devices refers to questions about the Unix/Linux device special files, normally these are under /dev. Do not use this tag for physical devices (for that use e.g. usb or pci).

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Creating a device similar to /dev/random from a script

I am writing a program for which I will create a script to generate test data in a specific format. How can I create a /dev/myprogram device that would work similar to /dev/random (preferably in ...
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1answer
23 views

Pushing changes to driver repos

My understanding of dkms is that its a way to dynamically manage all connected/disconnected device drivers on a Linux system. If that's correct, then I have to imagine that it allows you to configure ...
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How to write GPIO interrupt handler in Linux device driver? [on hold]

I am writing GPIO Device Driver for linux 3.14 on Beagleboard XM (RevB). I have done with simple ON/OFF LED blinking. But stuck at interrupt handler implementation. BB XM has GPIO_7 pin connected to ...
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1answer
21 views

Why does tapping a TTY device only capture every other character?

So, I came across the ttyname function (unistd.h) and had to test it out. #include <unistd.h> #include <stdio.h> int main(void) { printf("%s\n", ttyname(0)); return 0; } On my ...
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2answers
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how to know which device was open

is there any shell command, can let me know, current open device or device already in operation. For example, I use minicom to open a device /dev/ttyUSB0 or /dev/ttyS0, after I use program open this ...
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1answer
18 views

Does programmer use device files as interface to device drivers in their programs?

In Linux shell, a user can access a device driver, via its device file as the interface. When a Linux C programmer want to access a driver in his C program, does he also access the driver, via its ...
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9answers
4k views

Why do we need to mount on Linux?

I understand what mounting is in Linux, and I understand device files. However I do not understand WHY we need to mount. For example, as explained in the accepted answer of this question, using this ...
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0answers
37 views

Raspbian: USB storage device name changing after USB device power cycle

I'm running Raspbian 7.4 on a Raspberry PI that has two USB storage devices connected to it. This Raspberry PI will remain running during a power failure because it has console cable connected to it ...
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1answer
22 views

Is the directory that a file-system is mounted on (mount point) a device file of the file system's type?

A device file is an interface to the device driver of the device. When we mount a file system to a directory, is the directory considered a device file (of the file system's type)? If the ...
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Pegasus R6 Thunderbolt raid with CentOS 6.5

We have ourselves a rather expensive Mac Pegasus R6 external thunderbolt raid and a CentOS box that we would love to use it. On a Mac it's plug and play, however on our CentOS box it's not recognized ...
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1answer
369 views

Why does the UNIX system need so many [0-byte] drives at /dev/* [duplicate]

So I recently asked this question, which lead me to run this command: $ du -sk /dev/* Which outputs about 353 different entries that look like this: 0 /dev/sdt 0 /dev/stderr 0 /dev/stdin 0 ...
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3answers
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How to inspect the contents of /dev/sdt?

I have what I hope is not a huge problem, but could end up being a very large problem. For some context, I mistakenly ran this command on my 27'' iMac: sudo dd if=ubuntu-rescue.img of=/dev/sdt ...
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4answers
487 views

Trouble with understanding the concept of mounting

Having read both What is meant by mounting a device in Linux? and understanding "mount" as a concept in the OS, I have a problem where it is stated that All accessible storage must have ...
3
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1answer
57 views

Difference between /dev and /sys

Exactly what is the difference between devfs and sysfs? Both seem to maintain a list of hardwares attached to the system. Then why the need for 2 separate fs even arose? As far as I can get /sys ...
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1answer
82 views

What is the difference between /dev/sda and /dev/hda? [duplicate]

Sometimes internal harddrives are available as /dev/sda (with subsequent media located in /dev/sdb etc), and other times available as /dev/hda. What is the difference between the two? Does it vary ...
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0answers
37 views

Remote Mouse netcat (/dev/input/mice)

I was playing around with nc and I'm discovering how powerful and versatile this tool is. I was wondering how the file /dev/input/mice works because when I do cat /dev/input/mice you see the output, ...
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0answers
10 views

Device nodes for an ATSC tuner not created

I'm trying to use an external tuner to tune to ATSC signals. But when I plug in the USB-Tuner I could see only frontend created. $ ls -ld /dev/dvb/adapter*{,/*} drwxr-xr-x 2 root root 60 Dec 5 ...
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1answer
54 views

chroot with unionfs-fuse, can't access /dev/*

I have created the a chroot jail in combination with unionfs-fuse so that I don't need to install another system inside it. However, the resulting system's /dev entries are not readable.This is ...
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1answer
58 views

Do all devices under Linux have a device node?

