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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562 views

How to get device filename from lsusb output or by device path

Related question: USB connect/disconnect notification When the device is plugged/unplugged, I get instant notification, that's great. But to make it (almost) perfect, I also want to get device ...
3
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3answers
892 views

How to know if /dev/hda2 is Primary partition or Extended partition

If all four primary partitions exist on an IDE drive, they are numbered as follows: /dev/hda1 /dev/hda2 /dev/hda3 /dev/hda4 We have also the partitions on a disk with one primary partition and ...
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1answer
30 views

console (driver) not opening using any of the editor

In my initramfs, I have; [root@xilinx Peta_Microzed_15_05]# ls initramfs/dev/ console [root@xilinx Peta_Microzed_15_05]# nano initramfs/dev/console [root@xilinx Peta_Microzed_15_05]# The above ...
1
vote
1answer
888 views

Why isn't sda1 showing up in dev and how can I fix that?

I have an embedded Linux device and I was trying to copy some files to it. I plugged in a USB stick, the dmesg shows that it was recognized, but for some reason /dev/sda1 never showed up. I'm trying ...
3
votes
1answer
153 views

Can renaming a network device cause race conditions?

Arch uses predictable network interface names. MATLAB licenses are linked to the MAC address of eth0, so I need to rename one of my devices eth0. In a machines with only one NIC I can just turn off ...
0
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1answer
113 views

Two Linux Mint 16 systems Skyping--one can see both parties on webcam, the other can see neither

I installed Linux Mint 16 32-bit edition on my netbook and a friend's laptop. When we Skype, I can see her live image, and I can see my own live image, so everything looks and sounds right on my end. ...
3
votes
2answers
460 views

what is the difference between Device driver and kernel module

i know that driver is a software that can communicate with the hardware in order to control the device that attached to the computer.whereas kernel module is a small piece of code that can inserted ...
14
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2answers
29k views

How can I find available network interfaces?

This is in regard to linux, but if anyone knows of a general *nix method that would be good. I booted a system yesterday with an ethernet cable plugged in. "NetworkManager" is not installed, so once ...
2
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2answers
182 views

Check if a drive has been Zeroed with xxd and uniq?

I'm looking for a way to check if the entire binary contents of a USB device are purely 0s. I'm trying this command: sudo xxd /dev/sdb | uniq but it has no output and just runs forever. I've ...
7
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1answer
411 views

How to find which serial port is in use?

The Question: I plugged in a device (i.e. GSM modem) through a serial port (a.k.a. RS-232), and I need to see with which file in /dev/ filesystem this device was tied up, to be able to communicate ...
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2answers
2k views

Can I change devices permissions with chmod?

Before read: I don't want to use any udev rule. I need to change (programmatically) the permissions of some device. But first in order to underestand what I have to do (in code) I want to make the ...
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0answers
131 views

Debian - cannot find cdrom

Having a jessie/sid debian box on kernel 3.13 (had same issue on kernel 3.10) First thing I notices was that k3b didn't find any optical drives. Then: The optical drives (dvd-writers) are found in ...
3
votes
1answer
570 views

How to get address of connected USB modem?

I just connected my N81 telephone as USB modem to Linux Mint 14. All works fine, just wondering how to find a full path to this device, something like /dev/tty*.
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1answer
162 views

Why does RTC device have 254,0 instead of 10,135 as Major,Minor numbers?

Why isn't /dev/rtc the well known "c 10 135" device that it's on x86, but a magic undocumented "c 254 0" device? Devices.txt lists this major number as LOCAL/EXPERIMENTAL USE. I'm working on a ...
2
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1answer
538 views

Is it possible to simulate/force/fake an USB device unplug and replug on Linux?

So I've got a strange problem that I've been running onto. I've got a bitcoin usb miner, Bitfury, and I'm using CGMiner to mine. When I start the application, as root, the USB device is not detected ...
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0answers
283 views

Editing a device tree to disable driver loading

Below is a section of device tree. ps7_ethernet_0: ps7-ethernet@e000b000 { #address-cells = <1>; #size-cells = <0>; clock-names = "ref_clk", "aper_clk"; clocks = ...
2
votes
1answer
203 views

What are the two values in < > in a device tree .dts file?

