Script create a copy and terminate itself?

So far I used trap " call function" 2 fucntion { ./test.sh exit } but it never reaches the exit line and a whole bunch of process piles up any one got any idea? I tried & (bg) but i need to ...
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1answer
693 views

Does IE10 have an audio API?

Is there any way to do any audio processing(FFT,etc.) with javascript in Internet Explorer ? Does anyone know if IE10 does/will have any audio processing apis (similar to the Mozilla one) ?
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1answer
2k views

No signal after log off/ switch user

Periodically my monitor will go black and display "no signal" before turning off (power save mode) when I log off Windows or switch users. It doesn't do this every time, although most of the time the ...
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1answer
1k views

Trap ctrl-z key to perform cleanup

All, I have a shell script where I want to call a function to do some cleanup if user presses the ctrl-z key(SIGTSTP signal). I read about the trap command and found an example where I can trap the ...