I know that each device on Linux is either a char or block or network device. Do all physical devices that exist on Linux have a device node under the /dev directory? I'm not talking here about ...
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1answer
16 views

Does network interface device have device inodes [duplicate]

Does network devices have device nodes because i have looked inside /dev directory and have not found any corresponding device node although it's up and running
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1answer
24 views

who is accessing /dev/video0

I have a streaming video feed set up with the motion package. something like this: https://www.youtube.com/watch?v=jGkHSU-UPLU works Great. What I want to know, is who is connecting to my streaming ...
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0answers
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give group permissions to specific device

I have a panning web camera I built, (future robot arm). The camera pans via a web interface (cgi scripts and JS interface) which access an arduino. To enable sending of commands via the interface, I ...
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1answer
171 views

Trying to read USB Audio Device, but /dev/hidraw0 is unavailable for reading

I'm trying to write a simple driver for my USB Sound Card (just for fun) on Xubuntu 14.04 -- for example, I want to have an opportunity to control volume on my laptop via this device. The problem is ...
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0answers
26 views

Capturing data from a Fluke 1620a via Bash /dev/tcp file descriptor

I am currently trying to develop a script that will connect to a Fluke DewK 1620a Themo-Hygrometer and pull the current temperature and humidity readings from the device. While these devices have a ...
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0answers
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Is there support for flattened device tree in Sparc 32 port of the Linux kernel?

We are trying to write a minimal bootloader for booting the linux kernel on a Sparc V8 processor simulator. From what I understand, the interface between the bootloader and kernel consists of a data ...
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1answer
28 views

Can't Make a LDD for a Devkit8000

I'm trying to build a Linux Device Driver for a Devkit 8000. I'm getting the following errormessage: When I try to follow it's directions I get asked a bunch of yes/no questions I don't really ...
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2answers
40 views

How to run an application with certain group permissions?

I have a 3D printer, with which my PC can communicate through /dev/ttyACM0: crw-rw---- 1 root uucp 166, 0 16 nov 14:58 ttyACM0 The 3D printing application repetierHost requires read/write access ...
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1answer
46 views

create several /dev/xconsole files automatically upon boot

I understand from my previous question that the /dev/xconsole file can be created using mkfifo. On my system (Debian Wheezy), /dev/xconsole gets created automatically. I am wondering who creates it ...
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0answers
74 views

Why does a device show up as hidraw instead of hiddev?

I read the kernel documentation for hidraw and hiddev, and I understand the differences, but I am wondering how the kernel decides whether or not a device should show up as /dev/hidraw* or ...
2
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1answer
76 views

How to disable USB devices based on their vendor ID on GNU/Linux?

In that question someone wanted a blacklist for all USB devices, and then only allow specific devices. In this question, we want to accept all USB devices, but prevent the driver (e.g. cdc_acm) from ...
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0answers
24 views

PC speaker device missing

I've just connected a small internal PC speaker to my motherboard. The beep command is producing sounds correctly. The pcspkr is loaded but there is no /dev/pcsp, so I cannot send audio to it. How ...
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1answer
1k views

Why is my Mac, upgraded from Mavericks to Yosemite, no longer giving VMware Fusion needed resources?