Following is the code snippet in a device tree file: flash@0 { compatible = "n25q128"; reg = <0x0>; spi-max-frequency = <50000000>; ...
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5answers
6k views

Why does “cat ttyUSB0” not produce output?

I connected an infrared receiver to a USB port ... (the last line of dmesg tells device file) $ dmesg [10496.596063] usb 7-2: new full-speed USB device number 2 using uhci_hcd [10496.751112] usb 7-2: ...
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0answers
136 views

Why is my embedded Linux unable to detect the sd device?

I have this ARM9 SAM9G25 embedded System, running a Linux 2.6.39 Kernel and a Busybox. I put the Images (of the bootloaders, and the linux+initramfs) on a SD so that in the end the system is booting ...
8
votes
1answer
3k views

Difference between /dev and /sys/class?

What is the difference between the device representation in /dev between the one in /sys/class? Is one prefered over the other? Is there something one offers and the other doesn't?
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1answer
3k views

Is there a way to change device names in /dev directory?

I wrote this rule for testing purpose: SUBSYSTEMS=="usb", ATTRS{manufacturer}=="Kingston", ATTRS{serial}=="001CC0EC34A2BB318709004B", ATTRS{idVendor}=="0951", ATTRS{idProduct}=="1642", ...
3
votes
2answers
5k views

Unable to find root device / sda partitions missing

I have installed Archlinux, and after that GRUB. I manually entered menu entries for both my Windows and Arch installation. GRUB has no problems booting, and can successfully load in Windows. It ...
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2answers
313 views

What is a device tree and a device tree blob?

What exactly is a device tree, and a device tree blob? Where can I get its source code for a particular linux version? I found such name while running linux on xilinx chips (having ARM 9), for ...
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3answers
2k views

mv a file to /dev/null breaks dev/null

If I do: touch file; mv file /dev/null as root, /dev/null disappears. ls -lad /dev/null results in no such file or directory. This breaks applications which depend on /dev/null like SSH and can be ...
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1answer
308 views

Confusion about group `cdrom` in linux system

When I type command groups ubuntu, the output would we like, ubuntu : ubuntu adm dialout cdrom floppy audio dip video plugdev netdev admin I am interested in the cdrom group. What does the group ...
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0answers
33 views

Execute command when mouse is pluged/unpluged on GNU/Linux

Is it possible to have something like event handler for plugging unpluggig a mouse in Unix System? I want to have a script that will enable/disable touchpad but not only on startup (you can find ...
3
votes
1answer
2k views

Map physical USB device path to the Bus/Device number returned by lsusb

I need to get the title of the attached USB device. I can do that with lsusb. udev allows some substitutions when I write rules: say, we can use $kernel to get name of the device, or $devpath to get ...
7
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1answer
2k views

USB connect/disconnect notification

I use Linux Mint 13 MATE, and I'm trying to set up notifications when I plug/unplug devices. First of all, I found udev-notify package, but unfortunately it almost doesn't work for me: it works for ...
2
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0answers
458 views

Fedora unable to detect USB or wireless networks? [closed]

I installed Fedora(Gnome) 19 on a Dell Inspiron with Intel i3 processor, and a factory built-in Windows 7 home premium OS. The installation process completed successfully. But now when I log into ...
4
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1answer
4k views

How do I find out which process is using my V4L2 webcam?

I tried to run the following: $ vlc -I dummy v4l2:///dev/video0 --video-filter scene --no-audio --scene-path webcam.png --scene-prefix image_prefix --scene-format png vlc://quit --run-time=1 ...
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0answers
135 views

Mount partition with truecrypt using the commandline

I'm trying to mount a encrypted HDD with truecrypt, but I cann't find the device. Where can I finde my HDD and what is the command to mount it in truecrypt? I'm using Raspbian on Raspberypi.
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2answers
2k views

Allow non-root user to read/write /dev files

In my /dev folder, I would like the following files to be user readable and writable: /dev/ttyUSB0 /dev/gpib0 How do I do this without using chgrp? I can edit /etc/udev/rules.d but I do not know ...
1
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1answer
123 views

Disable emulated scroll wheel (EmulateWheel) for specific programs

Is it possible to disable evdev's EmulateWheel option when using specific programs? In my use case, I would like to be able to interact with the Acme text editor and with some VMs using my Thinkpad's ...
3
votes
1answer
239 views

Why does the SELinux filesystem have it's own null device?