I have a Mac upgraded from Mavericks to Yosemite. When I tried to run VMware Fusion, I got an error stating: Could not open /dev/vmmon: No such file or directory. Please make sure that the kernel ...
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1answer
35 views

talk to modbus device

I currently have a minimal install of Red Hat 6.5 running, on the machine I need to talk to a modbus device. I am wondering what tools and drivers are needed on a linux machine to talk to a modbus ...
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2answers
478 views

Mount an ISO virtually using /dev/sr0 device

I'm doing a study about how CD-ROM can be mounted virtually and all I could find out was mounting using loop devices. mount -o loop disk1.iso /mount-point This is fairly easy. I understand that ...
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0answers
50 views

Bad/strange USB device issue: failed to shutdown/restart

On a fresh Arch Linux installation with Intel i7 processor and an Nvidia graphics card, I noticed during boot log messages related to a usb device filled the screen before it reached the graphical ...
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2answers
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What happens if I run fsck on /dev/sda instead of /dev/sda1?

When I have run fsck in the past I have always run it on what I thought was a filesystem partition, ie. fsck -yf /dev/sdaN, where N is the partition number on disk A. A friend of mine recently ran ...
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0answers
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How/where are linux device capabilities / bitfields set?

I have a device that has this output in /proc/bus/input/devices: I: Bus=0003 Vendor=05b8 Product=3280 Version=0111 N: Name="PixArt USB Optical Mouse" P: Phys=usb-0000:00:1a.0-1.1/input0 S: ...
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0answers
103 views

How can I mount the Logitech C270 in the zynq-7000 (with Linaro linux)?

I am doing camera control programming for a university project using zynq 7000. I want to mount the camera module that's for the Logitech C270 (like this ...
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3answers
725 views

Are there alternatives to using `udev`?

While I understand the greatness of udev and appreciate the developers' effort, I was simply wondering if there is an alternative to it. For instance, I might imagine there should be a way to make ...
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1answer
76 views

create several /dev/xconsole files

I am using /dev/xconsole to send system logs from rsyslog. That works great, because I am don't have to store the logs on disk. I would like to have another similar file , i.e /dev/xconsole1 where I ...
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0answers
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How do you determine the capabilities of a WebCam?

I have a collection of WebCam's lying around. Some of them are new, some go back a decade (gotta love not having to "upgrade" devices in Linux :). Somehow I've developed the impression that ...
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0answers
31 views

Is the device tree compiler tied to the kernel version?

I have a situation in which same device trees are used with different kernels. Can the device trees be build only once and used with all kernels? The reason I ask this is because I found the device ...
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1answer
247 views

cannot create special file /dev/pts/0

When using midnight commander in console, I cannot "toggle" the window (using CTRL-o Not an xterm or Linux console; the panels cannot be toggled however, my $TERM is set to linux. After some ...
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0answers
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character device file (rtai_shm) disappears under runlevel=5 in fedora9 (exists when runlevel=3)

I am trying to run Realtime (RTAI) on my Linux Fedora 9 machine. For that, it is needed to have a character device file, named rtai_shm, in /dev, that takes care of shared memory. I have made this ...
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0answers
27 views

unitek nec upd720200 not detected

I've decided to buy an USB3.0 controller on PCI for my debian machine. I did a short research and it appeared that NEC chips will be fine. I've bought Unitek NEC UPD720200 and I does not work: I ...
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1answer
47 views

Determine driver for network interface [duplicate]

I wanted to see which driver was associated with some of the network interfaces listed by ip link. My first thought was to find the network interfaces in /dev and look at the device major and minor ...
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1answer
81 views

USB 3G dongle internet keeps failing on Fedora 20 laptop

I use a 3G dongle for internet in my summerhouse, it has worked fine all summer, but since yesterday it has been losing connection, or something and I have to unplug it and insert it again for the ...
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3answers
53 views

Looking at the content of a character device's file [duplicate]

Why is it possible to look at the contents of a block device's file like /dev/sda using cat or a hex editor? Why can I not do the same for a character device like /dev/pts/3?
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1answer
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How do I send RTSP video to a program that reads from a character device?

I have an IP-CAM that streams video over RTSP and I want to detect bar codes from it with zbarcam (from Ubuntu's zbar-tools package). According zbarcam's manual, it expects to be given a video4linux ...
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3answers
234 views

equivalent of `grep -a /dev/sda1` on Darwin?

I want to run something like % sudo grep -i -a 'some-string' <drive device> On Linux, <drive device> would be something like /dev/sda1. How can I find the equivalent on Darwin? (In ...