Looking through /sys/fs/selinux, I found this: # ls -l /sys/fs/selinux/null crw-rw-rw-. 1 root root 1, 3 Jan 24 02:47 /sys/fs/selinux/null Which is identical to /dev/null: # ls -l /dev/null ...
1
vote
1answer
108 views

Getting message “Error trying to open /dev/dvd exclusively” at the end of a DVD burning process when using growisofs

I am using Linux Fedora Core 4 (have to work with a legacy system) and trying to burn DVDs as a non-root user using the growisofs utility. I seem to be getting this error message at the end of the ...
1
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1answer
157 views

Permission of DVD device file not being retained when machine is rebooted

I am using Linux Fedora 4 and would like a non-root user to be able to write to DVDs using the DVD drive. I was able to do this by adding write access to the group of the device file /dev/scd0 and ...
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0answers
89 views

Create a fake read only device like file with incrond

I need to generate UUID with uuidgen (not through any function call, but external command, because processes which will read the file cannot call any APIs or external commands directly). My idea is ...
4
votes
1answer
2k views

can not create /dev/shm

I need to create /dev/shm on an embedded ARM system. From "Installed The Latest Changes to Current and......". I see that it can be created with mkdir /lib/udev/devices/shm, but I'm wondering what ...
4
votes
1answer
3k views

How creation of new USB device file in /dev/bus/usb/001/ directory work?

I noticed that every time I connect a USB device, a new device gets created in the /dev/bus/usb/001/ directory. Further on each reconnection of the same device, the "Device Number" and "ID" change. ...
3
votes
3answers
255 views

USB device to be detected at the “same” /dev point always?

In Linux (actually I'm with CentOS v6.5), whenever I plug in my USB Terminal/Character Device (some kind of USB Adapter) for the first time (after booted), it is detected at: /dev/ttyUSB0 But ...
3
votes
2answers
139 views

Is there a uniform way to discover information about devices?

UPD: Changed question title from manage devices to discover information about devices One of the frequent thing I do is look up info about devices on my systems. And I am constantly find myself ...
2
votes
1answer
79 views

What happens under the hood when some data is sent/received on an uart (or similar)?

I am trying to understand how computers work and I was thinking about peripherals. Here is what I understand so far but some parts are missing. Using an Arduino, I send some text every second (a then ...
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3answers
2k views

Why won't Linux let me play with /dev/dsp?

I'm working through a Linux textbook, and it's telling me about devices. It says that if I send the appropriate output to /dev/dsp, then it will play a sound. The example is cat file.wav > ...
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votes
1answer
353 views

How to debug a device that changes from /dev/ttyUSB0 to /dev/ttyUSB1 at will?

I have a device plugged to a CentOS server that changes randomly from /dev/ttyUSB0 to /dev/ttyUSB1 and vice versa. The device I'm trying to connect is this one. How can I debug this?
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1answer
1k views

Difference between Device file and device drivers

I am beginner in device driver programming. I don't get the difference between device drivers and device files in Linux. Can anyone explain the difference?
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1answer
705 views

What are high level and low level device drivers

Recently I read that there are two types of drivers (at least for disk), one that are called high level drivers and another called low level device drivers. Can some one tell me what these are, and ...
1
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1answer
186 views

2 or more programs in same USB serial converter

Having a network of lets say 10 devices in RS-485, connected to the linux PC with a RS-485 to USB Converter. Already there is a C program interacting with the serial converter at /dev/ttyUSB0. My ...
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0answers
101 views

Which Unixes support cross-device filesystem links (in particular for rename)?

Just read the following on the FreeBSD man page for the rename syscall: ... [EXDEV] The link named by to and the file named by from are on different logical devices (file systems). Note that ...
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0answers
505 views

Debian Wheezy USB2 ehci_hcd

I have a friend who decided to switch to Linux from Windows. I was helping her to get up and running as quickly as possible but we ran into a problem which I can't seem to solve. She uses Debian ...
4
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2answers
207 views

Can you identify transport via sysfs?

I'm writing a script, and I'm interested in being able to identify the transport class (fc - "fibre channel", scsi, iscsi, etc.) for a given block device. I can retrieve this information via ls -l ...